卧龙自然保护区亚高山暗针叶林林隙特征研究

Gap features of subalpine dark coniferous forest in Wolong Nature Reserve.

以卧龙亚高山暗针叶林为研究对象 ,分析了森林群落林隙的大小结构、形成方式及林隙形成木(GM)的结构特征 .结果表明 ,林隙密度为 18 5个·hm-2 ,冠林隙和扩展林隙分别占森林面积的 2 8 4 %和6 0 0 % ;冠林隙的大小变化在 10～ 1134 7m2 之间 ,平均面积为 15 3 4 5m2 ;扩展林隙的大小变化在 84 11～ 16 4 6 3m2 之间 ,平均面积为 32 4 34m2 ;平均每个林隙的形成木为 5 14株 ,单株形成木形成的林隙只占 8 1% .不同形成木类型对林隙形成的贡献大小次序为 :折干 >掘根 >枯立 >断梢 ;暗针叶林林隙大多由岷江冷杉、铁杉、糙皮桦形成 .径级在 6 0～ 70cm ,高度在 30～ 35m之间的林冠上层的岷江冷杉 ,发生折倒形成林隙的可能性最大 .

This paper studied the size structure and formation pattern of gaps and the characteristics of gap makers (GM) in subalpine dark coniferous forests in Wolong Giant Panda Nature Reserve,Sichuan Province,China.The results showed that the gap density was 18.5 per hm 2,and the area of canopy gap and extended gap accounted for 28.4% and 60% of total forest area,respectively.Canopy gap varied from 10 m 2 to 1 134.7 m 2,and expanded gap varied from 84.11 m 2 to 1 646.3 m 2.Canopy gaps and expanded gaps had an average area of 153.45 m 2 and 324.34 m 2,respectively.The average number of gap makers (GM) per gap was 5.14,and only 8.1% of all gaps were created by just one GM.The order of GM contributed to gap formation was trunk snap > uproot > standing death > branch breakage.Abies faxoniana,Tsuga chinensis,and Betula utilis were the major gap makers,while Abies faxoniana in the canopy layer with 60～70 cm DBH and 30～35 m high had the greatest probability of gap making.