文献类型：期刊文献

英文题名：Drought-affected Populus simonii Carr. Show lower growth and long-term increases in intrinsic water-use efficiency prior to tree mortality

作者：Sun, Shoujia[1,2] Qiu, Lanfen[3] He, Chunxia[1,2] Li, Chunyou[4] Zhang, Jinsong[1,2] Meng, Ping[1,2]

第一作者：孙守家;Sun, Shoujia

通信作者：Meng, Ping|[a00052b40b8123a9a37eb]孟平;

机构：[1] Key Laboratory of Tree Breeding and Cultivation of State Forestry Administration, Research Institute of Forestry, Chinese Academy of Forestry, Beijing, 100091, China; [2] Collaborative Innovation Center of Sustainable Forestry in Southern China, Nanjing Forestry University, Nanjing, 210037, China; [3] Beijing Key Laboratory of Ecologic Function Assessment and Regulation Technology of Green Space, Beijing Institute of Landscape Architecture, Beijing, 100102, China; [4] College of Landscape and Travel, Agricultural University of Hebei Baoding, Baoding, 071000, China

年份：2018

卷号：9

期号：9

外文期刊名：Forests

收录：EI(收录号：20183905856977);Scopus(收录号：2-s2.0-85053595082)

语种：英文

外文关键词：Ecology - Efficiency - Forestry - Storms

摘要：The Three-North Shelter Forest (TNSF) is a critical ecological barrier against sandstorms in northern China, but has shown extensive decline and death in Populus simonii Carr. in the last decade. We investigated the characteristics-tree-ring width, basal area increment (BAI), carbon isotope signature (13Ccor), and intrinsic water-use efficiency (iWUE)-of now-dead, dieback, and non-dieback trees in TNSF shelterbelts of Zhangbei County. Results from the three groups were compared to understand the long-term process of preceding drought-induced death and to identify potential early-warning proxies of drought-triggered damage. The diameter at breast height (DBH) was found to decrease with the severity of dieback, showing an inverse relationship. In all three groups, both tree-ring width and BAI showed quadratic relationships with age, and peaks earlier in the now-dead and dieback groups than in the non-dieback group. The tree-ring width and BAI became significantly lower in the now-dead and dieback groups than in the non-dieback group from 17 to 26 years before death, thus, these parameters can serve as early-warning signals for future drought-induced death. The now-dead and dieback groups had significantly higher δ13Ccor and iWUEs than the non-dieback group at 7-16 years prior to the mortality, indicating a more conservative water-use strategy under drought stress compared with non-dieback trees, possibly at the cost of canopy defoliation and long-term shoot dieback. The iWUE became significantly higher in the now-dead group than in the dieback group at 0-7 years before death, about 10 years later than the divergence of BAI. After the iWUE became significantly different among the groups, the now-dead trees showed lower growth and died over the next few years. This indicates that, for the TNSF shelterbelts studied, an abrupt iWUE increase can be used as a warning signal for acceleration of impending drought-induced tree death. In general, we found that long-term drought decreased growth and increased iWUE of poplar tree. Successive droughts could drive dieback and now-dead trees to their physiological limits of drought tolerance, potentially leading to decline and mortality episodes. ? 2018 by the authors.