大兴安岭天然林不同林分溶解有机碳变化特征

为确定不同林分和季节变化对森林碳库影响。在内蒙古大兴安岭根河林业局境内选取具有代表性的林分，即白桦林、白桦落叶松混交林以及落叶松林为研究对象。收集并测定了树干径流、有机质层和0-30 cm土层中DOC浓度，并分析了DOC变化特征以及不同月份对DOC的影响。结果表明:不同林分中树干径流中DOC平均浓度分别为60.12，172.77，205.02 mg/L；有机质层中DOC平均浓度分别为35.32，39.64，34.45 mg/L；0-30 cm土层中DOC平均浓度分别为26.23，37.08，26.53 mg/L。结果表明:不同林分中DOC浓度表现为树干径流 > 有机质层 > 0-30 cm土层，落叶松林树干径流DOC浓度明显高于白桦林（p<0.05），且落叶松树干比白桦树干淋溶DOC强；不同林分中有机质层和0-30 cm土层表现为白桦落叶松混交林>白桦林、落叶松林，但无明显的差异（p>0.05），而且有机质层和土层对DOC有吸附固定作用；不同林分6-9月份树干径流中DOC浓度呈现先升高后降低的趋势，7月份达到最大，机质层和0-30 cm土层中DOC浓度6月份最高，7月、8月最低，而9月份又升高。不同林分和月份的变化，影响了天然林中DOC浓度分布。

Change Characteristics of Dissolved Organic Carbon (DOC) in Natural Forests of Greater Khingan Mountains Region

In order to determine the effects of different forest stands and seasonal changes on forest carbon pool, the representative stands of Birch forest, Birch forest and Larix gmelinii mixed forests and Larix gmelinii forests were selected in Genhe Forestry Bureau of Greater Khingan Mountains region, Inner Mongolia. Dissolved organic carbon (DOC) concentrations in stemflow, organic matter layer and 0-30 cm soil layer were collected and measured. The variation characteristics of DOC and the effects of different months on DOC were analyzed. The results show that the average concentrations of DOC in stemflow of different stands are 60.12, 172.77, 205.02, 35.32, 39.64, 34.45 mg/L in organic matter layer, 26.23 mg/L, 37.08 mg/L, 26.53 mg/L in 0-30 cm soil layer, respectively. DOC concentration in different stands decreases in the order:stemflow > organic layer > 0-30 cm soil layer, and the DOC concentration in stemflow of Larix gmelinii forest is significantly higher than that of Birch forest forest (p<0.05), and the DOC concentration in the trunk of Larix gmelinii forest is higher than that in the trunk of Birch forest. DOC concentrations of the organic layer and 0-30 cm soil layer in different stands decrease in the order:Mixed forest of larch and birch>Birch forest and Larix gmelinii forest, but there is no significant difference (p>0.05). Organic and soil layers can adsorb and fix DOC. The concentration of DOC in stemflow increases first and then decreases from June to September and reaches the maximum in July. The concentration of DOC reaches the highest in June in organic layer and 0-30 cm soil layer, the lowest in July and August, and then increases in September. The variation of DOC concentration in different stands and months affects the distribution characteristics of DOC concentrations in natural forests.