study on sustainable nutrient supply in fast- growing ......rp rupiah, indonesia's currency...
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Tropical Forest Research
Study on SustainableNutrient Supply in Fast-Growing Plantations
Ecological and Economic Implicationsin East Kalimantan, Indonesia
Dr. Jens MackensenProf. Dr. Horst Fölster
Eschborn, 1999
TÖB publication number: TÖB FTWF-II/11e
Published by: Deutsche Gesellschaft fürTechnische Zusammenarbeit (GTZ) GmbHPostfach 5180D-65726 Eschborn
Responsible: Tropenökologisches Begleitprogramm (TÖB)Dr. Claus Baetke
Authors: Dr. Jens Mackensen, Büsgenweg 2, D-37077Göttingen,Tel.: 0551-399529, Fax: 00551-393310email: [email protected]
Prof. Dr. Horst Fölster, Büsgenweg 2, D-37077Göttingen,Tel.: 0551-399529, Fax: 00551-393310
Local Partners: Sustainable Forestry Management Project(SFMP), Dr. Huljus, Kotak Pos 10 97, Samarinda75001, East Kalimantan, Indonesien,Tel.: 0062-541-33434, Fax: 0062-541-33437email: [email protected]
Layout: Michaela Hammer
ISBN: 3-9806467
Nominal fee: 10,-DM
Produced by: TZ Verlagsgesellschaft mbH, D-64380 Rossdorf
© 1999 All rights reserved
PrefaceAdopted at the 1992 United Nations Conference on Environment andDevelopment, at which 178 countries were represented, Agenda 21 includes asection devoted to forests. Together with the UNCED Forests Statement, Agenda21 forms a basis for international cooperation on the management, conservationand sustainable development of all types of forests. The Rio resolutions alsoserve as the foundation for a process of national-policy modification designed tostimulate environmentally compatible sustainable development in bothindustrialized and emerging countries.Ideally, sustainable development builds on three primary guiding principles for allpolicy-related activities: economic efficiency, social equity and ecologicalsustainability. With regard to the management of natural resources, this meansthat their global utilization must not impair future generations' developmentalopportunities. With their myriad functions, forests in all climate zones not onlyprovide one of humankind's most vital needs but also help preserve biologicaldiversity around the world. Forest resources and wooded areas must therefore besustainably managed, preserved and developed. Otherwise, it would neither bepossible to ensure the long-term generation of timber, fodder, food, medicine,fuels and other forest-based products, nor sustainably and appropriately topreserve such other important functions of forests as the prevention of erosion,the conservation of biotopes, and the collection and storage of the greenhouse gasCO2.Implemented by the Deutsche Gesellschaft für Technische Zusammenarbeit(GTZ) GmbH on behalf of the German Federal Ministry for EconomicCooperation and Development (BMZ), the "Tropical Forest Research" projectaims to improve the scientific basis of sustainable forest development and, hence,to help implement the Rio resolutions within the context of developmentcooperation.Application-oriented research serves to improve our understanding of tropicalforest ecosystems and their reciprocity with the economic and social dimensionsof human development. The project also serves to promote and encouragepractice-oriented young German and local researchers as the basis fordevelopment and dissemination of ecologically, economically and sociallyappropriate forestry production systems.Through a series of publications, the "Tropical Forest Research" project makesthe studies' results and recommendations for action available in a form that isgenerally comprehensible both to organizations and institutions active in the fieldof development cooperation and to a public interested in environmental anddevelopment-policy affairs.
Dr. H.-P. Schipulle Dr. D. BurgerHead of Division:Environmental Policy, Protection of NaturalResources, Forestry; CSD, GDF
German Federal Ministry for EconomicCooperation and Development (BMZ)
Head of Division:Forest Resources Management, LivestockFarming, Fisheries, Nature Conservation
Deutsche Gesellschaft fürTechnische Zusammenarbeit (GTZ) GmbH
Table of contents
I
Table of contents
LIST OF FIGURES ......................................................................... III
LIST OF TABLES...........................................................................IV
GLOSSARY ..................................................................................VI
SUMMARY................................................................................ VIII
1 INTRODUCTION ......................................................................1
1.1 Problem Analysis and General Objectives .................................. 1
1.2 Terms of Reference .................................................................... 2
1.3 Cooperation Partners .................................................................. 3
2 RESULTS ................................................................................5
2.1 Plantation Policy in Indonesia .................................................... 5
2.2 Types of Sites and Nutrient Pools............................................... 7
2.2.1 Types of Sites ................................................................. 7
2.2.2 Nutrient Pools in the Soil................................................ 9
2.3 Plantation Productivity ............................................................. 10
2.3.1 Inventory of stands ....................................................... 11
2.3.2 Nutrient Pools in the Stand ........................................... 13
2.4 Nutrient Budgets....................................................................... 15
2.4.1 Nutrient Budgets and Plantation Management .............. 15
2.4.2 Quantifying Nutrient Fluxes ......................................... 20
2.4.3 Harvest Balance............................................................ 23
2.4.4 Overall Balance ............................................................ 26
2.5 Replacement of Nutrients ......................................................... 28
2.6 Plantation Economics ............................................................... 30
2.6.1 Costs of Fertilization to Replace Nutrient Losses ......... 30
Sustainable Nutrient Supply in Fast-Growing Plantations
II
2.6.2 Investment Analysis ......................................................34
2.6.3 Sensitivity Analysis .......................................................35
3 PRACTICAL RELEVANCE ......................................................39
3.1 Opportunities and Limitations of Timber Plantations ................39
3.2 Regional Development and Land-Use Planning.........................39
3.2.1 Further Need for Research .............................................41
4 RECOMMENDATIONS FOR ACTION .......................................43
4.1 Plantation Enterprises................................................................43
4.2 Land-Use Policy ........................................................................44
4.3 DC Institutions ..........................................................................44
4.3.1 Information Policy.........................................................45
4.3.2 Concepts for Action.......................................................46
5 REFERENCES ........................................................................47
6 APPENDIX ............................................................................51
List of figures
III
List of Figures
Fig 1: Nutrient concentrations in stemwood (H) and -bark (R)
of Eucalyptus deglupta (Ed), Acacia mangium (Am)
and Paraserianthes falcataria (Pf)........................................................ 13
Fig. 2: Plantation stand in the closed stand phase. ........................................ 15
Fig. 3: Plantation in the clear-cutting phase.................................................. 16
Fig. 4: Clear-cutting and land preparation phase........................................... 17
Fig. 5: Growing plantation forest in the open (1) and
closed stand phase (2)......................................................................... 18
Fig. 6: Time course of site productivity ........................................................ 19
Fig. 7: Estimation of the different fluxes of Nt within
one rotation period ............................................................................. 21
Fig. 8: Estimation of the different fluxes of Pt within
one rotation period ............................................................................. 21
Fig. 9: Proportion of K export [%] in relation to pools in
soil and harvest [m3] for Acacia mangium ......................................... 25
Fig. 10: Proportion of Ca export [%] in relation to pools in
soil and harvest [m3] for Acacia mangium ......................................... 25
Fig. 11: The internal rate of return as a function of changes
in the PT.IHM's costs or revenue........................................................ 35
Sustainable Nutrient Supply in Fast-Growing Plantations
IV
List of tables
Tab. 1: Pools of C, Nt , Pt and exchangeable cations
in 0-100 cm soil depth ........................................................................ 10
Tab. 2: Stand parameter for Acacia mangium (Am) and
Eucalyptus deglupta (Ed) ................................................................... 12
Tab. 3: Comparison of relative nutrient exports for Acacia mangium .......... 24
Tab. 4: Comparison of current costs for fertilizaion with the costs
of compensation of nutrients removed with the harvest ..................... 31
Tab. 5: Costs of fertilization in case of compensation of
total nutrient losses............................................................................. 32
Tab. 6: Parameter of the soil types in different soil depth............................. 52
Tab. 7: Export of nutrients with stemwood and -bark for
Acacia mangium................................................................................. 53
Tab. 8: Export of nutrients with stemwood and -bark for
Eucalyptus deglupta ........................................................................... 54
Tab. 9: Management-dependent export fluxes for N and P
in relation [%] to the exports by harvest ............................................. 55
Tab. 10: Management-dependent export fluxes for K, Ca and
Mg in relation [%] to the exports by harvest....................................... 56
Tab. 11: Sum of management-dependent nutrient export fluxes ................... 57
Tab. 12: Estimation of the amount of fertilizers necessary to
compensate management-dependent export fluxes of N ..................... 58
List of tables
V
Tab. 13: Estimation of the amount of fertilizers necessary to
compensate management-dependent export fluxes of P...................... 59
Tab. 14: Estimation of the amount of fertilizers necessary to
compensate management-dependent export fluxes of K ..................... 60
Tab. 15: Comparison of the current amount of fertilizers with the amount
of fertilizers necessary to compensate harvest export ......................... 61
Tab. 16: Costs of fertilization necessary to compensate total
nutrient losses with management variants .......................................... 62
Sustainable Nutrient Supply in Fast-Growing Plantations
VI
Glossary
Al Chemical symbol for aluminium
Al saturation Proportion of aluminium as a percentage of the ECEC
MAI Average total increment at the reference age (8 yrs) in m3/ha per
annum
Ca Chemical symbol for calcium
ECEC Effective cation exchange capacity. Ability, in particular of clay
minerals and organic substances, to adsorp and exchange cations at
their surface. Related to the pH range concerned
Degradation Deterioration in the quality, e.g. of a soil site, e.g as a result of
inappropriate use
GH5 Greatest height (at the reference age of 5 yrs), i.e. the height of a
stipulated number of tallest trees per unit area
INHUTANI Public forestry companies in Indonesia (outside Java)
K Chemical symbol for potassium
Mb cations Cations whose hydroxides are strong bases: Na, K, Ca, Mg
Melioration Soil-improving measures (liming, drainage, etc.)
Mg Unit of weight: megagram (106 g), formerly "ton"
Mg Chemical symbol for magnesium
N Chemical symbol for nitrogen
Nt Total N pool in the soil
Navail N fraction easily available to plants
NPK fertilizer Type of fertilizer containing nitrogen, phosphate and potassium
P Chemical symbol for phosphorus
Pt Total P pool in the soil
Pavail P fraction easily available to plants
Glossary
VII
Production forest According to the Indonesian classification system, an area of natural
forest intended for permanent use
Rotation period length of a management cycle
Rp Rupiah, Indonesia's currency
TPTI Tebang Pilih Tanam Indonesia – selective timber harvesting method
in Indonesia. According to this method, only trees with a diameter at
breast height (DBH) of more than 50 cm may be felled. Forest
manipulations are carried out every 35 years at the most, and stand
rejuvenation has to be ensured
Sustainable Nutrient Supply in Fast-Growing Plantations
VIII
Summary
Industrial fast-growing plantations in the tropics are acquiring increasing
significance for various reasons. Taking a plantation concession in East
Kalimantan (Indonesia) as an example, the present study shows that the
conversion of large areas of land into one-species plantations presents a
threat to the ecological and economic sustainability of various types of
sites.
Over 90% of the land used to cultivate plantations has highly weathered
soils with a moderate to poor supply of nutrients (Alisols, Acrisols,
Ferralsols and Arenosols). In contrast, azonal soil types such as Fluvisols
and Calcisols have a good to excellent supply of nutrients, but only very
small areas of these soils are found. The distribution of nutrients depends
inter alia on the relief. On lower parts of slope and in valleys, the supply of
nutrients is greater by a factor of 2-10 than on the corresponding upper
parts of slopes or ridges.
With a stand rotation cycle of 8 years, the average yield expected by
plantation concessions is 200 m3/ha or 25 m3/ha per annum. In the first
rotation cycle, the actual yield of Acacia mangium stands was higher and
that of Eucalyptus deglupta stands considerably lower than this expected
growth. As a pioneer species, Acacia mangium can show high rates of
growth in the first rotation cycle even on soils with a poor supply of
nutrients. In contrast, Eucalyptus deglupta requires a site with deep soil and
a good water supply (e.g. Fluvisols and Alisols/Acrisols on lower parts of
slopes). Moreover, this tree species requires intensive maintenance work, in
particular to monitor the accessory vegetation.
Summary
IX
Harvesting of stemwood and bark results in the removal of nutrients. The
extent of this loss depends on the volume of harvest and the species-
specific level of nutrients in the wood and bark. The removal of nutrients
with the harvest has a significant impact on the nutrient cycle of fast-
growing plantations.
Preparing nutrient budgets serves to compare the input and output of
nutrients in an ecosystem (in this case a fast-growing plantation). The
results of these balances allow conclusions to be drawn about the stability
of the system concerned. If the balance is negative, a plantation cannot be
managed sustainably. The input and output of nutrients (or nutrient fluxes)
taken into account in the balance include both the management-
independent and the management-dependent parameters. The management-
independent parameters include nutrient input by precipitation, silicate
weathering and biological N fixation and nutrient output by leaching (so-
called base fluxes). The management-dependent parameters include
nutrient output by harvesting (removal with the harvest), net leaching due
to management, erosion, and output as a result of burning due to
volatilization and ash loss (burning losses). In assessing the macronutrient
status (N, P, K, Ca, Mg), output is generally found to be higher than input,
resulting in a negative nutrient balance.
The management-dependent nutrient fluxes that occur in addition to the
base fluxes (the management-independent fluxes) are sometimes
considerably higher than the nutrients removed with the harvest alone.
Depending on the management intensity and the tree species, the
additional, management-dependent nutrient losses amount to 80-170% for
N, 80-250% for P, 50-280% for K, 30-190% for Ca and 70-450% for Mg
(as a percentage of the corresponding removal of nutrients with the
harvest).
Sustainable Nutrient Supply in Fast-Growing Plantations
X
By comparing the amount of nutrients removed with the harvest and the
site-specific nutrient pools in the soil (so-called harvest balance), it can be
seen that considerable amounts of base cations (K, Ca, Mg) are removed
from the plantation system during harvesting. The harvest balance depends
on the input variables volume of harvest and nutrient pools in the stand and
soil. On poor Alisols/Acrisols or Ferralsols, for example, if we assume a
volume of harvest of 200 m3/ha, 18-30% of the available Ca and K supplies
are lost in Acacia mangium stands after one rotation. Assuming linear stand
productivity, an average loss of 20% means that the available supplies of
the elements will be exhausted after five rotations. The continuous output
of nutrients leads to degradation of the site, resulting in decreased
productivity.
In addition to the nutrients removed with the harvest that are taken into
account in the harvest balance, the overall balance also includes all the
other management-dependent and management-independent nutrient fluxes
and compares these with the system's pools. The system's pools comprise
the nutrient pools in the soil (to a depth of 1 m), in the trees, in the forest
understorey and in the organic O-horizon. Assuming that the area is
managed conventionally (using tractors, harvesters, etc. and burning the
logging debris), the total loss of nutrients on typical sites (Alisols/Acrisols)
after one rotation amounts to 21-62% of the system's pools of K, 9-32% of
Ca and 5-20% of Mg, depending on the tree species. The losses of P
amount to a maximum of 17% and of N (for Eucalyptus deglupta only) to a
maximum of 53%. Using a form of management that preserves the land by
not burning the felling waste (slash) and by using methods that preserve the
soil (light-weight machines, high-lead cable car systems), the nutrient
losses that occur within one rotation can be reduced by approximately 50%.
