Impacts of Herbicide Application and Mechanical Cleanings on Growth and Mortality of Two Timber Species in Saccharum spontaneum Grasslands of the Panama Canal Watershed

background

This study evaluates the effectiveness of weed control treatments (herbicide application and mechanical cleanings) in promoting the growth and survival of the exotic tree species Tectona grandis and the native tree species Terminalia amazonia.

Goals & Methods

The goal of this study was to examine whether weed control treatments of varying intensities affected tree growth and mortality of two timber species and the costs of grass control treatments in S. spontaneum grasslands. The authors conducted a field study in June 2003, during which pure plots of T. grandis and T. amazonia were planted. Fire was excluded from each plot and each received a specific weed control treatment at regular intervals. Height (m), basal diameter (cm), live crown height (m), crown diameter (m), and tree mortality (number) were measured annually in July on all individuals from 2003 until 2006.

Conclusions & Takeaways

T. amazonia demonstrated slower growth than T. grandis; though, growth and survival of T. amazonia increased in the third year since establishment. Both species responded positively to the control treatments, with the most effective treatment being annual herbicide application with more frequent cleanings (greater than 4 per year). T. amazonia responded better than T. grandis to treatments with no herbicide. The authors assert that with weed control of S. spontaneum grass, reforestation can be viable.