亚高山针叶林人工恢复过程中生物量和材积动态研究

研究了近70年不同林龄亚高山人工云杉林的地上部分生物量及材积变化规律．结果表明，20年林龄前的云杉单株生物量增长缓慢，以小枝和叶生长为主，约占50％；20年以后，单株生物量增长加快，以树干积累为主，大体上超过60％；30年后增长速度相对减慢，自40年开始并保持快速增长．云杉种群生物量表现出类似的增长，但林龄在30至50年间增长速度减慢．群落生物量总体上持续增长，但灌木层生物量在初期快速增长，从20年林龄后逐渐减少；草本层生物量则一直减少，到70年时仅占不足0．2％．在近70年人工恢复过程中，云杉单株材积平均生长量和连年生长量都逐渐增大，越在后期生长越迅速；林分蓄积则在30至50年林龄之间有一段连年生长量相对减小的时期．根据树干解析资料，建立了70年人工云杉林的单株材积与胸径和树高的数学模型．

Dynamics of biomass and stem volume of Picea asperata stands in artificial restoration process of subalpine coniferous forest

The dynamics of aboveground biomass and stem volume in subalpine coniferous Picea asperata plantations with different stand ages in 70 years of artificial restoration process were studied by adopting the concept of space as a substitute for time.The results indicated that before 20 years of stand age,the biomass of spruce single tree grew quite slow,with that of the twigs and needles accounting for about 50%;after 20 years,it increased obviously,with 60% of biomass accumulated in stem;from 30 to 40 years,the increasing rate of biomass relatively slowed down,and maintained a rapid growth after 40 years.The biomass of spruce population showed a similar trend,though the period of relative slow-down of growth continued from 30 to 50 years.For the biomass of community as a whole,it presented a general continuous increase,but varied greatly for different layers.In shrub layer,the biomass rose rapidly at the early stage of plantation establishment and gradually decreased after 20 years,while that of the herbaceous plants reduced continuously and accounted less than 0.2% of the total biomass of community when the stand reached 70 years.Both the mean annual increment and the current annual increment of stem volume of spruce single tree went up with the increasing stand age,and more rapidly at the later stages.Similar changes were observed for the stock volume of the plantations,with the only difference that the current annual increment from 30 to 50 years was relatively reduced.Based on the data from stem analysis and growth ring measurement,regression models of stem volume with DBH and tree height of 70 years Picea asperata plantation were established.