Abstract: Fine roots play a key role in soil nutrient cycling. Most studies of fine root plasticity have focused on tree species in forest ecosystems, however, there is limited understanding of fine root plasticity of understory species. In order to understand the effects of intraspecific competition and forest management measure (litter covering) on fine root morphological traits and nutrient uptake strategy, a rootbag method was employed to investigate the effects of intraspecific competition and litter coverage on fine root morphological traits (specific root length, diameter, and branch ratio) of Cunninghamia lanceolata (tree species) and Loropetalum chinensis (shrub species). We found that litter coverage and competition had no significant influence on fine root morphological traits of C. lanceolata. However, litter coverage significantly improved the first two orders fine root branching ratios of L. chinensis. Litter coverage, intraspecific competition and their interaction effect significantly decreased the diameters of 1 and 2order fine roots of L. chinensis. These changes of L. chinensis fine root traits might increase the fine root nutrient absorption rate. Our results indicated that litter addition to C. lanceolata forest might help to improve the nutrient absorption ability of L. chinensis by influencing its fine root morphological traits and thus would enhance the nutrient competition between the overstory and understory species at the same soil depth.

Key words: survival function, static life table, survival curve, time series prediction, natural secondary forest, dominant population