Summary
XI
Generally speaking, plantation management is associated with significant
nutrient losses.
The estimated nutrient losses highlight the need for sustainable nutrient
supply, particularly on sites with poor nutrient stocks. Measures should be
taken to reduce and replace nutrient losses. The most direct method to
replace nutrient losses is to use mineral fertilizers.
Fertilization management has to fulfil various criteria on the sites studied.
Due to the acidic to highly acidic soil conditions, only fertilizer types that
cause no or little soil acidification may be used. The element-specific
utilization levels need to be estimated realistically. The utilization rate for P
fertilizers is 10-40%, but in highly acidic soils utilization is less than 10%
due to the P immobilization caused by aluminium. A utilization rate of 50-
70% can be assumed for N and K fertilizers. Species-specific differences
should also be taken into account when applying fertilizer, e.g. Acacia
mangium requires less K fertilization than Eucalyptus deglupta and no or
only very little N fertilization. Fertilization should also be adapted to suit
the particular site. On Alisols/Acrisols, the upper parts of slopes and ridges,
in particular, require fertilization, while on Fluvisols no fertilization is
needed and on Calcisols essentially only K fertilization is necessary. Due to
the high degree of P immobilization on acid soils, liming is recommended
on Alisols/Acrisols with pH values of less than 4.5.
The amounts of fertilizer currently used in plantation management are not
sufficient to replace the nutrient losses that occur, particularly if fertilizers
with a standard composition (e.g. NPK) are used.
Assuming an optimal composition of fertilizers, the costs of fertilizing to
replace total losses in plantation management are conservatively estimated
(see Min200) as 3.5-fold higher for Acacia mangium and 5.7-fold higher for
Sustainable Nutrient Supply in Fast-Growing Plantations
XII
Eucalyptus deglupta than the fertilizer costs actually estimated by the
concession.
While fertilization management currently accounts for an average of 4% of
the plantation's total costs, the costs of the fertilizer actually required to
replace losses range from 9% to 40% of the plantation's total costs,
depending on the tree species, management type and fertilizer used. In
intensively managed plantations, the measures required to replace nutrient
losses in order to ensure a sustainable nutrient supply thus constitute a
significant cost factor.
The internal rate of return on equity calculated by the company in
accordance with government stipulations is 17.7% (1991/92 conditions). If
fertilization management is geared towards replacing nutrient losses and
the plantation's costs therefore increase by 13% (replacing nutrients
removed with the harvest), the internal rate of return on equity drops to
11%. Investment calculations for plantations therefore need to take account
of the site-specific results of nutrient budgets. Establishing large, uniform
areas and managing them conventionally is economically inefficient in
comparison.
The results of the present study show that the technical and financial inputs
required to manage a plantation on the given sites on a permanent basis, i.e.
over the course of many rotation cycles with a constant level of
productivity, have to be considerably higher than the current expenditure in
conventional plantations. Under the given conditions, plantation
management cannot be carried out in accordance with the classical models
of extensive forestry.
Under the current conditions, the sustainability potential of intensively
cultivated fast-growing plantations in the region is regarded as being low.
Summary
XIII
In the interest of regional development policy, the following conclusion can
be drawn: If sustainable regional development and forest management
planning are to be achieved, attention needs to be paid to the ecological and
economic stability of industrial timber plantations.
Introduction
1
1 Introduction
1.1 Problem Analysis and General Objectives
According to the FAO (1995), after China and India, Indonesia already
showed the largest increase in plantation areas between 1980 and 1990 (cf.
Winjum and Schroeder 1997). In the current decade, in view of the
decreasing timber supply from natural forests, the Indonesian Government
has further intensified efforts to establish plantations. The creation of over
10 million ha of fast-growing plantations by the year 2010 has been
planned or already initiated.
The ecological and economic implications associated with this
development were studied using a concession in East Kalimantan as an
example. With decreasing areas of natural forest and rising costs for their
exploitation, large areas of overexploited natural forests in littoral regions
have been converted into fast-growing plantations since the beginning of
the 1990s. The average size of these plantation concessions is 100,000-
200,000 ha. On the same scale, 10,000-15,000 ha of contiguous land are
converted into plantations every year regardless of the site conditions. The
entire area is established as a unit regardless of whether the individual areas
are at all suitable for the intended use, thus consciously running the risk
that this conversion may be partially unsuccessful, with all the ecological
and economic losses this entails.
As part of the research project, the significance of site heterogeneity in
plantation management and the impact of management on the quality of the
site were studied with the aim of establishing the basis for site-specific
planning in the creation of plantations. In this context, the potential of
various sites was assessed using nutrient budgets on the basis of different
Sustainable Nutrient Supply in Fast-Growing Plantations
2
levels of productivity and different forms of management. In order to
clarify the importance of the nutrient pools and fluxes in plantation
management, the costs associated with the various management options
were investigated and assessed in terms of investment analysis. This
resulted in a site-specific assessment of the ecological and economic
sustainability of plantation management in the region.
1.2 Terms of Reference
Result A: Characterization of the predominant types of site.
Activities: Selection of suitable study areas within a plantation concession.
Differentiation of sites at the level of a reconnaissance survey
on the basis of relief differentiation of the soil cover.
Result B: A set of expectations for various potential management
concepts have been identified for the types of site characterized.
Activities: Use-related characterization of the types of site, including soil
analysis and calculation of the soil-borne nutrient pools,
assessment of the suitability of each type of site for particular
tree species, yield, expected use of natural forest on the basis of
regional experience and assessment of the expected
development of nutrient pools and the necessary fertilization to
replace losses according to the type of site and its management.
Result C: Various alternative management plans have been drawn up to
be assessed in terms of their silvicultural and ecological
prospects, measures and risks.
Activities: Selection of site-specific alternative management options taking
account of ecological sustainability criteria to different degrees.
Introduction
3
Development of alternative planning concepts for the site types
depending on the type of use.
Result D: The price-cost relations for various management concepts have
been clarified.
Activities: Calculation of expected profits and costs associated with the
various alternative management concepts on the basis of
previous operating figures. Evaluation of the alternatives from
an economic point of view, taking into account the changes to
be expected over longer periods.
1.3 Cooperation Partners
The project was conducted in close cooperation with the Institute of Soil
Science at the Forestry Faculty of Mulawarman University, Samarinda,
Indonesia, supervised by the dean Dr. Daddy Ruhiyat. In connection with
the cooperation between Mulawarman University and the PT.ITCI
concession, the fieldwork was actively promoted by the PT.ITCI/PT.IHM.
Logistic support for the present study was provided by the Indonesian-
German Forestry Project (IGFP) and later by the Deutsche Gesellschaft für
technische Zusammenarbeit (GTZ) GmbH's Sustainable Forestry
Management Project (SFMP) and Mulawarman University.
Results
15
2.4 Nutrient Budgets
2.4.1 Nutrient Budgets and Plantation Management
Figures 2-5 show the most important system parameters of plantation
management. These parameters are used as input and output variables in
nutrient budgets.
Fig. 2: Plantation stand in the closed stand phase. Three possible
undergrowth variants are shown: organic O-horizon only (1),
herbaceous understorey, often Imperata cylindrica or Chromolaena
odorata (2) and understorey with pioneer species (often Macaranga
spp.) or valuable timber species (e.g. Eusideroxylin zwaageri) (3).
Various nutirent fluxes are taken into account: precipitation
deposition (a), leaching (b), nutrient uptake (c), weathering of the
bedrock (d) and N-fixation (e).
a
2
3
b
c
de
1
Sustainable Nutrient Supply in Fast-Growing Plantations
16
Nutrient budgets serve to assess the stability of ecosystems (Ulrich 1993).
If there is an imbalance between the input and output of nutrients in a
system, it has to be assumed that, in the long term, the features of this
system will change and as far as the nutrient status is concerned will shift
to a lower or higher level. On the basis of nutrient budgets, the
sustainability of a particular form of management can be evaluated and the
need for and extent of nutrient replacement can be assessed (Ulrich 1993).
Fig 3: Plantation in the clear-cutting phase. A distinction is made
between the use of heavy machinery causing severe erosion and soil
compaction (1) and the use of high-lead cable yarding systems that
minimise erosion and soil compaction (2). The following processes
are outlined: timber harvest (a), residual phytomass (slash) remaining
on the site (b), soil compaction and destruction of the topsoil (c),
gully and sheet erosion (d).
1 2
a
b
c
c
d
d
Results
17
In estimating nutrient budgets, a distinction is generally made between
pools and fluxes, and the latter can be further divided into those within a
system and those between systems. Fluxes within a system are those
parameters that essentially lead to changes in the compartments of the
system (litter fall, canopy leaching, etc.). Fluxes between systems are those
parameters that cross the boundaries of an individual system (precipitation,
leaching, etc.).
Fig. 4: Clear-cutting and land preparation phase. A distinction is made
between land preparation by burning the residual phytomass (1) and
leaving the residual phytomass unburnt (2). If option 2 is chosen,
planting spots or lines have to be created before the seedlings can be
planted. The following processes are outlined: nutrient losses by
volatilization and in ash particle transport (a), ash beds and
unprotected mineral soil (b), gully and sheet erosion (c) and
herbaceous secondary vegetation (d).
1 2
c
c
b
b
a
d
Sustainable Nutrient Supply in Fast-Growing Plantations
18
Fig. 5: Growing plantation forest in the open (1) and closed stand
phase (2). The competition between trees and understorey in the
open stand phase (a) and land maintenance by monitoring and
controlling understorey (b) are outlined.
Various phases are distinguished. The clear-cutting phase is the period after
the land has been converted or after the harvesting of the previous stand
before the new stand is planted. The open stand phase is the period between
the establishment of the stand and canopy closure, a transitional period
leading up to the closed stand phase. The latter phase covers the period
between canopy closure and stand maturity and shows the greatest
differences from the subsequent clear-cutting phase.
A distinction is made between harvest and total nutrient balance
approaches (see Sects. 2.4.3, 2.4.4). If they are used as a frame of reference
for a rotation phase, both approaches are purely static in nature. To
determine the balance continuously , i.e. covering several rotation cycles,
12
a
b
Results
19
assumptions about the dynamic nature of the individual site parameters
have to be made. There are
basically three scenarios for the
time course of site productivity as
a function of the physical and
chemical properties of the soil
(Fig. 6): productivity that remains
constant over time (a), productivity
that increases in successive rotations (b) and decreasing productivity (c,d).
The first scenario (a) is feasible on sites with optimal supply if tree species
that suit the site are chosen. The second (b) may occur on sites which have
been improved by a pioneer forest stage, for example. Site degradation
(scenario c or d) may be caused by choosing an unsuitable tree species or
by inappropriate management.
Despite the rapid increase in area, particularly in South-East Asia (cf.
Sect. 1.1), few studies have been documented on forest productivity in
tropical plantations over the course of several rotation cycles. Declining
productivity in the second and third rotation has been reported in the SSSB
concession in Sabah, Malaysia (main tree species Acacia sp. and
Eucalyptus sp.) (Chia, personal communication) and in Paraserianthes
plantations on Java, Indonesia (Fakuara, personal communication).
Exceptions to this rule can only be expected on soils with very good
nutrient supply, such as those of volcanic origin, or in subtropical areas
under certain conditions (cf. Evans 1982, 1988). For the majority of the
tropical plantation sites, a decline in productivity is more likely in the
future (cf. Mackensen 1998).
Fig. 6: Time course of site productivity
time course of site productivity
(a)
(b)
(c)(d)
prod
uctiv
ity
Sustainable Nutrient Supply in Fast-Growing Plantations
20
2.4.2 Quantifying Nutrient Fluxes
2.4.2.1 Management-Independent Flux Parameters
In this context, management-independent flux parameters are those flux
variables within a system that occur as so-called base fluxes, regardless of
the type and intensity of management. The most important base fluxes for
nutrients are atmospheric deposition, rock weathering, biological N fixation
and leaching.
2.4.2.2 Management-Dependent Flux Parameters
The conversion of natural forest into other land use forms and the rotation
change on plantation sites result in changes in the hydrological,
microclimatic and physical-chemical soil parameters of the system. These
changes lead to nutrient losses (output fluxes). The output fluxes taken into
account in nutrient budgets include nutrients removed with the harvest,
management-dependent net leaching, erosion, and volatilization and loss of
ash particles caused by burning (burning losses).
In order to allow the flux parameters to be applied to specific plantation
conditions, parameters are expressed as a function of a variable that is
relevant within plantation management and assigned to the relevant stand
phase or management stage (cf. Mackensen 1998). Thus, nutrient export
with the harvest is a function of the species-specific nutrient concentrations
in the exported compartments (stemwood and -bark, see Sect. 2.3.2) and
the harvest volume. Management-dependent net leaching and the losses
caused by burning are a function of the nutrient pools in the residual
phytomass (including the understorey and the organic O-horizon). The
nutrient losses caused by the net leaching are modified by precipitation and
the buffering capacity of soil. The losses due to burning depend on the
Results
21
extent of burning and the intensity of the fire. The losses due to erosion in
this context are a function of the nutrient levels in the topsoil.
Fig. 7: Estimation of the different fluxes of Nt within one rotation
period
Fig. 8: Estimation of the different fluxes of Pt within one rotation
period
In Figs. 7 and 8 (and in the Appendix, Table 9), the range of N and P-losses
in the clear-cutting phase as a result of management-dependent leaching
(mAw), erosion (Ero) and burning (Br) are quantified and correlated with
the nutrients removed with the harvest (E), assuming a volume of harvest
0
10
20
30
40
P[k
gha
]t
-1
E Am E Ed E Pf Nie Aw mAw Ero Br
E Am, Ed, Pf
Br
= element export with harvest for Acacia mangium, Eucalyptus deglupta and Paraserianthes falcataria with a harvest volume of 100, 200 and 300 m ha .
= losses by burning ( with a residual vegetation of 200 m ha ).
3 -1
3 -1
Nie
Aw
mAw
Ero
= input via precipitation (data from literature).
= output via leaching (data from literature for primary tropical forests).
= management-dependent leaching in case of conversion of stands
= management depending leaching in case of conversion of stands.
1
0
100
200
300
400
500
N[k
gha
]t
-
E Am E Ed E Pf Nie Aw mAw Ero Br
E Am, Ed, Pf
Br
= element export with harvest for Acacia mangium, Eucalyptus deglupta and Paraserianthes falcataria with a harvest volume of 100, 200 and 300 m ha .
= losses by burning ( with a residual vegetation of 200 m ha ).
3 -1
3 -1
Nie
Aw
mAw
Ero
= input via precipitation (data from literature).
