STUDY ON SOIL SEEDBANK OF LARIX PRINCIPIS-RUPPRECHTII UNDER CANOPY IN PANGQUANGOU NATIONAL NATURAL RESERVE, SHANXI, CHINA

By sampling quarters in sample plots, the density, quality and distributionpattern of soil seedbank of Larix principis-rupprechtii under canopy in Pangquangou National Natural Reserve are studied. The affecters controlling soil seedbank characters areanalysed to provide the background of seedbank under canopy of Larix principis-rupprechtii forest for forther research. It present some valuable results for populus,community and landscape ecological researches in the area. After a common seeding-year,beforegermination in the next spring,the mean Total Soil Seed Density (TSSD) under canopyof four Larix forest types is up to 426 grain/m² Among the four forest types,the orderof TSSDis Carex-Larix forest>Herba-Larix forest>Betula-Larix forest>Frutex-Larix forest. The mean Vital Soil Seed Density (VSSD),is 124 grain/m² that is 29. 1 % of TSSD,the order of VSSD among four forest types is changed to that Carex-Larix forest>Herba-Larix forest>Betula-Larix forest>Frutex-Larix forest. The germination rateof TSSDis 24. 9%. The seed density that could germinate in the next year is 106grain/m². The seed distribution patterns in study area,controled by seeding wood distribution pattern and micro-topographical heterogeneity,present some degrees of clusteringtrends. The seedbank of Larix principis-rupprechtii under canopy is big enough in fourforest types to provide seed for regeneration in forest gaps after canopy disturbance instudy area.