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根据5个不同林龄15块1000m2样地的调查资料,利用15株不同林龄和径阶的栎类样木数据,建立以胸径平方乘以树高(D2H)为单变量的生物量估算模型。采用样木回归分析法(乔木层)和样方收获法(灌木层、草本层、地上凋落物)获取不同林龄栎类的生物量,并分析了其组成、分配特征及不同林龄生物量的变化趋势。结果表明:栎类林分的总生物量随林龄而增加,5个不同林龄的生物量分别为73.67Mg/hm2、127.47Mg/hm2、149.93Mg/hm2、169.90Mg/hm2、200.65Mg/hm2,其中活体植物的贡献达95.58%以上,地上凋落物的总量不超过4.42%;生物量的层次分配方面乔木层占绝对优势,占93.66%-98.68%,其次为地上凋落物,占1.02%-4.42%,灌木层和草本层生物量较小,分别占0.20%-2.13%和0.03%-0.27%,均随林龄的增加呈递减趋势;乔木层器官分配以干所占比例最高,占46.64%-80.78%,且随林龄而增加,枝、叶、根分别占11.61%-36.80%、1.00%-4.85%和6.61%-11.71%,均随林龄而下降;灌木层器官分配以枝所占比例最高,为32.50%-69.07%,叶和根分别占12.89%-25.00%和18.04%-42.50%;不同林龄栎类草本层生物量大小与林龄成反比例关系,地上部分的生物量大于地下部分的生物量。随着林龄的增加,凋落物呈现升→降→升的趋势。以上研究结果表明,林龄可以影响桂西地区栎类的生物量和分配格局。
According to the survey data of 15 1000m 2 plots of five different stand ages, 15 biomass estimation models were established by using the square root of DBH and the height of tree height (D2H) as the single variable . The biomass of oaks with different age were obtained by sampling and regression analysis (tree layer) and quadrat harvesting (shrub layer, herb layer and litter on the ground). The composition, distribution characteristics and biomass of different stand ages The trend of change. The results showed that the total biomass of Quercus variabilis forest increased with age, and the biomass of five different stands were 73.67Mg / hm2, 127.47Mg / hm2, 149.93Mg / hm2, 169.90Mg / hm2, 200.65Mg / hm2. The contribution of living plants reached more than 95.58% and the total amount of litter on the ground did not exceed 4.42%. The arborous layer accounted for 93.66% -98.68% of total biomass, followed by litter, accounting for 1.02 % -4.42%. The biomass of shrub layer and herb layer were relatively small, accounting for 0.20% -2.13% and 0.03% -0.27% respectively, both decreased with the increasing of age. The proportion of arborous layer was the highest in dry matter, Accounting for 46.64% -80.78%, and increased with age, branches, leaves and roots accounted for 11.61% -36.80%, 1.00% -4.85% and 6.61% -11.71%, respectively, The branches with the highest proportion of 32.50% -69.07%, leaves and roots accounted for 12.89% -25.00% and 18.04% -42.50%, respectively. The biomass of oak herbaceous layer in different age groups was inversely proportional to the age, Of the biomass is greater than the biomass of the underground part. With the increase of age, the litter showed a tendency of increasing, decreasing, increasing. The above results show that forest age can affect the biomass and distribution patterns of oaks in western Guangxi.