为探索杉木林演替机制,在杭州午潮山自然演替30a左右的杉阔混交林内选择海拔、坡度及坡向等生境相似的区块设置40 m× 40 m的杉阔混交林样地3个,在样地内布置种子雨收集器进行为期2a收集,并对凋落物层、0~5 cm腐殖质层和5~10 cm土壤层进行土壤种子库调查,取样面积为0.20 m×0.20 m,随即袋装并标记,每个样地每次取样75份,共计450份,并进行种子发芽实验。结果表明:研究区群落种子雨物种组成为9个树种,杉木(种子雨密度12.91粒/m²)和秃瓣杜英(种子雨密度7.60粒/m²)是其主要组成部分,占总数的94.16%。杉木落种持续7个月,高峰期为7月与10月,秃瓣杜英落种持续4个月,高峰期为11—12月。土壤种子库的主要物种也为杉木和秃瓣杜英。其中,杉木种子主要留存于凋落物层,秃瓣杜英种子主要留存于0~5cm土层,且秃瓣杜英种子密度和种子发芽率是杉木的2~5倍。土壤种子库非优势物种组成年际变化较大。导致杉木种子更新失败的重要因素是种子雨和种子库密度较低、种子主要留存于凋落物层。杉阔混交林自然演替过程中,阔叶树种可以利用种子进行天然更新。

In order to explore the succession mechanism of Chinese fir forests,three 40 m×40 m mixed fir and broad-leaved forests were set up in blocks with similar habitats,such as altitude,slope and aspect,in the mixed forest of fir and broadleaf that have been in natural succession for about 30 years in Wuchao Mountain,Hangzhou.In the sample plot,a seed rain collector was arranged in the sample plot for two years of collection,and the litter layer,0~5 cm humus layer and 5~10 cm soil layer were collected in a sampling area of 0.20 m×0.20 m,and then bagged and marked.75 samples were taken from each plot,in a total of 450 samples,and the seed germination experiment was carried out.Our results showed that there were nine species in the seed rain,of which Cunninghania lanceolata (seed rain density 12.91 seeds/m²)and Elaeocarpus(seed rain density 7.60 seeds/m²)were the main components,accounting for 94.16% of the total.The duration of C.lanceolata seed dispersal was 70 months,with two peaks in July and October,respectively.The duration of seed dispersal of Elaeocarpus was 4 months,with a peak in November to December.Seed of C.lanceolata and Elaeocarpus were also the main species in the soil seed bank.C.lanceolata seeds were mainly stored in the litter layer.In contrast,Elaeocarpus seeds were mainly stored in the 0~5cm soil layer.The seed density and germination rate of Elaeocarpus were 2~5 times higher than those of C.lanceolata.Moreover,the composition of non-dominant species in soil seed bank varied greatly from year to year.The retention of seeds in the litter layer resulted in low seed density in the C.lanceolata forest soil,which was the main reason for the difficulty of the natural regeneration of C.lanceolata.The results indicated that,broad-leaved species could regenerate via seeds in natural succession.