Longfei Chen, Zhibin He, Wenzhi Zhao, Xi Zhu, Qin Shen, Mingdan Song, Zhengpeng Li, Junqia Kong, Shuping Yang, Yuan Gao
{"title":"Long-term thinning decreases the contribution of heterotrophic respiration to soil respiration in subalpine plantations","authors":"Longfei Chen, Zhibin He, Wenzhi Zhao, Xi Zhu, Qin Shen, Mingdan Song, Zhengpeng Li, Junqia Kong, Shuping Yang, Yuan Gao","doi":"10.1007/s11676-024-01710-0","DOIUrl":null,"url":null,"abstract":"<p>Interest in the dynamics of soil respiration (<i>R</i><sub><i>s</i></sub>) in subalpine forest ecosystems is increasing due to their high soil carbon density and potential sensitivity to environmental changes. However, as a principal silvicultural practice, the long-term impacts of thinning on <i>R</i><sub><i>s</i></sub> and its heterotrophic and autotrophic respiration components (<i>R</i><sub><i>h</i></sub> and <i>R</i><sub><i>a</i></sub>, respectively) in subalpine plantations are poorly understood, especially in winter. A 3-year field observation was carried out with consideration of winter CO<sub>2</sub> efflux in middle-aged subalpine spruce plantations in northwestern China. A trenching method was used to explore the long-term impacts of thinning on <i>R</i><sub><i>s</i></sub>, <i>R</i><sub><i>h</i></sub> and <i>R</i><sub><i>a</i></sub>. Seventeen years after thinning, mean annual <i>R</i><sub><i>s</i></sub>, <i>R</i><sub><i>h</i></sub> and <i>R</i><sub><i>a</i></sub> increased, while the contribution of <i>R</i><sub><i>h</i></sub> to <i>R</i><sub><i>s</i></sub> decreased with thinning intensity. Thinning significantly decreased winter <i>R</i><sub><i>s</i></sub> because of the reduction in <i>R</i><sub><i>h</i></sub> but had no significant effect on <i>R</i><sub><i>a</i></sub>. The temperature sensitivity (<i>Q</i><sub>10</sub>) of <i>R</i><sub><i>h</i></sub> and <i>R</i><sub><i>a</i></sub> also increased with thinning intensity, with lower <i>Q</i><sub>10</sub> values for <i>R</i><sub><i>h</i></sub> (2.1–2.6) than for <i>R</i><sub><i>a</i></sub> (2.4–2.8). The results revealed the explanatory variables and pathways related to <i>R</i><sub><i>h</i></sub> and <i>R</i><sub><i>a</i></sub> dynamics. Thinning increased soil moisture and nitrate nitrogen (<span>\\({\\text{NO}}_{3}^{ - }\\)</span>-N), and the enhanced nitrogen and water availability promoted <i>R</i><sub><i>h</i></sub> and <i>R</i><sub><i>a</i></sub> by improving fine root biomass and microbial activity. Our results highlight the positive roles of <span>\\({\\text{NO}}_{3}^{ - }\\)</span>-N in stimulating <i>R</i><sub><i>s</i></sub> components following long-term thinning. Therefore, applications of nitrogen fertilizer are not recommended while thinning subalpine spruce plantations from the perspective of reducing soil CO<sub>2</sub> emissions. The increased <i>Q</i><sub>10</sub> values of <i>R</i><sub>s</sub> components indicate that a large increase in soil CO<sub>2</sub> emissions would be expected following thinning because of more pronounced climate warming in alpine regions.</p>","PeriodicalId":15830,"journal":{"name":"Journal of Forestry Research","volume":null,"pages":null},"PeriodicalIF":3.4000,"publicationDate":"2024-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of Forestry Research","FirstCategoryId":"97","ListUrlMain":"https://doi.org/10.1007/s11676-024-01710-0","RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"FORESTRY","Score":null,"Total":0}
引用次数: 0
Abstract
Interest in the dynamics of soil respiration (Rs) in subalpine forest ecosystems is increasing due to their high soil carbon density and potential sensitivity to environmental changes. However, as a principal silvicultural practice, the long-term impacts of thinning on Rs and its heterotrophic and autotrophic respiration components (Rh and Ra, respectively) in subalpine plantations are poorly understood, especially in winter. A 3-year field observation was carried out with consideration of winter CO2 efflux in middle-aged subalpine spruce plantations in northwestern China. A trenching method was used to explore the long-term impacts of thinning on Rs, Rh and Ra. Seventeen years after thinning, mean annual Rs, Rh and Ra increased, while the contribution of Rh to Rs decreased with thinning intensity. Thinning significantly decreased winter Rs because of the reduction in Rh but had no significant effect on Ra. The temperature sensitivity (Q10) of Rh and Ra also increased with thinning intensity, with lower Q10 values for Rh (2.1–2.6) than for Ra (2.4–2.8). The results revealed the explanatory variables and pathways related to Rh and Ra dynamics. Thinning increased soil moisture and nitrate nitrogen (\({\text{NO}}_{3}^{ - }\)-N), and the enhanced nitrogen and water availability promoted Rh and Ra by improving fine root biomass and microbial activity. Our results highlight the positive roles of \({\text{NO}}_{3}^{ - }\)-N in stimulating Rs components following long-term thinning. Therefore, applications of nitrogen fertilizer are not recommended while thinning subalpine spruce plantations from the perspective of reducing soil CO2 emissions. The increased Q10 values of Rs components indicate that a large increase in soil CO2 emissions would be expected following thinning because of more pronounced climate warming in alpine regions.
期刊介绍:
The Journal of Forestry Research (JFR), founded in 1990, is a peer-reviewed quarterly journal in English. JFR has rapidly emerged as an international journal published by Northeast Forestry University and Ecological Society of China in collaboration with Springer Verlag. The journal publishes scientific articles related to forestry for a broad range of international scientists, forest managers and practitioners.The scope of the journal covers the following five thematic categories and 20 subjects:
Basic Science of Forestry,
Forest biometrics,
Forest soils,
Forest hydrology,
Tree physiology,
Forest biomass, carbon, and bioenergy,
Forest biotechnology and molecular biology,
Forest Ecology,
Forest ecology,
Forest ecological services,
Restoration ecology,
Forest adaptation to climate change,
Wildlife ecology and management,
Silviculture and Forest Management,
Forest genetics and tree breeding,
Silviculture,
Forest RS, GIS, and modeling,
Forest management,
Forest Protection,
Forest entomology and pathology,
Forest fire,
Forest resources conservation,
Forest health monitoring and assessment,
Wood Science and Technology,
Wood Science and Technology.