Impact of private forestland tenure changes on forest cover, stocking and tree species diversity
in Amani Nature Reserve, Tanzania
Mathew MpandaICRAF EA Region
Seminar presentation26th April 2011
Background• Forests and woodlands in Tanzania occupy 37% (353 000 km2 ) of the land area
• These ecosystems makes Tanzania as one of the richest and most diverse countries in Africa in terms of both species and habitats
• These forests and woodlands comprise different vegetation types and serve for mitigation of and adaptation to climate change, for biodiversity conservation, watershed services, fuelwood and other services
Background cont…• The role of these forests has, however, been undermined by deforestation which is estimated between 150,000 ‐ 412,000 ha per annum
• Causes of deforestation are mainly human induced disturbances including encroachment, wildfire, illegal mining, pit‐sawing, illegal harvesting for building materials and excessive collection of fuelwood and herbal medicines
• No forest ecosystem in the country has exception in regard to these causes of disturbances
Background cont…..• In 1970s – 1980s the East Usambara Mtns suffered intense destructions of habitats and species due unsustainable use including excessive mechanized logging
• By mid 1980’s internal and external outcry on biodiversity loss and destruction of habitats was difficult to ignore
• This led to launching of AFIMP to see how best to reverse the negative trend to the East Usambara Mtns ecosystems(i) a need for biodiversity preservation by halting conversion of forestlands into other land uses,
(ii) enhancement of forest connectivity of isolated forest blocks of East Usambara Mountains
Background cont…..
Period Reserve Area enlarged
(Ha)
Number of
Farmers involved
Amount paid
(TZS)
1993-1994 Kambai 1046 44 26 113 374
Mtai 1234 87 20 711 409
Mlinga 840 88 35 413 930
1994-1995 ANR 1230 658 25 685 970
Nilo 2253 676 111 766 328
Manga 120 96 7 381 782
2002-2006 Derema corridor 790 1128 2 730 326 407
Total 7,843 2,777 2 957 399 200
Consolidation of existing forests was further translated into enlargement /annexing of private lands and general lands
Why this study……..?• The enlargement/annexing exercise in ANR had to affect the following private land categories;1. Land under the Tea Company2. Land under the Smallholder farmers3. Land under the Sisal Company
• This had implications in the resources by;1. Re‐defined ownership of the forestland2. Re‐defined accessibility to forest resources
Why this study….?• These changes on forestland tenure in ANR had to institutionalize the management aspect to capture the following;1. Enhance forest resources and other
conservation aspects2. Address livelihood component to the
surrounding communitiesThis study attempted to evaluate this
tenure changes on forest resources from private to state ownership
Narrowing down of Forest resources
• This study specifically attempted to address the following questions;1. What is the impact of tenure changes on forest
cover in ANR?2. What is the impact of tenure changes on stocking
in ANR?3. What is the impact of the tenure changes on
species diversity in ANR?
•EU Mountains are found in the north‐eastern part of Tanzania•Part of the Eastern Arc Mountains (global biodiversity hotspot)•ANR forms the largest block of EU Mountains•High biodiversity per unit area (both plants and invertebrates)•Over 3,450 species of vascular plants recorded•Over 1,000 plant species introduced from across the tropics btn 1902 ‐1930•Area of interest for research and biodiversity monitoring for the last 150 yrs
METHODS: Study site
Blue: Forestland converted from Tea company to state, 1065 haGreen: Forestland converted from smallholder farmers to state, 1112 haYellow: Forestland converted from Sisal company to state, 173 haGrey: Six merged forest reserves (tenure unchanged)
Methods: Data collection• Forest cover assessment1. Forest cover assessment was done using
remote sensing and GIS techniques2. Landsat TM satellite images of 2000 and
2006 were used.3. The 2000 image (taken on 22 January 2000)
