Comparison of the Radial Growth Response of Picea crassifolia to Climate Change in Different Regions of the Central and Eastern Qilian Mountains

Xuan Wu,Ruhong Xue,Changliang Qi,Dashi Du,Liang Jiao

doi:10.3390/f12081015

Abstract

It is important to explore the responses of radial tree growth in different regions to understand growth patterns and to enhance forest management and protection with climate change. We constructed tree ring width chronologies of Picea crassifolia from different regions of the Qilian Mountains of northwest China. We used Pearson correlation and moving correlation to analyze the main climate factors limiting radial growth of trees and the temporal stability of the growth–climate relationship, while spatial correlation is the result of further testing the first two terms in space. The conclusions were as follows: (1) Radial growth had different trends, showing an increasing followed by a decreasing trend in the central region, a continuously increasing trend in the eastern region, and a gradually decreasing trend in the isolated mountain. (2) Radial tree growth in the central region and isolated mountains was constrained by drought stress, and tree growth in the central region was significantly negatively correlated with growing season temperature. Isolated mountains showed a significant negative correlation with mean minimum of growing season and a significant positive correlation with total precipitation. (3) Temporal dynamic responses of radial growth in the central region to the temperatures and SPEI (the standardized precipitation evapotranspiration index) in the growing season were unstable, the isolated mountains to total precipitation was unstable, and that to SPEI was stable. The results of this study suggest that scientific management and maintenance plans of the forest ecosystem should be developed according to the response and growth patterns of the Qinghai spruce to climate change in different regions of the Qilian Mountains.

Highlights

Forest ecosystems cover about 30% of the Earth’s total land area [1]
We investigated the responses of radial growth of the Qinghai spruce to environmental conditions in different regions of the Qilian Mountains and confirmed that drought is the main factor for radial growth
Our results showed that the radial growth patterns of trees varied in different regions of the Qilian Mountains in 1957–2018, as evidenced by the increasing trend (3.35 cm2 /10 a, p < 0.05) and a decreasing trend (−2.2 cm2 /10 a, p < 0.05) in the central region, an increasing trend (4.02 cm2 /10 a, p < 0.05) in the eastern part, and a steadily decreasing trend (−0.95 cm2 /10 a, p < 0.05) in the isolated mountain (Figure 4)

Summary

Introduction

Forest ecosystems cover about 30% of the Earth’s total land area [1]. As an important part of terrestrial ecosystems, they play a key role in maintaining the global carbon balance, regulating the terrestrial water cycle, conserving soil and water, and preserving the environment [2,3]. Global warming has become an indisputable fact. The annual mean temperature of the northern hemisphere of the last 30 years is the hottest it has been in the past 800 to 1400 years [4]. It is estimated that the global average surface temperature will rise by 1.4 to 5.8 ◦ C by 2100 [5]. Climate change has profoundly affected tree growth, phenology, species composition, and distribution in forest ecosystems

Methods

Results

Discussion

Conclusion