DOI: 10.5061/dryad.2qh132f
title: Data from: Current and projected cumulative impacts of fire, drought and insects on timber volumes across Canada

description: Canada’s forests are shaped by disturbances such as fire, insect outbreaks
 and droughts that often overlap in time and space. The resulting
 cumulative disturbance risks and potential impacts on forests are
 generally not well accounted for by models used to predict future impacts
 of disturbances on forest. This study aims at projecting future cumulative
 effects of four main natural disturbances – fire, mountain pine beetle,
 spruce budworm and drought - on timber volumes across Canada’s forests
 using an approach that accounts for potential overlap among disturbances.
 Available predictive models for the four natural disturbances were used to
 project timber volumes at risk under aggressive climate forcing up to
 2100. Projections applied to the current vegetation suggest increases of
 volumes at risk related to fire, mountain pine beetle and drought over
 time in many regions of Canada, but a decrease of the volume at risk
 related to spruce budworm. When disturbance effects are cumulated,
 important changes in volumes at risk are projected to occur as early as
 2011-2041, particularly in central and eastern Canada. In our last
 simulation period covering 2071 to 2100, nearly all timber volumes in most
 of Canada’s forest regions could be at risk of being affected by at least
 one of the four natural disturbances considered in our analysis, a
 six-fold increase relative to the baseline period (1981-2010). Tree
 species particularly vulnerable to specific disturbances (e.g., trembling
 aspen to drought) could suffer disproportionate increases in their volume
 at risk with potential impacts on forest composition. By 2100, estimated
 wood volumes not considered to be at risk could be lower than current
 annual timber harvests in central and eastern Canada. Current level of
 harvesting could thus be difficult to maintain without the implementation
 of adaptation measures to cope with these disturbances.
description: Homogeneous Disturbance
 Regime zones_Volume at risk & Percentage of current harvesting volume
 relative to volume not at risk.shpShapefile of the
 Homogeneous Disturbance Regime zones. Table provides data for figures 4
 & 7.HDRzones_Vrisk_and_Harvest.zipVolume at riskProportions (%) of volume at risk associated with the four disturbance types for each HDR zone and each observed and predicted periods. Total volume at risk of the zone (in % and in M of m3) does not correspond to the sum of disturbance volumes at risk but rather follows Eq. 1 to take into account the overlaps between disturbances. HDR zones and their ID number are provided in the shapefile data.Volume_at_risk.txtVolume_at_risk_individual_disturbancesIndividual proportions (%) of volume at risk associated with the four disturbances for each HDR zone and each observed and predicted periods, before overlaps between drought and insect outbreaks have been considered. HDR zones ID are provided in the shapefile data.Tree compositionInitial composition (% of tree species volume) of each HDR zone forest, % of species volume at risk relatively to the total volume at risk (i.e., composition of volume at risk) and % of species volume at risk relatively to the total volume in each HDR zone for each projected period.Raster_volume_at_risk_FIREProjected wood volume at risk (m3/ha) related to fire at 250-m pixel scale for 1981-2010, 2011-2040, 2041-2070 and 2071-2100 periods, before the overlap between disturbances have been accounted. (Fig. 3)Raster_volume_at_risk_MPBProjected wood volume at risk (m3/ha) related to mountain pine beetle at 250-m pixel scale for 1981-2010, 2011-2040, 2041-2070 and 2071-2100 periods, before the overlap between disturbances have been accounted. (Fig. 3)Raster_volume_at_risk_SBWProjected wood volume at risk (m3/ha) related to spruce budworm at 250-m pixel scale for 1981-2010, 2011-2040, 2041-2070 and 2071-2100 periods, before the overlap between disturbances have been accounted. (Fig. 3)Raster_volume_at_risk_DROUGHTProjected wood volume at risk (m3/ha) related to drought at 250-m pixel scale for 1981-2010, 2011-2040, 2041-2070 and 2071-2100 periods, before the overlap between disturbances have been accounted. (Fig. 3)