燕山山地华北落叶松人工林碳密度及分配特征

为了定量研究燕山山地不同林龄华北落叶松人工林的碳密度特征及其分配格局,为森林碳汇服务功能提升提供科学依据。以河北省木兰围场国有林场管理局新丰林场3种林龄(11,21,32a)华北落叶松人工林为研究对象,基于9块样地本底调查和27株标准木树干解析数据,采用标准木回归分析法、样方收获法、土壤剖面取样法和重铬酸钾—浓硫酸氧化外加热法等,获取不同林龄华北落叶松人工林的碳密度,分析了其特征及变化趋势。结果表明:不同林龄华北落叶松人工林生态系统总碳密度表现为32a(97.29t/hm~2)21a(90.56t/hm~2)11a(44.57t/hm~2),以土壤层和乔木层为主要碳库,二者之和所占比例高达52.59%~71.51%;随着年龄的增长乔木层碳积累能力逐步增强,11,21,32a华北落叶松人工林乔木层碳密度分别为14.27,38.57,42.37t/hm~2,且达到了显著性差异水平;3个林龄华北落叶松各器官的碳密度均表现为干枝根皮叶,各器官贡献率之间均达到了极显著性差异。其中,树干贡献率最大;随着林龄的增加,树干的碳密度分配比例增加,树枝、树叶、树皮的分配比例下降,而根系的分配比例相对稳定;林冠下层碳密度大小呈现出凋落物层草本层灌木层的规律,且随着林龄的增加而增加;0—60cm土壤层碳密度表现为随着土层的加深,碳密度逐步降低,表层有机碳含量最高,且随着林龄的增加而增加,不同林龄间存在显著性差异;选择胸径、树高两因素构建乔木层二元可加性碳密度预测模型效果较好。可见,华北落叶松人工林碳密度的变化主要受到其自身生长发育的影响。同时,也受到人工抚育产生的密度变化的影响。

Carbon Density and Its Allocation Characteristics of Larix principis-rupprechtii Plantation in Yanshan Mountainous Area

This research was carried out to quantify the variation of biomass carbon density and distribution patterns of Larix priucipis-rupprechtii plantation at different forest ages in Yanshan Mountainous area.The results can provide a scientific foundation of service function of carbon sequestration.According to three forest ages of L.priucipis-rupprechtii Plantation of Xinfeng Experimental Forest Farm of the Mulan Stateowned Forest Farm Bureauin Hebei Province,basing on the data of 9 pieces of sample plots survey and 27 larch wood of different forest age,size order,we obtained larch biomass carbon density of different forest ages by using regression analysis,the method of quadrat harvest,soil profile sampling method and potassium dichromate oxidation-external heating method,and analyzed the characteristics and change tendency.The results showed that the performance of total ecosystem carbon density of different forest age of L.priucipisrupprechtii plantation were 32 years (97.29 t/hm2) ＞21 years (90.56 t/hm2) ＞11 years (44.57 t/hm2),the arbor layer and soil layer were the main carbon pools,the proportion of the sum of these two was as high as 52.59 ％ ～ 71.51％;the carbon accumulation ability of the arbor layer increased with the increase of standage,the tree layer carbon density of L.priucipis-rupprechtii plantation at the forest ages of 11,21,32 years were 14.27,38.57 和 42.37 t/hm2,and the difference reached the significant level;the carbon density of every organ of three forest ages of L.priucipis-rupprechtii were trunk ＞branch ＞root ＞bark ＞leaf,the difference of contribution rate between each organ had reached the extremely significant level.Among them,the contribution of trunk was the largest,with the increase of forest age,the proportion of carbon density of trunk increased,the proportion of carbon density of branch,leaf,bark declined,and the distribution ratio of root system was relatively stable.The tread of carbon density of the understory cover were litter layer ＞ herb layer ＞ shrub layer,and it increased with the increase of forest age;the carbon density of 0-60 cm soil layer showed that the carbon density decreased with the deepening of soil layer,the surface organic carbon content was the highest,and it increased with the increase of forest age,difference among different forest ages reached significant level;it was better to choose two factors of DBH and tree height to construct the model of predicting the carbon density of the tree layer with two elements.The change of carbon storage in L.priucipis-rupprechtii plantation was mainly affected by its own growth and development,at the same time,it was also affected by the density change caused by artificial tending.