冰雪灾害对粤北天然次生林的损害及产生的林冠残体量

采用样地调查和取样,研究了2008年初中国南方冰雪灾害对粤北天然次生林的损害特征及其产生的林冠残体量.结果表明,灾害对粤北天然林造成严重损害,林木受害特征主要是胸径较大的植株断枝、断梢和断干较多,胸径较小的容易压弯,坡度大的林分翻蔸受害率增加.灾后林地林冠残体总量为38.12～43.52 t hm-2,平均41.25 t hm-2;地表凋落叶11.79～12.87 t hm-2,平均12.47 t hm-2;灾害产生的枝、干木质残体量为24.27～30.65 t hm-2,平均28.41 t hm-2.天然常绿阔叶林产生的林冠残体量较常绿与落叶混交林和杉木人工林大,造成林地林冠残体量骤增,一方面使林地存在严重安全隐患(如发生火灾和病虫害的风险增加),另一方面大量的林冠残体归还林地、改变了森林生态系统的结构与功能.

Damage of the Frozen Rain and Snow to Natural Secondary Forests and Its Crown Debris in Northern Guangdong Province

Southern China suffered one of the most destructive frozen rain and snow ever since 1954, from the middle of January to early February in 2008. The damage status and crown debris amounts of natural secondary forests of Chebaling Nature Reserve and Tianjingshan Station of Nanling National Nature Reserve in northern Guangdong Province, were investigated after the disaster. The results showed that the natural secondary forests were damaged heavily, with the broken of branch, top and stem of the big trees, and stem bent of the smaller trees commonly. The proportions of uproot trees were increased with slope degree increasing. The total standing crop of crown debris in forests ranged from 38.12 to 43.52 t hm-2 with an average of 41.25 t hm-2. The leaf litter varied from 11.79 to 12.87 t hm-2 with an average of 12.47 t hm-2. The total amounts of woody debris of branch and trunk by the disaster varied from 24.27 to 30.65 t hm-2 with an average of 28.41 t hm-2. The crown debris of natural evergreen broadleaved forest caused by the disaster were significantly more than that of the evergreen and deciduous broadleaved mixed forest and Chinese fir plantation. The disaster increased litterfall debris in short period, which will not only increase dangers of fires, pests and diseases, but also change the structure and function of the forest ecosystem.