气候变化领域集成服务门户(CCPortal): Stand density effects on carbon and water fluxes in a semi-arid forest, from leaf to stand-scale

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DOI	10.1016/j.foreco.2019.117573
	Stand density effects on carbon and water fluxes in a semi-arid forest, from leaf to stand-scale
	Tsamir M.; Gottlieb S.; Preisler Y.; Rotenberg E.; Tatarinov F.; Yakir D.; Tague C.; Klein T.
发表日期	2019
ISSN	0378-1127
卷号	453
英文摘要	Drought-induced productivity reductions and tree mortality have been increasing in recent decades in forests around the globe. Prescribed reduction in stand density, i.e. thinning, has been proposed as a management tool to improve forest sustainability in face of a warmer, drier future. Thinning should potentially reduce net stand water use and improve water-availability for remaining trees, thus reducing their subsequent drought vulnerability. However, few studies have directly measured these effects. In 2009 we established a large-scale thinning experiment in a semi-arid, 40-years-old pine afforestation. Study plots (70 × 70 m) were thinned to 100, 200, and 300 trees ha−1, and compared with unthinned control plots (210–400 trees ha−1), each at five replications. Stem and needle growth, and needle gas exchange were measured along 3–9 consecutive years at seasonal to annual temporal resolution. Measurements at the tree-scale were further up-scaled using both simple upscaling relationships and using an ecosystem model of coupled carbon, energy and hydrology (Regional Hydro Ecologic Simulation System, RHESSys). At the needle scale, photosynthesis was 70% higher at the 100 trees ha−1 than at 300 trees ha−1, whereas transpiration was merely 10% higher. Consequently, stem and needle growth increased by 100% and 20%, respectively. For most parameters, there was little change between 200 and 100 trees ha−1. Applying RHESSys at the stand-scale, these effects on tree physiology translated into 35% reduction in CO2 uptake and a 47% reduction in tree water-use, which was compensated for by increased evaporation from exposed soil. Our long-term measurements at the dry timberline highlight the role of thinning in enhancing the activity and growth of remaining trees, with increased water-use efficiency. Unexpectedly, this density reduction was associated with a relatively small decrease in forest carbon uptake. Light availability was a limiting factor in the higher density plots, even in our light-abundant forest. © 2019 Elsevier B.V.
英文关键词	Carbon assimilation; Evaporation; Photosynthetically active radiation; Thinning; Transpiration; Water balance
语种	英语
scopus关键词	Carbon; Drought; Evaporation; Needles; Reforestation; Carbon assimilation; Forest sustainability; Large-scale thinning; Long-term measurements; Photosynthetically active radiation; Thinning; Water balance; Water use efficiency; Transpiration; afforestation; carbon; carbon flux; drought stress; evaporation; forest ecosystem; forestry production; light availability; limiting factor; long-term change; mortality; photosynthetically active radiation; scale effect; semiarid region; stand dynamics; stand structure; sustainability; thinning; transpiration; vulnerability; water availability; water budget; water flux; Carbon; Drought; Evaporation; Needles; Reforestation; Thinning
来源期刊	Forest Ecology and Management
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/155723
作者单位	Plant & Environmental Sciences Department, Weizmann Institute of Science, Rehovot, Israel; Earth and Planetary Science Department, Weizmann Institute of Science, Rehovot, Israel; Bren School of Environmental Science & Management, University of California, Santa BarbaraCA, United States
推荐引用方式 GB/T 7714	Tsamir M.,Gottlieb S.,Preisler Y.,et al. Stand density effects on carbon and water fluxes in a semi-arid forest, from leaf to stand-scale[J],2019,453.
APA	Tsamir M..,Gottlieb S..,Preisler Y..,Rotenberg E..,Tatarinov F..,...&Klein T..(2019).Stand density effects on carbon and water fluxes in a semi-arid forest, from leaf to stand-scale.Forest Ecology and Management,453.
MLA	Tsamir M.,et al."Stand density effects on carbon and water fluxes in a semi-arid forest, from leaf to stand-scale".Forest Ecology and Management 453(2019).