LTREB: Tropical rain forest ecosystem responses to climatic forcings

University Of Missouri-Saint Louis, Saint Louis MO

Investigators

Abstract

The research in this 5-yr project will extend the longest-running study of how tropical-forest productivity is controlled by climatic variation. In a network of 18 0.5-ha plots across a Costa Rican rain forest, each year's forest productivity (new wood, leaves, fruits and flowers) will be measured, as well as yearly changes in forest structure caused by tree death and in-growth. The measurements from the first 11 years showed that forest growth decreased dramatically in hotter and drier years. Extending the record a further 5 years will provide a globally-unique measurement series for assessing how a tropical rain forest is responding to on-going climatic and atmospheric changes. Tropical rain forest plants continuously absorb vast amounts of carbon dioxide from the atmosphere through the process of photosynthesis, while at the same time re-emitting large amounts of carbon dioxide in respiration. A decline in tropical-forest productivity, the balance between these two processes, would increase the rate of greenhouse-gas accumulation in the atmosphere, thus speeding global warming. It is therefore critical to monitor these processes in tropical forests, but the existing data records are sparse. By extending the long-term measurements in this Costa Rican rain forest to span 16 years, this study will produce a unique basis for refining current scientific understanding of how tropical forests are responding to, and contributing to, global climate change.