= output via leaching (data from literature for primary tropical forests).
= management-dependent leaching in case of conversion of stands
= management depending leaching in case of conversion of stands.
Sustainable Nutrient Supply in Fast-Growing Plantations
22
of 100, 200 or 300 m3/ha. The base fluxes precipitation (Nie) and runoff
(Aw) are also given. These variables have been extrapolated for a rotation
period of 8 years.
If we compare the nutrient input by precipitation (Nie) and the nutrient
output by management-independent leaching (Aw), there is a higher input
than output of Nt and Pt (cf. Figs. 7, 8), while the output of K, Ca and Mg is
higher than the input (cf. Appendix, Table 10). Ideally, however, the base
fluxes precipitation and leaching are assumed to be balanced in the long
term (cf. Bruijnzeel 1990; Lesack and Melack 1996; Mackensen 1998).
In summary: Taking into account the major nutrient fluxes, input is
considerably lower than output for all the elements considered. The
plantation system has a negative nutrient balance.
According to a very conservative estimate, if we assume a volume of
harvest of 200 m3/ha, the sum of all management-dependent N-losses
(above and beyond the nutrients removed with the harvest) range from 80%
to 170% of the nutrients removed with the harvest alone, depending on the
tree species. Management-dependent P-losses have been estimated at 80-
250% under the same conditions (cf. Appendix, Table 9). This means that,
depending on the management system, nutrient losses due to burning,
leaching and erosion are at least as high as, and often considerably higher
than, the nutrient losses caused by timber harvesting alone.
In the Appendix (Table 10), the management-dependent losses of the
nutrients K, Ca and Mg are compared. In comparison to the nutrients
removed with the harvest, the additional losses to be anticipated as a result
of plantation management range from 40% to 280% for K, depending on
the tree species. The Ca-losses caused by harvesting are very high, which is
why the additional management-dependent losses are relatively low,
Results
23
ranging from 16% to 190%. Additional management-dependent Mg-losses
are very high, amounting to 70-450% of the nutrients removed with the
harvest.
In summary: In addition to the nutrient losses caused by stand harvesting
(nutrients removed with the harvest), considerable additional nutrient losses
(losses caused by management) per unit area are to be expected in
plantation management as a result of management measures.
2.4.3 Harvest Balance
The harvest balance only takes into account those amounts of nutrients
removed from the area with the harvest (cf. Sect. 2.3.2) and compares these
losses with the corresponding pools in the soil (cf. Sect. 2.2.2). The relative
export value (in %) refers to the pool of elements in the harvested
compartments (stemwood and -bark) and the soil (cf. Table 3).
The nutrient pools in the phytomass compartments that are not exported,
such as the crown, the roots and the understorey, are not taken into account
in this balance. For the purposes of drawing up the balance, it is assumed
that the level of nutrients stored in these compartments remains constant in
quantitative terms in the development of the second and successive stand
generations (constant productivity, cf. Fig. 6).
The results of the harvest balance are summarized in Table 3 for Acacia
mangium. As Acacia trees are able to take up N from the atmosphere via
symbionts, the N status can be ignored for this species. If Ca and K pools in
the soil are low (cf. sandy Alisols, Ferralsols/Arenosols), 18-30% of the
nutrients available in the system are depleted in the first rotation (cf.
Table 3). Even in soils with average nutrient supply, the nutrients removed
Sustainable Nutrient Supply in Fast-Growing Plantations
24
with the harvest amount to approximately 10% of the pools taken into
account.
Tab. 3: Comparison of relative nutrient exports for Acacia mangium in case ofstemwood harvest only (H) with harvest of stemwood and -bark (HR)related to the nutrient pools in soil (0-100 cm) and in stem timber andstem bark
Navail Pavail K Ca Mg Mndata in [%] H HR H HR H HR H HR H HR H HRmedium. Alisol 12,6 24,0 1,3 3,1 3,7 8,8 3,2 9,9 0,9 1,6 0,0 0,5rich Alisol 6,8 13,9 0,6 1,4 2,2 5,5 1,1 3,7 0,3 0,5 0,0 0,2poor Alisol 20,4 36,0 3,4 8,0 7,7 17,5 11,3 30,0 4,3 7,5 0,1 2,3Acrisol 15,3 28,4 1,8 4,3 4,0 9,5 4,2 12,8 1,7 3,0 0,1 0,9Ferral-/Arenosol 22,4 38,7 2,9 6,9 10,9 23,6 7,8 22,1 2,1 3,8 0,1 2,0Calcisol 12,9 24,5 1,0 2,5 5,3 12,3 0,1 0,3 0,7 1,2 0,0 0,5Share of bark inexport
54,4 59,5 60,3 70,3 44,8 94,2
a Navail and. Pavail are N and P fraction easily available to plants. All data are related to a stand harvest of 200 m3 ha-1.
In summary: According to the results of the harvest balance, the proportion
of nutrients removed with the bark is 45-94%. If the bark were to remain on
the site, nutrient export by stem harvest would be considerably lower.
Figures 9 and 10 show the losses for different harvest volumes depending
on the nutrient pools concerned (cf. Table 1).
Results
25
Fig. 9: Proportion of K export [%] in relation to pools in soil and
harvest [m3] for Acacia mangium.
Fig. 10: Proportion of Ca export [%] in relation to pools in soil and
harvest [m3] for Acacia mangium.
0
10
20
30
40
50
60
70
80
100 300 500 700 900 1100 1300 1500
400 m3
300 m3
200 m3
100 m3
R 400 m3
R 200 m3
Pools of exchangeable K [kg ha ] in the soil-1
Expo
rt [%
of p
ools
in so
il an
d ha
rves
t]
R = Export by harvesting calculated with data of element concentration from Ruhiyat (1989)
0
10
20
30
40
50
60
70
80
100 300 600 900 1200 1500 1800 2100 2400 2700
100 m3
200 m3
300 m3
400 m3
Pools of exchangeable Ca [kg ha ] in the soil-1
Expo
rt [%
of p
ools
in s
oil a
nd h
arve
st]
Sustainable Nutrient Supply in Fast-Growing Plantations
26
If the volume of harvest is greater or the soil less deep, the amount of
nutrients removed with the harvest increases accordingly (see Figs. 9, 10;
Appendix, Tables 7, 8; cf. Mackensen 1998).
In summary: Losses due to harvesting amounting to 20% of the pools
concerned, for example, mean that, the nutrient pools will be exhausted
after five rotations at the latest (assuming constant productivity levels over
this time). The site is then deficient in nutrients or degraded.
2.4.4 Overall Balance
In addition to the variables included in the harvest balance, the overall
balance also takes into account all management-dependent fluxes discussed
in Sect. 2.4.2. The sum of all losses is correlated to the system's nutrient
pools that are taken into account. The system's pools include the nutrient
pools in the soil (0-100 cm), the trees, the organic O-horizon and the
understorey. The nutrient pools in the roots are here snot taken into
account.
Overall balances were drawn up both for conventional and for an
alternative form of plantation management (cf. Mackensen 1998). In this
context, conventional land management is understood as the use of
machines (tractors, harvesters and/or forwarders) and slash burning. In this
approach, a maximal and a minimal variant (Max200 and Min200) have been
distinguished. Alternative land management is defined in this context as
minimized soil destruction by using harvesting methods that preserve the
soil (e.g. high-lead cable yarding systems) and no slash burning (Alt200).
All variants assume a volume of harvest of 200 m3/ha (cf. Sect. 2.3). If
volumes of harvest are greater than this (cf. Table 2), the pools are
exhausted more rapidly (cf. Sect. 2.4.3).
Results
27
After one rotation of conventional management, depending on the site
quality, management intensity and tree species, K losses range from 7% to
65% of the system's pools, for example. For Ca, the figure can be as high as
approximately 50%. For P and Mg, the figures can be as high as 35%,
particularly on nutrient-poor soils (cf. Appendix, Table 11). Even on soils
with a good supply of nutrients (Fluvisols, Calcisols and loamy Alisols on
lower slope positions), pools of K and N in conventionally managed areas
are already exhausted after two to three rotations.
Declining productivity rates and soil degradation will be observed on the
ridges and upper parts of slopes first due to their poor nutrient statement. In
addition, these locations are particularly susceptible to erosion.
Alternative plantation management (Alt200) in which the residual
phytomass is not burned and soil-preserving measures (light machinery,
etc.) are taken, can reduce nutrient losses that occur within one rotation by
approximately 50% (cf. Appendix, Table 11).
In summary: Alternative management measures reduce nutrient losses in
fast-growing plantations by half.
Especially measures under the conventional management scheme lead to a
deterioration in the site quality. In this context, the organic O-horizon is
particularly significant. A loss of organic matter results in a reduction in the
cation exchange capacity and the water storage capacity of the topsoil. The
soil is no longer protected by an O-horizon and is thus more susceptible to
erosion, is compacted to a greater extent by the use of machines and dries
out more quickly; in addition, the existing N and P pools are mineralised
and depleted more rapidly (cf. detailed discussion in Mackensen 1998;
Klinge 1998; Malmer and Grip 1994).
Sustainable Nutrient Supply in Fast-Growing Plantations
28
The estimated total nutrient losses in conventional plantation management
highlight the need to take measures aimed at replacing and reducing
management-dependent nutrient losses and thus to improve the nutrient
status and to increase stand productivity as part of sustainable plantation
management.
In summary: A reduction of nutrient losses and the replacement of nutrients
is vital in order to achieve sustainable management of fast-growing
plantations on the given sites.
Results
5
2 Results
2.1 Plantation Policy in Indonesia
The annual rate of deforestation in Indonesia ranges from 0.9% to 1.2%
(Opitz 1995; WALHI 1992; Fearnside 1997). East Kalimantan's
deforestation rate is 1.6% and is thus higher than the national average
(WALHI 1992). Based on an estimated timber increment of 0.8 m3/ha per
annum the average annual cutting has been 24.5 million m3 since 1992,
while the Indonesian timber industry requires 52 million m3 per annum
(FAO 1990; WALHI 1992). A timber shortage already began to be forecast
as early as the mid-1980s as a result of the deforestation rate and stand
overexploitation (FAO 1990; Hamilton 1997).
Back in 1980, the Indonesian Government introduced a so-called
Reforestation Fund (Dana Jaminah Reboisasi, DR), into which taxes were
paid for timber felled in natural forests in order to finance the reforestation
of deforested areas. Once reforestation had taken place, money was to be
repaid to the concessionaires. However, in conjunction with the fact that
rights of use were limited to 20 years, many concessionaires regarded these
taxes as a payment to exempt them from their obligations, and the
reforestation objective largely failed to be achieved.
In 1984, in connection with the anticipated timber shortage and the need to
reforest unproductive areas of land, the Indonesian Government began an
Industrial Timber Plantation Programme (Hutan Tanaman Industri, HTI).
As part of this programme, the 1.6 million ha of plantation area that already
existed were to be supplemented by an additional 4.6 million ha of
plantation area for timber production by the year 2000, mainly on Sumatra,
Kalimantan, Sulawesi and Irian Jaya (FAO 1990).
Sustainable Nutrient Supply in Fast-Growing Plantations
6
Since 1990, the Government has been granting concession rights for
plantations (HPHTI) that give private investors special conditions. The
concession rights run for 35 years, and there is an extension option; the
rights apply to up to 300,000 ha and include an explicit guarantee for the
use of all areas that are established. Links between private enterprises and
the state-owned INHUTANI concession companies are particularly
promoted. In accordance with the guidelines for approving these plantation
concessions, the plantations are to be established primarily on grassland
and in unprofitable production forests (see glossary). Special approval is
required for the conversion of production forests.
The private sector's interest in establishing plantations has grown
considerably since the beginning of the 1990s, the reasons for this being
seen as the far-reaching concession rights that guarantee investments (see
above), the Government's subsidization policy and the so-called clear-
cutting profits (see below).
The state subsidy for a joint venture between a public company and a
private enterprise consists in an interest-free loan limited to the first
rotation, amounting to 32.5% of the costs of establishing the plantation
(Biaya pembanguan HTI), and exemption from land tax (PBB). The loan is
financed from the Reforestation Fund (DR), and the costs that can be
claimed for establishing a plantation are determined by region by the
Ministry of Forestry (Groome-Pöyry 1993). An additional 14% of the costs
are also paid out of the Reforestation Fund as the capital share of the public
company; 21% of the costs are borne by the private investor, and the
remaining 32.5% are financed by a bank loan at normal interest rates. The
costs of clearing the land and all subsequent reforestation activities (Biaya
pengusahaan HTI) are no longer financed by DR loans.
Results
7
According to WALHI (1992), many plantations are established on forest
land and fewer on grassland or scrubland. TPTI guidelines usually ban the
use of certain valuable timber species if their diameter is too small;
however, when plantations are established on production forest land, these
guidelines do not apply and concessionaires are able to use these species in
the conversion process. A greater harvesting efficiency is thus achieved at
minimal costs, as the entire infrastructure, in particular the road network,
already exists ("clear-cutting profits").
In summary: The Indonesian Government promotes fast-growing
plantations to a large extent. In order to ensure the nation's timber supplies
and to help set up a pulp industry, plantations are given a high priority on a
political level and in the private sector.
2.2 Types of Sites and Nutrient Pools
2.2.1 Types of Sites
In the study area, the predominant soil types are Alisols and Acrisols (FAO
Soil Classification, cf. WRB 1994). These soil types account for more than
80% of the total area. Alisols and Acrisols are old, highly weathered soils
that mainly develop on sedimentary rock. In the part of the soil profile
investigated (0-100 cm), the average ECEC values were 25-26 cmolc/kg
clay. The aluminium saturation is very high, averaging 85%. In general,
using the PPT (1983) guidelines, the nutrient status can be classified as
moderate to poor (cf. Appendix, Table 6). The specific physical and
chemical values of the soil are presented and discussed by Mackensen
(1998) and Ohta et al. (1992).
The spatial distribution of the Alisols/Acrisols depends on the soil texture.
If the substratum is sandy, the poorer Acrisols prevail, while Alisols
Sustainable Nutrient Supply in Fast-Growing Plantations
8
predominate on more loamy soils. Due to the similarity of their definitions
in the classification system used, it is not possible to make a clear
distinction between these two soil types in the field and by area. The soil
types vary greatly within small areas. In general, the nutrient status varies
depending on the position on the slope. On midslopes and lower parts of
slopes, the nutrient pools, particularly that of Mb cations, are a factor of 2-
10 higher than on the corresponding upper parts of slopes or ridges. On
account of the short slope lengths (50-200 m) in the study area, it is,
however, not feasible for the plantation mangement to differentiate
between types of sites on the basis of their relief. In order to assess the
quality of a site, it can be assumed in practical terms that loamy sites have a
better nutrient status than sandy ones.
