Radial Growth Responses to Climate of Pinus yunnanensis at Low Elevations of the Hengduan Mountains, China

Lian Sun,Yanpeng Cai,Björn E Gunnarson,Yesi Zhao,Fernando Jaramillo,Shiyuan Shi,Yang Zhou

doi:10.3390/f11101066

Abstract

The relationship between climate and forest is critical to understanding the influence of future climate change on terrestrial ecosystems. Research on trees at high elevations has uncovered the relationship in the Hengduan Mountains region, a critical biodiversity hotspot area in southwestern China. The relationship for the area at low elevations below 2800 m a.s.l. in the region remains unclear. In this study, we developed tree ring width chronologies of Pinus yunnanensis Franch. at five sites with elevations of 1170–1725 m in this area. Monthly precipitation, relative humidity, maximum/mean/minimum air temperature and the standardized precipitation evapotranspiration index (SPEI), a drought indicator with a multi-timescale, were used to investigate the radial growth-climate relationship. Results show that the growth of P. yunnanensis at different sites has a similar response pattern to climate variation. Relative humidity, precipitation, and air temperature in the dry season, especially in its last month (May), are critical to the radial growth of trees. Supplemental precipitation amounts and reduced mean or maximum air temperature can promote tree growth. The high correlations between chronologies and SPEI indicate that the radial growth of trees at the low elevations of the region is significantly limited by the moisture availability. Precipitation in the last month of the previous wet season determines the drought regime in the following dry seasons. In spite of some differences in the magnitudes of correlations in the low-elevation area of the Hengduan Mountains region, chronologies generally matched well with each other at different elevations, and the differences are not evident with the change in elevation.

Highlights

Future climate change is likely to influence the productivity of the world’s vegetation
We aimed to study the response of tree radial growth to climate variation in the low-elevation area of the Hengduan Mountains region and try to determine whether the responses were elevation dependent
Except for the combination of R3 and C1, the correlations among the tree ring width chronologies of different sites shared a high degree of coherence in their raw and first difference series (r ≥ 0.41, p < 0.01, Table 2)

Summary

Introduction

Future climate change is likely to influence the productivity of the world’s vegetation. In the context of global warming [1], vegetation in different latitudes and categories of assimilation varies in the magnitude and direction of their responses to climate variation [2,3]. Understanding the complex relationship between climate variation and vegetation dynamics is important to anticipating. Considering the heterogeneous landscape of the region, the change of productivity is spatially unbalanced within the Hengduan Mountains region [12]. This response of vegetation dynamics to future climate change might be more complex [13], as the possible leading climatic factors vary in different parts of the region [14]. It is essential to further explore the relationship between climate variation and vegetation dynamics in this region

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Conclusion