【摘要】 【目的】本研究选择湖南、安徽、江西3省杉木人工林为研究对象,构建乔灌层调查因子与其生物量之间的估算模型。试图获取更为可靠、精准的灌木层生物量估算模型,为提高估算杉木人工林灌木层生物量模型精度提供参考。【方法】在研究区域进行典型抽样调查,测定不同林龄杉木林上层乔木郁闭度Cs、林分密度Ds(株/hm~2)、平均胸径Dm(cm),下层灌木平均高度H(m)、平均地径D(cm)、盖度C、灌木层枝、干、叶、根干鲜质量(kg),通过计算获得乔木层杉木蓄积量V(m~3/hm~2)、灌木层生物量数据(t/hm~2)。通过Pearson相关性分析灌木层结构和乔木层调查因子对灌木层生物量的影响,选取最佳灌木层结构因子为模型参数建立枝叶、干、地上、地下生物量估算模型。将乔木层林分调查因子作为自变量加入模型中,对比分析模型R~2在乔木层调查因子作为自变量加入后的变化,并用样本外的数据进行检验,构建估算灌木层生物量更为精确的模型。【结果】研究结果显示:灌木层各组分生物量模型以幂函数为主,各林龄灌木层地下生物量与自变量D2H获取了最佳模型,R~2为0.516~0.955;其余部分生物量以盖度与高度乘积(CH)为自变量获得了拟合效果较好的模型,R~2为0.516~0.718。与单独采用灌木层结构因子为预测变量建立的灌木层生物量预估模型相比,乔木层平均胸径Dm作为自变量的加入使中幼龄林除地下生物量以外的各组分生物量模型拟合效果有了显著提高,R~2为0.718~0.990;郁闭度Cs的加入使近成过熟林除地下生物量以外的各组分生物量模型拟合效果有了显著提高,R~2为0.817~0.886。【结论】因此,评价和分析乔木林下层灌木生物量,不仅要考虑灌木层自身结构生物量关系,还要考虑到乔木层相关因子的影响,从而建立更符合灌木生物学与生态学相一致的生物学结构模型,本研究可为亚热带地区杉木人工林下层灌木生物量的估算提供参考。更多还原

【Abstract】 [Objective]The study selected Chinese fir plantations in Hunan Province,Anhui Province and Jiangxi Province of southern China as the research object to establish estimation models between the investigation factors of the tree-shrub layer and its biomass. The study tried to build a more reliable and accurate models for biomass estimation of shrub layer and provided reference for improving the accuracy ofmodels for biomass estimation of shrub layer under Chinese fir plantation. [Method]A typical sample survey was conducted in the study area and the canopy density Cs,stand density Ds( plant/ha),average height H( m),average diameter D( cm),cover degree C,fresh and dry mass( kg) of shrub branches,stems,leaves,roots were determined in this study. Through the calculation,the stock volume of tree layer V( m~3/ha) and the biomass of shrub layer( t/ha) were obtained. The effects of shrub layer structure and arbor layer investigation factors on shrub biomass were analyzed by Pearson’s correlation,and the optimal shrub layer structure parameters were selected as model parameters to establish the models for estimation of branch,stem,aboveground and underground biomass. The arbor layer surveying factors were added into the model as an independent variable to compare and analyze the changes of R~2 after arbor layer investigation factors were added. The models were tested with extra-sample data to construct a more accurate model for estimating shrub biomass. [Result]The results showed that the biomass model of shrub layer was dominated by power function,and the under-ground biomass of each forest age shrub layer was obtained,R~2 was 0. 516-0. 955 with independent variable D2 H. The rest biomass got a good fitting model fitted with CH as the independent variable,R~2 was 0. 516-0. 718. Compared with the models for estimating biomass of shrub layer using structural factors of irrigation alone as independent variables,except underground biomass,the adding of average diameter Dmof young-middle age forest tree layer,as a variable,made the accuracy of models for other component increased significantly,R~2 was 0. 718-0. 990; the adding of canopy density Csof mature age tree layer,as a variable made the accuracy of models for other component increased significantly,R~2 was 0. 817-0. 886. [Conclusion]Therefore,if we evaluate and analyze the shrub biomass in the subtropical shrub layer,not only the relationship between the structural biomass of the shrub layer itself should be considered,but also the influence of the relevant factors in the arbor layer should be taken into account to establish a biological structure more consistent with the shrub biology and ecology. This study may provide a reference for the estimation of shrub biomass in the subtropical area of Chinese fir plantation.更多还原