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

【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