祁连山青海云杉中龄林混交度对细根形态特征的影响  

Effects of Mingling Intensity on Morphological Characteristics of Fine Roots of a Middle-Aged Picea crassifolia Natural Forests in Qilian Mountains

作　　者：邓磊 朱春云[1,6] 于世川 祁银燕 张文辉 杜盛[3,4] 关晋宏[2,5] Deng Lei;Zhu Chunyun;Yu Shichuan;Qi Yinyan;Zhang Wenhui;Du Sheng;Guan Jinhong(Academy of Agriculture and Forestry Sciences,Qinghai University Xining 810016;College of Forestry,Northwest A&F University ,Yangling 712100;Institute of Soil and Water Conservation,Northwest A&F University ,Yangling 712100;Institute of Soil and Water Conservation,Chinese Academy of Sciences and Ministry of Water Resources ,Yangling 712100;Max Planck Institute for Biogeochemistry,Germany Jena 07745;Qinghai Plateau Key Laboratory of Tree Genetics and Breeding ,Xining 810016)

机构地区：[1]青海大学农林科学院,西宁810016 [2]西北农林科技大学林学院,杨凌712100 [3]西北农林科技大学水土保持研究所,杨凌712100 [4]中国科学院水利部水土保持研究所,杨凌712100 [5]德国马克斯-普朗克学会生物地球化学研究所,耶拿07745 [6]青海省高原林木遗传育种重点实验室,西宁810016

出　　处：《林业科学》2020年第1期191-200,共10页Scientia Silvae Sinicae

基　　金：国家重点研发计划“高寒丘陵区林草植被的结构优化与功能提升技术”(2017YFC0504604);中国博士后科学基金(2015M580877);青海省农林科学院创新基金(2017-NKY-02)

摘　　要：【目的】研究青藏高原东部祁连山地区青海云杉中龄林混交度对各土层细根生物量和形态特征的影响,以期为当地森林恢复和林分经营提供理论依据。【方法】选择混交度分别为0、0.2、0.4和0.6的青海云杉天然中龄林样地,调查混交度对0~20和20~40 cm土层各树种细根生物量密度、比根长、比表面积、根表面积密度和根长密度的影响。【结果】混交度为0.4的青海云杉林以10~25 cm径级(63.72%)、24~32 m高度级(48.72%)和16~20 m高度级(11.18%)乔木占比最大,且均显著高于其他3个混交度的林分;青海云杉林总细根生物量密度主要分布在0~20 cm土层,占细根总量的68.31%~83.49%,其数值随混交度增大呈现先升后降趋势,混交度0.4时最大,为616.26 g·m^-3;20~40 cm土层总细根生物量密度随混交度增大而增大,在混交度0.6时最大,为227.17g·m^-3;在0~20 cm土层,细根根长密度和根表面积密度表现为混交度0.4>混交度0.2>混交度0>混交度0.6,比根长和比表面积表现为混交度0.4>混交度0.2>混交度0.6>混交度0;在20~40 cm土层,根长密度、根表面积密度和比根长均表现为混交度0.6>混交度0.4>混交度0.2>混交度0,比表面积表现为混交度0.6>混交度0.2>混交度0.4>混交度0;随混交度增大,云杉对0~40 cm土层林分细根生物量密度、比根长、比表面积、根表面积密度和根长密度的贡献逐渐减小,而白桦对0~40 cm土层林分细根生物量密度、比根长、比表面积、根表面积密度和根长密度的贡献持续增大;混交度对细根根长密度和根表面积密度的影响主要表现在0~1 mm径级细根上。【结论】与其他混交度林分相比,混交度为0.4的青海云杉中龄林具有更合理的径级结构和高度级结构,异龄、复层的林分结构可以减小相邻植株间生态位竞争重叠范围,优化林分空间利用效率,提高群落稳定性,细根生物量密度及细根形态特征如比根长、比表面积、�【Objective】Picea crassifolia is the dominant native species in the northeast Qinghai-Tibetan Plateau,and thus is believed to be important in regulating regional soil and water conservation and carbon cycle.The objective of this research was to investigate the effects of mingling intensity on the dynamics of fine root biomass,morphological characteristics and their impact mechanism in P.crassifolia mixed natural forests.The result would provide a theoretical basis for forest rehabilitation and management in the eastern Tibetan Plateau.【Method】A suite of mixed middle-aged P.crassifolia natural forests representing different mingling intensities(0,0.2,0.4,and 0.6)were selected in Datong,Xining,eastern Qinghai-Tibetan Plateau of China.Fine root biomass density,specific root length,specific root surface area,root surface area density,and root length density were analyzed from two soil depths(0-20 and 20-40 cm)by taking soil cores.【Result】In the P.crassifolia forest of mingling intensity 0.4,the diameter class of 10-25 cm(63.72%),height classes of 24-32 cm(48.72%)and 16-20 cm(11.18%),accounted for the largest proportion of all trees,which are significantly higher than the forests with other 3 mingling intensities.Fine root biomass density was mainly distributed in 0-20 cm soil depth,accounting for 68.31%-83.49%of the total.Values of fine root biomass density in the soil depth of 0-20 cm increased with the increasing mingling intensity and peaked at the mingling intensity of 0.4(616.26 g·m^-3)and then decreased in the mingling intensity of 0.6.Fine root biomass density in the soil depth of 20-40 cm increased with increasing mingling intensity,which peaked at the intensity of 0.6(227.17 g·m^-3).Changes of morphological characteristics of fine root highly depended on the mingling intensity.Specifically,in the soil depth of 0-20 cm,root length density and root surface area density showed as mingling intensity of 0.4>0.2>0>0.6,while specific root length and specific root surface area showed as mingling intensi

关 键 词：混交度 青海云杉中龄林 林分结构 细根 分布 生物量 形态特征 

分 类 号：S756.9[农业科学—森林经理学]