Abstract:

Quercus variabilis is an important constructive species in the warm temperate and the subtropical forests in China, and it is also a resource tree for tannin and cork. Most of natural Q. variabilis forests in China have degenerated to secondary forests after long time overexploitation. Lack of regeneration resource as well as low productivity is among the worst problems for the forests. Therefore, it is crucial to clearly understand how to promote population and forest regeneration to recover the secondary forests. Stump sprouting is an important type of vegetative regeneration of Q. variabilis. In order to understand the role of stump sprouts in population regeneration in different habitats, 25 plots, distributed in forest gap, forest edge and understory of Louguantai, Zhouzhi county, Shaanxi Province, were set to investigate the influence of different environment conditions on the sprouting ability, survival rate and growth features in July 2009. The results showed: 1) There were three kinds of regeneration recruits in the research area, named as seedlings, stump sprouts and stem sprouts, among which stump sprouts were the main asexual recruits. 2) Stump sprouting contributed differently to the population regeneration in different habitats. In forest understory, both stump sprouts and seedlings were dominant regeneration recruits, while in forest gap and forest edge, stump sprouts were the most dominant recruits.3) Habitats conditions, especially the illumination, affected stump sprouting ability, survival rate and growth characteristics of stump sprouts. Stumps in forest gaps had greater sprouting ability, however the sprouts had greater dead rate compared with those in forest understory and forest edge. The sprouting seedlings, in terms of base diameter, height, leaf area and aboveground biomass, grew best. 4) Forest gaps were a friendly habitat which was beneficial for stump sprouting and sprouting seedlings growth compared with forest understory and forest edge, thus appropriately thinning cuttings would promote the asexual regeneration of some secondary Q. variabilis forests which lacked regeneration recruits.

Key words: Quercus variabilis, stump sprout, forest gap, forest edge and forest understory, growth features, population regeneration