What ecosystem services can forests provide?Bart Muys

Forest Ecology and Management Research GroupK.U.Leuven, Belgium

Conference Adapting Forest Management to Maintain the Environmental Services

22-25 Sept 2009, Koli, Finland

Ecoystem services, a new hype?

• Definition: benefits people obtain from ecosystems• Popularized and formalized by MEA (2005)

ECOSYSTEM SERVICES Examples of forest ecosystem services (FES)

Supporting services nutrient cycling, gene pool, pollination

Provisioning services Wood, non-wood forest products, drinking water

Regulating services Climate regulation, erosion control, windbreak

Cultural services Recreation, archaeology, religion

FES equal forest functions?

FES Forest functionsProvisioning services (P)

Production function

Regulating services (R)

Protection function

Supporting services (S)

Ecological or Life supporting function

Cultural services (C)

Social or amenity functionLand reserve

Managing ecoystem services

• Sustainable ecosystem management =(min S) + max [P,R,S,C]

• Challenge: – participatory prioritization of P,R,S,C– impacts of max (P,R,S,C) on S– relationships between P,R,S,C

• Positive versus inverse • Correlational versus causal • Linear versus non-linear

conservation Multiple use

Causal relations between FES

Effect of…

Wood harvest

BOC SOC Water recharge

Erosion control

Plant biodiversity

Wood harvestBOC

SOC

Water rechargeErosion controlPlant biodiversity

Fill from experiments, observations, and expert knowledge…

Causal relations between FES

Effect of…

Wood harvest

BOC SOC Water recharge

Erosion control

Plant biodiversity

Wood harvestBOC

SOC

Water rechargeErosion controlPlant biodiversity

• Feedback mechanisms: A improves B, but B degrades A (e.g. A= BOC; B= wood harvest)• Feedforward mechanisms: A improves B, and B improves A (e.g. A=BOC; B=SOC in case of heathland afforestation)• Strong non-linearity and probably strong site specificity

In search of FES theory…

• Can we find order in this complexity?• Could we find some general rules, e.g.

– Forests more performing than non-forests– Natural forests more performing than plantations– More diverse forests more performing than monocultures

Ecosystem exergy theory

A model of self-organization in living systems with 4 key elements:

1. Ecosystems are open systems receiving exogenic exergy fluxes (mainly solar exergy);

2. Ecosystems absorb part of it to build up their internal exergy level (order from disorder)

3. Ecosystems maintain and improve this capability through inheritage and evolutionary learning (order from order)

4. Ecosystems with high exergy level can perform more work of dissipating exogenic exergy flows; they are better buffered, thus have higher stability

Dewulf et al. (2008) Env Sci & Techn

Ecosystem exergy and FES

Ecosystem

Goal function max[buffer exergy flows] by max[exergy storage]

Exergy storage

biomass, structure, (DNA)

Buffering activity

Radiation gradients, temperature change, nutrient loss, water run-off, sediment loss, wind

Main exergy source

solar radiation

Memory and learning

Mainly DNA

Wagendorp et al. (2006) Energy

Provisioning services

Regulating services

Supporting services

exergy storage and ecosystem development

Successional stage: Ecosystem attribute

Abiotic (no vegetation)

Develop-mental (pioneer vegetation)

Mature (climax vegetation)

Internal thermodynamic characteristics Entropy level High medium Low Exergy level (state and change)

Low Medium High

Gross production/ respiration

Absent >1 Approaches 1

Gross production/ standing biomass

Absent High Low

Net production (yield) Absent High Low Biochemical diversity Absent Low High Stratification and

spatial heterogeneity Absent Poorly

organized Well-organized

Size of organisms Absent Small Large Growth form and life

cycle Absent r-strategy K-strategy

Niche specialization Absent Broad Narrow Information Low Medium High

After Odum (1969) Science

Provisioningservices

Biodiversity conservation

exergy dissipation and ecosystem development

After Odum (1969) Science

Successional stage: Ecosystem attribute

Abiotic Develop-mental

Mature

External thermodynamic characteristics Dissipation rate of exogenic exergy flows

Low Medium High

Microclimate (buffering of radiation, temperature and humidity changes)

Weak Medium Strong

Control over water flows

Low Medium High

Control over nutrient flows

Low Medium High

Stability (resistance/ resilience to perturbations)

Low Medium High

Regulating services

Example: ecosystem thermal buffering

Surface temperature from DAIS long wave scanner at St. Truiden, Belgium, 24 June 2001, 11.26 am

Dark blue is the temperature increase between 11.26 and 12.36

Maes et al. (2009) in prep. for Ecol. Mod.

