Abstract:

Studies on alluvial pollen from 13 hydrological stations in different river flow periods（low river flow, flood, normal river flow）show that alluvial pollen assemblages are influenced by florescence changes of the plants growing in the Luan he River Basin Arboreal pollen percentage was higher than that of herb pollen during the low river flow period, which corresponded with the flowering period of most trees in spring Herb pollen percentage was higher than that of arboreal pollen during the normal river flow period, which corresponded with the flowering period of most herbs in late summer and autumn Herb pollen percentage was slightly higher than that of arboreal pollen during the flood period Arboreal pollen in alluvium mainly came from the surface pollen fallen on the ground in spring which was carried by sheet flow during the floodsAlluviums in Yanshan area are mainly formed by floodsTherefore, 20%～40% aboreal pollen of alluvial pollen assemblages during the floods represent 20%～25% of forest cover of Yanshan area This is a useful reference to reconstruct forest cover quantitatively

摘要：

滦河流域13 个水文站不同时期(枯水期、洪水期、平水期)新鲜冲积物花粉分析表明，冲积物花粉组合受流域内植物花期影响。枯水期木本植物花粉含量高于草本植物，对应春季多数乔木花期。平水期草本植物花粉含量高于木本植物，对应夏、秋季多数草本植物花期。洪水期草本植物花粉含量略高于木本植物。洪水期冲积物中的木本植物花粉主要是由雨水片流将春季落入表土的花粉带入河水中所致。燕山地区的冲积物主要系洪水期沉积，所以燕山地区冲积物花粉组合中20%～40%的乔木花粉代表了现在燕山山区20%～25%的森林覆盖率，这为根据冲积物花粉定量恢复古植被森林覆盖率提供了现代依据。