DOI: 10.5061/dryad.18790
title: Data from: Cross-scale interactions among bark beetles, climate change and wind disturbances a landscape modeling approach

description: Bark beetles are a key forest disturbance agent worldwide, with their
 impact shaped by climate, forest susceptibility, and interactions with
 other disturbances such as windthrow and fire. There is ample evidence on
 the interactions among these factors at small spatial and temporal scales,
 but projecting their long-term and landscape-scale impacts remains a
 challenge. We developed a spatially explicit model of European spruce bark
 beetle (Ips typographus) dynamics that incorporates beetle phenology and
 forest susceptibility, and integrated it in a climate-sensitive landscape
 model (LandClim). We first corroborated model outputs at various spatial
 and temporal scales and then applied the model in three case studies (in
 the Black Forest, Germany, and Davos, Switzerland) that cover an extended
 climatic gradient. We used this model and case study framework to examine
 the mechanisms and feedbacks that are driving short-term and long-term
 interactions among beetle disturbance, climate change and windthrow, and
 how they may shift in the future. At the current cold-wet end of the
 Norway spruce (Picea abies) distribution, climate change is projected to
 increase temperature and drought, such that beetles become a more dominant
 disturbance agent. At the warm-dry end of the spruce distribution, where
 under current climate beetle outbreaks were confined to the simultaneous
 occurrence of drought and windthrow, the simulated level of drought alone
 sufficed for triggering beetle outbreaks, such that elevated drought- and
 beetle-induced spruce mortality would negatively feed back on beetle
 disturbance in the long term leading to receding beetle populations due to
 the local extinction of Norway spruce. These results suggest that
 depending on initial environmental conditions climate change may shift the
 importance of direct and indirect drivers of disturbances. These shifts
 may affect the sign and strength of cross-scale disturbance interactions
 and may impact the cost-benefit trade-off between beetle suppression and
 preventive management strategies.
description: Aggregated LandClim
 simulation output dataData are on tree species
 biomass (Norway spruce and others, Mg/ha), disturbance damage (bark
 beetles and wind, Mg/ha) and forest susceptibility indices (drought-, age-
 and spruce share-induced susceptibility and all combined, dimensionless)
 for three case studies (Black Forest low and high elevation and Davos),
 three climate and wind scenarios and with and without beetle disturbance
 for decades within AD 2000-2200. The data were generated using the forest
 landscape model LandClim and are averages of cell-specific data over the
 three study areas. Fig. 8 and Fig. B1-4 in Appendix B of the publication
 visualize the data.LandClim_simulation_data.csvAnnotated C++ source code of the LandClim beetle modelThe .zip file contains three text files (beetle.cpp, climate.cpp and cohort.cpp) that contain the C++ source code for the beetle model implemented in LandClim. The code is annotated with references to variable names and equations in the published article. beetle.cpp contains the main routines of the beetle model, climate.cpp calculations of bioclimatic variables and cohort.cpp contains the routines used to simulate beetle-induced tree mortality.LandClim_beetle_model_source_code.zip