Collaborative Research: Effects of Species on Forest Carbon Balances in Lowland Costa Rica

潮湿的热带森林的生物量和土壤中含有大量的碳，生产力很高：因此，热带森林的生长、干扰和土地利用对大气二氧化碳水平有潜在的重大影响。森林碳吸收和释放的准确模型对全球变化分析至关重要，但我们甚至不知道热带森林吸收或产生多少二氧化碳。该项目将利用哥斯达黎加低地19年生的复制种植园来评估对全森林碳循环的物种水平控制。在四个物种之间的比较中，将评估影响生态系统水平碳平衡的三个关键植物性状：1)碳利用效率(CUE)；2)在不同的植物部分(如叶子、木材)之间的分配；以及3)影响碳循环速率的组织生物化学。该项目的更广泛影响包括为本科生和研究生提供培训和国际经验。广泛使用的世纪模型的进一步发展将在预测物种组成变化对生态系统水平碳平衡的影响的能力方面取得重大进展。该研究场地的维护将为其他研究人员提供基础设施，并展示生态系统服务的恢复。结果将向科学界以及该地区的非政府组织和土地所有者传播。通过与费尔柴尔德热带植物园的合作，开发用户友好的雨林模拟模型将增加佛罗里达州迈阿密地区29,500名K-12学生的教育机会。

Moist tropical forests have huge amounts of carbon in their biomass and soils, and high rates of productivity: tropical forest growth, disturbance, and land use therefore have potentially large impacts on atmospheric CO2 levels. Accurate modeling of carbon uptake and release by forests is essential for global-change analyses, yet we do not even know how much CO2 tropical forests capture or produce. This project will make use of 19-yr-old replicated plantations in lowland Costa Rica to evaluate species-level controls over whole-forest carbon cycling. In comparisons among four species, three key plant traits that influence ecosystem-level carbon balance will be evaluated: 1) carbon use efficiency (CUE); 2) partitioning among plant parts that have differences in CUE (e.g., leaves, wood); and 3) tissue biochemistry, which influences carbon cycling rates. The broader impacts of this project include training and international experience for both undergraduate and graduate students. Further development of the widely used Century model will offer a major advance in the ability to predict the effects of shifts in species composition on ecosystem-level carbon balances. Maintenance of this research site will provide infrastructure for other researchers, and a demonstration of restoration of ecosystem services. Results will be disseminated to the scientific community, and also to NGO's and land-holders in the area. Development of a user-friendly rainforest simulation model will enhance education opportunities for 29,500 K-12 students in the Miami, FL area, though a partnership with the Fairchild Tropical Botanical Garden.