欢迎访问林业科学,今天是

林业科学 ›› 2025, Vol. 61 ›› Issue (12): 72-82.doi: 10.11707/j.1001-7488.LYKX20240492

• 研究论文 • 上一篇    

基于分解重构与机器学习的华北平原杨树人工林净碳交换模拟

李倩1,张帆1,*(),孟祥雪2,吴小云1,庞建壮1,许行1,张志强1   

  1. 1. 北京林业大学水土保持学院 北京?100083
    2. 北京市共青林场 北京?101300
  • 收稿日期:2024-08-19 修回日期:2025-03-07 出版日期:2025-12-25 发布日期:2026-01-08
  • 通讯作者: 张帆 E-mail:Zhang_fan@bjfu.edu.cn
  • 基金资助:
    中国科协青年人才托举工程项目(YESS20240294);中央高校基本业务费项目(QNTD202508);北京市科协青年人才托举工程项目(BYESS2024217)。

Simulation of Net Carbon Exchange of Poplar Plantation in North China Plain Based on Decomposition-Reconstruction and Machine Learning

Qian Li1,Fan Zhang1,*(),Xiangxue Meng2,Xiaoyun Wu1,Jianzhuang Pang1,Hang Xu1,Zhiqiang Zhang1   

  1. 1. School of Soil and Water Conservation, Beijing Forestry University Beijing 100083
    2. Beijing Gongqing Forest Farm Beijing 101300
  • Received:2024-08-19 Revised:2025-03-07 Online:2025-12-25 Published:2026-01-08
  • Contact: Fan Zhang E-mail:Zhang_fan@bjfu.edu.cn

摘要:

目的: 将分解重构思想与机器学习相结合,模拟人工林生态系统净碳交换量,为“三北”地区人工林生态系统固碳能力的高精度模拟预测提供有效工具。方法: 基于北京市顺义区共青林场杨树人工林通量观测系统与微气象观测系统2015—2018年生长季(4—10月)的逐日观测数据集,采用随机森林重要性排序法分析获得净生态系统碳交换量(NEE)的主要驱动要素。应用经验模态分解法(EMD)将NEE和主要驱动要素分解重构为波动项和趋势项,分别运用BP神经网络、支持向量机(SVM)、随机森林(RF)和极致梯度提升(XG-Boost)4种机器学习模型进行模拟,优选模型后进行NEE序列重构。结果: 1) 共青林场杨树人工林NEE受总辐射和温度影响显著,土壤体积含水量(5 cm)、饱和水汽压差和空气相对湿度对NEE的影响较弱,环境因子对NEE的影响重要性从大到小依次为总辐射、平均气温、最高气温、最低气温、土壤体积含水量(5 cm)、饱和水汽压差、空气相对湿度。2) NEE分解重构后,对波动项和趋势项模拟效果最好的模型分别为支持向量机和随机森林模型;3) 与直接运用机器学习模拟的方法相比,分解重构后的模拟测试集精度显著提升,R2由0.520提高至0.676,RMSE由1.998下降至1.646 μmol·m?2s?1,MAE由1.578下降至1.273 μmol·m?2s?1结论: 总辐射、平均气温、最高气温和最低气温是影响杨树人工林生态系统NEE逐日变化的最关键因素。本研究提出的分解重构与机器学习相结合的方法可有效提升NEE的模拟准确度,为“三北”地区森林生态系统固碳能力模拟提供新思路。

关键词: 净生态系统碳交换量, 经验模态分解法, 机器学习, 杨树人工林

Abstract:

Objective: The decomposition-reconstruction method is integrated with machine learning model to simulate the net carbon exchange capacity of plantation ecosystems, aiming to provide an effective tool for high-precision simulation and prediction of the carbon sequestration capacity of artificial forest ecosystems in the “Three North” region. Method: Based on the daily observation dataset from the poplar plantation flux observation system and the microclimate observation system in Gongqing Forest Farm, Shunyi, Beijing during the growing season (April?October) from 2015 to 2018, the main driving factors of net ecosystem carbon exchange (NEE) were identified by the random forest importance ranking method. The empirical mode decomposition (EMD) method was used to decompose and reconstruct the NEE and the main driving factors into fluctuation and trend series. Then, four machine learning models, BP neural network, support vector machine (SVM), random forest (RF) and extreme gradient boosting (XG-Boost), were applied to simulate fluctuation and trend series of NEE. After comparing the model performance, the optimal model was selected to reconstruct the NEE time series. Result: 1) The NEE of poplar plantation ecosystem in Gongqing Forest Farm was significantly affected by total radiation and temperature. The soil volumetric water content (5 cm), saturated vapor pressure difference, and relative humidity had weak effects on NEE. The importance rank of environmental factors on NEE was ordered as: total radiation, average temperature, maximum temperature, minimum temperature, soil volumetric water content (5 cm), saturated vapor pressure difference and relative humidity. 2) After NEE decomposition and reconstruction, the models with the best simulation effects for the fluctuation term and trend series were the SVM and the RF model, respectively. 3) Compared with the simulation method without decomposition-reconstruction method, the accuracy of the simulated test set using decomposition-reconstruction method was significantly improved, with R2 increasing from 0.520 to 0.676, RMSE decreasing from 1.998 to 1.646 μmol·m?2 s?1, and MAE decreasing from 1.578 to 1.273 μmol·m?2 s?1. Conclusion: Total radiation, mean air temperature, maximum air temperature and minimum air temperature are the most critical factors affecting the NEE daily variation of poplar plantation ecosystem in the study area. This method proposed in this paper, combining decomposition-reconstruction method with machine learning model, can effectively improve the simulation accuracy of NEE, and provide a new tool for simulating carbon sequestration capacity of forest ecosystem in the “Three North” regions.

Key words: net ecosystem carbon exchange (NEE), empirical mode decomposition (EMD), machine learning, poplar plantation

中图分类号: