PARENT SESSION
Contributed Oral Session 146: Biogeochemistry: Nutrient Dynamics; Carbon Sequestration
Thursday, August 11, 1:30 PM - 5:00 PM, Meeting Room 524 C, Level 5, Palais des congrès de Montréal
Biomass production and carbon sequestration by tropical tree species in experimental plantations in humid lowland Costa Rica.
Raich, James*,1, Bedoya, Ricardo2, González, Eugenio2, Russell, Ann1, 1 Iowa State University, Ames, Iowa2 Organization for Tropical Studies, Inc., San José, Costa Rica
ABSTRACT- To what extent can the unique characteristics of individual tree species affect rates of net primary production and biomass accumulation in a warm, humid environment that strongly favors both processes? This question is at the heart of models that predict tropical forest responses to environmental changes using biome-level parameterizations. We compared aboveground productivity and biomass accumulation among plantations of six tree species planted in 1988 in replicated mono-dominant plots. Hyeronima alchorneoides, Pentaclethra macroloba, Virola koschnyi, Vochysia ferruginea, and V. guatemalensis are native species, whereas Pinus patula is not. Aboveground tree growth was similar among all species at 5 Mg ha-1 y-1, but V. ferruginea had substantial levels of tree mortality. Fine litter production varied from 7.5 Mg ha-1 y-1 in Virola to 11.5 Mg ha-1 y-1 in Hyeronima. Branchfall generated by self-pruning increased aboveground detritus production by 11 Mg ha-1 y-1 in Virola and by 29 Mg ha-1 y-1 in V. guatemalensis. Total aboveground NPP ranged from 22-46 Mg ha-1 y-1 among species, which is one to two times the estimated rate in mature forest on similar soils. Aboveground tree biomass varied from 90-180 Mg ha-1 among species, compared to published estimates of 210-310 Mg ha-1 in mature forest. Thus, species identity influenced carbon cycling and accumulation, and such variation can be expected to influence the results of landscape-level carbon-cycling models. At currently observed rates of tree net biomass accumulation, two hectares of trees can sequester as much CO2-C as is produced by one average American per year: this may reflect a best-case scenario.
Key words: NPP, carbon sequestration, tropical tree species, forest restoration