was used to assess forest cover at the endof the private tenure regime
4. The 2006 image (taken on 23 February2006) was used to depict the situation aftersix years of state tenure regime
Forest Inventory1. In 1999/2000, a number
of permanent sampleplots (PSPs) wereestablished in ANR
2. The reserve was firstdivided into a rectangular450 x 900 m grid.
3. Then 50 x 20 m PSPs,altogether 180, weresystematically laid in thesouth-east corner ofeach rectangle
Methods: Data collection
4. In 2008 a repetitive survey was carried out on 28 PSPs belonging to the blocks that previously were under private tenure i.e. those experienced tenure changes
5. All trees greater or equal to 10 cm were re‐identified with respect to location and speciesby means of a botanist and local people, and re‐measurements were taken for diameter atbreast height (dbh)
6. Additional, height measurement of three treeper plot was taken
Methods: Data collection....Forest inventory
Methods: Data analysesForest cover analyses1. ERDAS Imagine, ArcView GIS 3.2 and ArcGIS Desktop 10 software
were used in image data pre‐processing and analysis. Image sub‐setting was conducted to the images of 2000 and 2006 to obtain areas of interest
2. Forest cover maps for 2000 and 2006 were developed containing the following five classes: dense forest, semi‐closed forest, open forest/woodland, bush/grassland and open areas
3. Then post classification change detection was performed in which classified forest cover maps of 2000 and 2006 were compared.
4. The areas extracted from classification results were used assuming linear relationship to make direct computation of percentage total and annual change;i. Total change (%) = ((Area year x – Area year x + t )/ (Area year x)) x 100%; ii. Annual change (%) = (Area year x – Area year x + t )/ (Area year x x t
years))/ x 100%,
Methods: Data analyses….Forest inventory analyses• Identical procedures for estimating forest stocking and tree
diversity were applied for the year 1999/2000 and 2008 data• Number of trees per plot was summarized and transformed
into per hectare values (N)• The basal area for individual trees were calculated according to
dbh, summarised and transformed into per hectare values for the plot (G)
• Finally, the volume of individual trees was summarized within plots and transformed into per hectare values (V)
• Shannon‐Wiener index was computed within each block and for the 1999/2000 and 2008 data
• The statistical significance of temporal changes for stocking parameters and Shannon‐Wiener index were analysed using two‐tailed t‐tests
RESULTS: Forest cover changes1. Results of forest cover analyses show positive
changes for dense and semi‐closed forest in the block previously owned by the tea company
2. For the block previously under smallholder farmers the area with dense forest has decreased while the area of semi‐closed forest has increased
3. For the block previously owned by the sisal company the area of both dense and semi‐closed forests has decreased
RESULTS: Forest cover cont….Forest block Description Private tenure
(2000)State tenure (2006)
Total change
Total change
Annual change
Area (ha) (%) Area (ha) (%) (ha) (%) (%)
Tea company Dense forest 697 71.8 729 75.1 +32 +5 +0.8 Semi‐closed forest 72 7.4 182 18.7 +110 +153 +25.5 Open Forest/Woodland 48 4.9 17 1.8 ‐31 ‐65 ‐10.8 Bushland/Grassland 119 12.3 31 3.2 ‐88 ‐74 ‐12.3 Open area 35 3.6 12 1.2 ‐23 ‐66 ‐11.0 All 971 100.0 971 100.0 ‐ ‐ ‐
Farmland Dense forest 769 69.2 714 64.2 ‐55 ‐7 ‐1.2 Semi‐closed forest 133 12.0 183 16.5 +50 +38 +6.3 Open Forest/Woodland 45 4.0 39 3.5 ‐6 ‐13 ‐2.2 Bushland/Grassland 161 14.5 173 15.6 +12 +7 +1.2 Open area 4 0.4 3 0.3 ‐1 ‐25 ‐4.2 All 1112 100.0 1112 100.0 ‐ ‐ ‐
Sisal company Dense Forest 46 26.6 33 19.1 ‐13 ‐28 ‐4.7 Semi‐closed Forest 21 12.1 12 6.9 ‐9 ‐43 ‐7.1 Open Forest/Woodland 26 15.0 21 12.1 ‐5 ‐19 ‐3.2 Bushland/Grassland 76 43.9 106 61.3 +30 +39 +6.6 Open area 4 2.3 1 0.6 ‐3 ‐75 ‐12.5 All 173 100.0 173 100.0 ‐ ‐ ‐
RESULTS: Forest cover changes…..
