Abstract

Climate change has an inevitable impact on tree radial growth, particularly at mountain timeberlines. To understand climate effects on conifer radial growth in the central Hengduan Mountains, and the potential impacts of future climate change on conifer forests, we studied the growth responses to climate variables in Abies georgei, the major tree species of conifer forest in the Hengduan Mountains. We collected tree ring samples from four sites near the timberlines and analyzed the relationship between principle components (PC#1) of four chronologies and climatic variables (monthly mean temperature and monthly total precipitation) by using response function analysis (RFA), redundancy analysis (RDA), and moving interval analysis (MIA). A. georgei growth was affected by both temperature (positive effects) and precipitation (negative effects). Specifically, the radial growth of A. georgei was significantly and positively correlated with current July (by 6.1%) and previous November temperature (by 17.3%) (detected by both RFA and RDA), while precipitation of current June (by 6.6%) and September (by 11.7%) inhibited tree growth (detected by RDA). More rapid warming in the most recent 20 years (1990–2010) clearly enhanced growth responses to July and November temperature, whereas the relationship was weakened for June and September precipitation, according to MIA. Under the climate trend of the study area, if the increasing temperature could offset the negative effects of excessive precipitation, A. georgei radial growth would likely benefit from warming.

Highlights

  • Instrumental climate records suggest that mountain forests in high elevation areas have been subject to higher rates of temperature change than the surrounding lowlands [1]

  • We studied the relationships between the residual chronologies of A. georgei and climatic variables, and discussed the potential effects of future climate change on A. georgei and related forest growth

  • The expressed population signal (EPS) values of all four chronologies were above 0.85, suggesting that the chronologies could represent the characteristics of tree-ring width in the area, and that they could be used in this dendrochronological study

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Summary

Introduction

Instrumental climate records suggest that mountain forests in high elevation areas have been subject to higher rates of temperature change than the surrounding lowlands [1]. During the past five decades, the area of central Hengduan Mountains has experienced a significant warming trend at a rate of 0.3 ◦ C/decade [2]. This climate change has a great influence on tree regeneration, growth, and migrating abilities in high elevation areas [1,3], affecting the structure, productivity, and dynamics of forests in high mountain regions [4,5].

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