冰雪灾害对粤北杉木林林冠残体和凋落物持水特性的影响

Effect of ice-storm damage on water holding characteristics of crown debris and litter in a Cunninghamia lanceolata stand

2008年1~2月广东粤北地区遭受冰雪灾害的袭击,导致杉木林产生了大量的林冠残体。作者对2008年林冠残体各组分和2008-2011年各年的凋落物持水特性进行研究,可以了解灾后杉木林凋落物的涵养水源特点和为生态系统的修复提供参考。结果表明：2008年,各组分最大持水量为叶（10.9 t/hm2）〉凋落物（8.22 t/hm2）〉枝（8.13 t/hm2）〉干（6.25 t/hm2）〉皮（2.72 t/hm2）,各组分最大持水率呈现叶（320%）〉干（296%）〉皮（280%）〉凋落物（227%）〉枝（214%）;各年度凋落物层的最大持水量呈现2008年（27.25t/hm2）〉2011年（19.68 t/hm2）〉2010年（22.71 t/hm2）〉2009年（24.06 t/hm2）。2008年凋落物层的最大持水率为268%,2009—2011年在194%~200%之间。林冠残体或凋落物持水量与浸泡时间、持水率与浸泡时间的关系均按照自然对数方程变化,而各组分和各年度的吸水速率随浸泡时间按负指数方程下降。

A huge ice storm stroke on the north of Guangdong province from January to February 2008, resulting in a lot of crown debris in a Cunninghamia lanceolata stand. Water Holding Characteristic of components of crown debris in 2008 and litter from 2008 to 2011 were studied, to understand hydrological function of litter and to provide basis for the recovery of the C. lanceolata stand suffering from ice storm damage. The order of maximum water holding capacity of the components was leaves （10.9 thun2） 〉 litter （8.22 t/hm2） 〉 branches （8.13 t/hm2） 〉 stem （6.25 t/hm2） 〉 bark （2.72 t/hm2）. The proportional water holding capacity as a percentage of dry weight in the components was 320%, 296%, 280%, 227% and 214% for leaves, stem, bark, litter and branches, respectively. The order of maximum water holding capacity was 27.25, 24.06, 22.71 and 19.68 t/hm2 for 2008, 2009, 2010 and 2011, respectively, and the proportional water holding capacity was 268% in 2008 and 194% - 200% from 2009 to 2011. The total water holding capacity and proportional water holding capacity of the components or litter increased logarithmically with increasing time immersed in water, whereas their water absorption rates decreased according to negative exponential equation with increasing time immersed in water.