RESULTS: Forest structure• Results of the stocking levels and changes between 1999/2000 and 2008 shows an increase in number of stems, basal area and volume per hectare in all blocks except for number of stems per hectare in the block formerly owned by the tea company
• The changes however, were not statistically significant at 5% level
RESULTS: Forest structure……Forest block Parameters Private tenure
(1999/2000)State tenure
(2008)Change (% in brackets)
P-value
Mean SE Mean SE
Tea company (n=18) N (no.ha-1) 435 37 424 33 -11 (-2.5) 0.4027
G (m2h-1) 46.0 5.4 46.8 5.2 0.8 (1.7) 0.6369
V (m3ha-1) 946.5 133.2 965.3 131.2 18.8 (2.0) 0.6826
Farmland (n=7) N (no.ha-1) 290 32 310 35 20 (6.9) 0.1453
G (m2h-1) 28.7 4.9 32.8 4.8 4.1 (14.3) 0.3762
V (m3ha-1) 563.1 113.9 651.4 103.6 88.3 (15.7) 0.4696
Sisal company (n=3) N (no.ha-1) 137 64 163 55 26 (19.0) 0.2697
G (m2h-1) 11.5 5.9 13.2 6.5 1.7 (14.8) 0.0996
V (m3ha-1) 209.9 119.9 239.8 132.7 29.9 (14.2) 0.1476
RESULTS: Tree species diversity
• Number of species recorded in 1999/2000 and 2008 (in brackets) were 67 (76), 45 (49) and 24 (27) for the three forest blocks previously owned by the tea company, smallholder farmers and sisal company, respectively.
• Shannon‐Wiener diversity indices in 1999/2000 and 2008 were not significantly different
Forest block Private tenure (1999/2000)
State tenure (2008) Change P-value
Tea company (n=18) 3.50 3.49 -0.01 0.3943
Farmland (n=7) 3.36 3.39 +0.03 0.4650
Sisal company (n=3) 2.97 3.07 +0.10 0.2654
Main observation and explanation……Positive changes‐ Stable climatic conditions have been reported forthe whole of the Eastern Arc mountains over along period of time i.e. no incidences of extremeweather‐High growth rates of tree species andcolonization of forest gaps by fast growing species‐ Reduced human disturbances and compliance torules and regulations by adjacent communities‐ Promoted harvesting of tree from nearbyLonguza Forest Plantation, harvesting ofEucalyptus sp. woodlots in highland villages i.e.reduced wood demands
Main observation and explanation……
Negative changes‐ Uncontrolled fire e.g. adjacent farms preparation,hunting inside the reserve‐ Eruption of god rush in 2003‐ Competition between tree species and grasses i.e.ground covered by long grasses that hindersestablishment of tree species‐ Illegal extraction of timber and poles‐ Natural ecological processes e.g. death of biggertrees vs climbers, winds vs Maesopsis
Illegal gold mining inside ANR
Use of fire in farm preparations in the Western and Southern parts of ANR
Illegal timber extraction in ANR
Pole extraction in ANR
Main observation and explanation……
Are the changes enough/as expect‐ Short period of time to expect much changesespecially in natural forest of this nature‐ Generally conditions of most forests in theEastern Arc Mountains are relatively better, oneshould expect very small changes‐ Low number of sample plots and size of theblocks and high variations between plots
Main observation and explanation……
Spatial differences between blocks
1.Conditions of the forest resources were quite different for the three blocks around the time when tenure changes occurred
2.Other factors may explain the differences among the blocks as location and include human activities (e.g. accessibility and adjacency to villages) as well as natural conditions (e.g. terrain, elevation, vegetation)
ConclusionThe results for changes in forest conditions from when thetenure changed until 2006/2008 are somewhat ambiguous
There are several exceptions and modifications regarding differences between the blocks
When considering the three blocks as one entity one may in general maintain that there have been positive changes regarding forest cover as well as forest stocking and tree species diversity
Generally one may expect that without state intervention and a change of tenure major parts of the ANR could have accelerated into more clearing as appears in other areas under private ownerships in the East Usambara Mountains
Opening up forest patches for crop cultivation in Mbomole village
What are the gaps…?Human dimension in terms of livelihood and governance
Bradypodion fischeri
Thank you