Using an ensemble of downscaled climate model projections to assess impacts of climate change on the potential distribution of spruce and Douglas-fir forests in British Columbia

Many of the world's forests are likely to face multiple stresses under a rapidly changing climate. Understanding the impact of climate change on tree species suitability is therefore crucial for forest management planning and policy development. We use the Douglas-fir and spruce (white spruce, Engelmann spruce, and interior spruce) forests of British Columbia as a case study. The impact of projected climate change on these forests was assessed using flexible bioclimatic envelope models appropriate for areas with sparse species locations records. Analysis of the model results focused on quantifying uncertainty due to differences between global climate models, emissions scenarios, and spatial resolution of climate data. To this end, future suitability was modelled using downscaled climate data from a collection of 10 climate projections that sampled across nine different global climate models and three different emissions scenarios (A2, A1B, and B1). All projections indicate a rapid shift in suitability for both spruce and Douglas-fir to higher elevations and latitudes relative to their current range. However, significant differences exist between the projections with regard to the pace, extent, and fine-scale details of these changes. This research was conducted as part of a collaborative interdisciplinary assessment involving both scientists and resource managers.

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► We modelled future changes in climatic suitability for forests in British Columbia.
► We developed bioclimatic envelope models for spruce and Douglas-fir forests.
► Both models are more sensitive to changes in temperature than precipitation.
► Climatically suitable areas rapidly shift to higher elevations and latitudes.
► We quantified and mapped uncertainty due to differences among climate projections.