古田山常绿阔叶林凋落量时间动态及冰雪灾害的影响

Temporal dynamics of and effects of an ice storm on litter production in an evergreen broad-leaved forest in Gutianshan National Nature Reserve

2006年10月至2009年12月期间,我们通过对古田山24ha常绿阔叶林动态样地169个种子雨收集器的凋落物进行烘干、分类、称量和数据分析,研究了凋落量的组成特征和时间动态,以及受2008年2月特大冰雪灾害的影响。2007年和2009年凋落量分别为532.05g/m2和375.17g/m2,年际变化显著,这与2008年的冰雪灾害有关。2007年古田山常绿阔叶林各组分在凋落量中所占比例依次为:叶(78.99%)>枝(14.69%)>皮(3.33%)>其他(2.99%);叶凋落量中各组分所占比例依次为:常绿阔叶树种叶(78.70%)>落叶阔叶树种叶(12.37%)>针叶树种叶(8.92%),其中甜槠(Castanopsis eyrei)、木荷(Schima superba)、马尾松(Pinus massoniana)和短柄枹(Quercus serratavar.brevipetiolata)4个优势种年凋落量合计占叶凋落总量的71.36%,它们的动态直接影响着凋落总量的变化格局。凋落量高峰发生在春季(4月)和秋冬季(10月末至12月初),其中总凋落量、叶凋落量动态呈双峰型,枝条凋落量和树皮凋落量动态为不规则峰型,其他凋落量动态为单峰型。冰雪灾害后总凋落量、叶凋落量、枝条凋落量显著减少(P<0.05),其中甜槠、杨梅叶蚊母树(Distyliummyricoides)叶凋落量显著减少(P<0.05)、木荷叶凋落量减少达到边缘显著水平(P<0.1),这也反映了冰雪灾害期间森林群落的受损情况。其他凋落量(主要成分为虫粪)在4月份增加极其显著(P<0.01),说明灾后植物的枝叶出现了补偿性生长。

To study litter production, composition, temporal dynamics, and the effects of an ice storm on litter production in a 24-ha evergreen broad-leaved forest dynamic plot in Gutianshan National Nature Reserve, Zhejiang, we set up 169 seed traps, and collected litterfall weekly from October 2006 to December 2009. Total annual litter production in 2007 and 2009 was 532.05 g/m2 and 375.17 g/m2, respectively. We attribute the remarkable drop in production due to an ice storm in February 2008. Leaves, twigs, bark and miscellaneous materials accounted for 79.0%, 14.7%, 3.3% and 3.0% of mass, respectively. The annual leaf litter production of four dominant tree species （Castanopsis eyrei, Schima superba, Pinus massoniana and Quercus serrata var. brevipetiolata） contributed about 71.36% of the total leaf litter production in 2007. There were two litter fall peaks each year, one in spring （April） and the other in autumn to early winter （between late October and early December）. Total litter production, leaf production and twig production decreased significantly after the ice storm （P0.05）, as did the annual leaf production of C. eyrei and Distylium myricoides （P0.05） and S. superba （P0.1）. The production of miscellaneous materials mainly composed of insect dung increased （P0.01） in April immediately following the ice storm, indicating that a compensating growth of branches and leaves was occurring in the damaged community.