Using Bigcone Douglas-Fir Fire Scars and Tree Rings to Reconstruct Interior Chaparral Fire History
Using Bigcone Douglas-Fir Fire Scars and Tree Rings to Reconstruct Interior Chaparral Fire History
复制标题
使用大锥花旗松火痕和树木年轮重建内部丛林火灾历史
DOI：
10.4996/fireecology.0503035
复制
发表时间：
2009
期刊：
影响因子：
5.1
通讯作者：
M. Borchert
中科院分区：
文献类型：
--
作者：
Keith J. Lombardo;T. Swetnam;C. Baisan;M. Borchert
大锥花旗松（Pseudotsuga macrocarpa [Vasey] Mayr）是一种长寿的，适应火的针叶树，是加州南部横贯山脉的特有树种。在其海拔分布的下游和中游，孤立的大锥花旗松林被广泛的查帕拉尔林所包围。我们的树木年代学调查显示，这些古老的树木通常记录了多次过去的火灾，作为其下部树干的火痕。我们假设，火痕记录内和大锥道格拉斯冷杉林分之间发现，反映了火灾的时间和空间模式，在周围的查帕拉尔。我们将火痕结果与独立的世纪火灾地图集数据进行了比较，以评估我们的解释。利用火痕和年轮变化重建了美国Los Padres国家森林的火灾历史，并调查了近几个世纪以来的火灾动态特征变化，我们的分析证实，树木年轮记录可以用来准确地重建大锥道格拉斯冷杉林和周围查帕拉尔林过去火灾发生和程度的模式。在世纪前后发生了许多大面积火灾，表明这类事件是该系统的一个自然组成部分。然而，在树木年轮记录中也可以看到许多小规模的火灾，而且这些类型的火灾发生在世纪（以及更早）比发生在20世纪更多。我们还确定了一个转变后，世纪后期，潜在的更严重的火灾内和之间的立场，并推断周围的查帕拉尔。这些研究结果表明，土地管理政策，人为纵火率，或气候变化可能发挥了作用，在塑造当代火灾制度，这最近的时期是从世纪前的制度在某些方面不同。复制这项工作在其他山脉，除了与气候和人类历史的比较，将提供有价值的见解，我们的理解的相对作用，人类与气候变化的大锥花旗松和查帕拉尔火制度。
Bigcone Douglas-fir (Pseudotsuga macrocarpa [Vasey] Mayr) is a long-lived, fire-adapted conifer that is endemic to the Transverse Ranges of southern California. At the lower and middle reaches of its elevational distribution, isolated stands of bigcone Douglas-fir are surrounded by extensive stands of chaparral. Our dendrochronology investigations have revealed that these ancient trees commonly record multiple past fires as fire scars in their lower boles. We hypothesized that the fire-scar record found within and among bigcone Douglas-fir stands reflects the temporal and spatial patterns of fire in the surrounding chaparral. We compared the fire scar results with independent, twentieth century fire atlas data to assess our interpretations. Using fire scars and ring-growth changes, we reconstructed fire history in Los Padres National Forest and investigated changes in fire regime characteristics over the past several centuries.Our analyses confirm that the tree-ring record can be used to accurately reconstruct past fire occurrence and extent patterns both within bigcone Douglas-fir stands and surrounding chaparral stands. Many extensive fires were apparent in both the pre- and post-twentieth century period indicating that such events were a natural component of the system. However, many smaller fires were also evident in the tree-ring record, and more of these types of events occurred during the nineteenth century (and earlier) than during the twentieth century. We also identified a shift after the late nineteenth century to potentially more severe fires within and among stands, and by inference the surrounding chaparral. These findings suggest that land management policies, rates of human-set fires, or climatic variations may have played a role in shaping the contemporary fire regime, and that this recent period is different in some respects from the pre-twentieth century regime. Replication of this work in other mountain ranges, in addition to comparisons with climate and human histories, will provide valuable insights into our understanding of the relative roles of humans versus climate in changing bigcone Douglas-fir and chaparral fire regimes.