Ferralsols and Arenosols account for only a relatively small share of the
study area. Ferralsols are very highly weathered soils and differ from
Alisols/Acrisols in that they have even lower ECEC values (<12 cmolc/kg
clay). Arenosols also have a very low ECEC, as they have a high sand
content. They account for 10-15% of the area.
Both types of soil are usually found on gentler slopes and are easy to
distinguish in the field due to their high sand content. In the part of the soil
profile investigated, their clay fraction is less than 20%. In contrast to the
other soil types, these soil types are generally poor in nutrients (cf.
Appendix, Table 6) due to their high kaolinite content and the concomitant
low ECEC (2.5 cmolc/kg soil). Their pH values are slightly higher than
those of the Alisols/Acrisols, and the aluminium saturation in these soils
averages 70-80%.
Azonal soils, such as the Calcisols that develop on limestone or the
Fluvisols found in valleys, were treated separately. These two soil types
each account for less than 5% of the area. Calcisol sites are found to be
Results
9
extended enough to be managed separately. In contrast, Fluvisols are only
found in valleys, and these are often narrow; a separate treatment of this
soil type would thus not appear to be economically feasible.
Fluvisols and Calcisols are soils with a very good nutrient supply.
However, using the criteria of the PPT (1983), the K supply in Calcisols is
low and is comparable to the corresponding values for Alisols/Acrisols (cf.
Appendix, Table 6). The ECEC of the Calcisols, in particular, is extremely
high (>85 cmolc/kg clay). The pH values range from 5 to 7.
In summary: More than 90% of the land used for plantations has highly
weathered soils with moderate to poor nutrient supply.
2.2.2 Nutrient Pools in the Soil
The nutrient pools in the soil that are available for plant nutrition
(exchangeable nutrients) are mainly a function of the nutrient
concentration, content of remaining stones and the soil density. Soil density
averages 1.2 cm3/g in the topsoil and 1.5 cm3/g in the subsoil. The
differences between sandy and loamy soils are relatively small in this
respect. The amount of stones is low, except for in Calcisol sites. The
average nutrient pools in the soil are lowest in Ferralsols/Arenols, higher in
Acrisols and highest in Alisols. Calcisols have higher levels of C, Pt, Ca
and Mg than the main soil types (Ali-/Acrisols). Fluvisols have above-
average levels of C, Nt, Pt and Mb cations (cf. Table 1). In the main soil
group of Alisols/Acrisols, higher nutrient pools are found in the loamy soils
than in the sandy ones (cf. Mackensen 1998).
Sustainable Nutrient Supply in Fast-Growing Plantations
10
Tab. 1: Pools of C, Nt , Pt and exchangeable cations in 0-100 cm soil depth.
Soil typ C N P Na K Ca Mg Fe Mn Al[Mg ha-1] [kg ha-1]
Alisol X 93,0 11,4 1691,0 345,4 756,6 1454,6 617,7 99,8 124,0 8454,7(n=29) Med 89,9 11,1 1606,3 393,4 769,9 1185,9 396,5 81,3 115,8 8212,6
Stdabw 19,4 3,2 641,4 158,7 252,7 936,0 517,0 93,8 64,7 2649,1Max 148,2 22,4 3742,5 552,8 1255,2 4188,7 1876,7 321,3 271,4 14925,7Min 59,7 6,4 616,9 95,9 343,7 374,9 120,8 0,0 27,2 4570,5
Acrisol X 83,3 9,1 1186,7 276,6 693,4 1091,7 311,3 87,0 67,1 6468,4(n=7) Med 86,1 9,1 1189,3 163,5 702,7 961,4 271,6 57,0 73,6 6384,6
Stdabw 18,6 1,6 231,6 147,5 163,2 626,5 126,0 67,7 35,8 1134,7Max 108,2 12,2 1621,7 450,9 947,2 2101,2 501,9 215,5 104,9 8551,2Min 49,2 6,8 917,6 152,6 454,5 504,7 198,4 23,5 12,6 4844,8
Ferralsol- X 78,8 5,7 721,4 372,2 236,0 565,5 246,6 89,5 31,2 2423,1Arenosol Med 75,4 5,4 740,7 445,2 226,9 547,0 278,3 85,1 31,8 1905,8(n=4) Stdabw 17,4 1,2 57,0 153,4 22,9 145,0 92,6 37,7 10,4 1194,1
Max 102,8 7,2 766,4 455,9 269,6 749,2 318,7 134,1 41,1 4199,4Min 61,4 4,5 637,9 142,4 220,5 418,9 111,1 53,7 20,3 1681,4
Calcisol X 111,4 11,1 2100,8 218,9 516,7 51012,7 824,1 0,0 123,5 486,7(n=2)Fluvisol (n=1) 130,3 19,0 4176,6 649,1 1314,5 12537,9 7681,3 0,0 383,4 2263,9x=mean, med=median, Stdabw=standard deviation, max/min=maximum/minimum.
2.3 Plantation Productivity
Acacia mangium, Eucalyptus deglupta and Paraserianthes falcataria (syn.
Albizzia falcataria) are the tree species mainly used in the PT.IHM
plantation concession. The primary aim is the production of pulpwood. Up
to 1996, 80% of the land was planted with Eucalyptus deglupta. As the
yield of this tree species did not match expectations, 70-80% of the land
has been planted with Acacia mangium since 1996/97. Acacia mangium is
by far the most common tree species planted in the pulp plantations in
Indonesia and Malaysia.
Regardless of the tree species planted, the planting space used by PT.IHM
was 3×3 m. A stand rotation period of 8 years is planned for the stands.
Thinning is not carried out. The anticipated yield (MAI) is 25 m3/ha per
annum, corresponding to a harvesting efficiency of 200 m3/ha after 8 years.
Results
11
2.3.1 Inventory of stands
In connection with the soil profile analyses (see Sect. 2.2.1), a total of 42
stands were investigated. On study plots of 0.05 ha Eucalyptus deglupta
and Acacia mangium stands of different ages, the diameter at breast height
(DBH) and tree height were recorded. The values are summarized in
Table 2. The yield on which the concession based its investment
calculations is usually exceeded in the Acacia stands and not attained in the
Eucalyptus stands.
The high volume output of the Acacia stands in the first rotation is due,
among others, to the high stand density and the large number of stems per
tree of the provenance used ("Queensland"). On the basis of the yield
classification criteria (GH5) given by Forss (1994), the productivity of the
Acacia stands investigated in this study can be classified as moderate to
low. Acacia mangium is a relatively undemanding pioneer tree species and
is thus able to achieve high yield in the first rotation even on comparatively
poor sites (Ferralsols/Arenosols, cf. Sect. 2.2.1).
The growth of Eucalyptus deglupta is considerably lower than the values
originally assumed by the management (cf. Sect. 2.3). The low yield of
Eucalyptus deglupta is due to the unsuitable choice of site and insufficient
maintenance work on the stands. The species requires deep soil and a good
water supply (e.g. Fluvisols) for optimal growth rates. During the early
growth phase, Eucalyptus deglupta is not able to compete very successfully
with accessory vegetation, and the mortality rate is correspondingly high,
especially if adequate tending of stands is not carried out (cf. Table 2, cf.
Mackensen 1998).
Sustainable Nutrient Supply in Fast-Growing Plantations
12
Tab. 2: Stand parameter for Acacia mangium (Am) and Eucalyptus deglupta (Ed).
spec. age [a] n mean range of values stand density [%]a
ATG [m3 ha-1] Ed 7,5 6 14,3 6,3-17,7 51 (24-78)Am 7,5 4 50,5 43,4-59,2 100 (62-169)Ed 8,5 15 16,1 5,2-23,2 71 (42-89)Am 8,5 2 47,4 36,2-58,8 84 (53-115)Ed 9,5 4 27,1 22,8-33,1 69 (55-78)Ed 9,5 2 17,0 52Am 9,5 3 42,1 34,9-53,8 100 (75-118)Ed 14,5 6 20,3 13,8-28,3 36 (24-44)
Vol [m3 ha-1] Ed 7,5 6 97 46,9-132,5Am 7,5 4 379 325,4-444Ed 8,5 15 136 44,4-196,9Am 8,5 2 404 307,8-500Ed 9,5 4 257 216,8-314,6Ed 9,5 2 161 149,8-172,7Am 9,5 3 400 331,8-510,9Ed 14,5 6 295 200,4-410,3
GH [m] Ed 7,5 6 19,7 14,2-24,2Am 7,5 4 27,5 25,5-29,2Ed 8,5 15 20,6 15,4-25,9Am 8,5 2 27,5 27-28Ed 9,5 4 26,1 24,2-27,6Ed 9,5 2 24,2 23,7-24,6Am 9,5 3 29,0 26,4-31,6Ed 14,5 6 31,6 27,9-37,5
ATG = average total increment for listed age, Vol = volume of stem timber, GH= height of the 5 tallesttrees per area (0,05 ha), stand density = amount of still growing trees in relation to number of plantedtrees (n=1111 ha-1), n = number of research plots; a :values >100% caused by trees with several stems.For basics of calculation cf. Mackensen (1998)
A relatively clear correlation between relief and stand productivity can be
observed. Stands on lower parts of slopes and in valleys are taller than
those with comparable forest cover on ridges and upper parts of slopes.
However, as changes in the topography occur within very small areas
(short slope lengths, etc., cf. Sect. 2.2.1), these relationships are of only
secondary practical relevance for the plantation management in the study
area.
Results
13
2.3.2 Nutrient Pools in the Stand
The nutrient pools in the stand depend on the stand volume and the element
concentration in the individual stand compartments. The stand
compartments considered include the stemwood, -bark, branches and
leaves. The stemwood and -bark are removed from the site in the course of
harvesting (exported compartments). The branches and leaves remain on
the site as residual phytomass (slash). Other compartments assessed include
the forest understorey (accessory vegetation) and the organic O-horizon.
Fig. 1: Nutrient concentrations in stemwood (H) and bark (R) of
Eucalyptus deglupta (Ed), Acacia mangium (Am) and
Paraserianthes falcataria (Pf).
N = 15 in each case.
N [%]
0,0
0,5
1,0
1,5P [mg g ]-1
0
10
20
30K [mg g ]-1
0
5
10
15
20Ca [mg g ]-1
0
1
2
3
Ed-H
Ed-
R
Am
-H
Am
-R
Pf-H
Pf-R
Mg [mg g ]-1
0,0
0,2
0,4
0,6
Ed-H
Ed-R
Am
-H
Am
-R
Pf-H
Pf-R
Mn [mg g ]-1
0,0
0,5
1,0
1,5
2,0
Sustainable Nutrient Supply in Fast-Growing Plantations
14
The stand nutrient pools vary depending on the species. Figure 1 shows the
concentration of elements in the compartments stemwood and -bark for the
main tree species. The nutrient levels in the bark are particularly high. On
the basis of available data (Ruhiyat 1989; Mackensen 1998), a correlation
between the tree and stand volume and the dry weight of the compartments
stemwood, -bark, branches and leaves can be made for the main tree
species. Using the concentration data, the nutrient supply can thus be
estimated for given stand supply levels (cf. Appendix, Tables 7, 8).
Assuming a volume of harvest of 350 m3/ha, for example, the amounts of
nutrients removed with the stemwood and -bark of Acacia mangium stands
are 266-332 kg N/ha, 3.4-4.3 kg P/ha, 34-36 kg Na/ha, 93-119 kg K/ha,
192-259 kg Ca/ha and 14-16 kg Mg/ha (cf. Appendix, Tables 7, 8).
Detailed data on the pools of nutrients in the residual phytomass, the
understorey and the organic O-horizon can be found in Ruhiyat (1989) and
Mackensen (1998).
In summary: Harvesting of the stand entails nutrient losses (nutrients
removed with the harvest). The extent of nutrient loss depends on the
volume of the harvest and the species-specific nutrient levels in stemwood
and -bark.
Sustainable Nutrient Supply in Fast-Growing Plantations
28
2.5 Replacement of Nutrients
The most direct method to replace nutrient losses is to use mineral
fertilizers or organic manure. This can be referred to as fertilization to
restore nutrient levels. In contrast to soil-enhancing fertilization, in which
additional amounts of nutrients are used in order to increase the level of
productivity, fertilization to restore nutrient levels is primarily designed to
maintain the level of productivity. However, a clear distinction between
these two forms cannot be made. The fertilizer-specific uptake efficiency
by plants (utilization rate) and the interaction with the soil chemistry have
to be taken into account in fertilization.
The use of fertilizer in conventional plantation management is usually
regarded by the plantation concessions as soil-enhancing fertilization. The
amount of fertilizer used is primarily based on the results of experiments
carried out in young stands or on data given in the literature. Standard
fertilizers are generally used, and fertilizers are usually applied without
taking into account the tree species or the conditions of the site.
As the soil conditions are already acidic to highly acidic (cf. Table 6), only
fertilizers that cause no or little soil acidification should be used. In order to
Results
29
calculate the amount of fertilizer necessary to replace nutrient losses, the
following utilization rates are assumed: N and K fertilizers 50-70%, P
fertilizers 10-40%. For P fertilizers, in particular, a high level of P fixation
(immobilization) is assumed for the soils that were studied (cf. Grüneberg
1983; Voss et al. 1977). Despite a high level of P fertilization, only a very
low level of uptake by the plant can therefore be expected.
By comparing the amount of fertilizer actually used and the amount
necessary to replace the nutrients removed with the harvest (cf. Sect. 2.4.3),
it can be seen that there is a considerably greater need for fertilizers.
Depending on the tree species, fertilizer type and utilization rate, the
amount of N fertilizer used needs to be increased by a factor of 8-22. For P,
assuming a utilization rate of 40%, the amount currently used is sufficient.
In order to replace the K pools lost during harvesting, the amount of
fertilizer used has to be increased six- to 17-fold. The amount of fertilizer
required to replace the total losses (cf. Sect. 2.4.4) is considerably higher
(cf. Appendix, Tables 12-14).
Fertilization management needs to be varied according to the species
concerned. In Eucalyptus deglupta, for example, a much greater need for K
fertilization should be reckoned with to replace losses than in Acacia
mangium. The nutrient composition of standard fertilizers (e.g. NPK
fertilizers) is poorly suited to replace the nutrient losses (cf. Mackensen
1998).
In summary: The amount of fertilizer currently used in plantation
management is not sufficient to replace nutrient losses. Species- and site-
specific fertilization management is necessary to replace the nutrient losses
occurring in plantation management.
Sustainable Nutrient Supply in Fast-Growing Plantations
30
In addition to fertilization, general soil melioration by liming is necessary
on many sites. On sites with a high level of aluminium saturation in the
topsoil, in particular, liming is required to reduce the aluminium levels in
the soil solution and to decrease P fixation. For sites with a pH value of
≤4.7, liming with 2.5 Mg dolomitic limestone per ha is thus recommended.
On sites with an aluminium saturation of more than 80% in the topsoil, 4-
8 Mg limestone per ha is necessary to offset soil acidity (cf. Mackensen
1998). In the PT.IHM plantation management, less than 1 Mg limestone
per ha is currently applied.