Determination and chaos united

• Unidirectional succession rightfully criticized• But exergy theory can be reconciled with chaos theory

and alternative stable states (Kay, s.d., Dewulf et al., 2008)

Thermodynamicequilibrium

EcosystemStabilitylandscape

Eco

syst

em s

ervi

cepe

rform

ance

Potential natural vegetation

Paraclimax(e.g. coppice, plantation, maquis)

Species poolDisturbanceregime

Performingnewcomer added

Dispersal limitation of pioneers

Forest ecosystemmanagement

Diversity/FES relationships

Biodiversity function:

• Selection effect and insuranceMore species = higher probability of high performing speciesMore species = higher probability of alternative pathways

• ComplementarityNiche differentiation and facilitation

Diversity/FES relationships

• Diversity/productivity hypothesis provisioning services• Diversity/stability hypothesis supporting and

regulating services

• Net diversity effect (NDE) = [observed FES] – [expected FES]

• Transgressive overyielding (Dmax) = [observed FES] – [Max. single species FES]

• NDE<0: competition• NDE=0: no effect• NDE>0; Dmax<0: selection effect• NDE>0; Dmax>0: complementarity effect

Diversity/FES in forests1a. Species with similar ecological amplitude1b. Species with different ecological amplitude

2a. Dashed: no interaction; continuous: overyielding; dotted: underyielding

(from Pretzsch (2005) Ecol.Stud. 176)

Transgressive overyielding in forests was demonstrated for the first time by Pretzsch & Schütze (2009) Eur. J. For. Res. In mixed beech/spruce stands

Scale issues

• FES maximization on-site can have negative feedback off-site (e.g. green vs. blue water)

• Example: green water / blue water conflict

Figure: % decrease in water discharge by an increase in vapor flow resulting from land use change to CDM-AR.

Trabucco et al. (2008) Agr. Ecosyst. Env.

Integrated assessment of terrestrial/aquatic water services

ET

PNV

ET

EW

R

ET

min =0

ET

PNV

,min

ET

PNV

,max

TAW

I1

0

ETPNV ETEWRETmin=0

TWI

10

ETPNV ETEWRETmin=0

AW

I1

0

a.

b.

ETPNV ETEWRETmin=0

TAW

I1

0

c.

d.

Water quantity impact as a function of land management a. in terrestrial ecosystems (TWI), b. in aquatic ecosystems (AWI), c. and d. on both aquatic and terrestrial ecosystems (TAWI) as a function of evapotranspiration (ET) of the potential natural vegetation (PNV) and a threshold ETEWR

Maes et al. (2009) Env. Sci. Techn.

Integrated assessment of terrestrial/aquatic water services

sDSS

Time

Initial system Metafore Afforested system

Afforestation Strategy

Afforested system

Time

Initial system MetaforeMetafore Afforested system

Afforestation Strategy

Afforested system

Afforested system

Afforestation system analysis

www.sl.kvl.dk/afforest

Gilliams et al. / New Forests (2005) 30:33–53

Management issues

Example of a complex question solved in AFFOREST sDSS by goal programmingoptimizationWhat management strategy must be followed by a Danish municipality on sandy soils to produce a max. of clean drinking water and as a second priority max. C sequestration over the coming 15 years?

‘How’ question looking for the afforestation strategy meeting the multiple objective with high weight on maximizing water recharge and minimizing nitrate leaching, and with low weight on carbon sequestration.

Best strategy = 14: afforestation of beechwith moderate management intensity

FES optimization by simulation and DSS

Where in NL plan 30,000 ha of oak forests for maximizing carbon sequestration, but not provoking nitrate leaching exceeding the drinking water norm of 50 mg/l ?

where’ question solved by the ‘locate afforestation area’ query with multicriteria option. In order to get a focused answer it is wise to specify a time horizon and the used afforestation strategy.

Heil et al. (2007) Springer Plant & Vegetation Series, 1

FES optimization by simulation and DSS

Some conclusions

• Optimizing between FES is a complex non-linear exercise• Theoretically:

– Regulating services seem strongly related to late successional phases, while provisioning services more with early phases

– FES are high in PNV, but performance is influenced by species pool and disturbance regime

– FES might be higher and more sustained in diverse systems

• In practice: – Effect of mixed forests on FES is not straightforward but has been

demonstrated in a few cases– Optimizing FES needs consideration of on-site and off-site effects at

different scale levels– Optimizing forest management for particular FES can benefit from

mechanistic modeling and advanced optimization algorithms.

Thank you for your attention

Forest Ecology and Management Research GroupK.U.Leuven, Belgium

www.kuleuven.be/forecoman

Conference

22-25 September 2009 Koli, Finland