Tropical Forest Restoration - Project Information
Tropical rainforests are disappearing at an alarming rate throughout the world, which is resulting in a loss of large numbers of species and accounts for nearly 20% of carbon emissions worldwide. The highest priority should be to conserve the remaining, intact rain forests which are critical for providing for the well-being of people living in these countries, as well as maintaining the global climate on which all humans depend for food, water, and other environmental services. In areas where tropical forests have been cleared and the forest is slow to recover after extensive agricultural uses, tropical forest restoration is promising option to improve the conservation value of these lands, although they will never replace the original forest.
For over 15 years, Dr. Karen Holl has studied factors limiting recovery, such as lack of seed dispersal, low nutrient soils, and competition with pasture grasses, as well as strategies to accelerate the recovery of forests in degraded areas of the tropics. Her own field work is in Costa Rica, but she has advised students studying tropical forest restoration in Mexico, Panama, Brazil, and other countries in Latin America. In 2004 she started a long-term, large-scale tropical forest restoration study with collaborator Dr. Zak Zahawi (Director of the Organization for Tropical Studies, Las Cruces Biological Station) and funding from the National Science Foundation and the Earthwatch Institute. They, along with many collaborators, are studying the novel idea of planting small patches of trees (islands) as a low-cost method to encourage seed dispersal and shade out pasture grasses. They are also studying the effect of the amount of surrounding forest cover on forest recover in these sites. They and collaborators have been measuring seed rain, seedling establishment, litterfall, birds, bats, and other variables in these sites. For more information on research results, see the selected reports and publications below. They welcome other collaborators and are particularly interested in working with students at Costa Rican educational institutions – interested students should contact Drs. Holl and/or Zahawi.
In addition to their scientific studies, Dr. Holl and collaborators are working in many ways with Costa Ricans in the area where they work. They have worked with the Community Agroecology Network at UC Santa Cruz to help market coffee directly from farmers in the region to consumers; for more information see www.unatazacompartida.org. Dr. Zahawi has led fund raising efforts for a land campaign that has already resulted in over 60 ha (144 acres) of land being protected. Collaborator Dr. Rebecca Cole has worked with the women’s group on making and selling coffee jewelry, which has brought over $40,000 to the local economy.
Selected Publications
Celentano, D., R. A. Zahawi, B. Finegan, R. Ostertag, R. J. Cole, and K. D. Holl. In press. Litterfall dynamics under different tropical forest restoration strategies. Biotropica. pdf
Cole, R. J., Keene, C., Zahawi, R. A., Holl, K. D., in press. Direct seeding of late successional trees to restore tropical montane forest. Forest Ecology and Management. pdf
Holl, K. D. R. A. Zahawi, R. J. Cole, R. Ostertag, and S. Cordell. In press. Planting seedlings in tree islands versus plantations as a large-scale tropical forest restoration strategy. Restoration Ecology. pdf
Cole, R.J., Holl, K.D., Zahawi, R.A., 2010. Seed rain under tree islands planted to restore degraded lands in a tropical agricultural landscape. Ecological Applications 20: 1255-1269. pdf
Cole, R.J., 2010. Social and environmental impacts of payments for environmental services for agroforestry on small-scale farms, southern Costa Rica. International Journal of Sustainable Development & World Ecology 17: 208-216. pdf
Morrison, E. B., C. A. Lindell, K. D. Holl and R. A. Zahawi. 2010. Patch size effects on avian foraging behaviour: implications for tropical forest restoration design. Journal of Applied Ecology 47: 130–138. pdf
Sady, G. C., K. D. Holl, R. J. Cole, R. A. Zahawi. 2010. Germination and survival of tree seeds in a tropical montane forest restoration study (Costa Rica). Ecological Restoration 28: 121-124. pdf
Zahawi, R.A., Holl, K.D., 2010. Bridging the gap between scientific research and tropical forest restoration: a multifaceted research, conservation, education, and outreach program in southern Costa Rica. Ecological Restoration 28: 143-146. pdf
Fink, R. A., C. A. Lindell, E. B. Morrison, R. A. Zahawi, and K. D. Holl. 2009. Patch size and tree species influence the number and duration of bird visits in forest restoration plots in southern Costa Rica. Restoration Ecology 16: 479-486. pdf
Zahawi, R. A. and K. D. Holl. 2009. Comparing the performance of tree stakes and seedlings to restore abandoned tropical pastures. Restoration Ecology 16: 854-864. pdf
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