The integration of functional traits into vulnerability assessments is a promising approach to quantitatively capture differences in species sensitivity and adaptive capacity to climate change, allowing the refinement of tree species distribution models. In response to a clear need to identify traits that are responsive to climate change and applicable in amanagement context, we review the state of knowledge of the main mechanisms, and their associated traits, that underpin the ability of boreal and temperate tree species to persist and (or) shift their distribution in a changing climate. We aimed to determine whether current knowledge is sufficiently mature and available to be used effectively in vulnerability assessments. Marshalling recent conceptual advances and assessing data availability, our ultimate objective is to guide modellers and practitioners in finding and selecting sets of traits that can be used to capture differences in species’ ability to persist and migrate. While the physiological mechanisms that determine sensitivity to climate change are relatively well understood (e.g., drought-induced cavitation),manyassociated traits have not been systematically documented for North American trees and differences in methodology preclude their widespread integration into vulnerability assessments (e.g., xylem recovery capacity). In contrast, traits traditionally associated with the ability to migrate and withstand fire are generally well documented, but new key traits are emerging in the context of climate change that have not been as well characterized (e.g., age of optimum seed production). More generally, lack of knowledge surrounding the extent and patterns in intraspecific trait variation, as well as co-variation and interaction among traits, limit our ability to use this approach to assess tree adaptive capacity.We conclude by outlining research needs and potential strategies for the development of trait-based knowledge applicable in large-scale modelling efforts, sketching out important aspects of trait data organization that should be part of a coordinated effort by the forest science community

Projected changes in climate conditions vary widely across Canada's 350 M ha of forests, and so does the capacity of forest species to cope with these changes (sensitivity). Development and prioritization of adaptation strategies for sustainable forest management will depend on integrated assessments of relative stand vulnerability. We developed species‐specific indices of sensitivity to (1) drought‐induced mortality and (2) migration failure, based on traits for 22 of the most abundant tree species in Canada. By combining this information with stand composition data and spatially explicit climate change projections, we were able to map Canadian forest vulnerability to drought and migration failure. Our maps show forest vulnerability changing rapidly under a high carbon emission scenario (RCP 8.5) between short‐ (2011–2040), medium‐ (2041–2070), and long‐term projections (2071–2100). Several zones of special concern emerged based on the biomass involved, stand sensitivity, and vulnerability trends across time. Boreal forests in the central regions of Alberta and Saskatchewan appeared most vulnerable to drought‐induced mortality in the mid to long term. In the short term, distance to suitable habitat is projected to shift quickly along latitudinal gradients, particularly in Central Canada, while zones of vulnerability to migration failure appeared across the Rockies region in the long term as suitable conditions disappear from mountainous areas. This spatial assessment of vulnerability, which integrates species‐specific sensitivity, highlights important regional contrasts between vulnerability to drought (from high exposure, high proportion of sensitive species, or both) and to migration failure. By affecting either species’ ability to persist in place or to migrate, different climate change impacts can yield distinct biotic responses, with important implications for regional climate change adaptation strategies. Multi‐faceted vulnerability assessments, integrating both exposure and sensitivity indices specific to expected impacts of climate change, have the potential to provide crucial information to managers. We discuss some of these implications, explore the current limitations of our approach, and suggest a path forward.

Coarse woody debris supports large numbers of saproxylic fungal species. However, most of the current knowledge comes from Scandinavia and studies relating the effect of stand or log characteristics on the diversity and composition of decomposer fungi have not been conducted in Northeastern Canada. Logs from five tree species were sampled along a decomposition gradient in nine stands representing three successional stages of the boreal mixed forest of Northwestern Quebec, Canada. Using a molecular fingerprinting technique, we assessed fungal community Shannon-Weaver diversity index, richness, and composition. We used linear mixed models and multivariate analyses to link changes in fungal communities to log and stand characteristics. We found a total of 33 operational taxonomic units (OTUs) including an indicator species for balsam fir (similar to Athelia sp.) and one found only in aspen stands (similar to Calocera cornea). Spruce logs supported the highest fungal Shannon-Weaver diversity index and OTU number. Our results support the hypothesis that log species influences fungal richness and diversity. However, log decay class does not. Stand composition, volume of coarse woody debris, and log chemical composition were all involved in structuring fungal communities. Maintaining the diversity of wood-decomposing communities therefore requires the presence of dead wood from diverse log species.