Tree-ring evidence for the historical cyclic defoliator outbreaks on Larix potaninii in the central Hengduan Mountains, SW China

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• 作者：Ze-Xin Fan^a ; ^{fanzexin@xtbg.org.cn} ; Achim Brä ; uning^b
• 关键词：Climate response ; Dendroecology ; Hengduan Mountains ; Insect outbreak ; Larix potaninii ; Tree rings
• 刊名：Ecological Indicators
• 出版年：2017
• 出版时间：March 2017
• 年：2017
• 卷：74
• 期：Complete
• 页码：160-171
• 全文大小：5737 K
• 卷排序：74

文摘

Dendrochronological methods have been used to reconstruct insect outbreaks, yet the application has been scarce in the high Asia. We compiled tree-ring data from 4 host (Larix potaninii) and 4 non-host (Abies and Picea) sites in the central Hengduan Mountains, southwestern China. We assessed site-specific growth-climate responses and applied two methods to detecting larch insect defoliation events during the past 250 years. Compared with the non-host chronologies, larch trees (host) showed periodic reduction in radial growth, which may be associated with outbreaks of a larch defoliator. Synchronously, growth reductions was found for three low-elevation sites, such as during 1783–1790, 1846–1850, 1860–1865, 1873–1878, 1900–1909, 1939–1945, 1965–1970 and 1981–1986. However, these periods of outbreaks differ from those of a high-elevation site. With spectral analyses, we found 11–13 years frequency domains for three low-elevation larch chronologies, while 7–9 year peaks presented one high-elevation site. Contrastively, no significant frequency domains within the same periodicity were found in ring-width chronologies of co-occurring non-host species. We provide tree-ring evidence that larch trees growing in the central Hengduan Mountains have been infected by insect defoliators repeatedly. We suggest that appropriate approaches should be applied to correct insect-defoliation signals when using larch tree-ring data as a climatic proxy.