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融合神经网络与集成学习的复杂地形竹林生物量估测OACHSSCD

Estimation of bamboo forest biomass in complex terrain via ensemble learning fusing neural networks

中文摘要英文摘要

针对复杂地形下高密度竹林地上生物量(AGB)遥感估算面临的光学信号饱和与星载LiDAR数据空间不连续双重难题,以云南新平县龙竹林为对象,提出了一种融合经验贝叶斯克里金回归预测(EBKRP)与异质堆叠集成学习(Stacking)的协同反演框架.该框架通过两个递进阶段实现多源数据的深度融合与空间尺度扩展:首先,利用EBKRP模型,在Sentinel-2光谱特征与地形因子的辅助下,将ICESat-2与GEDI的离散结构参数外推为空间连续的特征图层;继而,构建了一个包含多层感知机(MLP)的异质Stacking集成模型.该模型引入具有全局逼近能力的MLP,与传统的kNN及决策树基模型(RF,GBRT,XGBoost)共同组成基学习器池,旨在利用神经网络强大的非线性映射能力弥补传统模型在处理复杂地形效应时的局限,并通过岭回归元学习器实现异质算法优势的互补融合.结果显示,Stacking模型表现卓越,决定系数(R2)达0.78,均方根误差(RMSE)为12.89 Mg/hm2,精度显著优于表现最佳的单一基学习器MLP.基于该模型估算出研究区龙竹林平均AGB密度为77.0 Mg/hm2,总储量为1.126×106 Mg.融合神经网络的异质集成策略能有效克服复杂山地环境下的估测偏差,为区域森林碳储量的高精度评估提供了一套稳健的方法学范式.

Accurate estimation of Aboveground Biomass(AGB)in bamboo forests is of paramount importance for assessing regional carbon budgets and supporting sustainable forest management,particularly given the high carbon sequestration potential of bamboo ecosystems.However,in mountainous regions characterized by complex terrain,such estimations face severe methodological challenges.These include the rapid saturation of optical remote sensing signals caused by the unique high-density,single-layer canopy structure of bamboo,as well as the spatial discontinuity of vertical structure data acquired by spaceborne LiDAR systems.Focusing on the Dendrocalamus giganteus forests in Xinping County,Yunnan,this study proposes a novel collaborative inversion framework that synergistically integrates Empirical Bayesian Kriging Regression Prediction(EBKRP)with a Heterogeneous Stacking Ensemble Learning strategy.To address the spatial limitations of LiDAR data,the framework first employs the EBKRP model,utilizing Sentinel-2 spectral features and topographic factors as auxiliary covariates,to spatially extrapolate discrete structural parameters from ICESat-2 and GEDI footprints into spatially continuous feature layers.Building upon this data foundation,the study constructs a robust two-layer Stacking ensemble model designed to maximize model heterogeneity.A significant methodological innovation of this framework is the strategic incorporation of a Multi-Layer Perceptron(MLP)into the base learner pool,alongside traditional machine learning algorithms including k-Nearest Neighbors(kNN),Random Forest(RF),Gradient Boosting Regression Tree(GBRT),and XGBoost.The introduction of the MLP is motivated by its distinct inductive bias compared to tree-based models;while traditional decision trees rely on recursive partitioning and orthogonal thresholds,the MLP utilizes a feedforward neural network architecture with non-linear activation functions to perform global approximation.This capability allows the model to effectively capture the highly non-linear mapping relationships between biomass and rugged terrain features that traditional shallow models often fail to resolve.A Ridge Regression meta-learner is then applied to integrate the predictions from these heterogeneous base learners,thereby achieving complementary advantages and reducing estimation bias.The experimental results demonstrate that the Stacking model achieved exceptional performance,with a Coefficient of Determination(R2)of 0.78 and a Root Mean Square Error(RMSE)of 12.89 Mg/hm2,significantly outperforming all individual base learners.Notably,the MLP emerged as the most effective single model,surpassing RF and kNN,which empirically validates the superiority of neural networks in handling complex topographic effects.The study estimated the average AGB density of the Dendrocalamus giganteus forest in the study area to be 77.0 Mg/hm2,with a total carbon stock of 1.126 × 106 Mg.Conclusively,this research confirms that a heterogeneous ensemble strategy incorporating neural networks provides a robust,high-precision paradigm for forest biomass mapping in complex mountainous environments,offering valuable methodological insights for future remote sensing applications.

付连进;舒清态;夏翠芬

西南林业大学,昆明 650224西南林业大学,昆明 650224西南林业大学,昆明 650224

地上生物量龙竹数据融合经验贝叶斯克里金回归预测堆叠集成学习

above-ground biomassDendrocalamus giganteusdata fusionEmpirical Bayesian Kriging regression predictionstacking ensemble learning

《生态学报》 2026 (10)

5495-5509,15

"十四五"国家重点研发计划项目(2023YFD2201205)云南省农业联合专项-重点项目(202301BD070001-002)

10.20103/j.stxb.202507241929

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