Effects of Near Natural Forest Management on Soil Greenhouse Gas Flux in Pinus massoniana (Lamb.) and Cunninghamia lanceolata (Lamb.) Hook. Plantations

Angang Ming,Yuanfa Li,Yujing Yang,Dongjing Sun,You Nong,Daoxiong Cai,Yi Tao,Hongyan Jia,Shirong Liu,Hui Wang,Hua Li

doi:10.3390/f9050229

Abstract

Greenhouse gases are the main cause of global warming, and forest soil plays an important role in greenhouse gas flux. Near natural forest management is one of the most promising options for improving the function of forests as carbon sinks. However, its effects on greenhouse gas emissions are not yet clear. It is therefore necessary to characterise the effects of near natural forest management on greenhouse gas emissions and soil carbon management in plantation ecosystems. We analysed the influence of near natural management on the flux of three major greenhouse gases (carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O)) in Pinus massoniana Lamb. and Cunninghamia lanceolata (Lamb.) Hook. plantations. The average emission rates of CO2 and N2O in the near natural plantations were higher than those in the corresponding unimproved pure plantations of P. massoniana and C. lanceolata, and the average absorption rate of CH4 in the pure plantations was lower than that in the near natural plantations. The differences in the CO2 emission rates between plantations could be explained by differences in the C:N ratio of the fine roots. The differences in the N2O emission rates could be attributed to differences in soil available N content and the C:N ratio of leaf litter, while the differences in CH4 uptake rate could be explained by differences in the C:N ratio of leaf litter only. Near natural forest management negatively affected the soil greenhouse gas emissions in P. massoniana and C. lanceolata plantations. The potential impact of greenhouse gas flux should be considered when selecting tree species for enrichment planting.

Highlights

Increased emissions of greenhouse gases, dominated by carbon dioxide (CO2 ), methane (CH4 ), and nitrous oxide (N2 O), are the main cause of global climate change [1]
N2 O is released from the soil to the atmosphere through microbe-regulated nitrification and denitrification [4], while forest soil usually serves as the absorption sink for atmosphere
The present study showed that the seasonal variation in the soil CO2 emission rate in most cases can be attributed to soil temperature rather than soil moisture (Figure 3 and Table 2)

Summary

Introduction

Increased emissions of greenhouse gases, dominated by carbon dioxide (CO2 ), methane (CH4 ), and nitrous oxide (N2 O), are the main cause of global climate change [1]. Most greenhouse gases in the atmosphere are produced and absorbed by soil [2]. Forest soils have the largest carbon pool in terrestrial ecosystems owing to soil respiration processes, mainly root respiration, microbial respiration, and soil. About 6% of global CH4 is absorbed through soil processes by methanogenic bacteria [6,7]. A comprehensive understanding of the rates of greenhouse gas emissions and absorption and their key influencing factors in forest soils is critical to assessing the contribution of forest ecosystems to global climate change [9,10]

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Conclusion