Age and Growth History of Scattered Ancient Cypresses in Angren County,Xizang

Danzeng Ouzhu; Yu Wu; Zhang Qibin

doi:10.3969/j.issn.1004-3403.2025.12.003

Abstract：Rare ancient trees in the alpine region of western Xizang possess significant ecological,scientific and so-cial value,However,current knowledge about the baseline information and growth conditions of these resources re-mains insufficient.Using dendrochronological method,this paper investigated the baseline resources of scattered an-cient cypresses in Angren county,Rikaze.A total of 20 scattered ancient cypresses were discovered,including 1 in first-class protection,3 in second-class and 16 in third-class.The majority of these trees are distributed in the south-eastern part of the county,with 13 in Duobai and Kaga town,5 in Daju and Yamu town,and only 2 in Sangsang and Xiongba town.Narrow rings occurred synchronously in many cypresses across different periods,whereas wide rings occurred mostly between 1989 and 2006.The tree ring growth pattern,including stable period,fluctuating period,suppressive period,releasing period and growth trend showed both synchronicity and variability.These results sug-gested their spatial distribution pattern characterized by a"higher density in southeastern river valleys,scattered in-dividuals in remote mountains,,and large ones near temples".The ancient cypresses have developed diverse ecologi-cal resilience among individuals in response to climatic change and natural disturbances over centuries.The findings have enriched the baseline information about ancient cypresses in western Xizang,providing data support for the ar-chival work of famous and notable trees.