Collaborative Research: Spatial and temporal patterns of secondary tropical forest succession

Around the world, there is growing interest in restoring forests, which improve water quality, store carbon, conserve biodiversity, and ensure human wellbeing. But there are few long-term studies to guide forest restoration, especially in the tropics. This project builds on an existing long-term, experiment that compares different ways of restoring tropical forest.

The research will measure how well forests are recovering after nearly two decades of different treatments at many sites. The study will also answer questions about how important nearby forest patches are to the recovery of the restored sites. Results will provide critical guidance to land managers and policymakers on how and where to invest limited resources to improve forest restoration efforts.

The project will develop online lessons about forest management and restoration for college-level students and continue an inquiry-based learning program for high school students.

More than 15-years ago, 12 experimental sites were established over a 100 square-kilometer area in southern Costa Rica. Sites are surrounded by a range of low to high forest cover. Each site has three experimental treatments: (1) low intensity -- no tree planting and natural recovery, (2) medium intensity -- planting tree islands of three sizes, and (3) high intensity -- planting the entire plot with trees.

New research activities will include conducting an intensive survey of all tree recruits in restoration and reference forest plots for the first time to thoroughly quantify rare, later-successional recruits. A detailed map of forest cover and individual focal tree species surrounding the sites will be created to assess the importance of proximity to seed sources.

To better understand factors limiting forest recovery, investigators will measure seed dispersal and conduct seed-additional experiments. Overall, the project will use field data and remote sensing techniques to address a host of key debates in tropical community ecology about the dynamics of later-successional tree recruitment. These debates include the relative importance of seed dispersal, seedling establishment, and tree growth in determining secondary forest community composition; the degree to which manipulations of initial site conditions affect changes in species composition over time; and the importance of landscape-scale processes on long-term forest recovery.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.