Water flux responses of tropical trees and lianas to foliage loss caused by a heavy hailstorm

Abstract

AbstractLarge‐diameter hail is unusual in the lowland tropics; consequently, its impact on water flux responses of trees and lianas due to foliage loss is unknown. In December 2012, Xishuangbanna Tropical Botanical Garden (21°55′N) in southern Yunnan, China, experienced the most severe hailstorm in approximately 30 years, with hailstones of 8‐ to 17‐mm diameter falling for 10–30 min. We assessed the effect of this hailstorm on sap flux density (SFD) in response to foliage loss in six tree and three liana species. Among the trees, for a given atmospheric vapour pressure deficit (VPD), Tectona grandis and Dipterocarpus tuberculatus showed a significant reduction in sap flux density and water use during the post‐hailstorm week in comparison to pre‐hailstorm week. In contrast, a liana Ventilago calyculata showed a significant increase in SFD during the first post‐hailstorm week, whereas the other tree and liana species showed no significant change in their SFD and water use. T. grandis also showed visible wilting during the first 5 days post‐hailstorm. However, this tree species showed recovery from wilting and also no more reduction in SFD after ~7–9 days. D. tuberculatus also showed SFD recovery a week post‐hailstorm. We conclude that the impact of a heavy hailstorm on the water flux of tropical trees and lianas was mild or neglectable. Our study documented a rare severe hailstorm occurrence and its impact on ecosystem processes of tropical forest and enhances our understanding about water flux of tropical woody species exposed to hailstorm.