Simulating Carbon Stocks and Fluxes of an African Tropical Montane Forest with an Individual-Based Forest Model

Tropical forests are carbon-dense and highly productive ecosystems. Consequently, they play an important role in the global carbon cycle. In the present study we used an individual-based forest model (FORMIND) to analyze the carbon balances of a tropical forest. The main processes of this model are tree growth, mortality, regeneration, and competition. Model parameters were calibrated using forest inventory data from a tropical forest at Mt. Kilimanjaro. The simulation results showed that the model successfully reproduces important characteristics of tropical forests (aboveground biomass, stem size distribution and leaf area index). The estimated aboveground biomass (385 t/ha) is comparable to biomass values in the Amazon and other tropical forests in Africa. The simulated forest reveals a gross primary production of 24 tcha-1yr-1. Modeling above- and belowground carbon stocks, we analyzed the carbon balance of the investigated tropical forest. The simulated carbon balance of this old-growth forest is zero on average. This study provides an example of how forest models can be used in combination with forest inventory data to investigate forest structure and local carbon balances.

热带森林是碳密集且生产力极高的生态系统。因此，它们在全球碳循环中发挥着关键作用。本研究采用基于个体的森林模型（individual-based forest model，FORMIND）分析了一处热带森林的碳平衡。该模型的核心过程涵盖树木生长、死亡、更新以及种间竞争。研究使用乞力马扎罗山一处热带森林的森林清查数据对模型参数进行了校准。模拟结果表明，该模型成功复现了热带森林的关键特征：地上生物量（aboveground biomass）、茎干尺寸分布（stem size distribution）以及叶面积指数（leaf area index）。估算得到的地上生物量为385 吨/公顷，该数值与亚马逊流域及非洲其他热带森林的生物量水平相当。模拟得到的森林总初级生产力为24 吨碳·公顷⁻¹·年⁻¹。通过模拟地上与地下碳库，本研究分析了所调查热带森林的碳平衡。该原始成熟林的模拟碳平衡平均为零。本研究展示了如何将森林模型与森林清查数据相结合，以探究森林结构与局地碳平衡。