![]() In addition, soil microsites on hilltops tend to be more favorable for the germination and growth of temperate tree species because of better drained soils (Goldblum and Rigg 2002). In the BF–PB domain, only marginal stands of these temperate species can be found on the top of hills where, due to frequent temperature inversions, climatic conditions are more favorable than in lower elevation plains and valleys (Jin et al. The northern limit of red maple Acer rubrum is in the spruce–moss forest, further north (Tremblay et al. The BF–PB domain corresponds with the northern limit of the temperate species sugar maple Acer saccharum and yellow birch Betula alleghaniensis (Saucier et al. ![]() The Canadian boreal mixedwood forest ecotone is composed of two distinct bioclimatic domains: the balsam fir–yellow birch (BF–YB) bioclimatic domain in the south and the balsam fir–paper birch (BF–PB) bioclimatic domain in the north (Saucier et al. In particular, tree species with limited dispersal and late sexual maturity may be at greater risk of not keeping pace with high climate change velocity (Aitken et al. Consequently, we observe a lag between shifts of bioclimatic envelopes and occupancy of these envelopes through migration. At the local scale, other factors influence tree species distributions, including edaphic conditions, biotic mechanisms and dispersal abilities (Fisichelli et al. Under a warming climate, tree species are projected to migrate poleward, tracking their optimal climatic niche, as temperature and precipitation are known to shape the geographical range of tree species at the global scale (Morin et al. Global climate change is expected to produce complex impacts on forest ecosystems and tree species distributions (Boulanger et al. Our results suggest that both current climate and competitive interactions between temperate species and boreal species should not impede the ability of temperate species to grow and survive in the BF–PB domain. For stands that were recently clear cut, temperate seedlings were unable to grow due to intense competition from aspen regeneration. Species assemblages of host stands were impacted by the presence of temperate species when the addition of seedlings was above 5000 temperate seedlings per hectare at the beginning of the simulation. Of the temperate species introduced, sugar maple had the lowest ability to grow and survive by the end of the simulation. Our results show that current BF–PB domain climate conditions do not limit growth and survival of temperate species in boreal stands. ![]() After validating our model with data from permanent forest inventory plots, we modeled the dynamics of unharvested stands at different successional stages, as well as post-harvest stands, after the addition of sugar maple, red maple and yellow birch seedlings at different densities. We performed a novel parameterization of the SORTIE-ND tree growth equation allowing for the inclusion of climate modifiers on tree growth. SORTIE-ND is a spatially explicit, individual-based forest stand model that simulates tree growth, regeneration and mortality. Here, we use the SORTIE-ND forest simulation model to determine the potential for the persistence of three temperate species (sugar maple, red maple and yellow birch) when introduced at seedling stage in typical balsam fir–paper birch (BF–PB) bioclimatic domain stands of eastern Canada, quantifying the consequences on the native species composition. Temperate hardwood tree species may take advantage of the release of climate constraints and forest management to migrate into the boreal forest. With climate change, climatic optima are shifting poleward more rapidly than tree migration processes, resulting in a mismatch between species distributions and bioclimatic envelopes. ![]()
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