In summary: The measures currently used to improve soil quality are not
adequate to ensure the long-term availability of nutrients.
2.6 Plantation Economics
2.6.1 Costs of Fertilization to Replace Nutrient Losses
The amount of fertilization to replace nutrient losses that is deemed
necessary to achieve a sustainable nutrient balance (cf. Sect. 2.5) entails
additional costs. Table 4 compares the PT.IHM's costs for fertilization
management with the costs of replacing nutrients removed with the harvest
(costs 1996/97, cf. Mackensen 1998). PT.IHM's fertilization management
costs Rp 193,680 per ha for each rotation (based on official market prices,
not including labor). This calculation is based on the use of 100 g NPK,
40 g TSP and 840 g dolomitic limestone per plant, with a stand density of
800 trees per ha.
If the same fertilizer types as used by the company were applied to replace
the nutrients removed with the harvest (cf. Sect. 2.4.3), the expenditure on
fertilizer would increase by 13.7- or 10.7-fold (cf. Table 4). If no N
fertilizer is used for N-fixing tree species (Acacia mangium), the costs still
Results
31
rise by a factor of 5.2 (Table 4, see Appendix, Table 15). This demonstrates
both, the huge quantity needed for a minimum nutrient replenishment and
the inefficiency of standard fertilizer combinations.
Tab. 4: Comparison of current costs for fertilization with the costs of
compensation of nutrients removed with the harvest (200m3 ha-1)
variant costs for fertilizationPT.IHM Am Ed[Rp ha-1] [%] [Rp ha-1] [%] [Rp ha-1] [%]
current costs (PT.IHM, 1996) including NPK, TSPand dolomite 193.680
100
Compensation of harvest exports by standardfertilizers (NPK, TSP, dolomite)
2.654.475 1371 2.076.880 1072
Compensation of harvest exports (NPK, TSP,dolomite), but without NPK-N for Acacia mangium
1.007.005 520
Compensation of harvest exports by alternativefertilizers (Urea, TSP, potash, dolomite)
783.838 405 820.039 423
Compensation of harvest exports by alternativefertilizers (TSP, potash, dolomite),no N-fertilization for Acacia mangium
505.990 261
(Am) Acacia mangium, (Ed) Eucalyptus deglupta . Harvest volume for each stand: 200m3 ha-1
costs related to 1996/97 (1 US$ =. 2200 Rp.)
If more effective types of fertilizer are used (Urea, CIRP, K2SO4, dolomitic
limestone), the costs of fertilizers to replace nutrients removed with the
harvest are lower, but still 2.6-fold (Acacia mangium, without using Urea)
and 4.2-fold (Eucalyptus deglupta) higher than the costs of the company's
current use of fertilizers (cf. Table 4).
Compared with the data for Acacia mangium, the fertilization programme
for Eucalyptus deglupta stands is approximately 60% more expensive. As
the nutrient costs for Eucalyptus deglupta are generally higher, this species
is only profitable on sites with natural good nutrient supply (Fluvisols and
Calcisols, Alisols with above-average nutrient pools, cf. Sect. 2.2) on
which fertilization to replace nutrient losses is not necessary or is only
Sustainable Nutrient Supply in Fast-Growing Plantations
32
necessary to a limited degree in later rotations (e.g. K fertilization on
Calcisols) (cf. Mackensen 1998).
Replacing total management-dependent losses (cf. Sect. 2.4.4) entails
higher expenditure on fertilizer (Tab. 5; cf. Mackensen 1998). At a
conservative estimate (cf. minimal variant Min200, cf. Sect. 2.4.4.),
compared with the company's current expenditure on fertilizer, the costs of
fertilizer to replace the total losses are 350-570% higher, if alternative
fertilizers are used (Tab. 5, cf. Appendix, Tab. 16).
Tab. 5: Costs of fertilization in case of compensation of total nutrient losses for themanagement variants Min200 and Alt200 (cf. Appendix Tab.12-14).
Acacia mangium Eucalyptus degluptaVariant Min200
a Alt200b Min200
a Alt200b
[Rp ha-1] [%]c [Rp ha-1] [%]c [Rp ha-1] [%]c [Rp ha-1] [%]c
standard (NPK, TSP, dolomite) 4.317.620 2229 2.561.622 1323 2.431.655 1256 1.232.945 637
standard (NPK, TSP, dolomite),without NPK-N
1.904.665 983 1.197.550 618
alternative fertilizers (Urea, TSP,potash, dolomite)
1.166.719 602 810.021 418 1.099.578 568 841.318 434
alternative fertilizers (TSP,potash, dolomite), without N-fertilizers
685.210 354 543.275 281
a harvest volume: 200 m3,minimal losses by leaching, burning and erosion.b harvest volume: 200 m3, minimal losses by leaching and erosion. Without burning.c related to the costs of fertilization management of PT.IHM (100% = 193.680 Rp ha-1; Tab.4).
Assuming very low total losses by alternative plantation management
(Alt200, cf. Sect. 2.4.4), the costs of replacing the total losses are
comparable to the costs of replacing the nutrients removed with the harvest
(cf. Table 4, cf. Mackensen 1998).
In summary: The costs of replacing the total nutrient losses are at least
three- to sixfold higher than the current expenditure on fertilizer.
Results
33
While the PT.IHM's current fertilization management accounts for an
average of 4% of the plantation's total costs, the costs of the fertilizer
necessary to replace nutrient losses range from 9% to 40% of the
plantation's total costs, depending on the tree species, type of management
and fertilizer (cf. Mackensen 1998).
In summary: The replacement of nutrients that is necessary to ensure
sustainable nutrient pools in intensively managed timber plantations
constitutes a major operating cost factor.
To obtain a conservative estimate of the fertilizer costs, it is assumed that
only the nutrients removed with the harvest or small total losses (variants
Min200 or Alt200, cf. Sect. 2.4.4) are replaced. Variant Max200 is not
considered. In the assumptions made, it is also assumed that all the types of
fertilizer are available. If, for example, raw phosphate fertilizer is not
available in the region, either acquisition costs will be higher or more
expensive alternatives (e.g. TSP) will have to be used. It is also assumed
that fertilization does not entail any additional costs in other cost groups
apart from operating costs. Thus this simplified assumption does not take
account of any further cost changes in planning, infrastructure, research or
training. Possible increases in the costs of labour or fertilizer as a result of a
greater demand and a lower supply are also not taken into account.
In summary: On the basis of the above-mentioned assumptions for the
economic evaluation of nutrient losses, it should be assumed that the
estimates presented here are minimum values.
Sustainable Nutrient Supply in Fast-Growing Plantations
34
2.6.2 Investment Analysis
The internal rate of return is used to examine the profitability of
investments. The internal rate of return is the effective return on an
investment. It is defined as the interest rate at which the net present value
of an investment would be zero (Heinrichsmeyer et al. 1988). An
investment can be regarded as lucrative if the internal rate of return is
higher than the rate of return from other investment options would be.
Calculated over a period of 44 years (rights of use for 35 years plus a
further rotation, cf. Sect. 2.1), the internal rate of return on establishing and
managing HTI-plantations is 14.0% (basis of calculation according to
PT.IHM 1991). The financial expenses of the private loans and
reinvestment profits are not taken into account. All the figures are adjusted
for inflation as specified by the Indonesian Ministry of Forestry (MoF
1994).
As no interest has to be paid on the government loan of 32.5% from the
Reforestation Fund (DR), while interest is charged on the bank loan (32.5%
of the total capital) at a rate of 24%, the internal rate of return on the
company's equity capital (totalling 35%, cf. Sect. 2.1) increases to 17.7%
(cf. PT.IHM 1991; Mackensen 1998). Data presented by the FAO (1990),
Groome-Pöyry (1993) and the MoF (1995) are comparable with these
results.
A comparison with risk-free bank deposits (the interest on principal for
bank deposits was over 18% up to the middle of 1997) shows that the
classical plantation model has a below-average rate of return on equity
combined with risks that are difficult to calculate as a result of productivity
losses due to pests or fire, for instance. It therefore seems reasonable to
suppose that a plantation is not established merely to engage in profitable
Results
35
timber production. The "clear-cutting profits" obtained when converting
land (cf. Sect. 2.1), internal processing to obtain more profitable end-
products such as paper and cardboard and political considerations all play
an important role in the establishment of plantation concessions (cf.
Groome Pöyry 1993).
2.6.3 Sensitivity Analysis
Figure 11 shows the changes in the internal rate of return under the
PT.IHM's investment conditions (1991) for an increase or decrease in costs
or revenue.
Fig. 11: The internal rate of return as a function of changes in the
PT.IHM's costs or revenue.
If costs rise or revenue decreases, the internal rate of return drops. If the
total costs increase by 9-40% (cf. Sect. 2.6.1) and revenue remains
constant, the internal rate of return drops to approximately 8-12% (cf.
Fig. 11). The return on equity then amounts to 12.9% to -0.3%.
If the costs were to increase by 13% to replace the nutrients removed with
the harvest using alternative types of fertilizer, the internal rate of return
0
5
10
15
20
25
30
35
-60 -40 -20 0 20 40 60
Inte
rnal
rate
of r
etur
n [%
]
Changes in costs and revenue
costsrevenue
Sustainable Nutrient Supply in Fast-Growing Plantations
36
would drop to 11.8%, and the internal rate of return on equity would drop
to 11.1% due to the high bank interest (see above).
In summary: An increase in costs due to the need to use fertilizer to replace
nutrient losses reduces the internal rate of return significantly in some
cases. The poorer the quality of the site, the lower the internal rate of
return.
If both costs and revenue change, the internal rate of return changes as
follows: For a volume of harvest of 300 m3 in Acacia mangium stands (cf.
Sect. 2.3.1), revenue increases by 50% compared with the initial situation if
the other conditions remain the same; at the same time, the costs of
replacing the nutrients removed with the harvest rise by 19% (optimized
fertilization, including N fertilization). The overall internal rate of return
increases to 18.0%, and the return on equity increases accordingly to
29.3%. For an average volume of harvest in Eucalyptus deglupta stands of
150 m3, revenue decreases by 25% and costs increase by 15% due to the
amount of fertilizer required to replace the nutrients removed with the
harvest (cf. Mackensen 1998). The internal rate of return then drops to
5.8%, and the return on equity is therefore -5.7%. However, the additional
expenditure on felling and transport, for example, cannot be taken into
account in these estimates, and this calculation is therefore of limited use.
The biggest problem in calculating the internal rate of return is estimating
the development of timber prices. The revenue from timber assumed in the
investment analysis is merely a price estimate (cf. Mackensen 1998).
However, many companies are able to set their prices internally if timber is
purchased by a pulp factory owned by the company itself; under certain
circumstances, price are thus set solely to cover the costs of timber
production. The costs of timber harvesting also constitute a variable that is
Results
37
difficult to calculate, as no data are available in Indonesia yet for this area
(cf. Mackensen 1998). The economic significance of nutrient losses can
therefore only be shown to a limited extent using the internal rate of return
method.
Sites with low nutrient pools that already have to be fertilized in the second
rotation (Ferralsols/Arenosols, sandy Alisols/Acrisols; cf. Sects. 2.2 and
2.5) have a particularly low rate of return and are unprofitable in the long
run. According to the results of this study, even average sites with
Alisols/Acrisols requiring an increasingly intensive use of fertilizers as
productivity declines have a below-average rate of return and profitability
(cf. Mackensen 1998). The form of management has a decisive impact on
the profitability of the land. A form of "gentle" management in which the
slash is not burned and losses due to erosion and leaching are minimized by
optimizing harvesting techniques leads to lower nutrient costs than
conventional methods.
In summary: Investment calculations for plantation projects need to take
account of the site-specific results of nutrient budgets. Setting up large
areas of uniform fast-growing plantations and managing them
conventionally is economically inefficient and ecologically unsound.
Practical Relevance
39
3 Practical Relevance
3.1 Opportunities and Limitations of Timber Plantations
Fast-growing tropical plantations are regarded as very productive and easy
to manage. The present results provide a range of instruments that can be
used to assess the ecological feasibility and economic efficiency of fast-
growing plantations. It can thus be shown that a high level of productivity
and an intensive form of management place a very great strain on the sites.
It is incorrect to assume that plantations intrinsically have a constant level
of productivity and do not require a great amount of management
resources.
On the basis of the results of this study, the amount of technical and
financial resources required to manage a plantation on the given sites and
to maintain a constant level of productivity on a long-term basis, i.e. over
many rotation cycles, needs to be considerably greater than it is at present
in conventionally managed plantations. Thus, under the given conditions,
plantation management cannot be carried out in accordance with the
classical models of extensive forestry.
The results of nutrient budgets highlight the fact that alternative, resource-
saving management concepts need to be developed (cf. Sect. 4.1) in order
to guarantee the intensive use of sites on a long-term basis.
3.2 Regional Development and Land-Use Planning
The results obtained by drawing up nutrient budgets show the need to
improve land-use planning for intensively managed fast-growing
plantations. It would seem sensible to draw up nutrient budgets along the
Sustainable Nutrient Supply in Fast-Growing Plantations
40
lines specified as part of the environmental-impact assessments (EIAs) of
the preliminary planning phase. Establishing plantations on unsuitable sites
can thus be avoided.
It is often claimed that timber production in plantations is able to reduce the
pressure on natural forests (Nambiar and Brown 1997). This assumption
only appears to be justified if plantations can be stably managed on a long-
term basis. Plantations that have to be abandoned after only a few rotation
cycles due to the wrong site having been chosen, inappropriate
management methods being used or profitability being too low represent a
threat to development aimed at stabilizing the region.
Plantation concessions that become unprofitable for the above-mentioned
reasons also jeopardize the livelihood of the people who have been brought
there to settle as part of transmigration projects. In this respect, inadequate
land-use policies have a specific impact on the socio-economic conditions
of a region.
A capital-intensive pulp-processing industry is currently being established
in Indonesia, particularly in Kalimantan (cf. WALHI 1992). This industry
has to rely on the input of raw materials from intensively managed fast-
growing plantations. Plantation sites that are becoming degraded will cause
plantation companies to extend their plantation areas in order to ensure that
the felling volume remains constant, largely at the expense of areas of
natural forest. This development is not compatible with long-term land-use
planning.
Plantation sites that have to be abandoned as a result of inappropriate
management or an unsuitable choice of site increase the proportion of
unproductive land. This runs counter to the aim of putting degraded land to
use again by establishing plantations (cf. FAO 1990; WALHI 1992).
Practical Relevance
41
3.2.1 Further Need for Research
In the near future, plantations will play an increasingly important role in
forestry, particularly in the tropics. This development should be
accompanied by scientific research. On the one hand, research in this area
enables the use of the various resources to be improved and is thus
important for the economic success of such enterprises. On the other hand,
independent research on various aspects of plantations provides
information about the need for accompanying measures for nature
conservation and landscape protection.
