Impacts of Change in Atmospheric CO2 Concentration on Larix gmelinii Forest Growth in Northeast China from 1950 to 2010

Bin Wang,Weiwei Jia,Ying Yu,Wenyi Fan,Mingze Li

doi:10.3390/f10050454

Abstract

Although CO2 fertilization on plant growth has been repeatedly modeled to be the main reason for the current changes in the terrestrial carbon sink at the global scale, there have been controversial findings on the CO2 fertilization effects on forests from tree-ring analyses. In this study, we employed conventional dendrochronological tree-ring datasets from Northeast China, to detect the effect of CO2 fertilization on Larix gmelinii growth from 1950 to 2010. Among four sites, there were two sites exhibiting a significant residual growth enhancement at a 90% confidence level after removing the size, age and climaterelated trends of tree-ring indices. In addition, we found consistency (R from 0.26 to 0.33, p < 0.1) between the high frequency CO2 fluctuation and residual growth indices at two of the four sites during the common period. A biogeochemical model was used to quantitatively predict the contribution of elevated atmospheric CO2 on accumulated residual growth enhancement. As found in the tree-ring data, 14% of the residual growth was attributed to the CO2 fertilization effect, while climate was responsible for approximately the remainding 86%.

Highlights

The rapid increase in CO2 concentration in the atmosphere as a greenhouse gas is thought to be responsible for the increase in earth’s surface temperature [1]
Recent studies based on terrestrial carbon cycle models suggested that the strength of the terrestrial C sink was growing at the global scale, while CO2 fertilization was the predominant driver of the growth in the terrestrial C sink [3,4,5,6]
The growing season precipitation was positively correlated with the tree growth, while negative correlations could be found in the winter months

Summary

Introduction

The rapid increase in CO2 concentration in the atmosphere as a greenhouse gas is thought to be responsible for the increase in earth’s surface temperature [1]. The response of forest ecosystems to elevated atmospheric CO2 concentration will affect their net uptake or loss of carbon and may, have large consequences on the global carbon cycle [2]. Numerous global-level experiments were conducted to investigate and understand how the terrestrial ecosystem carbon cycle responds to rising atmospheric CO2. Recent studies based on terrestrial carbon cycle models suggested that the strength of the terrestrial C sink was growing at the global scale, while CO2 fertilization was the predominant driver of the growth in the terrestrial C sink [3,4,5,6]. In spite of the wealth of global assessments and experimental evidences on CO2 fertilization on tree growth, results from tree-ring studies on the CO2 fertilization effect are controversial and still under debate [11,12,13,14,15,16,17]

Objectives

Methods

Results

Discussion

Conclusion