Individual size but not additional nitrogen regulates tree carbon sequestration in a subtropical forest

Jianping Wu,Xiaohua Wei,Honglang Duan,Houbao Fan,Yingchun Liao,Wenfei Liu

doi:10.1038/srep46293

Jianping Wu, Xiaohua Wei + Show 4 more

Open Access

https://doi.org/10.1038/srep46293

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Abstract

Recent studies have indicated that tree carbon accumulation in subtropical forests has been negatively affected by global change phenomena such as warming and drought. However, the long-term effect of nitrogen addition on plant carbon storage remains poorly understood in these regions. In this study, we conducted a 10-year field experiment examining the effect of experimental N addition on plant growth and carbon storage in a subtropical Chinese fir forest. The N levels were 0 (control), 60, 120, and 240 kg ha−1 yr−1, and the N effects on tree carbon were divided into stand and individual levels. The results indicated that tree carbon storage at the stand scale was not affected by long-term N addition in the subtropical forest. By contrast, significant impacts of different tree size classes on carbon sequestration were found under different N treatments, which indicated that the amount of plant carbon sequestration was significantly enhanced with tree size class. Our findings highlight the importance of community structure and growth characteristics in Chinese fir forests, in which individual size but not additional N regulates tree carbon sequestration in this subtropical forest.

Highlights

Deposition on plant carbon has been found in temperate and boreal forests[24,25]
We used data from a10-year observation plot in a Chinese fir forest to examine whether N addition affects net primary production at the stand level and whether the responses of plant carbon sequestration are affected by tree size
Our data indicated that N addition did not affect plant carbon storage after 10 years of treatment at the stand level

Summary

Introduction

Deposition on plant carbon has been found in temperate and boreal forests[24,25]. There were several N addition experiments concerning tree growth more than 10 years long[14,18,20], as far as we know, no study has used long-term (>10 years) manipulation experiments to investigate the responses of individual trees to N addition in China. It is unclear whether unchanged plant growth after N deposition is affected by different growth dynamics among different tree sizes. We predicted that tree size would play a greater role in carbon storage overtime due to its growth characteristics

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Results

Conclusion