Stand‐level drivers most important in determining boreal forest response to climate change

Abstract

Forest ecosystems contain several climate‐sensitive drivers that respond differentially to changes in climate and climate variability. For example, growth and regeneration processes are “stand‐scale” drivers, while natural disturbances operate at “landscape scale”. The relative contributions of these different scale drivers of change in ecosystems create great uncertainty when simulating potential responses of a forest to changes in climate. Here, we assess those contributions, along with harvesting effects, on biomass (both total and of individual species) in the southern boreal forest of Canada under three climate scenarios (RCP 2.6, RCP 4.5 and RCP 8.5). Projections were performed for three future 30‐year time periods, in four study regions located on an east–west transect, using a forest landscape model (LANDIS‐II), parameterized using a forest patch model (PICUS). Projected future impacts were assessed for each driver of change, and found to vary greatly among regions, species, future period and forcing scenarios. Fire, and stand‐scale climate‐induced impacts, had the strongest effects on forest vegetation, as well as on total and species’ biomass under most RCP scenarios, but the largest impacts occurred mostly after 2050, particularly with the RCP 8.5 scenario. The relative importance and trends in species‐specific impacts varied, both spatially and according to the different RCP scenarios. Western regions were generally more sensitive to stand‐scale climate‐induced changes, whereas eastern regions were more sensitive to changes in fire regime. Our study also highlights the importance of considering the prevalence of species‐level functional traits when assessing the sensitivity of forest landscapes to a given driver of change in the context of increasing anthropogenic climate forcing. Synthesis. Increases in fire activity, and direct impacts of climate change on forest growth and regeneration, will be the most important drivers of future changes in southern boreal forest landscapes.

Divergent responses to climate change and disturbance drive recruitment patterns underlying latitudinal shifts of tree species

“…For A. saccharum north of the 90th percentile, spring warming and recent natural disturbances interacted negatively, possibly limiting range expansion, whereas for F. grandifolia in the south, spring warming interacted positively with logging. It is possible that for some species, changes in the disturbance regime, including fire, may limit their ability to migrate and persist in the boreal forest (Boulanger, Taylor, Price, Cyr, & Sainte‐Marie, ). Using physiologically based simulations in the northeastern United States, Liang et al () reported that disturbances may expedite species' recruitment into new sites, but they had little effect on the velocity of simulated range boundary shifts.…”

Possible Increases in Flood Frequency Due to the Loss of Eastern Hemlock in the Northeastern United States: Observational Insights and Predicted Impacts

“…Giuntoli et al (2018) review hydrologic land surface models for operational flood forecasts and demonstrate high variability in the complexity of plant dynamics. It is therefore not surprising that recent projections of future riverine flooding risk have focused so heavily on shifts in atmospheric forcing with simplified or static numerical representations of vegetation (e.g., Chen et al, 2018 ;Hirabayashi et al, 2013 ;Stryker et al, 2018) despite clear evidence for climate-driven changes in the density and composition of temperate forests (Boulanger et al, 2018;Dunckel et al, 2017).…”

Spatial Pattern of Climate Change Effects on Lithuanian Forestry

“…The predictions achieved here are aimed to support strategic or long-term forest planning. Climate change-induced long-term changes in forest growth; however, are considered to have a more significant impact on forest conditions than both harvesting and natural disturbances [68]. We test only current forest management approaches, i.e., forest management specifications in Kupolis have been defined by best describing current forest management practices in Lithuania [41][42][43], or more precisely, as they have been during the last one to two decades.…”