Tree mortality and regeneration of Euphrates poplar riparian forests along the Tarim River, Northwest China

作者：Ayjamal Keram, Ümüt Halik, Tayierjiang Aishan, Maierdang Keyimu, Kadeliya Jiapaer, Guolei Li · 发表于：Forest Ecosystems · 年份：2021 · DOI：10.1186/s40663-021-00323-x · 被引用次数：33 · 研究领域：Plant Water Relations and Carbon Dynamics、Tree-ring climate responses、Forest ecology and management

Abstract Background Tree mortality and regeneration (seedling and sapling recruitment) are essential components of forest dynamics in arid regions, especially where subjected to serious eco-hydrological problems. In recent decades, the mortality of the Euphrates poplar ( Populus euphratica ) along the Tarim River in Northwest China has increased. However, few studies have quantified the causes of mortality and regeneration in this azonal riparian forest type. Methods The present study describes the annual hydrological response of tree mortality and regeneration in forest gaps. A total of 60 canopy gaps were investigated in six replicate grid plots (50 m × 50 m) and the annual runoff and water consumption data during the period of 1955–2016 were collected from hydrological stations in the middle reaches of the Tarim River. We compared the regeneration density of seedlings and saplings within the canopy gap areas (CGAs), undercanopy areas (UCAs), and uncovered riverbank areas (RBAs) through detailed field investigation. Results Our study found that the mortality of young and middle-aged gap makers has increased remarkably over recent decades, particularly since the year 1996. The main results indicated that regional water scarcity was the primary limiting factor for long-term changes in tree mortality, as shown by a significant correlation between the diameter at breast height (DBH) of dead trees and the annual surface water. The average density (or regeneration rate) of seedli...