我国落叶松林生物量碳计量参数的初步研究

 通过整理归纳落叶松(Larix)天然林和人工林的生物量文献数据，研究探讨了有关生物量碳计量参数，结果表明：1) 落叶松生物量转化与扩展因子(Biomass conversion and expansion factor, BCEF)的平均值为0.683 4 Mg&#8226;m^－3 (n=113, SD=0.355 1)，其中天然林为 0.555 1 Mg&#8226;m^－3 (n=56, SD=0.058 2)，明显小于人工林的0.809 5 Mg&#8226;m^－3 (n=57, SD=0.465 0)(p<0.05)；生物量扩展因子(Biomass expansion factor, BEF)的平均值为1.349 3 (n= 134,SD=0.384 4)，其中天然林为1.176 3 (n=63,SD=0.039 9)，也明显小于人工林的1.502 9 (n=71,SD=0.478 0)(p<0.05)。天然林与人工林的BCEF和BEF随林龄(Stand age,A)、 平均胸径(Diameter at breast height, DBH)和林分密度(Stand density,D)的增加呈现相反的变化趋势。天然林的BCEF和BEF随A和DBH的增加而增加，随D的增加而呈降低趋势。人工林随A和DBH的增加呈指数降低并趋于稳定值，随D的增加而呈增加趋势。2) 根茎比(Root∶shoot ratio, R)的平均值为0.245 6 (n=156,SD=0.092 6)，其中天然林为0.237 6 (n=64,SD=0.061 8))，人工林为0.251 1 (n=92,SD=0.109 0)，二者无明显差异(p<0.05)。天然林的R随A和DBH的增加分别呈明显的指数和幂函数增加，而随D的增加呈幂函数下降 ，而人工林的R与A、DBH和D没有显著相关性(p<0.05)。3) 群落生物量扩展因子(Community biomass expansion factor,CBEF)的平均值为1.079 2 (n=49,SD=0.100 5)，其中天然林为1.103 9 (n=29,SD=0.114 9)，明显大于人工林的1.043 4 (n=20,SD=0.061 4) ( p<0.05)。由于天然林和人工林的某些碳计量参数(如BCEF、BEF、CBEF)间存在明显差异，在进行落叶松林生物量碳计量时需分别天然林和人工林计算，在使用有关参数时还需考虑A、DBH和D等因素，有利于降低计量中的不确定性。但是人工林的有些参数(如人工林BCEF和BEF与D的关系、天然林和人工林的CBEF等)尚需进一步研究。

BIOMASS CARBON ACCOUNTING FACTORS OF LARIX FORESTS IN CHINA BASED ON LITERATURE DATA

Aims Larix forest is important in northern China. Our objective was to understand its biomass carbon accounting factors: biomass conversion and expansion factor (BCEF), biomass expansion factor (BEF), root-shoot ratio ( R) and community biomass expansion factor (CBEF).  Methods We collected data on biomass and related parameters for natural forests and plantations from published literature, calculated carbon accounting factors , and analyzed their relationships to stand age (A), diameter at breast height (DBH) and stand density (D). Natural forests and plantations were analyzed separately.  Important findings Mean BCEF for Larix forests was 0.683 4 t&#8226;m^－3 (n=113, SD=0.355 1), and BCEF for natural stands (0.555 1 t&#8226;m^－3 (n=56,SD=0.058 2)) was significantly smaller than for plantations (0.809 5 t&#8226;m^－3 (n=57, SD=0.465 0)) (p<0.05). Mean BEF was 1.349 3 (n=134, SD=0.384 4),and plantations had larger meanBEF value (1.176 3 (n=63, SD=0.039 9)) than natural stands (1.502 9 (n=71,SD=0.478 0)) (p<0.05) . Values of BCEF and BEF for natural forests increased exponentially with increasing A and DBH and decreased exponentially with increasing D. MeanR was 0.245 6 (n=156, SD=0.092 6), and there was no significant difference between natural forests (0.237 6 (n=64, SD=0.061 8)) and plantations (0.251 1(n=92, SD=0.109 0)) (p<0.05). R value of natural stands increased exponentially with increasing A andDBH, but decreased with increasing D. Moreover, R values of plantations had no significant correlations to A, DBH and D. Mean CBEF was 1.102 0 (n=51, SD=0.150 5), and the CBEF value of natural forests (1.139 8 (n=31, SD=0.177 8)) was larger than plantations (1.043 4 (n=20,SD=0.061 4)) (p<0.05). Due to significant differences between natural forests and plantations, it is better to account biomass carbon stock for natural forests and plantations separately. The relationships of these biomass factors (i.e. BCEF vs. D and BEF vs. D of plantations and CBEF of natural forests and plantations) deserve further study.