Chin J Plant Ecol ›› 2018, Vol. 42 ›› Issue (1): 66-77.DOI: 10.17521/cjpe.2017.0251

Special Issue: 青藏高原植物生态学:种群生态学

• Research Articles • Previous Articles     Next Articles

Comparison of growth-climate relationship of Sabina przewalskii at different timberlines along a precipitation gradient in the northeast Qinghai-Xizang Plateau, China

SONG Wen-Qi1,ZHU Liang-Jun1,ZHANG Xu1,WANG Xiao-Chun1,*(),ZHANG Yuan-Dong2,*()   

  1. 1 Center For Ecological Research, Northeast Forestry University, Harbin 150040, China
    and
    2 Institute of Forest Ecology, Environment and Protection, Chinese Academy of Forestry Key Laboratory of Forest Ecology and Environment, State Forestry Administration, Beijing 100091, China
  • Online:2018-01-20 Published:2018-01-18
  • Contact: WANG Xiao-Chun ORCID: 0000-0002-8897-5077, ZHANG Yuan-Dong
  • Supported by:
    Supported by the National Natural Science Foundation of China(31370463);Supported by the National Natural Science Foundation of China(41471168);Supported by the National Natural Science Foundation of China(31770490);Supported by the National Natural Science Foundation of China(31370463);Supported by the National Natural Science Foundation of China(41471168);Supported by the National Natural Science Foundation of China(31770490);the International Key Science Research Program(2016YFA0600800);the Fundamental Science Research Funds for the Central Universities High-level Talents Development.

Abstract:

Aims To test the hypothesis that water is the main limiting factor of tree growth at the arid alpine timberline, and to explore the effects of water on growth-climate relationships of Sabina przewalskii along a precipitation gradient in the northeast Qinghai-Xizang Plateau.

Methods Three sides were selected to sample the alpine timberline along a precipitation gradient in the northeast Qinghai-Xizang Plateau: Halihatu National Forest Park in Wulan County (HL, annual precipitation 217 mm), Qushigang in Dulan County (QS, 281 mm) and Hebei Forest Farm in Tongde County (HB, 470 mm). The correlation and response analysis at seasonal and extreme climate year scales were used to examine the spatial variations of the growth-climate relationship of S. przewalskii at different timberlines.

Important findings Our results do not support the hypothesis that water is the main limiting factor of tree growth at the arid alpine timberline. The effect of precipitation on the radial growth of S. przewalskii were consistent across all three sampling sites, while the effects of temperature were different across sites. At HL site (low precipitation), the winter and summer minimum temperature were the main limiting factor of S. przewalskii radial growth, and this relationship did not significantly change in different extreme climate years. At QS site (middle precipitation), the radial growth of S. przewalskii was mainly limited by the minimum temperature in spring and summer, but its effect was weaker than that at low precipitation site. At HB site (high precipitation), the spring temperature had a significant negative effect on tree growth, and the positive effect of spring precipitation on tree growth was significantly enhanced in comparison with those at low and middle precipitation sites, especially in extreme high temperature and drought years. Summer precipitation did not significantly affect tree growth at high precipitation site. Our results did not support the hypothesis that the radial growth of trees at alpine timberline in arid/humid area is mainly limited by water/temperature. However, precipitation at timberline will affect the relationship between tree growth and temperature at different seasons. With the warming and humidification of the northeastern Qinghai-Xizang Plateau, the climatic limiting factors of tree growth in different timberline areas may be complicated.

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Key words: alpine timberline, climate limiting factors, precipitation gradient, Sabina przewalskii, Qinghai-?Xizang Plateau, tree-ring index