The site-specific results of this study need to be applied to higher planning
levels. How much intensively managed fast-growing plantation can a
region tolerate and how high is the potential? In the long run, a
diversification of land use in forestry needs to be developed, involving fast-
growing plantations in combination with valuable timber plantations and
semi-natural commercial forests in small areas.
Considerable research is required to stabilize plantation systems in order to
create a sustainable form of management, including the associated potential
for development. Studies on the relationship between management
intensity, nutrient fluxes, type of soil and fertilization management are
urgently needed. On the basis of such studies, criteria can be developed for
a stabilizing land-use policy at various levels.
The plantation management studied is limited to a very few species and
follows a standard pattern. Research is required to study and introduce new,
native species in plantations. Methods need to be further developed to
allow work on hilly terrain without damaging the land (small high-lead
systems, etc.).
Recommendations for Action
43
4 Recommendations for Action
4.1 Plantation Estates
The following recommendations are made for plantation management with
fast-growing tree species on the sites that were studied:
Soil mapping on the basis of the soil type (sandy, loamy, clayey) and the
pH value. Nutrient analyses of samples. Additional recording of important
site parameters (inclination and length of slopes, etc.). Information of this
kind is entered in a Geographical Information System (GIS). Identification
of site units.
No uniform conversion of Ferralsol/Arenosol and sandy Alisol/Acrisol
sites into fast-growing plantations. Similar to sites on steep slopes and at
riverbanks, retaining the natural forest cover is also recommended for these
sites.
Minimization of nutrient losses by appropriate plantation management, in
particular by not burning residual phytomass (slash) to prepare land and by
using technologies to harvest timber that avoid soil damage.
Site-specific calculation of nutrient fluxes and, on the basis of these
calculations, optimized fertilization management, i.e. taking into account
the soil type, tree species and management form.
Development of alternative management concepts: change of tree species,
use of alternative species, mixed-species stands, use of green manure,
understorey management, spreading ash, etc.
Inclusion of nutrient budgets in business costing processes.
Sustainable Nutrient Supply in Fast-Growing Plantations
44
4.2 Land-Use Policy
The following general recommendations can be made for land-use policy,
regional planning and forest management planning:
Stricter requirements for establishing fast-growing plantations. As part of
an environmental-impact assessment, enterprises have to show that the site
is suitable for intensive management by providing nutrient budgets and
taking account of fertilizer costs. Management concepts addressing the
issue of the species planned to be used, the fertilization management and
the harvesting methods should also be presented or demonstrated.
Promotion of small units. Greater stratification of land-use units, i.e. higher
density of various management concepts within a single planning unit.
Support programmes for the actual use of degraded land as plantations.
Stricter ban on the conversion of natural forest and more thorough
implementation of existing guidelines.
4.3 DC Institutions
In future, plantations will acquire increasing economic and political
significance in Indonesia, in particular, but also in the tropics and
subtropics as a whole. This development is based on the need to offset the
declining timber yields from natural forests by fast-growing timber species
in plantations and, at the same time, to establish a processing industry and
to use unproductive areas of land to contribute to further regional and
national economic development. This will have impacts on the ecological,
socio-economic, technological and political development of a region. It is
thus the task of development cooperation (DC) to exert a positive influence
on the potential and steering of such processes in the interests of a
sustainable use of resources.
Recommendations for Action
45
In addition to the specific recommendations for action mentioned above,
we regard the following aspects as particularly important in the context of
international development work:
4.3.1 Information Policy
A crucial criterion for all the measures for planning and action that are to
be derived is that there should be a transparent flux of information. In this
context, it is important that an information policy such as this does not only
emphasize the plantation aspect or is restricted to this aspect, but also
highlights and discusses the links with neighbouring disciplines and areas
of life. Taking the specific example of East Kalimantan, even a partial
failure of plantation projects results in soil degradation, the destruction of
natural forests and timber shortages and jeopardizes economic development
and the source of income associated with it for the population. The need for
action and information is thus correspondingly large.
It would appear to be particularly useful in this context to cooperate with
specialist institutions at an international level (e.g. CIFOR) with the aim of
passing on knowledge acquired in connection with the results to the
national decision-makers.
The key role in sustainable development that the GTZ (1993) has ascribed
to forests also applies to the same extent to plantations. In the view of the
authors, plantation management only plays a very minor role in German
DC compared with the management of natural forests. This does not do
justice to regional conditions, and in our opinion, the positive and negative
potential of the plantation sector in terms of regional development merits
greater attention.
Sustainable Nutrient Supply in Fast-Growing Plantations
46
4.3.2 Concepts for Action
Concepts for the protection and sustainable management of natural tropical
forests need to include criteria for the stabilization of areas at the forest
margins. The results presented above highlight the fact that inadequate
plantation policy and management can play a significant role in
destabilizing natural and production forests.
We thus regard it as important that development programmes to stabilize
areas at forest margins should include industrial plantations and other non-
traditional forms of management. The range of levels affected by
inappropriate regional development indicates that the stabilization
programmes need to be correspondingly broad. The accompanying research
necessary in this context is outlined in Sect. 3.3.
The German Federal Government's Advisory Council on Global Change
(Wissenschaftlicher Beirat Globale Umweltveränderungen; WBGU 1996)
has classified the area of non-sustainable industrial land and water
management, the so-called "dust-bowl syndrome", as belonging to the
highest priority category. Intensive plantation management on unsuitable
sites is explicitly mentioned in this context. The syndromes defined by the
WBGU (1996) are characterized by their trans-sectoral and global nature,
and strategies to solve these problems should thus be developed regionally
and put in a global context.
References
47
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EVANS J., 1982. Plantation forestry in the tropics. Clarendon, Oxford. 472S.
EVANS J., 1988. The Usutu forest: 20 years later. Unasylva 159 (40):19-29.
FAO, 1990. Situation and outlook of the forestry sector in Indonesia. Vol.2: Forest Resource Base. FAO and Ministry of Forestry, Indonesia.Forestry Studies Technical Report No.1. 265 S.
FAO, 1995. Forest resources assessment 1990. Global synthesis. FAO,Rome. FAO Forestry Paper 124. 89 S.
FEARNSIDE P.M., 1997. Transmigration in Indonesia: Lessons from itsenvironmental and social impacts. Environmental Management21(4): 553-570.
FORSS E., 1994. Zur Modellierung des Wachstums der Baumart Acaciamangium Willd. in Südkalimantan, Indonesien. Magister-Arbeit amForstwissenschaftlichen Fachbereich, Universität Göttingen. 83 S.
GROOME-PÖYRY Consulting, 1993. Institutional strengthening for timberplantation development. Asian Development Bank AdvisoryTechnical Assistance 1244-INO, Ministry of Forestry, Directorate ofIndustrial Timber Estates. Jakarta, Indonesia. 99 S.
GRÜNEBERG F., 1983. Böden der humiden Tropen und Probleme ihrerNutzung, dargestellt an Beispielen aus der indonesischen ProvinzOstkalimantan. I. Böden aus miozänen Sedimentgesteinen. GiessenerBeiträge zur Entwicklungsforschung, Reihe I, Band 9: 109-128.
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GTZ, 1993. Waldkonzepte - Konzeption und Handlungsfelder desArbeitsfeldes Waldwirtschaft. GTZ-Abteilung Waldwirtschaft,Waldprodukte und Naturschutz. Eschborn. 19 S.
HAMILTON C., 1997. The sustainability of logging in Indonesia's tropicalfor-ests: A dynamic input-output analysis. Ecological Economics21:183-195.
HEINRICHSMEYER W., Gans O. & Evers I., 1988. Einführung in dieVolkswirtschaftslehre. UTB, Stuttgart. 600 S.
KLINGE R., 1998. Wasser- und Nährstoffdynamik im Boden und Bestandbeim Aufbau einer Holzplantage im östlichen Amazonasgebiet.Göttinger Beiträge zur Land- und Forstwirtschaftin den Tropen undSubtropen, 122:1-260.
LESACK L.F.W. & MELACK J.M., 1996. Mass balance of major solutes in arainforest catchment in the Central Amazon: Implications for nutrientbudgets in tropical rainforests. Biogeochemistry 32:115-142.
MACKENSEN J. 1998. Untersuchung zur nachhaltigen Nährstoffversorgungin schnellwachsenden Plantagensystemen in Ost-Kalimantan,Indonesien - ökologische und ökonomische Implikationen. GöttingerBeiträge zur Land- und Forstwirtschaftin den Tropen und Subtropen,127:1-209.
MALMER A. & GRIP, H., 1994. Converting tropical rainforest to forestplantation in Sabah, Malaysia. Part II. Effects on nutrient dynamicsand net losses in streamwater. Hydrological Processes 8:195-209.
MoF (Ministry of Forestry), 1994. Pedoman penyusunan studi kelayakanpembanguan hutan tanaman industri.161/Kpts/IV-PPH/1994. 48 S.
MoF (Ministry of Forestry), Directorate General of Reforestation and LandRehabilitation, 1995. National Masterplan for forest planta-tions.Vol. 1: Synopsis. DHV Consultants, PT. Tricon Jaya & PT. CaturTunggal Sarana Consult, Jakarta, Indonesien.
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NAMBIAR E.K.S & BROWN A.G., 1997. Management of soil, nutrients andwater in tropical plantation forests. ACIAR Monograph No. 43. 571S.
OHTA S., EFFENDI S., TANAKA N. & MIURA S., 1992. Characteristics ofmajor soils under lowland Dipterocarp forest in East Kalimantan,Indonesia. PUSREHUT Special Publication No. 2. 72 S.
OPITZ M., 1995. Indonesien - Holzland am Scheideweg? Teil 1: Wird dienachhaltig mögliche Holznutzung im Land Überschätzt? Holz-Zentralblatt 18:1pp.
PPT (Pusat Penelitian Tanah), 1983. Terms of reference klassifikasi lahan.Dept. Pertanian Rap. No. 59B/1983. P3MT, Soil Research Institute,Bogor, Indonesia.
PT.IHM, 1991. Unpublished study on project planning and environmental-impact assessment of PT.IHM, Kenangan, Kalimamtan Timur,Indonesia.
RUHIYAT D., 1989. Die Entwicklung der standörtlichen Nährstoffvorrätebei naturnaher Waldbewirtschaftung und im Plantagenbetrieb,Ostkalimantan, Indonesien. Göttinger Beiträge zur Land- undForstwirtschaft in den Tropen und Subtropen, Heft 35. 206 S.
ULRICH B., 1993. 25 Jahre Forstökosystem- und Waldschadensforschungim Solling. Forstarchiv 64:147-152.
VOSS R., Dykstra G. & Suherman T., 1977. Phosphate fixation by tropicalUltisols in East-Kalimantan, Indonesia. In: Joseph, K.T. (ed.), Proc.of the Conference on Classification and Management of TropicalSoils, 15-20 August 1977, Kuala Lumpur: 258-264.
WALHI (Wahana Lingkungan Hidup Indonesia - The Indonesia Forum forthe Environment), 1992. Mistaking plantations for the Indonesiantropical forest. 1-70.
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WINJUM J.K. & Schroeder P.E., 1997. Forest plantations of the world: theirextent, ecological atttributes, and carbon storage. Agriculturla andForest Meteorology 84:153-167.
WISSENSCHAFTLICHER BEIRAT DER BUNDESREGIERUNG: GlobaleUmweltveränderung (WBGU), 1996. Welt im Wandel -Herausforderung für die deutsche Wissenschaft. Jahresgutachten1996. Springer Verlag Berlin. 200 S.
WORLD REFERENCE BASE FOR SOIL RESOURCES (WRB), 1994. 1. Draft.International Society of Soil Science (ISSS), International SoilReference and Information Centre (ISRIC) and FAO. Wageningen,Rome. 161 S.
Appendix
6 Appendix
Tab. 6: Parameter of the soil types in different soil depth. Data for total soil profile (0-100 cm) calculated from means of single soil depth
considering different thickness of layers. BS= base saturation, Al-S.= Aluminum saturation
n depth C Nt C/N Pt C/P P/N pH K Ca Mg Na Fe Mn Al H KAKe CECeclay BS Al-S.[cm] [%] [%] (H2O) (KCl) [µmol+ g-1] [cmol+ kg-1] [%]
Alisol 29 0-100 0,74 0,09 8,5 0,0136 61,8 0,15 4,6 3,5 1,52 5,67 4,12 1,17 0,41 0,35 73,1 0,07 86,4 25,7 14 850-10 2,27 0,17 13,6 0,0176 139,4 0,10 4,6 3,6 2,21 22,75 9,29 1,19 1,03 1,27 46,8 0,49 85,1 25,5 41 56
10-30 0,89 0,1 9,07 0,0139 71,2 0,14 4,5 3,5 1,55 7,37 4,48 1,15 0,68 0,40 65,5 0,06 81,2 26,1 18 8130-50 0,61 0,08 7,9 0,0129 54,0 0,16 4,6 3,5 1,44 3,70 3,20 1,15 0,38 0,25 74,9 0,02 85,0 25,2 11 88
50-100 0,43 0,08 6,2 0,0131 38,4 0,17 4,7 3,5 1,40 2,36 3,31 1,18 0,19 0,19 80,6 0,01 89,2 26,1 9 90Acrisol 7 0-100 0,64 0,07 9,3 0,0089 73,2 0,13 4,7 3,7 1,32 4,1 1,91 0,90 0,35 0,18 53,2 0,04 62,0 18,3 14 85
0-10 1,91 0,14 13,5 0,0119 159,5 0,09 4,8 3,7 2,13 16,84 5,91 0,94 1,27 0,74 38,7 0,23 66,7 18,1 40 5610-30 0,75 0,08 9,5 0,0091 83,0 0,12 4,6 3,6 1,31 4,23 1,93 0,88 0,61 0,16 51,2 0,03 60,4 18,9 15 8430-50 0,53 0,06 8,6 0,0087 63,3 0,14 4,7 3,6 1,25 2,6 1,36 0,94 0,31 0,14 53,6 0,02 60,2 18,5 11 88
50-100 0,39 0,05 7,4 0,0083 48,63 0,15 4,8 3,6 1,19 2,0 1,32 0,88 0,08 0,10 56,8 0,01 62,5 17,6 9 91Ferral- 4 0-100 0,60 0,04 14,0 0,0053 112,7 0,13 4,7 3,9 0,43 2,04 1,46 1,13 0,36 0,08 19,0 0,06 24,6 9,1 21 77Arenosol 0-10 1,80 0,11 15,9 0,0081 220,5 0,07 4,6 3,8 0,97 4,91 3,29 1,22 1,28 0,25 27,5 0,56 40,0 8,7 27 68
10-30 0,85 0,06 14,0 0,0061 137,2 0,10 4,7 3,9 0,50 2,40 1,82 1,15 0,60 0,09 21,5 0,01 28,1 10,2 22 7630-50 0,48 0,04 13,5 0,0052 91,6 0,15 4,8 3,9 0,39 2,02 1,54 1,12 0,27 0,07 17,5 0,00 22,9 8,8 23 75
50-100 0,30 0,02 12,6 0,0044 69,0 0,19 4,7 3,9 0,32 1,33 0,92 1,12 0,11 0,05 16,9 0,00 20,8 8,5 20 80Calcisol 2 0-100 2,00 0,19 10,0 0,0350 53,1 0,19 7,6 6,5 2,04 416,3 10,76 1,48 0,00 0,53 8,8 0,08 440,0 97,2 89 11
0-10 3,99 0,33 12,1 0,0392 98,4 0,12 7,1 6,2 3,39 358,2 21,62 1,45 0,00 1,17 0,0 0,00 385,8 96,3 99 010-30 1,79 0,20 8,7 0,0349 49,1 0,18 7,5 6,5 2,27 392,1 12,09 1,44 0,00 0,45 3,3 0,00 411,6 103,8 94 530-50 1,46 0,18 8,0 0,0371 37,0 0,22 7,6 6,6 1,81 434,5 9,72 1,41 0,00 0,44 7,0 0,00 454,8 101,3 90 10
50-100 1,91 0,16 10,7 0,0334 51,3 0,21 7,8 6,6 1,78 430,3 8,48 1,53 0,00 0,46 13,6 0,15 456,3 87,4 84 15Fluvisol 0-100 0,95 0,14 6,9 0,0299 31,8 0,218 5,6 4,2 2,41 45,82 45,18 2,01 0,00 1,0 17,6 0,00 114,0 20,2 82 17
0-10 2,45 0,240 10,2 0,0342 71,6 0,143 6,2 5,3 2,75 120,16
49,54 1,53 0,00 0,9 0,0 0,00 174,9 20,2 100 0
10-30 1,01 0,150 6,7 0,0298 33,9 0,199 5,6 3,9 2,26 56,89 45,49 1,86 0,00 0,9 10,2 0,00 117,6 21,7 91 930-50 0,89 0,140 6,4 0,0291 30,6 0,208 5,6 4,2 2,30 57,69 36,80 1,81 0,00 0,7 4,4 0,00 103,8 18,5 95 4
50-100 0,65 0,110 5,9 0,0294 22,1 0,267 5,5 3,8 2,43 21,78 47,53 2,24 0,00 1,2 29,4 0,00 104,5 20,6 71 28
52
Sustainable Nutrient Supply in Fast-G
rowing Plantations
Appendix
Tab. 7: Export of nutrients with stemwood and -bark for Acacia mangium.
