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Scientia Silvae Sinicae ›› 2025, Vol. 61 ›› Issue (12): 72-82.doi: 10.11707/j.1001-7488.LYKX20240492

• Research papers • Previous Articles    

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

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

CLC Number: