Responses of water holding characteristic of crown debris and litter in a Cunninghamia lanceolata stand to ice-snow damage

摘要

Severe ice-snows caused break of many trees and a lot of crown debris in south China in 2008. Stem damage and crown debris. In order to determine the water holding characteristics of the crown debris, the water holding rate and water absorption rates of crown debris and litter were studied in a Cunninghamia lanceolata stand suffering from ice-snow damage occurring from January to February, 2008. The order of water-holding capacity of the components was leaves > litter > branches> stemwood > stembark in each stage of immersing water. The maximum water holding capacities of stemwood, branch, leaves, stembark and litter were 6.75, 8.13, 10.9, 2.72 and 8.22 t·ha~1, respectively. Maximum water holding rates of stemwood, branch, leaves, stembark and litter were 2271, 2144, 3199, 2800 and 3018 g·kg~1, respectively. Water absorption rate of each component sharply decreased with increasing immersed time from 0.5 to 4 hours, and then slowly decreased. The logarithm equation predicted water-holding capacity and water holding rates of crown debris and litter quite well and the negative exponential equation predicted water absorption rate within an 8.5% error.