To analyze the effect of forest growth years

litter and soil depth at different slope positions to the formation of seed banks

soil seed banks changes and vegetation succession of 8 forest communities in 20 years were studied in Liupan mountain.The results indicated that seed reserves followed the order of mid-slope>underside slope>upside slope for different layers.Seed bank reserves in litter layer was larger than that in 0-15 cm soils.The seed reserves in soils of 8 forest communities presented the order of Larix principis-rupprechtii forest>Pinus armandii forest>Quercus liaotungensis forest>Populus davidiana forest>Betula platyphylla forest>shrubbery land>grass land.The maximum accumulation age of seed reserves varied greatly with vegetation communitites.The times for the approach of the maximum seed reserves was about 30 to 40 years for Pinus armandii and P.tabulaeformis communities

20 years for Larix principis-rupprechtii community

15 to 20 years for Quercus liaotungensis

Populus davidiana

and Betula platyphylla communities

and 10 to 20years for shrubbery and grass communities..The relationship between forest growth times and seed bank reserves changes followed an exponential equation and the relation was significant at p<0.05.Soil seed banks at different vegetation communities were rich in species composition

and that was higher in grass and shrubbery species than that in arbor species.Only 3 to 5 species of seed banks were arbor species and the majority of arbor species were invasive species.The frequently occurred species of grass

shrub

and arbor species are Artemisia

Spiraea pubescens and Hippophae reamnoides

and Quercus liaotungensis

respectively.Therefore

these species are the driving and pioneering species during the succession and natural renovation course.