Effect of thinning intensity on the stem CO2 efflux of Larix principis-rupprechtii Mayr
Abstract Background Stem CO2 efflux (E S) plays a critical role in the carbon budget of forest ecosystems. Thinning is a core practice for sustainable management of plantations. It is therefore necessary and urgent to study the effect and mechanism of thinning intensity (TI) on E S. Methods In this...
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| Format: | Article |
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KeAi Communications Co., Ltd.
2021-09-01
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| Series: | Forest Ecosystems |
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| Online Access: | https://doi.org/10.1186/s40663-021-00346-4 |
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| author | Kuangji Zhao Timothy J. Fahey Xiangzhen Wang Jie Wang Fang He Chuan Fan Zhongkui Jia Xianwei Li |
| author_facet | Kuangji Zhao Timothy J. Fahey Xiangzhen Wang Jie Wang Fang He Chuan Fan Zhongkui Jia Xianwei Li |
| author_sort | Kuangji Zhao |
| collection | DOAJ |
| description | Abstract Background Stem CO2 efflux (E S) plays a critical role in the carbon budget of forest ecosystems. Thinning is a core practice for sustainable management of plantations. It is therefore necessary and urgent to study the effect and mechanism of thinning intensity (TI) on E S. Methods In this study, five TIs were applied in Larix principis-rupprechtii Mayr 21-, 25-, and 41-year-old stands in North China in 2010. Portable infrared gas analyzer (Li-8100 A) was used to measure E S and its association with environmental factors at monthly intervals from May to October in 2013 to 2015. In addition, nutrients, wood structure and nonstructural carbon (NSC) data were measured in August 2016. Results The results show that E S increased with increasing TI. The maximum E S values occurred at a TI of 35 % (3.29, 4.57 and 2.98 µmol∙m-2∙s-1) and were 1.54-, 1.94- and 2.89-fold greater than the minimum E S value in the CK stands (2.14, 2.35 and 1.03 µmol∙m-2∙s-1) in July for the 21-, 25- and 41-year-old forests, respectively. The E S of the trees in low-density stands was more sensitive to temperature than that of the trees in high-density stands. Soluble sugars (SS) and temperature are the main factors affecting E S. When the stand density is low enough as 41-year-old L. principis-rupprechtii forests with TI 35 %, bark thickness (BT) and humidity should be considered in addition to air temperature (T a), wood temperature (T w), sapwood width (SW), nitrogen concentration (N) and SS in the evaluation of E S. If a change in stand density is ignored, the CO2 released from individual 21-, 25- and 41-year-old trees could be underestimated by 168.89 %, 101.94 % and 200.49 %, respectively. CO2 release was estimated based on the stem equation in combination with the factors influencing E S for reference. Conclusions We suggest that it is not sufficient to conventional models which quantify E S only by temperature and that incorporating the associated drivers (e.g. density, SS, SW and N) based on stand density into conventional models can improve the accuracy of E S estimates. |
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| spelling | doaj.art-cd8fc5bd35f746cbb72fc94ece3965c92023-01-02T08:51:12ZengKeAi Communications Co., Ltd.Forest Ecosystems2197-56202021-09-018111510.1186/s40663-021-00346-4Effect of thinning intensity on the stem CO2 efflux of Larix principis-rupprechtii MayrKuangji Zhao0Timothy J. Fahey1Xiangzhen Wang2Jie Wang3Fang He4Chuan Fan5Zhongkui Jia6Xianwei Li7Sichuan Province Key Laboratory of Ecological Forestry Engineering on the Upper Reaches of the Yangtze River, College of Forestry, Sichuan Agricultural University,Department of Natural Resources, Cornell UniversityKey Laboratory for Silviculture and Conservation of the Ministry of Education, College of Forestry, Beijing Forestry UniversityKey Laboratory for Silviculture and Conservation of the Ministry of Education, College of