N P Na K Ca Mg S Mn[m3] [n ha-1] [m3 Vx] [kg ha-1]100 700 0,143 117,7 1,6 11,0 43,1 97,6 5,6 8,0 0,4100 800 0,125 122,5 1,6 11,1 45,0 102,5 5,8 8,3 0,4100 900 0,111 126,9 1,7 11,2 46,8 107,1 5,9 8,6 0,5100 1000 0,100 131,1 1,7 11,3 48,5 111,4 6,1 8,8 0,5100 1100 0,091 135,1 1,8 11,5 50,1 115,5 6,3 9,1 0,5150 700 0,214 157,6 2,1 15,9 57,1 126,9 7,6 10,8 0,5150 800 0,188 163,5 2,1 16,0 59,4 132,9 7,8 11,2 0,5150 900 0,167 168,9 2,2 16,2 61,6 138,6 8,0 11,5 0,6150 1000 0,150 174,1 2,3 16,4 63,7 143,9 8,2 11,8 0,6150 1100 0,136 179,0 2,4 16,5 65,7 149,0 8,4 12,1 0,6200 700 0,286 194,9 2,5 20,7 70,0 153,5 9,5 13,5 0,6200 800 0,250 201,7 2,6 20,9 72,8 160,5 9,8 14,0 0,6200 900 0,222 208,1 2,7 21,1 75,3 167,1 10,0 14,3 0,7200 1000 0,200 214,1 2,8 21,3 77,7 173,3 10,3 14,7 0,7200 1100 0,182 219,8 2,9 21,5 80,0 179,2 10,5 15,0 0,7250 700 0,357 230,6 3,0 25,5 82,3 178,5 11,4 16,1 0,7250 800 0,313 238,2 3,1 25,8 85,4 186,4 11,7 16,6 0,7250 900 0,278 245,4 3,2 26,0 88,3 193,7 12,0 17,0 0,8250 1000 0,250 252,1 3,3 26,2 91,0 200,7 12,2 17,4 0,8250 1100 0,227 258,5 3,4 26,4 93,5 207,3 12,5 17,8 0,8300 700 0,429 265,1 3,4 30,3 94,1 202,3 13,2 18,7 0,8300 800 0,375 273,5 3,5 30,6 97,5 210,9 13,5 19,2 0,8300 900 0,333 281,3 3,7 30,8 100,7 219,0 13,8 19,6 0,8300 1000 0,300 288,8 3,8 31,0 103,6 226,6 14,1 20,1 0,9300 1100 0,273 295,8 3,9 31,2 106,5 233,9 14,4 20,5 0,9350 700 0,500 298,7 3,8 35,1 105,6 225,1 14,9 21,1 0,8350 800 0,438 307,8 4,0 35,3 109,3 234,5 15,3 21,7 0,9350 900 0,389 316,3 4,1 35,6 112,7 243,2 15,6 22,2 0,9350 1000 0,350 324,4 4,2 35,8 115,9 251,5 16,0 22,7 1,0350 1100 0,318 332,0 4,3 36,0 119,0 259,4 16,3 23,1 1,0400 700 0,571 331,6 4,2 39,8 116,8 247,2 16,7 23,6 0,9400 800 0,500 341,3 4,4 40,1 120,7 257,3 17,1 24,1 0,9400 900 0,444 350,5 4,5 40,3 124,4 266,7 17,4 24,7 1,0400 1000 0,400 359,1 4,6 40,6 127,8 275,5 17,8 25,2 1,0400 1100 0,364 367,3 4,8 40,8 131,1 284,0 18,1 25,7 1,1450 700 0,643 363,9 4,6 44,5 127,7 268,7 18,4 25,9 0,9450 800 0,563 374,3 4,8 44,8 131,9 279,4 18,8 26,6 1,0450 900 0,500 384,0 4,9 45,1 135,8 289,4 19,2 27,2 1,1450 1000 0,450 393,2 5,1 45,4 139,5 298,9 19,6 27,7 1,1450 1100 0,409 401,9 5,2 45,6 142,9 307,8 19,9 28,2 1,1500 600 0,833 383,9 4,9 48,9 133,8 277,6 19,6 27,6 0,9500 800 0,625 406,7 5,2 49,5 142,9 301,0 20,6 29,0 1,1500 900 0,556 417,0 5,3 49,8 147,0 311,6 21,0 29,6 1,1500 1000 0,500 426,7 5,5 50,1 150,9 321,6 21,3 30,2 1,2[m3]=volume of harvest, [n ha-1]=number of trees, [m3 Vx]=volume of stem of medium volume
54
Tab. 8: Export of nutrients with stemwood and -bark for Eucalyptus deglupta.
N P Na K Ca Mg S Mn[m3] [n ha-1] [m3 V
x] [kg ha-1]
100 500 0,200 38,9 2,0 0,3 107,3 44,3 10,9 4,9 1,5100 600 0,167 40,1 2,0 0,4 111,2 45,9 11,2 5,1 1,5100 700 0,143 41,2 2,1 0,4 114,7 47,4 11,5 5,2 1,6100 800 0,125 42,1 2,1 0,4 117,8 48,7 11,7 5,3 1,6100 900 0,111 42,9 2,2 0,4 120,6 50,0 12,0 5,4 1,7100 1000 0,100 43,7 2,2 0,4 123,2 51,1 12,2 5,5 1,7100 1100 0,091 44,4 2,3 0,4 125,7 52,1 12,4 5,6 1,7150 500 0,300 54,7 2,7 0,5 149,0 61,3 15,3 6,9 2,1150 600 0,250 56,3 2,8 0,5 154,2 63,5 15,7 7,1 2,1150 700 0,214 57,7 2,9 0,5 158,8 65,5 16,1 7,3 2,2150 800 0,188 59,0 3,0 0,5 163,0 67,3 16,5 7,5 2,3150 900 0,167 60,2 3,0 0,5 166,8 68,9 16,8 7,6 2,3150 1000 0,150 61,2 3,1 0,5 170,3 70,4 17,1 7,7 2,3150 1100 0,136 62,2 3,1 0,6 173,6 71,8 17,3 7,9 2,4200 500 0,400 69,8 3,4 0,6 188,3 77,3 19,5 8,9 2,6200 600 0,333 71,8 3,6 0,6 194,8 80,0 20,0 9,1 2,7200 700 0,286 73,5 3,7 0,6 200,5 82,5 20,5 9,3 2,8200 800 0,250 75,1 3,7 0,7 205,6 84,7 21,0 9,5 2,8200 900 0,222 76,5 3,8 0,7 210,3 86,7 21,4 9,7 2,9200 1000 0,200 77,9 3,9 0,7 214,6 88,5 21,7 9,9 3,0200 1100 0,182 79,1 4,0 0,7 218,7 90,2 22,1 10,0 3,0250 500 0,500 84,3 4,1 0,7 226,0 92,6 23,5 10,7 3,2250 600 0,417 86,7 4,3 0,7 233,6 95,8 24,2 11,0 3,3250 700 0,357 88,8 4,4 0,8 240,4 98,7 24,8 11,3 3,3250 800 0,313 90,6 4,5 0,8 246,4 101,3 25,3 11,5 3,4250 900 0,278 92,3 4,6 0,8 251,9 103,6 25,8 11,7 3,5250 1000 0,250 93,9 4,7 0,8 257,0 105,8 26,2 11,9 3,6250 1100 0,227 95,3 4,8 0,8 261,8 107,8 26,6 12,1 3,6300 500 0,600 98,5 4,8 0,8 262,5 107,4 27,5 12,5 3,7300 600 0,500 101,2 5,0 0,9 271,2 111,1 28,2 12,9 3,8300 700 0,429 103,6 5,1 0,9 278,9 114,4 28,9 13,2 3,9300 800 0,375 105,7 5,2 0,9 285,8 117,3 29,5 13,4 4,0300 900 0,333 107,7 5,3 0,9 292,1 120,0 30,0 13,7 4,1300 1000 0,300 109,5 5,4 0,9 298,0 122,5 30,5 13,9 4,1300 1100 0,273 111,1 5,5 1,0 303,4 124,8 31,0 14,1 4,2350 500 0,700 112,3 5,5 0,9 298,1 121,8 31,4 14,3 4,2350 600 0,583 115,4 5,7 1,0 307,8 125,9 32,2 14,7 4,3350 700 0,500 118,1 5,8 1,0 316,4 129,6 33,0 15,0 4,4350 800 0,438 120,5 5,9 1,0 324,2 132,9 33,6 15,3 4,5350 900 0,389 122,7 6,1 1,0 331,2 135,9 34,2 15,6 4,6350 1000 0,350 124,7 6,2 1,1 337,8 138,7 34,8 15,8 4,7350 1100 0,318 126,5 6,3 1,1 343,8 141,3 35,3 16,1 4,8[m3]=volume of harvest, [n ha-1]=number of trees, [m3 Vx]=volume of stem of medium volume
Tab. 9: Management-dependent export fluxes (B-D) for N and P in relation [%] to the exports by harvest (A) for Acacia mangium (Am), Eucalyptus deglupta (Ed)
and Paraserianthes falcataria (Pf). The net leaching losses and the losses into atmosphere by burning are related to the residual phytomass (crown,
understorey and org. O-horizon) of stands with a harvest volume of 200 m3. For E1 values of median order are listed, not the mean, and for E2 minimum
values are listed. IL: losses independent of tree species
Nt Pt
iL Am Ed Pf iL Am Ed Pf[kg] [kg] [%] [kg] [%] [kg] [%] [kg] [kg] [%] [kg] [%] [kg] [%]
A export with harvest [kg ha-1] 202 100 75 100 133 100 2,6 100 3,8 100 9,5 100stem timber and bark, 200 m3
B management-dependent leachingB1 net losses (KLINGE, 1997; A2, 9 MON.) 144 71 192 144 0,0 0 0 0B2 net losses (KLINGE, 1997; A3, 9 MON.) 180 89 239 179 0,0 0 0 0B3 net losses (MALMER ET AL,, 1994; W5, 9 MON.) 13 6 17 13 0,9 34 24 9B4 25% of K-, 5% of Ca and 10% of Mg-pools in 16 8 11 15 10 7 0,3 11 0,1 3 0,5 5
crowns, understorey, org. O-horizons 80 40 53 71 48 36C losses into atmosphere by burningC1 average losses by burning 318 158 212 282 335 251 2,5 95 1,1 29 4,3 45C2 maximum losses by burning 393 195 262 349 413 310 3 114 1,4 37 5,3 56C3 minimum losses by burning 92 46 61 81 97 73 1,6 61 0,7 19 2,8 29D ErosionD1 50 Mg ha-1 loss of top soil, medium Alisol 84,5 42 75 56 8,8 333 235 93D2 50 Mg ha-1 loss of top soil, rich Alisol 140 69 112 84 16,95 642 452 178D3 50 Mg ha-1 loss of top soil, poor Alisol 56,7 28 186 139 4,95 188 132 52D4 200 Mg ha-1 loss of top soil, medium Alisol 338 168 450 337 35,2 1333 939 371E1 Sum of and amount of average losses (B4/5 and B3+C1+D1), respec. 483 239 350 465 468 351 12 439 10 267 13 139E2 Sum of and amount of minimum losses (B3/4 and B1+C3+D3), respec. 162 80 129 171 164 123 7 248 6 151 8 82
55
56
Tab. 10: Management-dependent export fluxes (B-D) for K, Ca and Mg in relation [%] to the exports by harvest (A) for Acacia mangium (Am), Eucalyptus
deglupta (Ed) and Paraserianthes falcataria (Pf). The net leaching losses and the losses into atmosphere by burning are related to the residual phytomass
(crown, understorey and org. O-horizon) of stands with a harvest volume of 200 m 3. For E1 values of median order are listed, not the mean, and for E 2
minimum values are listed. IL: losses independent of tree species
K Ca MgiL Am Ed Pf iL Am Ed Pf uV Am Ed Pf
[kg] [kg] [%] [kg] [%] [kg] [%] [kg] [kg] [%] [kg] [%] [kg] [%] [kg] [kg] [%] [kg] [%] [kg] [%]A export with harvest [kg ha -1] 73 100 206 100 208 100 161 100 85 100 157 100 9,8 100 21,0 100 11,6 100
stem timber and bark, 200 m3
B management-dependent leachingB1 net losses (KLINGE, 1997; A2, 9 MON.) 38 52 18 18 49 31 58 31 20 207 96 174B2 net losses (KLINGE, 1997; A3, 9 MON.) 88 121 43 42 79 49 93 50 20 200 94 169B3 net losses (MALMER ET AL,, 1994; W5, 9 MON.) 102 140 50 49 12 7 14 8 8 82 38 69B4 25% of K-, 5% of Ca and 10% of Mg-pools in 62 85 49 24 62 30 8 5 9 11 16 10 5 51 5 24 6 52
crowns, understorey, org. O-horizonsC losses into atmosphere by burningC1 average losses by burning 112 154 90 44 114 55 63 39 65 77 121 77 20 204 30 95 24 207C2 maximum losses by burning 194 267 156 76 197 95 127 79 133 157 246 156 30 307 31 148 36 311C3 minimum losses by burning 39 54 32 16 40 19 15 9 15 18 28 18 9 92 9 43 10 86D erosionD1 50 Mg ha-1 loss of top soil, medium Alisol 4,3 6 2 2 19,9 12 23 13 4,6 14 22 40D2 50 Mg ha-1 loss of top soil, rich Alisol 6,7 9 3 3 83,6 52 99 53 13,7 140 65 118D3 50 Mg ha-1 loss of top soil, poor Alisol 2,1 3 1 1 4,5 3 5 3 1,4 14 7 12D4 200 Mg ha-1 loss of top soil, medium Alisol 17,2 24 8 8 79,4 49 94 50 18,4 188 88 159E1 Sum / amount of average losses (B1/2 +C1+D1), 204 280 182 89 206 99 155 97 157 186 213 135 44 449 54 257 48 414E2 Sum / amount of average losses (B4 +C3+D3), 103 142 83 40 104 50 25 16 26 31 46 29 15 157 15 73 17 150
Tab. 11: Sum of management-dependent nutrient export fluxes (harvest, management-dependent leaching, burning and erosion) in relation [%] to the total
stand pools (nutrient pools of Navail, Pavail and exchangeable cations K, Ca and Mg in the soil from 0-100 cm, stand, understorey and org. O-
horizon) of different soil types
N P K Ca MgMax200
a Min200b Alt200 Max200 Min200 Alt200 Max200 Min200 Alt200 Max200 Min200 Alt200 Max200 Min200 Alt200
