林龄和林分密度对杨树人工林有机碳储量的影响  

Influences of stand ages and densities on organic carbon storage in poplar plantations

作　　者：郑思静 方杰[1] 左思敏 刘钰[1] 方升佐[1,2] ZHENG Sijing;FANG Jie;ZUO Simin;LIU Yu;FANG Shengzuo(College of Forestry and Grassland,Nanjing Forestry University,Nanjing,Jiangsu 210037,China;Co-Innovation Center for the Sustainable Forestry in Southern China,Nanjing,Jiangsu 210037,China)

机构地区：[1]南京林业大学林草学院,江苏南京210037 [2]南方现代林业协同创新中心,江苏南京210037

出　　处：《森林与环境学报》2025年第3期264-272,共9页Journal of Forest and Environment

基　　金：江苏省碳达峰碳中和科技创新专项“江苏省杨树人工林碳动态及减排增汇关键技术”(BK20220017)。

摘　　要：为明确杨树人工林有机碳储量与林龄、密度之间的关系,以江苏省泗洪县马浪湖林场的杨树人工林为研究对象,调查分析林龄在5~21 a、林分密度在200~451株·hm^(-2)的37个杨树人工林样地的生物量及器官碳含量、不同土层深度的有机碳含量和土壤容重,结合回归模型、机器学习模型拟合以及空间特征分析方法,建立杨树人工林有机碳储量与林龄、密度关系的预测模型,揭示马浪湖林场杨树人工林有机碳储量的空间分布特征。结果表明:不同林龄和林分密度的杨树人工林林分总生物量为5.25~193.82 t·hm^(-2),平均总生物量为79.15 t·hm^(-2),且林分各器官生物量均表现为树干>树枝>根系>树叶,树干生物量显著高于其他器官(P<0.05)。杨树不同器官的碳含量为42.31~49.05 g·kg^(-1),表现为树干>树枝>根系>树叶。土壤有机碳含量随土层加深逐渐降低,而土壤容重则逐渐增大。林龄及林分密度均对杨树人工林林分碳储量和总有机碳储量有显著影响(P<0.05)且两者之间存在明显的交互作用;林龄显著影响土壤(0~60 cm土层深度)有机碳储量(P<0.05),而林分密度对土壤有机碳储量的影响不显著(P>0.05)。与回归模型相比,机器学习模型中的梯度提升回归(GBR)和随机森林(RF)在揭示林龄、林分密度与有机碳储量之间的非线性关系时,均表现出较高的拟合度(R2>0.9),预测误差较小,能够有效揭示林龄、林分密度与杨树人工林有机碳储量之间的复杂关系。马浪湖林场杨树人工林总有机碳储量呈带状分布,总有机碳储量为41.00~964.76 t·hm^(-2)。The effects of stand ages and densities on organic carbon storage in the poplar plantations in Malanghu Forest Farm,Sihong County,Jiangsu Province were studied.The biomass and organ carbon content in 37 sample plots of poplar plantations with the stand age ranging from 5 to 21 years and densities between 200 and 451 plant·hm^(-2),as well as the organic carbon content and bulk density at different soil layers were investigated and analyzed.The prediction model of organic carbon storage in poplar plantations based on stand ages and densities was established by regression and machine learning model fitting and spatial feature analysis.The spatial distribution of organic carbon storage in poplar plantations in Malanghu Forest Farm was characterized.The results showed that the total biomass of poplar plantations with different stand ages and densities varied within the range of 5.25-193.82 t·hm^(-2),and the average total biomass of the investigated stands was 79.15 t·hm^(-2).The biomass of each stand component followed the order of trunk>branches>roots>leaves,and the trunk biomass was higher than that of other components(P<0.05).The carbon content of different biological components of poplar trees ranged from 42.31 g·kg^(-1) to 49.05 g·kg^(-1),showing a trend of trunk>branches>roots>leaves.The organic carbon content in soil gradually decreased with the deepening of soil layers,while the soil bulk density gradually increased.Both stand ages and densities affected the carbon storage of poplar stands and the total organic carbon storage in plantations,and the two factors had interactive effects(P<0.05).Stand ages affected organic carbon storage in the 0~60 cm soil(P<0.05),while stand densities had no significant effect on the organic carbon storage in soil(P>0.05).The machine learning models gradient boosting regression and random forest showed higher fitting degrees(R2>0.9)and lower prediction errors than the regression model when revealing the nonlinear relationship of stand ages and densities with organic carbon

关 键 词：杨树 经营措施 林分生物量 土壤有机碳 回归模型 机器学习模型 空间分布 

分 类 号：S714[农业科学—林学] S757