Seasonal Drought Effects on Intra-Annual Stem Growth of Taiwan Pine along an Elevational Gradient in Subtropical China

被引:14
|
作者
Liu, Xinsheng [1 ,2 ]
Wang, Chunsong [1 ]
Zhao, Junkai [1 ]
机构
[1] Jiujiang Univ, Coll Tourism & Geog, East Qianjin Rd 551, Jiujiang 332005, Peoples R China
[2] Univ Nevada, Dept Nat Resources & Environm Sci, DendroLab, Reno, NV 89557 USA
来源
FORESTS | 2019年 / 10卷 / 12期
基金
中国国家自然科学基金;
关键词
elevational gradient; seasonal drought; tree growth; tree water deficit; Pinus taiwanensis Hayata; subtropical forest; WOOD FORMATION; GROWING-SEASON; CLIMATE-CHANGE; TREE GROWTH; RADIAL GROWTH; COASTAL AREA; CENTURIES; TEMPERATURE; MOUNTAIN; XYLOGENESIS;
D O I
10.3390/f10121128
中图分类号
S7 [林业];
学科分类号
0829 ; 0907 ;
摘要
Knowledge of intra-annual stem growth dynamics across environmental gradients is important for advancing our ability to understand the adaptability and vulnerability of subtropical tree species to future climate change. To assess the effects of seasonal drought on intra-annual stem growth, stem radial variation of Taiwan pine (Pinus taiwanensis Hayata) was monitored with band dendrometers for two years along an elevation transect from 921 to 1402 m in the Lushan Mountains, a transect that covers the contrasting climatic growing conditions for Taiwan pine in southeastern China. We found that the onset of stem growth was nearly synchronous across the transect, in early April 2017 and in late March 2018, whereas large elevational differences were observed for the end of the growing season, which was much earlier at lower elevations. Tree stems frequently rehydrated during the dry growing seasons at the two higher elevations, suggesting that seasonal drought had minor influence on the offset of high-elevation stem growth. A substantial and continuous tree water deficit of low-elevation Taiwan pine was detected during dry seasons, leading to an early growth cessation in late July in both years. Tree water status (reflected by tree water deficit) revealed a higher sensitivity to precipitation and soil water content across wet- and dry-seasons at the lowest elevation than at high elevations, indicating that low-elevation stem radial growth was highly dependent on moisture variables over the whole growing season. Due to the influences of seasonal drought on growth cessation and rates, Taiwan pine produced a rather narrow annual growth at the lowest site, whereas high-elevation Taiwan pine could benefit from the optimal wet-season environmental conditions and the reactivation of cambial activity during dry seasons. Our findings suggest that the more frequent and intensive drought episodes in the future will reduce tree growth of Taiwan pine at the dry edge, probably resulting in upward shifting of the optimal elevation for Taiwan pine in subtropical China.
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页数:16
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