浙江省森林生物量动态

The forest biomass dynamics of Zhejiang Province

以浙江省1976至2004年森林资源连续清查资料为数据源,采用基于生物量与蓄积之间关系的生物量转换因子连续函数法,对全省林分生物量和包括林分在内的森林生物量动态进行估计。森林生物量为包括林分、疏林、灌木林、竹林、经济林和四旁树在内的所有林木生物量之和。结果表明,浙江省1976至2004年间森林生物量从1.00828×108Mg上升到2.44426×108Mg;其中,林分生物量由0.5712×108Mg上升到1.51128×108Mg。森林生物量和林分生物量的年平均增长速度分别为5.1%和9.1%。在1999至2004年间,森林生物量和林分生物量增长速度均明显加快,分别达到8.6%和10.1%。在1976至2004年间,全省森林面积年均增长速度为1.0%,森林平均生物量从16.50Mg·hm-2上升到36.59Mg·hm-2。但是,在森林资源总量不断增加的同时,全省林分质量仍维持较低水平。2004年全省林分单位面积生物量为38.40Mg·hm-2,远低于全国平均水平(77.40Mg·hm-2)。研究还表明,利用森林资源连续清查数据和基于单株测树因子的森林生物量模型能够估计大尺度范围内的森林生物量及其动态,但亟待在统一标准下建立和完善覆盖所有树种的生物量模型。

We estimated total forest biomass and the biomass of forest stands in Zhejiang Province between 1976 and 2004 using data from continuous forest resource inventory and conversion models that account for the relationship between volume and biomass using the Variable Biomass Expansion Factor （VBEF） method. Total-forest biomass included forest stands, bamboo stands, cash forests, open forest, shrub forest and trees on non-forest land. Between 1976 and 2004, Zhejiang Province total-forest biomass increased from 1. 00828 × 10^8 Mg to 2. 44426 × 10^8 Mg, whereas forest-stand biomass rose from 0. 5712 × 10^8 Mg to 1. 51128 × 10^8 Mg. That is, total-forest biomass and forest-stand and increased on average by 5.1% and 9.1% annually respectively. Between 1999 and 2004, biomass growth accelerated, reaching an average of 8.6 % and 10.1% for total-forest and forest-stand biomass respectively. The total forest area of the Province increased on average by 1.0% annually between 1976 and 2004, resulting in an average forest biomass of 16.50 Mg· hm ^-2 in 1976 and 36.59 Mg· hm^-2 in 2004. However, the quality of the Zhejiang Province forests may be considered relatively poor as evidenced by the 2004 forest-stand biomass per unit of area （38.40 Mg· hm^-2 ）, which was still much lower than the average across China （77.40 Mg·hm^-2）. This study showed that data from continuous forest resource inventory and individual-tree based models may be used to estimate forest biomass and its change at regional levels. However, further studies are needed to either develop new biomass models for various species or improve existing models by implementing consistent standards.