The Effects Of Dwarf Bamboo On The Gap Regeneration Of Subalpine Dark Coniferous Forest In Wolong Nature Reserve

Abies faxoniana is a dominant tree species of subalpine dark coniferous forests in the southwest of China, and is mainly distributed over the upper reaches of the Minjiang, Dadu and Bailong Rivers. Few studies on gap regeneration of subalpine dark coniferous forest has been carries out today. Effects of gap size and dwarf bamboo coverage on the trees regeneration, seedlings structure and spatial pattern of subalpine dark coniferous forest in Wolong Giant Panda Nature Reserve were surveyed during the time of 2003-2004. Of the total gaps surveyed in Abies faxoniana forest, 27%were small (canopy gap area ≤50m2), 41%were medium sized(50~150m2)and32%were large(>150m2) gaps. Most gaps result from the treefalls of Abies faxoniana which reached the canopy layer. Nine types of sampling site differing in the three size canopy gaps were selected, and three contrasting understory bamboo cover conditions(≤ 20%, 20%~50% and >50%) were contained the same sized gaps. The results show as follows:(1) No matter forest gap grows, the number of tree seedlings in the gaps was more than that in the non-gap stand. Gap regeneration is the primary approach of the community regeneration of Abies faxoniana.(2) In large gaps with dense bamboo very resembles that in small gaps or understory, and gaps with high crown density be loss to the growth of seedlings. The seedling density increased with reduced bamboo coverage, the dense bamboo growth evidently impeded the forest regeneration process.(3) The response of seedlings density of Abies faxoniana to bamboo coverage is more obviously than that to Betula utilis and Acer caudatum var. prattii. The number of saplings...