Climate change, wildfire, and vegetation shifts in a high-inertia forest landscape: Western Washington, U.S.A.
Climate change, wildfire, and vegetation shifts in a high-inertia forest landscape: Western Washington, U.S.A.
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DOI：
10.1371/journal.pone.0209490
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发表时间：
2018-12
期刊：
影响因子：
3.7
通讯作者：
Joshua S. Halofsky;D. Conklin;D. Donato;J. Halofsky;John B. Kim
中科院分区：
文献类型：
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作者：
Joshua S. Halofsky;D. Conklin;D. Donato;J. Halofsky;John B. Kim
未来植被变化下的气候变化是不确定的森林与不频繁的立场取代干扰制度。这些高惯性森林即使在气候变化的情况下也可能具有长期的持久性，因为无干扰期可以跨越几个世纪，大规模再生的机会相对于频繁火灾的系统较少，成熟的树种寿命长，对次优生长条件的耐受性相对较高。在这里，我们使用了经验和基于过程的建模方法相结合，以检查植被预测在高惯性森林的华盛顿州，美国，在不同的气候和野火的未来。我们在没有森林管理的情况下运行我们的模型（以评估固有的系统行为/潜力），同时也使用野火抑制。预测表明，尽管预计野火会增加，但到世纪末，中海拔森林将相对稳定。最大的变化预计在最低和最高的森林边界，最干燥的低海拔森林和寒冷，高海拔亚高山公园的收缩向上扩张。虽然森林总体上相对稳定的模拟，增加早期seral条件和减少后期seral条件发生野火变得更加频繁。部分灭火，预计的变化被抑制或延迟，这表明一个潜在的工具，以阻止一些（但不是所有）高惯性森林的变化，特别是因为延长无火期没有改变这些系统中的整体火灾制度。模型预测还说明了火灾状况背景的重要性和预测的局限性;扰动最终使系统发生变化的时间跨度很长，以至于发生许多变化的主要气候条件超出了大多数气候模型所能肯定预测的范围。这将对设定期望和管理这些系统的长期变化提出根本性挑战。
Future vegetation shifts under changing climate are uncertain for forests with infrequent stand-replacing disturbance regimes. These high-inertia forests may have long persistence even with climate change because disturbance-free periods can span centuries, broad-scale regeneration opportunities are fewer relative to frequent-fire systems, and mature tree species are long-lived with relatively high tolerance for sub-optimal growing conditions. Here, we used a combination of empirical and process-based modeling approaches to examine vegetation projections across high-inertia forests of Washington State, USA, under different climate and wildfire futures. We ran our models without forest management (to assess inherent system behavior/potential) and also with wildfire suppression. Projections suggested relatively stable mid-elevation forests through the end of the century despite anticipated increases in wildfire. The largest changes were projected at the lowest and uppermost forest boundaries, with upward expansion of the driest low-elevation forests and contraction of cold, high-elevation subalpine parklands. While forests were overall relatively stable in simulations, increases in early-seral conditions and decreases in late-seral conditions occurred as wildfire became more frequent. With partial fire suppression, projected changes were dampened or delayed, suggesting a potential tool to forestall change in some (but not all) high-inertia forests, especially since extending fire-free periods does little to alter overall fire regimes in these systems. Model projections also illustrated the importance of fire regime context and projection limitations; the time horizon over which disturbances will eventually allow the system to shift are so long that the prevailing climatic conditions under which many of those shifts will occur are beyond what most climate models can predict with any certainty. This will present a fundamental challenge to setting expectations and managing for long-term change in these systems.