About Us
News
Announcement
Research
Conservation & Horticulture
Public Education
Graduate Study
Scientist
International Cooperation
Resources
Annual Reports
Publications & Papers
Visit XTBG
Societies
XTBG Seminar
Open Positions
ATBC Asia 2017
CAS-SEABRI
PFS-Tropical Asia
Links
 
   Location:Home > Research > Research Progress
Tree-ring data proves larch trees repeatedly infected by insect defoliators in central Hengduan Mountains
Author: Fan Zexin
ArticleSource:
Update time: 2016-11-28
Close
Text Size: A A A
Print

 

Dendrochronological methods can be used to analyze growth reductions in annual rings and changes in morphology that are indicative of defoliation, and thus to reconstruct the history of insect outbreaks. However, yet the application has been scarce and there are very few records about insects outbreaks in the Hengduan Mountains.

   Dr. FAN Zexin of Xishuangbanna Tropical Botanical Garden (XTBG) and Dr. Achim Bräuning of University of Erlangen-Nürnberg compiled tree-ring data from 4 host (Larix potaninii) and 4 non-host (Abies and Picea) sites in the central Hengduan Mountains, southwestern China. They analyzed growth patterns in larch (Larix potentii) and non-host spruce (Picea brachytyla, P. likiangensis) and fir (A. georgei) tree-ring chronologies and detected growth depressions in larch tree populations.

   The researchers applied two methods (i.e. host and non-host comparison approach and running minima approach) to identify growth depressions induced by larch insect outbreaks from those caused by climatic and other abiotic factors.

   They found that larch trees show higher inter-series and cross-sites correlations than co-occurring fir and spruce, which indicate that the larch chronologies contain a higher common signal related to biotic and/or abiotic factors. Radial growth depressions of larch trees, accompanying with reduced latewood density, were found synchronously within and across sties in the central Hengduan Mountains.

  The tree-ring data provide evidences that insect defoliators have infected larch trees growing in the central Hengduan Mountains repeatedly. Eight major outbreaks coincided at regional scale were identified over the past 250 years. Spectral analyses indicate that insect outbreaks occurred regularly every 11–13 years, with no such periodicity exist in non-host tree-ring chronologies.

  The study entitled “Tree-ring evidence for the historical cyclic defoliator outbreaks on Larix potaninii in the central Hengduan Mountains, SW China” has been published in Ecological Indicators.

 

 

Contact

FAN Zexin  Ph.D Principal Investigator

Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, Yunnan 666303, China
E-mail: fanzexin@xtbg.org.cn

 

  Appendix Download
Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences. Menglun, Mengla, Yunnan 666303, China
Copyright XTBG 2005-2014 Powered by XTBG Information Center