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Policies for the management of landscape diversity and collectively managed forests: the case of Galicia. Julia Touza - Montero and Charles Perrings Environment Department, University of York. Presentation overview. Motivation

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Policies for the management of landscape diversity and collectively managed forests:

the case of Galicia

Julia Touza-Montero and Charles Perrings

Environment Department, University of York

presentation overview
Presentation overview
  • Motivation
  • Multiple stand landscape model -optimal harvesting rule -
  • Case study: Galician collective forests in Spain
  • Policy implications
  • Management of forest resources has moved towards a
  • landscape-based approach to manage for multiple values
  • Think beyond individual stands -- mosaic of stands
  • Why?
    • Management at a stand level impedes the assessment of the implications of the management actions at a landscape scale
    • Lack of spatial consideractions (stands size, shape, proximity, dispersion, adjacency) Unanticipated ecological changes
motivation cont
Motivation - Cont….
  • Forest management at a landscape scale is increasingly recognised as a key for conservation of biodiversity
  • Focus on maintaining the habitats
  • Interactions between spatially dispersed stands determine forest ecological processes (e.g. movement of species, spread of disturbances)
motivation cont1
Motivation - Cont….
  • Case study focuses on Galicia (Northwest of Spain)
  • Forest area covers 69% of the territory
  • Pinus pinaster, Eucalyptus globulus, and mixed forest of
  • these species 35%
  • Quercus robur and Quercus pyrenaica 14%
  • Non-wooded (scrublands) 31%
  • Galicia has patchy forest land
motivation cont2
Motivation - Cont….
  • Individual ownership:68% of forest land- 2.3 ha mean size
  • Collective ownership:30% of forest land- 231 hamean size
  • Members of a rural community have the rights to the forest resources without parcelling the rights to the forest itself
  • Forestry, support for cattle raising and agriculture, amenities, hunting, etc.
  • Multiple forest uses and spatial interactions between stands are integrated within the decision making process
multiple stand mo d el
Multiple stand model
  • Harvest decisions, i.e. rotation periods, in a multiple stand forest managed fortimber and non-timber values
  • Stand interactions are assumed to influence the flow of non-timber benefits provided for the entire forest landscape
  • Bowes and Krutilla, 1985, Swallow et al. 1997, Thavonen and Salo, 1999, Amacher et al. 2002
  • A dynamic optimal cutting rule in a multiple stand forest landscape
  • Note: theoretical results independent of type of ownership
multiple stand mo d el2
Multiple stand model
  • Choose the optimum time moments of the stands’ harvests, to maximise timber and non-timber benefits


  (s1[a1(t)],..,sn[an(t)])e-t dt +  [pixi(ij-)-cipxip] e- ij

subject to

xi = Fi[xi(t)]between harvests

ai= 1 between harvests

xi(ij+) - xi(ij-) = - xi(ij-) + xip at harvest

ai(ij+) - ai(ij-) = - a(ij-) + aip at harvest



multiple stand mo d el3
Multiple stand model
  • Optimal cutting condition for any stand in the forest landscape
  • Forest MB = Forest MC

(s1[a1(ij-)],., sn[an(ij-)])e- ij-(s1[a1(ij+)],.., sn[an(ij+)])e- ij+piFi[xi(ij-)]e- ij

= [pixi(ij-)-cipxip] e- ij+pi Fi[xi(ij+1-)] e- ij+1+i(ij+)

(ij-)-(ij+)stand i relative contribution to the forest NTB

if its harvest is delayed

Stands’ interactions

i(ij+)opportunity costs of delaying future forest NTB and

altering the age of stand i relative to the other stands’ age

case s t udy galician collective lands
Case study: Galician collective lands
  • Analysis of harvesting decisions accounting for landscape pattern differences between collective forests
  • Dependent variable: rotation length
  • Baixo-Miño (68% forest land – 73% collective forests)
  • Reports on clear-cuttings undertaken on collective forests under contract mechanisms - from 1995 to 2001
case s t udy galician collective lands1
Case study: Galician collective lands

Duration analysis: parameter estimates from the Weibull distribution

(a) We compute this estimation with dummies for those harvesting reports which contain several tree species but the p-values suggested omitting them from the model

*** significant at 1% level; ** significant at 5%; * significant at 10%

conclusions and policy implications
Conclusions and policy implications
  • Optimal harvesting strategies at a single-stand scale are not necessarily optimal when a larger spatial scale is adoped and spatial interactions inform the decisions
  • What is the difference?
  • Single-stand: the flow of the stand’s NTB influences when the
  • stand should be harvested (Faustmann-Hartman rule)
  • Multiple-stand: it is the relative contribution of each stand to the NTB from the overall forest landscape that affects the rotation intervals
policy implications cont
Policy implications – Cont...
  • Fragmentation, diversity and clumpiness are relevant determinants of harvesting behaviour in Galicia collective forests
  • Policy implications:
  • •Non-harvesting policies may be optimal for those areas that
  • contribute highly valuable environmental goods and services to
  • forest landscape benefits
  • • It may be optimal never to harvest any of the stands in the forest
  • if NTB increase with age and are significant with respect to other
  • uses
policy implications cont1
Policy implications – Cont...

• The ecological and economic consequences of alternative actions

taken at small scales (stands) on a wider spatial context (i.e. forest

landscape) must be allowed for in forest management decision


• The weight attached to the forest benefits from a particular stand

depend on the interdependence between stands

• Importance of spatial interactions on harvesting strategies – Scale

policy implications cont2
Policy implications – Cont...

98% of forest land is in private hands

Individual ownerships have a mean size of 2.3 hectares

•In Galicia

Public planning of forest landscapes is essential to account both

for: (a) spatial interactions between the stands; (b) preferences of


Public policies, which encourage coordination and cooperation

among forest owners, are necessary to ensure that private owners’

actions are consistent with environmental and economic goals set

at a landscape level

Problems: Inventories of single and collective forest ownerships are scarce

Weakened communal institutions