Context

Increased anthropogenic climate forcing is projected to have tremendous impacts on global forest ecosystems, with northern biomes being more at risk.

Objectives

To model the impacts of harvest and increased anthropogenic climate forcing on eastern Canada’s forest landscapes and to assess the strong spatial heterogeneity in the severity, the nature and direction of the impacts expected within northern forest regions.

Methods

We used LANDIS-II to project species-specific aboveground biomass (AGB) between 2020 and 2150 under three climate (baseline, RCP 4.5 and RCP 8.5) and two harvest (baseline harvest, no harvest) scenarios within four forest regions (boreal west, boreal east, mixedwood and northern hardwood).

Results

Climate change impacts within the boreal forest regions would mainly result from increases in wildfires activity which will strongly alter total AGB. In the mixedwood and northern hardwood, changes will be less important and will result from climate-induced growth constraints that will alter species composition towards more thermophilous species. Climate-induced impacts were much more important and swifter under RCP 8.5 after 2080 suggesting that eastern Canada’s forests might cross important tipping points under strong anthropogenic climate forcing.

Conclusions

Boreal forest regions will be much less resilient than mixedwood or northern hardwoods to the projected changes in climate regimes. Current harvest strategies will interact with anthropogenic climate forcing to further modify forest landscapes, notably by accelerating thermophilous species AGB gain in southernmost regions. Major changes to harvest practices are strongly needed to preserve the long-term sustainability of wood supply in eastern Canada. Adaptation strategies should be region-specific.

中文翻译：

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与加拿大东部的混合木和北部硬木森林相比，预计的人为气候强迫对北方森林的影响更大

语境

预计人为气候强迫的增加将对全球森林生态系统产生巨大影响，而北部生物群落则面临更大的风险。

目标

为了模拟采伐和增加的人为气候强迫对加拿大东部森林景观的影响，并评估北部森林地区预期影响的严重性，性质和方向的强烈空间异质性。

方法

我们使用LANDIS-II预测了2020年至2150年之间三种气候（基准，RCP 4.5和RCP 8.5）和两种采伐（基准采收，无采伐）情景下四个森林区域（北西部，北美洲，北方的北方，混合木和北方的硬木）。

结果

北方森林地区的气候变化影响主要来自野火活动的增加，这将大大改变总AGB。在混合木和北部硬木中，变化将变得不那么重要，并且将由气候引起的生长限制而导致，该限制将使物种组成向更嗜热的物种转变。在2080年之后，根据RCP 8.5，气候引起的影响更为重要和迅速，这表明在强烈的人为气候强迫下，加拿大东部森林可能越过重要的临界点。

结论

相对于预计的气候变化，北方森林地区的抵抗力将比混合木或北方硬木低得多。当前的采伐策略将与人为气候强迫相互作用，以进一步修改森林景观，特别是通过加速最南端地区嗜热菌种AGB的获得。为了保持加拿大东部木材供应的长期可持续性，强烈需要对采伐方式进行重大改变。适应策略应针对特定地区。