Department of Plant Pathology, University of California, Davis, California 95616, USA.
Ecol Appl. 2011 Mar;21(2):313-20. doi: 10.1890/10-0419.1.
Sudden oak death (SOD) is an emerging forest disease causing extensive tree mortality in coastal California forests. Recent California wildfires provided an opportunity to test a major assumption underlying discussions of SOD and land management: SOD mortality will increase fire severity. We examined prefire fuels from host species in a forest monitoring plot network in Big Sur, California (USA), to understand the interactions between disease-caused mortality and wildfire severity during the 2008 Basin Complex wildfire. Detailed measurements of standing dead woody stems and downed woody debris 1-2 years prior to the Basin fire provided a rare picture of the increased fuels attributable to SOD mortality. Despite great differences in host fuel abundance, we found no significant difference in burn severity between infested and uninfested plots. Instead, the relationship between SOD and fire reflected the changing nature of the disease impacts over time. Increased SOD mortality contributed to overstory burn severity only in areas where the pathogen had recently invaded. Where longer-term disease establishment allowed dead material to fall and accumulate, increasing log volumes led to increased substrate burn severity. These patterns help inform forest management decisions regarding fire, both in Big Sur and in other areas of California as the pathogen continues to expand throughout coastal forests.
突发 oak 死亡 (SOD) 是一种新兴的森林疾病，导致加利福尼亚沿海森林大量树木死亡。最近的加利福尼亚野火为测试 SOD 和土地管理讨论的一个主要假设提供了机会：SOD 死亡率将增加火灾严重程度。我们检查了加利福尼亚大苏尔 (Big Sur，美国) 森林监测网络中宿主物种的火灾前燃料，以了解 2008 年盆地区域大火期间疾病引起的死亡率和野火严重程度之间的相互作用。在盆地区域火灾发生前 1-2 年对直立枯木和倒下的木质碎片进行了详细测量，为归因于 SOD 死亡率的增加燃料提供了罕见的图片。尽管宿主燃料丰度存在很大差异，但我们发现受感染和未受感染的地段之间的燃烧严重程度没有显著差异。相反，SOD 和火灾之间的关系反映了随着时间的推移疾病影响的变化性质。只有在病原体最近入侵的地区，增加的 SOD 死亡率才会导致林冠燃烧严重程度增加。在长期疾病建立的地方，允许死物质倒下和积累，增加原木数量会导致基质燃烧严重程度增加。这些模式有助于为森林管理决策提供信息，无论是在大苏尔还是在加利福尼亚的其他地区，因为病原体继续在沿海森林中扩散。
