TY - JOUR
T1 - Simulating wind disturbance impacts on forest landscapes
T2 - Tree-level heterogeneity matters
AU - Seidl, Rupert
AU - Rammer, Werner
AU - Blennow, Kristina
N1 - Funding Information:
We thank S. Hale, Forest Research, UK, for providing data on tree size, competition, and turning moment coefficients for reanalysis, the Department of Forest Resource Management, Swedish University of Agricultural Sciences, for providing kNN data on forest cover, M. Andersson, Swedish University of Agricultural Sciences, for preparing the tree cover data, and the Swedish Forest Agency for providing satellite data on wind damage after the storm “Gudrun”. We furthermore thank B. Gardiner, INRA, France for helpful comments on the intricacies of mechanistic wind modeling. Two anonymous reviewers are acknowledged for providing detailed and insightful comments that helped to improve the manuscript further. This work was partly funded by two European Community's Seventh Framework Program Marie Curie Fellowship to RS (grant agreements 237085 and 334104 ). KB acknowledges funding from the research program Models for Adaptive Forest Management (MOTIVE) within the European Community's Seventh Framework Program (project no. 226544).
PY - 2014/1
Y1 - 2014/1
N2 - Wind is the most detrimental disturbance agent in Europe's forest ecosystems. In recent years, disturbance frequency and severity have been increasing at continental scale, a trend that is expected to continue under future anthropogenic climate change. Disturbance management is thus increasingly important for sustainable stewardship of forests, and requires tools to evaluate the effects of management alternatives and climatic changes on disturbance risk and ecosystem services. We here present a process-based model of wind disturbance impacts on forest ecosystems, integrated into the dynamic landscape simulation model iLand. The model operates at the level of individual trees and simulates wind disturbance events iteratively, i.e., dynamically accounting for changes in forest structure and newly created edges during the course of a storm. Both upwind gap size and local shelter from neighboring trees are considered in this regard, and critical wind speeds for uprooting and stem breakage are distinguished. The simulated disturbance size, pattern, and severity are thus emergent properties of the model. We evaluated the new simulation tool against satellite-derived data on the impact of the storm Gudrun (January 2005) on a 1391ha forest landscape in south central Sweden. Both the overall damage percentage (observation: 21.7%, simulation: 21.4%) as well as the comparison of spatial damage patterns showed good correspondence between observations and predictions (prediction accuracy: 60.4%) if the full satellite-derived structural and spatial heterogeneity of the landscape was taken into account. Neglecting within-stand heterogeneity in forest conditions, i.e., the state-of-the-art in many stand-level risk models, resulted in a considerable underestimation of simulated damage, supporting the notion that tree-level complexity matters for assessing and modeling large-scale disturbances. A sensitivity analysis further showed that changes in wind speed and soil freezing could have potentially large impacts on disturbed area and patch size. The model presented here is available as open source. It can be used to study the effects of different silvicultural systems and future climates on wind risk, as well as to quantify the impacts of wind disturbance on ecosystem services such as carbon sequestration. It thus contributes to improving our capacity to address changing disturbance regimes in ecosystem management.
AB - Wind is the most detrimental disturbance agent in Europe's forest ecosystems. In recent years, disturbance frequency and severity have been increasing at continental scale, a trend that is expected to continue under future anthropogenic climate change. Disturbance management is thus increasingly important for sustainable stewardship of forests, and requires tools to evaluate the effects of management alternatives and climatic changes on disturbance risk and ecosystem services. We here present a process-based model of wind disturbance impacts on forest ecosystems, integrated into the dynamic landscape simulation model iLand. The model operates at the level of individual trees and simulates wind disturbance events iteratively, i.e., dynamically accounting for changes in forest structure and newly created edges during the course of a storm. Both upwind gap size and local shelter from neighboring trees are considered in this regard, and critical wind speeds for uprooting and stem breakage are distinguished. The simulated disturbance size, pattern, and severity are thus emergent properties of the model. We evaluated the new simulation tool against satellite-derived data on the impact of the storm Gudrun (January 2005) on a 1391ha forest landscape in south central Sweden. Both the overall damage percentage (observation: 21.7%, simulation: 21.4%) as well as the comparison of spatial damage patterns showed good correspondence between observations and predictions (prediction accuracy: 60.4%) if the full satellite-derived structural and spatial heterogeneity of the landscape was taken into account. Neglecting within-stand heterogeneity in forest conditions, i.e., the state-of-the-art in many stand-level risk models, resulted in a considerable underestimation of simulated damage, supporting the notion that tree-level complexity matters for assessing and modeling large-scale disturbances. A sensitivity analysis further showed that changes in wind speed and soil freezing could have potentially large impacts on disturbed area and patch size. The model presented here is available as open source. It can be used to study the effects of different silvicultural systems and future climates on wind risk, as well as to quantify the impacts of wind disturbance on ecosystem services such as carbon sequestration. It thus contributes to improving our capacity to address changing disturbance regimes in ecosystem management.
KW - Ecosystem heterogeneity
KW - Forest disturbance
KW - ILand
KW - Landscape modeling
KW - Wind model
KW - Windthrow
UR - http://www.scopus.com/inward/record.url?scp=84885908030&partnerID=8YFLogxK
U2 - 10.1016/j.envsoft.2013.09.018
DO - 10.1016/j.envsoft.2013.09.018
M3 - Article
AN - SCOPUS:84885908030
SN - 1364-8152
VL - 51
SP - 1
EP - 11
JO - Environmental Modelling and Software
JF - Environmental Modelling and Software
ER -