安徽大别山区杉木人工林乔木层生物量模型及碳贮量

根据杉木人工林年龄(10、22、45、48和50年生)梯度,在安徽大别山海拔较高山地调查了23块20m×20m的样地,采集18株不同径阶和树高的标准木,进行了生物量测定。利用7种常用的分别以D、D2、DH和D2 H为自变量的生物量模型对其进行拟合,得到35个生物量估算模型。结果显示,幂函数模型的拟合效果较好,多项式模型效果较差,从中优选出5个最优模型,枝、干、根和全株的最优模型是W=aDb形式的幂函数模型,叶的最优模型是W=a+bD2+cD4形式的多项式模型。杉木不同器官的碳含量变化范围在46.64%~53.13%,过熟林(45~50年生)杉木不同器官的碳含量按高低排列均为树皮树根树叶树枝树干,根系碳含量高于地上部枝叶的碳含量,而中幼林龄(10和22年生)杉木地下部分树根的碳含量明显低于地上部分。碳贮量在不同器官中的分配,10和22年生的高低排序为树干树枝树根树叶,过熟林杉木的高低排序为树干树根树枝树叶。不同林龄杉木林生物量碳贮量分别为10年生59.39、22年生59.55、45年生136.92、48年生201.25和50年生134.60Mg C/hm2。不同林龄的杉木林根系生物量碳贮量比例为14.84%~23.79%,随林龄的增长而提高。研究结果显示较高海拔的立地环境促进了杉木林地下根系生物量积累,这种生物量分配可能对土壤有机碳蓄积产生重要影响。

BIOMASS MODEL AND CARBON STORAGE OF CHINESE FIR PLANTATION IN DABIESHAN MOUNTAINS IN ANHUI

In order to reveal the biomass allometry of Chinese fir plantation at high altitudes, an investigation was conducted in the Dabieshan Mountains in Anhui Province. A total of 23 sampling plots (20 m×20 m) was set up in Chinese fir plantations with different ages (10, 22, 45, 48 and 50 years old) and 18 trees with different diameters and heights were sampled for biomass measurement. A total of 7 biomass models were adopted to estimate the biomass of whole tree and organs with D, D², DH and D²H, respectively for the independent variables. There were totally 35 biomass models fitted. The results showed that the power function models fitted the data best, but the polynomial models were poor. The optimal models for branch, trunk, roots and whole tree were power function models in the form of W=aD^b. However, the optimal models for foliage was polynomial models in the form of W=a+bD²+cD⁴. The carbon concentrations in different organs varied from 46.64% to 53.13%. The carbon concentrations of over-matured stands (45-50 year-old) were ranked as order of bark > root > foliage > branch > trunk. The carbon concentration was higher in roots than in branches and foliage, while for the young- and middle-aged stands the carbon concentration was significantly lower in roots than in the aboveground organs. The carbon storage in different organs of Chinese fir was ordered as trunk > branch > root > foliage. The order of carbon storage for the over-matured stands by organs was trunk > root > branch > foliage. The biomass carbon storages in the above-mentioned Chinese fir stands ranged from 59.39 (10-year-old) to 201.25 (48-year-old) Mg C/hm². In addition, our results demonstrated that the underground biomass and its carbon storage of Chinese fir plantation increased with the stand age, with a range of 14.84%-23.79% for the root biomass carbon storage to the stand total at this higher altitude. This suggests that the higher altitude environment tends to favor underground biomass accumulation of Chinese fir plantation, which can be important to increase soil organic carbon accumulation.