PARENT SESSION
Contributed Oral Session 163: Forest Ecology: Vegetation Change and Succession
Friday, August 12, 8:00 AM - 11:30 AM, Meeting Room 520 B, Level 5, Palais des congrès de Montréal
Dipteryx panamensis trees: Growth and fruit production in a lowland Costa Rican forest.
McClearn, Deedra1, Campos, Leonel1, Clark, Deborah 2, Clark, David2, 1 Organization for Tropical Studies, San Jose, Costa Rica2 University of Missouri, St. Louis, St. Louis, Missouri, USA
ABSTRACT- We are monitoring growth, flowering, and fruiting patterns of 40 individual Dipteryx panamensis trees (Papilionaceae) in primary forest and 50 planted individuals on former agricultural land at the La Selva Biological Station in the Caribbean lowlands of Costa Rica. Among the large forest trees (mean dbh 784mm) there is no relation between tree size and fruit crop size, nor is there a relation between crop size and fruit size. Individual trees produce fruits with characteristic shapes and sizes that are consistent across years (excluding soft fruits that fall early in the season). Several individual trees have put forth moderate to large fruit crops every year for five years. Other trees have been fruitless for two or three years before producing a crop, but the year of fruit production has not been the same for all trees (i.e., no clear "good year" for all trees). Among the small roadside trees (mean dbh 152mm) we have measured dbh monthly for 15 months. In 2004, minimum growth occurred during the period midApril-midMay and maximum growth came in the period midJune-midJuly. Some but not all of these small trees became completely leafless for a period of weeks. For an individual tree, minimum and maximum growth periods are linked to loss of leaves and flushing of new leaves, respectively. Several of these trees, which are approximately ten years old, are producing fruits. Trees of these diameters in the primary forest are not producing fruits. By following the fates of forest and roadside trees over extended periods of time, we hope to understand better the influence of large scale abiotic factors on primary and secondary forest dynamics. By tracking individual trees, we hope to identify possibly mechanisms of response to factors such as local flooding, loss of leaves, and branch falls. The incorporation of these trees into a genetic analysis will also promote insight into population structure and the pollination biology of this important canopy emergent species.
Key words: Dipteryx panamensis, fruit production, growth, long-term monitoring