冰灾对车八岭山地常绿阔叶林区系和群落的影响

研究了2008年年初南方冰雪冻雨灾害对车八岭常绿阔叶林不同区系的冠层植被所造成的影响.结果显示,研究样地内温带分布的乔木受损比例高于热带分布的乔木受损比例.2检验说明不同区系间的冠层乔木个体受损比例差异显著(P0.01);东亚分布及其变型受损个体比例最小,热带亚洲至热带非洲分布及变型、东亚和北美间断分布及其变型、热带亚洲分布及其变型受损个体比例较大.冠层乔木都以重度受损为主,中度受损和轻度受损个体数都远小于前者.CCA多元分析显示,株数密度、平均胸高断面积、坡度、海拔各自对不同物种的受损乔木的分布有显著影响(Monte Carlo test,P=0.010 0).优势种米槠Castanopsis carlesii受损植株的分布与群落的平均胸高断面积显著正相关;亚优势种栲Castanopsis fargesii、鸭公青Neolitsea chuii、尾尖叶柃Eurya acum inata受损植株的分布与坡度显著负相关;亚优势种荷木Schima superb与海拔显著正相关.总之,在相同的生境中能够占据林冠优势层的区系类型往往受灾更严重.

Floristic and Coenological Analyses of the Montane Evergreen Broadleaved Forest in Chebaling National Nature Reserve Impacted by a Huge Ice Storm

The evergreen broadleaved forest ecosystem of Chebaling National Nature Reserve was severely damaged by the freezing rain and ice storm in the early 2008. Proportions of damaged stems were compared among 10 generic areal-types.The proportion of damaged stems belonged to temperate areal-type was higher than that to the tropical areal-type.X~2 test indicated that the proportions of damaged stems were significantly different (P<0.01)among the 10 generic areal-types. The damage proportion of the Eastern Asia areal-type was the smallest, whereas the damage proportion of the tropical Asia and Africa,Eastern Asia and North America,and tropical Asia areal-types were greater than others.All the generic areal-types were dominated by serious damage class,and the proportion of damaged stems in moderate damage class and slight damage class were far less than serious damage class.Canonical correspondance analysis(CCA)indicated that density,basal area,slope and elevation could significantly affect the distribution of damaged trees(Monte Carlo test,P=0.010 0).The distribution of damaged trees of the dominant species,Castanopsis carlesii,was positively correlated with basal area, while the three subdominant species,Castanopsis fargesii,Neolitsea chuii and Eurya acuminate,were negatively affected by slope, and the other subdominant species,Schima superba,was positively affected by elevation.In sum,the areal-type most seriously damaged was that in which species were dominant and took up the dominant layer of the forest canopy.