About This Project

Tropical forests store 20-40% of terrestrial carbon (C) and contain 90% of all tree species. Land-use change causes species loss and greenhouse gas emissions. However, human-modified tropical landscapes can also mitigate climate change and conserve biodiversity. We are interested in the long-term monitoring of tree diversity and C-sequestration in different land-use types because we have found synergies between tree diversity and C-storage in coffee farms, pastures, and forests in Costa Rica.

Ask the Scientists

What is the context of this research?

The importance of managed landscapes for biodiversity conservation and C-storage is increasingly acknowledged, especially in the case of agroforestry (the integration of trees with crops or livestock). In addition, there is growing evidence that species diversity and composition are linked to ecosystem function in managed and natural systems, although the mechanisms behind these relationships are debated. We found that shade-grown coffee farms and pastures with trees store about 60% the amount of C and maintain nearly 20% of the tree diversity found in natural forests. Tree species diversity and composition appear to determine the amount of C stored. Understanding the linkage between biological diversity and C-sequestration is critical for effectively managing tropical landscapes.

What is the significance of this project?

This project is relevant for tropical regions, where the management of altered landscapes will determine the future capacity of biological systems to remain functional. Costa Rica is recognized for its efforts in conserving tropical forests and for its goal of becoming carbon neutral. A government program provides payments for landowners who implement forest conservation or agroforestry practices, which are both components of the national climate change mitigation plan. These policies require robust estimates of C-storage in different land-use types. In addition, we need to understand the relationships between tree diversity and carbon storage in order to manage landscapes for both biodiversity conservation and greenhouse gas mitigation.

What are the goals of the project?

We want to know how tree diversity and land management affect C-sequestration in vegetation and soils in the long term. We will establish permanent plots in coffee farms, pastures and forests that have been assessed during the past 8 years. Plots will differ in tree diversity and composition. Trees will be tagged and re-measured annually over 5 years to estimate aboveground C-sequestration. We will install dendrometer tapes on dominant tree species with different functional traits (e.g. fast vs. slower growth rates), to monitor their growth precisely. Re-sampling the soils at these sites during the next 5 years will allow us to estimate soil C-sequestration over a period of 10 years for coffee agroforestry. To date information on soil C-sequestration in agricultural systems is scarce.