雪灾干扰后林冠开阔度对黄心树幼苗更新的影响  

Effects of canopy openness on seedling regeneration of Machilus bombycina after a snow damage

作　　者：冯力 陈斯 夏尚文[2] 王博[2] FENG Li;CHEN Si;XIA Shang-wen;WANG Bo(Southwest Forestry University,Kunming 650224,China;Xishuangbannn Tropical Botanical Garden,Chinese Academy of Sciences,Menglun 666303,Yunnan,China;Ailaoshan Station for Subtropical Forest Ecosystem Studies,Chinese Academy of Sciences,Jingdong 676200,Yunnan,China)

机构地区：[1]西南林业大学园林学院,昆明650224 [2]中国科学院西双版纳热带植物园,云南勐仑666303 [3]中国科学院哀牢山亚热带森林生态系统研究站,云南景东676200

出　　处：《生态学杂志》2020年第3期786-793,共8页Chinese Journal of Ecology

基　　金：国家自然科学基金项目(31971444,31770570)资助。

摘　　要：幼苗更新是森林更新的关键过程,而林窗对于植物幼苗更新、生长及最终存活具有重要影响。极端气候事件会使森林在短时间内形成大量林窗,从而显著影响林内幼苗更新和存活。本研究以2015年雪灾后云南省哀牢山中山湿性常绿阔叶林优势种黄心树(Machilus bombycina)幼苗为对象,对194个1 m×1 m样方中的幼苗生长和死亡动态进行为期4年的监测,利用线性混合模型(LMM)和广义线性混合模型(GLMM),分析林冠开阔度对幼苗高度相对生长率、叶片相对增长率、新增率和死亡率的影响,研究了雪灾干扰后的林冠开阔度对植物幼苗更新的影响。结果表明:(1)林冠开阔度随时间推移逐渐变小(20.07%~9.97%),且速度由快到慢;(2)2015-2016年,已有幼苗高度相对生长率与林冠开阔度呈显著正相关(P<0.05),其余年份两者间无显著相关性;2016-2017年已有幼苗叶片相对增长率与林冠开阔度呈显著正相关(P<0.05),其余年份两者间无显著相关性;(3)林冠开阔度与幼苗新增率和死亡率均无显著相关性。本研究表明,雪灾后造成的林冠开阔度增加有利于黄心树幼苗生长。Seedling recruitment is a key process in forest regeneration.Canopy openness plays an important role in seedling establishment,growth and survival,especially after extreme climate events.In this study,we monitored the seedling recruitment dynamics of a dominant tree species Machilus bombycina with 194 plots(1 m×1 m)over four consecutive years after a snow damage event that happened in January 2015,in a mid-mountain moist evergreen broad-leaved forest in Ailaoshan,Yunnan Province.The effects of canopy openness on the seedling growth,recruitment rate and mortality rate were analyzed by Linear Mixed Model(LMM)and Generalized Linear Mixed Model(GLMM).Our results showed that:(1)canopy openness decreased quickly especially in the first year after the snow damage,from 20.07%to 9.97%;(2)the relative increase rate of existing seedlings’height was positively correlated to canopy openness during 2015-2016(P<0.05),but not in other years;the relative growth rate of existing seedlings’leaves was positively correlated to canopy openness during 2016-2017,but not in other years;(3)canopy openness did not correlate with either seedling recruitment rate or mortality rate.Overall,our findings indicated that the increases of canopy openness after snow damage benefited the growth of M.bombycina seedlings.

关 键 词：极端气候事件 光照强度 亚热带 森林更新 

分 类 号：S754[农业科学—森林经理学]