Areas of Agreement and Disagreement Regarding Ponderosa Pine and Mixed Conifer Forest Fire Regimes: A Dialogue with Stevens et al.
Areas of Agreement and Disagreement Regarding Ponderosa Pine and Mixed Conifer Forest Fire Regimes: A Dialogue with Stevens et al.
复制标题
关于黄松和混合针叶林森林火灾制度的一致和分歧领域：与史蒂文斯等人的对话。
作者：
D. Odion;C. Hanson;W. Baker;D. DellaSala;Mark A. Williams
在最近的PLOS ONE论文中，我们对当前与历史火灾制度进行了基于证据的分析，并得出结论，传统定义的黄松（Pinus ponderosa）和混合针叶林的低严重火灾制度的参考条件是不完整的，缺少森林结构和火灾制度的相当大的变化。Stevens等人（本期）同意，严重的火灾是这些森林的一个组成部分，但不同意的几个证据来源之一，来自美国西部大量森林清查和分析（FIA）地块的林分年龄，支持我们的研究结果，即严重的火灾在这些森林中发挥的生态作用不仅仅是次要的。在这里，我们强调的协议和分歧的领域，对过去的火灾，并分析史蒂文斯等人的方法。我们发现了一个主要的问题，他们使用的计算得出结论，国际汽联的数据是没有用的评估火灾制度。他们的计算，以及从我们使用的定义中缩小了高严重性火灾的定义，导致大大低估了与历史高严重性火灾一致的条件。国际汽联的林分年龄数据确实有局限性，但它们与其他非线性推断数据源一致，支持一个更广泛的范式，关于美国黄松和混合针叶林火灾的历史变异性，而不是传统上公认的，正如我们以前的PLOS论文中所描述的。
In a recent PLOS ONE paper, we conducted an evidence-based analysis of current versus historical fire regimes and concluded that traditionally defined reference conditions of low-severity fire regimes for ponderosa pine (Pinus ponderosa) and mixed-conifer forests were incomplete, missing considerable variability in forest structure and fire regimes. Stevens et al. (this issue) agree that high-severity fire was a component of these forests, but disagree that one of the several sources of evidence, stand age from a large number of forest inventory and analysis (FIA) plots across the western USA, support our findings that severe fire played more than a minor role ecologically in these forests. Here we highlight areas of agreement and disagreement about past fire, and analyze the methods Stevens et al. used to assess the FIA stand-age data. We found a major problem with a calculation they used to conclude that the FIA data were not useful for evaluating fire regimes. Their calculation, as well as a narrowing of the definition of high-severity fire from the one we used, leads to a large underestimate of conditions consistent with historical high-severity fire. The FIA stand age data do have limitations but they are consistent with other landscape-inference data sources in supporting a broader paradigm about historical variability of fire in ponderosa and mixed-conifer forests than had been traditionally recognized, as described in our previous PLOS paper.