林下植被清除对不同径级中龄杉木生长速率的影响机制  

Effects of Understory Removal on Growth Rate of Middle-Aged Chinese Fir with Different DBH Classes

作　　者：陈奕帆 付晓莉[1] 王辉民[1,2] 戴晓琴 寇亮[1] 陈伏生[3] 卜文圣[3] 傅晓莉 Chen Yifan;Fu Xiaoli;Wang Huimin;Dai Xiaoqin;Kou Liang;Chen Fusheng;Bu Wensheng(Qianyanzhou Ecological Research Station,Key Laboratory of Ecosystem Network Observation and Modeling Institute of Geographic Sciences and Natural Resources Research,Chinese Academy of Sciences,Beijing 100101;College of Resource and Environment,University of Chinese Academy of Sciences,Beijing 100049;School of Forestry,Jiangxi Agricultural University,Nanchang 330045)

机构地区：[1]中国科学院地理科学与资源研究所生态系统网络观测与模拟重点实验室千烟洲生态站,北京100101 [2]中国科学院大学资源与环境学院,北京100049 [3]江西农业大学林学院,南昌330045 [4]不详

出　　处：《林业科学》2020年第11期21-30,共10页Scientia Silvae Sinicae

基　　金：国家重点研发计划课题(2016YFD0600202);江西省重点研发计划项目课题(20181ACH80006-01)。

摘　　要：【目的】探讨不同径级中龄杉木生长速率对林下植被管理措施的响应机制,为中龄杉木的科学管理策略提供理论支撑。【方法】依托2013年建立的亚热带中龄杉木人工林林下植被管理实验平台中1998年种植的杉木林。试验处理为保留林下植被(CK)和清除林下植被(UR)。至2016年,12-14 cm和16-18 cm两径级杉木占CK处理总林木数的42.6%,占UR处理总林木数的77.1%。2016—2018年研究了这两径级中龄杉木的化学计量、资源获取及利用效率、碳分配模式(如结构vs非结构性碳(NSC)间的分配,NSC在不同器官间的分配)及相对生长速率(RGR)。【结果】清除林下植被对不同径级的中龄杉木RGR的影响不同。清除林下植被对12-14 cm径级中龄杉木RGR无显著影响,但会减缓16-18 cm径级中龄杉木的生长。清除林下植被对12-14 cm、16-18 cm两径级的中龄杉木最大净光合速率、水分利用效率、光合氮利用率、叶片全氮(N)、全磷(P)含量、N/P及叶片NSC(NSC leaf)、枝条NSC(NSC branch)和树干NSC(NSC trunk)均无显著影响。对于16-18 cm径级的中龄杉木而言,清除林下植被显著降低新叶NSC(尤其是可溶性糖,SS)含量,增大NSC trunk/RGR和NSC leaf/RGR,使林木光合产物优先用于存储而非生长,进而减缓了林木的RGR。对于12-14 cm径级的中龄杉木而言,清除林下植被虽然显著增加新叶与老叶间SS的比值,但NSC leaf/RGR是影响该径级的中龄杉木RGR的主要因素,而清除林下植被对该径级NSC leaf/RGR无显著影响。【结论】林下植被去除对中龄杉木生长速率影响的径级依赖性主要受碳分配机制调控,而非受养分化学计量、资源获取及利用效率等机制影响。【Objective】The study aims to determine how growth rate of middle-aged Chinese fir responds to understory management.【Method】This study was conducted in the framework of an understory management experiment ofsubtropical middle-aged Chinese fir established in 2013.The plantation on the platform was established in 1998.Weset a paired-treatment experiment,with understory left intact in one treatment(CK)and understory removed for the other treatment(UR).By 2016,trees with DBH classes of 12-14 cm and 16-18 cm accounted for 42.6%in CK treatment and 77.1%in UR treatment.During 2016-2018,we studied the stoichiometry,resource acquisition and utilization efficiency,carbon allocation patterns(e.g.,structural vs non-structural carbohydrates(NSC)allocations and NSC allocations among different organs)and relative growth rate(RGR)of trees withthese two DBHclasses.【Result】The effects of understory removal on the RGR of middle-aged Chinese fir depended on DBH.The understory removal had no significant effect on the RGR of the Chinese fir with 12-14 cm DBH,however decreased the RGR of the Chinese fir with 16-18 cm DBH.For the Chinese fir of 12-14 cm and 16-18 cm DBH classes,the understory removal had no significant effect on the maximum photosynthetic rate,instantaneous water-use efficiency,instantaneous nitrogen-use efficiency,leaf total nitrogen(N)content,leaf total phosphorus(P)content,leaf N/P,leaf NSC(NSC leaf),branch NSC(NSC branch),and trunk NSC(NSC trunk).For the Chinese fir with16-18 cm DBH,understory removal significantly reduced the NSC of new leaves(especially soluble sugar,SS),increased NSC trunk/RGR and NSC leaf/RGR(indicatinga priority of carbon storage over growth),and thus decreased the RGR.For the Chinese fir with 12-14 cm DBH,although the understory removal significantly increased the ratio of new leaf SS and old leaf SS,the NSC leaf/RGR was the main factor in regulating the RGR and the understory removal did not significantly affect NSC leaf/RGR of Chinese fir with this DBH class.【Conclusion】The D

关 键 词：杉木 林下植被清除 非结构性碳水化合物 碳分配 化学计量 资源获取效率 资源利用效率 

分 类 号：S718.43[农业科学—林学]