Forestry, Beijing Forestry UniversityKey Laboratory for Silviculture and Conservation of the Ministry of Education, College of Forestry, Beijing Forestry UniversitySichuan Province Key Laboratory of Ecological Forestry Engineering on the Upper Reaches of the Yangtze River, College of Forestry, Sichuan Agricultural University,Key Laboratory for Silviculture and Conservation of the Ministry of Education, College of Forestry, Beijing Forestry UniversitySichuan Province Key Laboratory of Ecological Forestry Engineering on the Upper Reaches of the Yangtze River, College of Forestry, Sichuan Agricultural University,Abstract Background Stem CO2 efflux (E S) plays a critical role in the carbon budget of forest ecosystems. Thinning is a core practice for sustainable management of plantations. It is therefore necessary and urgent to study the effect and mechanism of thinning intensity (TI) on E S. Methods In this study, five TIs were applied in Larix principis-rupprechtii Mayr 21-, 25-, and 41-year-old stands in North China in 2010. Portable infrared gas analyzer (Li-8100 A) was used to measure E S and its association with environmental factors at monthly intervals from May to October in 2013 to 2015. In addition, nutrients, wood structure and nonstructural carbon (NSC) data were measured in August 2016. Results The results show that E S increased with increasing TI. The maximum E S values occurred at a TI of 35 % (3.29, 4.57 and 2.98 µmol∙m-2∙s-1) and were 1.54-, 1.94- and 2.89-fold greater than the minimum E S value in the CK stands (2.14, 2.35 and 1.03 µmol∙m-2∙s-1) in July for the 21-, 25- and 41-year-old forests, respectively. The E S of the trees in low-density stands was more sensitive to temperature than that of the trees in high-density stands. Soluble sugars (SS) and temperature are the main factors affecting E S. When the stand density is low enough as 41-year-old L. principis-rupprechtii forests with TI 35 %, bark thickness (BT) and humidity should be considered in addition to air temperature (T a), wood temperature (T w), sapwood width (SW), nitrogen concentration (N) and SS in the evaluation of E S. If a change in stand density is ignored, the CO2 released from individual 21-, 25- and 41-year-old trees could be underestimated by 168.89 %, 101.94 % and 200.49 %, respectively. CO2 release was estimated based on the stem equation in combination with the factors influencing E S for reference. Conclusions We suggest that it is not sufficient to conventional models which quantify E S only by temperature and that incorporating the associated drivers (e.g. density, SS, SW and N) based on stand density into conventional models can improve the accuracy of E S estimates.https://doi.org/10.1186/s40663-021-00346-4Stem CO2 effluxThinning intensityEnvironmental factorsNutrient contentWood structureNonstructural carbon |
| spellingShingle | Kuangji Zhao Timothy J. Fahey Xiangzhen Wang Jie Wang Fang He Chuan Fan Zhongkui Jia Xianwei Li Effect of thinning intensity on the stem CO2 efflux of Larix principis-rupprechtii Mayr Forest Ecosystems Stem CO2 efflux Thinning intensity Environmental factors Nutrient content Wood structure Nonstructural carbon |
| title | Effect of thinning intensity on the stem CO2 efflux of Larix principis-rupprechtii Mayr |
| title_full | Effect of thinning intensity on the stem CO2 efflux of Larix principis-rupprechtii Mayr |
| title_fullStr | Effect of thinning intensity on the stem CO2 efflux of Larix principis-rupprechtii Mayr |
| title_full_unstemmed | Effect of thinning intensity on the stem CO2 efflux of Larix principis-rupprechtii Mayr |
| title_short | Effect of thinning intensity on the stem CO2 efflux of Larix principis-rupprechtii Mayr |
| title_sort | effect of thinning intensity on the stem co2 efflux of larix principis rupprechtii mayr |
| topic | Stem CO2 efflux Thinning intensity Environmental factors Nutrient content Wood structure Nonstructural carbon |
| url | https://doi.org/10.1186/s40663-021-00346-4 |
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