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了解高山森林林隙结构与形成机制对认识气候变化情景下的森林群落更新具有重要意义,但一直缺乏必要关注.通过典型样地法研究了川西高山岷江冷杉林隙结构特征和干扰状况.结果表明,林隙大小以中小型为主,密度为14.67个/hm-2,63.64%以折干形成.扩展林隙(EG)和林冠林隙(CG)分别占森林景观面积的12.60%和23.05%,干扰频率分别为115.25 m2 hm-2 a-1和63.02 m2 hm-2 a-1,林隙周转率为260.30 a.形成木径级集中于40-60 cm,树高主要在25-30 m,由单株形成木形成的林隙占50.09%;每个林隙约1.52株形成木,每株形成EG和CG面积分别为103.20 m2和56.43 m2.边界木平均胸径为50.16 cm,胸径结构分布曲线尖峰左偏,平均胸径和高度与EG和CG面积呈幂函数相关.综上所述,相对于亚高山针叶林,高山森林近20 a形成的林隙比例更高,形成木和边界木的高度更低但胸径更大,折干比例也更高,恶劣的环境条件(如风雪)可能是高山森林群落更新的主要原因.图5表4参33
It is important to understand the gap structure and formation mechanism of Alpine forests in order to understand the forest community renewal under the climate change scenarios, but the lack of necessary attention has been paid to study the gap structure and disturbance of the Abies faxoniana stands in the western Sichuan, , The size of the gap was dominated by medium and small size, and the density was 14.67 /hm-2 and 63.64%, respectively, which formed by folding drying.The extension gap (CG) and canopy gap (CG) accounted for 12.60% and 23.05% of the forest landscape area, , The interference frequencies were 115.25 m2 hm-2 a-1 and 63.02 m2 hm-2 a-1, respectively, and the gap turnover rate was 260.30 a. The formation of wood-diameter grade was concentrated in 40-60 cm and the tree height was mainly in the range of 25-30 m , Accounting for 50.09% of the gaps formed by the trees forming the individual plants, and 1.52 trees per forest gap forming the EG and CG areas of 103.20 m2 and 56.43 m2 respectively. The average DBH of the border trees was 50.16 cm and the DBH distribution The left spike curve, average DBH and height are related to the power function of EG and CG area.In conclusion, compared with the sub-alpine coniferous forest, alpine forest has a higher proportion of gaps formed in the past 20 years, forming wood and border wood The height of the lower but larger diameter, dry fold ratio is higher, the harsh environmental conditions (such as snow) may Is the main reason for the alpine forest community renewal