Sustainable Seed Harvest Projections for a Tropical Tree (Carapa guianensis): A Matrix Modeling ApproachEPA Grant Number: FP916440
Title: Sustainable Seed Harvest Projections for a Tropical Tree (Carapa guianensis): A Matrix Modeling Approach
Investigators: Klimas, Christie A.
Institution: University of Florida
EPA Project Officer: Zambrana, Jose
Project Period: January 1, 2004 through December 31, 2006
Project Amount: $101,138
RFA: STAR Graduate Fellowships (2004) RFA Text | Recipients Lists
Research Category: Fellowship - Forestry , Academic Fellowships , Biology/Life Sciences , Ecological Indicators/Assessment/Restoration
Harvesting of nontimber forest products (NTFP) is viewed as a viable alternative to more intensive land uses because it: (1) contributes to the livelihood and welfare of forest residents; (2) typically results in less ecological destruction than timber harvesting and other forest uses; and (3) may add to the perceived value of standing tropical forest. However, NTFP harvesting can cause alteration or degradation to the resource and affect the persistence of the species if not managed sustainably. Population models and viability analyses are powerful tools for identifying population trends and responses to management regimes. Using a size-class matrix modeling approach, this research will address the possible effects of different harvest scenarios on the population viability of Carapa guianensis Aublet (andiroba), a tree found throughout the Amazon basin and valued for its high quality oil extracted from seed. The lack of basic ecological information available to guide managed extraction of economically important non-timber forest products (NTFP) continues to slow availability of deforestation alternatives for small landholders. Research on alternative income sources like NTFP that encourage forest conservation through sustainable use can produce tangible benefits for local communities while maintaining forest health.
Tree size as well as growth, reproduction, and survival rates will be used as the basic parameters for a projection matrix to determine population growth rate, sensitivity and elasticity, followed by analysis of the future reproductive potential of Carapa. To determine distribution and density patterns of Carapa at the landscape level, I will survey all trees above 10 cm diameter at breast height (dbh) in four plots measuring 400 m x 400 m within a 1,200 hectare federal research site. Because Carapa has higher densities in swamps and alluvial flats than in dry areas, two plots will be located in seasonally inundated areas and two in areas considered “terra firme.” For a subset of these trees, I will install dendrometer bands for recording growth at yearly intervals. On this same subset, I will record phenology data. Ten small plots measuring 25 m x 25 m will be randomly nested within the larger plots. I will use these small plots to determine regeneration (all trees less than 10 cm dbh). I will tag all seedlings within these plots, measuring survival, basal diameter, and height yearly. Seed yield will be calculated for a subset of adult trees in various size classes, and experiments will be used to determine natural germination rates in the two environments. I hypothesize that the projection models constructed from the field data will demonstrate that Carapa populations in wet areas can be harvested more intensively (in time and in space) than populations found on terra firme because of more favorable environmental conditions. I also hypothesize that simulations of intensive seed harvesting will project a drop in population growth rate to below sustainable levels as a result of lowered seedling recruitment.