Methods to enhance tropical forest restoration and education at the Cloud Forest School in Monteverde, Costa Rica

Background/Question/Methods

The natural regeneration of tropical forest from abandoned pasture is limited by seed dispersal and recruitment of dispersed seeds.  Artificial perches can be an effective at enhancing seed dispersal by birds into pastures, but alone are not effective because even though seed dispersal is increased, there is no recruitment beneath perches.  This study tests techniques to facilitate plant recruitment past the barriers of post-dispersal, germination, grass competition and seedling survival. The addition of rotting logs may be a useful tool in aiding germination by improving microsite conditions by blocking desiccating sunlight.  The elimination or reduction of grass competition may improve seedling survival and growth.  In February 2005, I started this research in a tropical pre-montane pasture on the campus of the Cloud Forest School in Monteverde, Costa Rica.  The school provides a unique opportunity to combine research and environmental education for high school students.  I created 78 plots of 2 x 2m, which were randomly assigned to three treatment types, control, cut to reduce grass competition, and solarize to kill the grass by super heating the soil with a clear plastic tarp.  I then randomly added logs to half of the plots in each grass treatment type.  I added seeds from eight animal-dispersed and one wind-dispersed tree species that are important to forest regeneration. 

Results/Conclusions

After 3 months, I checked the seeds for germination, viability, desiccation, removal, depredation, and fungus.  Logs increase germination for most species, and grass reduction and elimination to hinders instead of helps seed germination.  Since September 2005 I have monitored the seedlings in the plots tri-annually.  Recent results indicate that while seeds germinate best in the moist conditions of the pasture grasses, seedlings are slowly dying out due to the direct competition with pasture grasses.  A strategy that combines logs with grass reduction may be the best technique for increasing tree recruitment in abandoned pastures.  Students at the Cloud Forest School will assist in the long term monitoring of the project and the results will assist in their reforestation programs.