Living on the edge: trailing edge forests at risk of fire‐facilitated conversion to non‐forest
Living on the edge: trailing edge forests at risk of fire‐facilitated conversion to non‐forest
复制标题
生活在边缘：后缘森林面临因火灾而转变为非森林的风险
作者：
S. Parks;S. Dobrowski;J. Shaw;Carol Miller
森林是全球非常重要的资源，但它们受到气候变化的威胁，如干旱、虫害爆发和野火。后缘森林——那些在气候变化下预计会经历范围缩小的地区——特别值得关注，因为它们有可能突然转变为非森林。然而，由于植物-气候不平衡，如果没有干扰催化剂（如野火），后缘森林不太可能在短时间内（<~ 25-50年）发生大规模森林死亡和范围缩小。这强调了对气候和干扰的明确关注对于理解森林的分布如何对气候变化作出反应是必要的。因此，我们首先确定了到21世纪中叶美国西部山间森林的预期位置。然后，我们确定了那些极有可能发生林分替代火灾的后缘森林，并认为这些地点具有火灾促进向非森林过渡的高风险。结果表明，到21世纪中叶，美国西部山间地带18%的尾缘森林和6.6%的森林将面临由火促进向非森林转化的高风险。然而，这一估计是假设火灾在平均天气条件下燃烧。对于研究区域的一个子集（美国西南部），我们能够在极端天气条件下纳入预期的火灾严重程度。对于这一空间子集，我们发现61%的后缘森林和30%的所有森林在极端燃烧条件下处于火促转化为非森林的高风险中。然而，由于我们的过程中的复合误差导致了不可知的不确定性，我们敦促在严格解释这些估计时保持谨慎。然而，我们的研究结果表明，美国西部山间景观的潜在转变将影响生态系统服务，如流域完整性、野生动物栖息地、木材生产和娱乐。
Forests are an incredibly important resource across the globe, yet they are threatened by climate change through stressors such as drought, insect outbreaks, and wildfire. Trailing edge forests—those areas expected to experience range contractions under a changing climate—are of particular concern because of the potential for abrupt conversion to non‐forest. However, due to plant‐climate disequilibrium, broad‐scale forest die‐off and range contraction in trailing edge forests are unlikely to occur over short timeframes (<~25–50 yr) without a disturbance catalyst (e.g., wildfire). This underscores that explicit attention to both climate and disturbance is necessary to understand how the distribution of forests will respond to climate change. As such, we first identify the expected location of trailing edge forests in the intermountain western United States by mid‐21st century. We then identify those trailing edge forests that have a high probability of stand‐replacing fire and consider such sites to have an elevated risk of fire‐facilitated transition to non‐forest. Results show that 18% of trailing edge forest and 6.6% of all forest are at elevated risk of fire‐facilitated conversion to non‐forest in the intermountain western United States by mid‐21st century. This estimate, however, assumes that fire burns under average weather conditions. For a subset of the study area (the southwestern United States), we were able to incorporate expected fire severity under extreme weather conditions. For this spatial subset, we found that 61% of trailing edge forest and 30% of all forest are at elevated risk of fire‐facilitated conversion to non‐forest under extreme burning conditions. However, due to compounding error in our process that results in unknowable uncertainty, we urge caution in a strict interpretation of these estimates. Nevertheless, our findings suggest the potential for transformed landscapes in the intermountain western United States that will affect ecosystem services such as watershed integrity, wildlife habitat, wood production, and recreation.
DOI：
10.1073/pnas.0505734102
发表时间：
2005-10-18
影响因子：
11.1
作者：
Breshears, DD;Cobb, NS;Meyer, CW
通讯作者：
Meyer, CW
影响因子：
6.4
作者：
Hickler, Thomas;Vohland, Katrin;Sykes, Martin T.
通讯作者：
Sykes, Martin T.