Acacia mangiumAli-/Acrisol, medium nutrient supply 50 38 25 8 5 4 28 21 12 20 14 10 9 5 2Ali-/Acrisol, high nutrient supply 34 24 14 5 3 2 20 14 8 13 6 4 5 2 1Ali-/Acrisol, low nutrient supply 63 51 37 17 12 9 46 36 23 42 36 31 28 18 9Ferral-/Arenosol 67 55 40 15 10 7 55 45 31 32 27 23 17 10 5Calcisol 52 39 25 9 5 3 38 28 17 3 1 0 11 4 2Fluvisol 17 13 7 2 2 1 1 0 0Eucalyptus degluptaAli-/Acrisol, medium nutrient supply 37 24 11 8 5 4 34 29 23 16 9 6 11 6 4Ali-/Acrisol, high nutrient supply 23 14 6 4 3 2 24 20 16 12 5 2 6 3 1Ali-/Acrisol, low nutrient supply 50 35 18 16 13 11 53 47 40 34 26 19 33 24 16Ferral-/Arenosol 53 38 20 14 11 10 62 56 49 26 19 14 20 14 9Calcisol 39 25 12 8 5 4 44 38 31 3 1 0 12 6 3Fluvisol 22 19 15 1 1 1 1 0 0Paraserianthes falcatariaAli-/Acrisol, medium nutrient supply 39 28 18 16 13 10 37 31 24 23 15 10 11 5 2Ali-/Acrisol, high nutrient supply 25 16 10 9 6 5 26 21 16 14 7 4 5 2 1Ali-/Acrisol, low nutrient supply 52 40 28 34 28 24 55 49 41 48 39 31 32 21 11Ferral-/Arenosol 56 43 30 30 25 21 65 58 50 38 30 23 19 11 6Calcisol 41 29 18 15 11 9 47 40 32 3 1 0 11 5 2Fluvisol 24 20 15 2 2 1 1 0 0a Maximum variant: harvest of 200 m3, max. losses by leaching, burning and erosion.b Minimum variant: harvest of 200 m3, min. losses by leaching and burning; medium losses of erosion..c Variant with alternative management: harvest of 200 m 3, min. losses by leaching, burning and erosion.Relative losses of 50% means that the stand can grow for 2 rotation periods (100/50)
57
Sustainable Nutrient Supply in Fast-Growing Plantations
58
Tab. 12: Estimation of the amount of fertilizers necessary to compensate management-
dependent export fluxes of N, depending on N content and utilization efficiency
type of fertilizer losses NPK (13% N) Urea (46% N) Ammonium-Nitrate (35% N)
Nitrate fertilizer(16% N)
utilization efficiency [kg ha-1] 50% 60% 70% 50% 60% 70% 50% 60% 70% 50% 60% 70%Eucalyptus degl., soil type: medium Ali-/Acrisolharvest of 200 m3 75 1155 960 825 323 270 233 428 360 308 938 780 668amount of bark withexport
23 354 294 253 99 83 71 131 110 94 288 239 205
max. leaching 53 816 678 583 228 191 164 302 254 217 663 551 472min. leaching 11 169 141 121 47 40 34 63 53 45 138 114 98burning (100% of area) 211 3249 2701 2321 907 760 654 1203 1013 865 2638 2194 1878burning (50% of area) 106 1632 1357 1166 456 382 329 604 509 435 1325 1102 943erosion (200 Mg ha-1) 18,9 291 242 208 81 68 59 108 91 77 236 197 168erosion (50 Mg ha-1) 4,7 72 60 52 20 17 15 27 23 19 59 49 42erosion (10 Mg ha-1) 0,9 14 12 10 4 3 3 5 4 4 11 9 8sum Max200a 358 5513 4582 3938 1539 1289 1110 2041 1718 1468 4475 3723 3186sum Min200b 197 3034 2522 2167 847 709 611 1123 946 808 2463 2049 1753sum Alt200a 81 1247 1037 891 348 292 251 462 389 332 1013 842 721a Maximum variant: harvest of 200 m3, max. losses by leaching, burning and erosion.b Minimum variant: harvest of 200 m3, min. losses by leaching and burning; medium losses of erosion..c Variant with alternative management: harvest of 200 m3, min. losses by leaching, burning and erosion.
Appendix
Tab. 13: Estimation of the amount of fertilizers necessary to compensate management-
dependent export fluxes of P, depending on P content and utilization efficiency
type of fertilizer losses NPK (5,7% P) TSP (22% P) CIRP (15,8% P) SP (8% P)utilization efficiency [kg ha-1] 10% 15% 40% 10% 15% 40% 10% 15% 40% 10% 15% 40%Acacia mangium, soil type: medium Ali-/Acrisolharvest of 200 m3 2,6 466 311 116 118 79 30 165 110 41 325 217 81amount of bark withexport
1,6 287 191 72 73 48 18 101 68 25 200 133 50
max. leaching 0,3 54 36 13 14 9 3 19 13 5 38 25 9min. leachingburning (100% of area) 2,4 430 287 108 109 73 27 152 101 38 300 200 75burning (50% of area) 1,2 215 143 54 55 36 14 76 51 19 150 100 38erosion (200 Mg ha-1) 1,7 305 203 76 77 52 19 108 72 27 213 142 53erosion (50 Mg ha-1) 0,4 72 48 18 18 12 5 25 17 6 50 33 13erosion (10 Mg ha-1) 0,1 18 12 4 5 3 1 6 4 2 13 8 3sum Max200a 7 1254 837 314 319 212 80 443 295 111 875 583 219sum Min200b 4,2 753 502 188 191 127 48 266 177 66 525 350 131sum Alt200a 2,7 484 323 121 123 82 31 171 114 43 338 225 85Eucalyptus degl., soil type: medium Ali-/Acrisolharvest of 200 m3 3,8 681 454 170 173 115 43 241 160 60 475 317 119amount of bark withexport
1,5 269 179 67 68 45 17 95 63 24 188 125 47
max. leaching 0,1 18 12 4 5 3 1 6 4 2 13 8 3min. leachingburning (100% of area) 1,1 197 131 49 50 33 13 70 46 17 138 92 34burning (50% of area) 0,5 90 60 22 23 15 6 32 21 8 63 42 16erosion (200 Mg ha-1) 1,7 305 203 76 77 52 19 108 72 27 213 142 53erosion (50 Mg ha-1) 0,4 72 48 18 18 12 5 25 17 6 50 33 13erosion (10 Mg ha-1) 0,1 18 12 4 5 3 1 6 4 2 13 8 3sum Max200a 6,7 1201 801 300 305 203 76 424 283 106 838 558 210sum Min200b 4,7 842 562 211 214 142 54 298 198 74 588 392 147sum Alt200a 3,9 699 466 175 177 118 44 247 165 62 488 325 122a Maximum variant: harvest of 200 m3, max. losses by leaching, burning and erosion.b Minimum variant: harvest of 200 m3, min. losses by leaching and burning; medium losses of erosion..c Variant with alternative management: harvest of 200 m3, min. losses by leaching, burning and erosion.
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Tab. 14: Estimation of the amount of fertilizers necessary to compensate management-
dependent export fluxes of K, depending on K content and utilization efficiency
type of fertilizer losses NPK (17,4% K) 42 potash (42% K) 50 potash (50% K)utilization efficiency [kg ha-1] 50% 60% 70% 50% 60% 70% 50% 60% 70%Acacia mangium, soil type: medium Ali-/Acrisolharvest of 200 m3 73 840 701 599 350 292 248 292 241 212amount of bark withexport
44 506 422 361 211 176 150 176 145 128
max. leaching 86 989 826 705 413 344 292 344 284 249min. leaching 62 713 595 508 298 248 211 248 205 180burning (100% of area) 113 1300 1085 927 542 452 384 452 373 328burning (50% of area) 57 656 547 467 274 228 194 228 188 165erosion (200 Mg ha-1) 17 196 163 139 82 68 58 68 56 49erosion (50 Mg ha-1) 4,3 49 41 35 21 17 15 17 14 12erosion (10 Mg ha-1) 0,9 10 9 7 4 4 3 4 3 3sum Max200a 289 3324 2774 2370 1387 1156 983 1156 954 838sum Min200b 196 2254 1882 1607 941 784 666 784 647 568sum Alt200a 105 1208 1008 861 504 420 357 420 347 305Eucalyptus degl., soil type: medium Ali-/Acrisolharvest of 200 m3 206 2369 1978 1689 989 824 700 824 680 597amount of bark withexport
88 1012 845 722 422 352 299 352 290 255
max. leaching 69 794 662 566 331 276 235 276 228 200min. leaching 49 564 470 402 235 196 167 196 162 142burning (100% of area) 91 1047 874 746 437 364 309 364 300 264burning (50% of area) 45 518 432 369 216 180 153 180 149 131erosion (200 Mg ha-1) 17 196 163 139 82 68 58 68 56 49erosion (50 Mg ha-1) 4,3 49 41 35 21 17 15 17 14 12erosion (10 Mg ha-1) 0,9 10 9 7 4 4 3 4 3 3sum Max200a 383 4405 3677 3141 1838 1532 1302 1532 1264 1111sum Min200b 304 3496 2918 2493 1459 1216 1034 1216 1003 882sum Alt200a 232 2668 2227 1902 1114 928 789 928 766 673a Maximum variant: harvest of 200 m3, max. losses by leaching, burning and erosion.b Minimum variant: harvest of 200 m3, min. losses by leaching and burning; medium losses of erosion..c Variant with alternative management: harvest of 200 m3, min. losses by leaching, burning and erosion.
Appendix
Tab. 15: Comparison of the current amount of fertilizers (PT.IHM) with the amount of
fertilizers necessary to compensate harvest export (200m3 ha-1), including costs of
fertilizers. Acacia mangium (Am), Eucalyptus deglupta (Ed).
Nutrients and fertilizers Amount of fertilizer Costs of fertilizationfertilizer conc. UE PT.IHM Am Ed PT.IHM Am Ed
[%] [%] [kg ha-1] [Rp ha-1] [%] [Rp ha-1] [%] [Rp ha-1] [%]A1 N NPK 13 70 80 2418 879 74.800 2.260.830 821.865A2 Urea 46 70 681 248 277.848 101.184B1 P NPK 5,7 40 80 129 178 74.800 120.615 166.430B2 TSP 22 40 32 33 45 18.080 18.645 25.425B3 CIRP 15,8 40 46 63 10.350 14.175C1 K NPK 17,4 70 80 656 1793 74.800 613.360 1.676.455C2 potash 50 70 232 634 120.640 329.680D1 Ca TSP 100D2 dolomite 100 672 2500 2500 100.800 375.000 375.000D2 Mg dolomite 100 672 2500 2500 100.800 375.000 375.000conventional fertilization (A1+B2+D2): 193.680 100 2.654.475 1371 2.076.880 1072conventional fertilization (without costs for NPK-N) 1.007.005 520alternative fertilization (A2+B2+C2+D2) 783.838 405 820.039 423alternative fertilization (without N-fertilizer for Am) 505.990 261conc. = concentration of nutrient in fertilizer, UE = estimated utilization efficiency.
Sustainable Nutrient Supply in Fast-Growing Plantations
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Tab. 16: Costs of fertilization necessary to compensate total nutrient losses with management
variants Min200 and Alt200 (cf. Appendix Tab.12-14).
Nutrients and fertilizers Acacia mangium Eucalyptus degluptafertilizer conc UE Min200
a Alt200b Min200
a Alt200b
[%] [%] [Rp ha-1] [%]c [Rp ha-1] [%]c [Rp ha-1] [%]c [Rp ha-1] [%]c
A1 N NPK 13 70 3.915.500 2.169.107 2.026.145 833.085A2 Urea 46 70 481.509 266.746 249.288 102.408B1 P NPK 5,7 40 175.780 113.135 197.285 163.625B2 TSP 22 40 27.120 17.515 30.510 24.860B3 CIRP 15,8 40 14.850 9.675 16.650 13.950C1 K NPK 17,4 70 1.502.545 805.035 2.330.955 1.778.370C2 potash 50 70 295.360 158.600 458.640 349.960D1 Ca TSP 100D2 dolomite 100 375.000 375.000 375.000 375.000D2 Mg dolomite 100 375.000 375.000 375.000 375.000conv. fertilization (A1+B2+D2): 4.317.620 2229 2.561.622 1323 2.431.655 1256 1.232.945 637conv. fertilization (without A1) 1.904.665 983 1.197.550 618altern. fertilization (A2+B2+C2+D2) 1.166.719 602 810.021 418 1.099.578 568 841.318 434altern. fertilization (without A2) 685.210 354 543.275 281a maximum variant: harvest of 200 m3, max. losses by leaching, burning and erosion.b alternative management: harvest of 200 m3, min. losses by leaching, burning and erosionc.relative to costs for fertilization management at PT.IHM (100% = 193.680 Rp ha-1; s. Tab. 15)conc. = concentration of nutrient in fertilizer, UE = estimated utilization efficiency.