Species- and Elevation-Dependent Growth Responses to Climate Warming of Mountain Forests in the Qinling Mountains, Central China

Bo Liu,J Camarero,Kang Liu,Eryuan Liang

doi:10.3390/f9050248

Abstract

Climate warming is significantly affecting the composition and function of forest ecosystems. However, the forest responses to climate change in sub-humid and temperate areas are understudied compared with cold and semi-arid areas. Here, we investigate the radial-growth responses of two subalpine conifer species along an elevational gradient located in the Qinling Mountains, a sub-humid and temperate area situated in central China. Three sites dominated by larch (Larix chinensis Beissn.) and two other sites dominated by fir (Abies fargesii Franch.) located at different elevations were sampled. L. chinensis at a higher elevation showed more common and stronger climatic signals than A. fargesii at a lower elevation. The radial growth of L. chinensis was limited by low pre-growing season temperatures and showed an increasing growth trend in the last few years. On the other hand, A. fargesii growth was limited by summer water shortage and it was characterized by a declining trend in the most recent decade. Consequently, L. chinensis would benefit from climate warming, whereas A. fargesii could be regarded as a vulnerable tree species to warming-induced drought stress.

Highlights

Global warming has been significantly influencing the composition, structure, and dynamics of forest ecosystems during the last decades [1,2]
It has been reported that forests are subjected to an increasing risk of growth decline, canopy dieback, and mortality under warming-induced drought stress in semi-arid areas [3,4,5,6], but on the other hand, climate warming has increased tree growth and recruitment in cold biomes [7,8]
The objectives of this study are: (1) to explore the dominant climatic factors limiting the radial growth of L. chinensis and A. fargesii across a 500-m elevation gradient (3360–2860 m) located in the Qinling Mountains; and (2) to assess if there are elevation- and species-dependent growth responses to climatic change

Summary

Introduction

Global warming has been significantly influencing the composition, structure, and dynamics of forest ecosystems during the last decades [1,2]. It has been reported that forests are subjected to an increasing risk of growth decline, canopy dieback, and mortality under warming-induced drought stress in semi-arid areas [3,4,5,6], but on the other hand, climate warming has increased tree growth and recruitment in cold biomes [7,8]. The climate-growth relationship seems to be more complex in humid and sub-humid mountainous areas [9,10,11], where forest dieback and mortality episodes have been recorded [2]. In light of the critical role played by these forests in the global carbon cycle, it is necessary to have a better understanding of their growth responses to climate warming. There is growing evidence that these biomes are experiencing more rapid changes in temperature at high rather than low Forests 2018, 9, 248; doi:10.3390/f9050248 www.mdpi.com/journal/forests

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