Document: ROB-3-75-4

Estimating mangrove harvest rates.

HAUFF, R.D.* and K.C.EWEL

Institute of Pacific Islands Forestry, USDA Forest Service, Honolulu, HI 96813 ¹

Abstract:
Forest clearing for short-term economic benefits is a well-documented cause of mangrove destruction worldwide. Estimating harvest rates is needed to assess a forest's capacity for providing human and ecological goods and services. On the high volcanic island of Kosrae, Federated States of Micronesia, remoteness and high annual rainfall preclude regular aerial photography coverage. Harvesting trees for firewood and construction by islanders is the primary cause of forest clearing. The Kosrae State Division of Forestry and Wildlife and the USDA Forest Service have quantified recent annual harvest rates for the island's mangrove forests. Stump decomposition characteristics such as presence and quantity of bark, tannins, sapwood, exposed hardwood, prop roots, and structural integrity, as well as seedling growth rates in terms of node elongation provided data for estimating harvest gap age within two to three years. Data obtained from harvested gaps along transects suggest that 8.4% of the island's mangrove forest area has been harvested over the last 10 years. Calculations of wood volume harvested were comparable at 8.7% of standing volume. Harvest rates based on weighted averages have increased from 0.6% to 1.5% of total mangrove forest per year during this time.

Keywords: mangroves, Micronesia, harvest rates, stump decomposition

This abstract is being presented at: 2:45 PM in session:
Oral Session #18: Mangrove Ecology.