The results shoed that most of the forests in pearl river delta were of young - medium age , which occupied 80 % or more of the total forest area , and their undergrowth biomass accounted for about 33 % of the total forest biomass indicating that the regional forest biomass could be estimated more exactly if undergrowth biomass was fully concerned 结果表明：珠江三角洲的中幼林面积占森林总面积的80 %以上，其林下植被生物量约占森林总生物量的33 % ，充分考虑林下植被生物量能提高区域森林生物量估算的精度。
Soil saturated capacity , capillary capacity , total porosity and capillary porosity showed the trend of the " u " during the successional course of artificial forest , namely , they reduced on the early successional stages , after picea reached mature forest , soil porosity recovered slowly . the content of natural water was mainly affected by capillary porosity . from soil chemical properties analysis , the content of soil organic , humus , ha , fa and ha / fa of topsoil was more than that of bottom layer 即人工云杉幼林向成熟林演替阶段，土壤饱和持水量、毛管持水量及总孔隙和毛管孔隙则减少，在40年生云杉林达最低值，之后随着云杉自疏，微生态改善，林地凋落物分解加快，土壤饱和持水量、毛管持水量及总孔隙和毛管孔有上升的趋势，毛管持水量是决定林地自然含水量的主要因子。
