NPP Tropical Forest: Barro Colorado, Panama, 1969-1990


[PHOTOGRAPH]
Photograph: Buttressed tree at the Barro Colorado tropical forest site (click on the photo to view a series of images from this site).

Data Citation

Cite this data set as follows:

Condit, R., D. M. Windsor, and S. P. Hubbell. 1996. NPP Tropical Forest: Barro Colorado, Panama, 1969-1990. Data set. Available on-line [http://www.daac.ornl.gov] from Oak Ridge National Laboratory Distributed Active Archive Center, Oak Ridge, Tennessee, U.S.A.

Description

Litter-fall and grazing (herbivory) of leaves were monitored for a tropical forest at Barro Colorado Island from 1969 to 1979, as part of intensive ecological studies carried out by the Smithsonian Tropical Research Institute's Environmental Sciences Program. Net primary production (NPP) was not completely estimated. More recent studies of tree recruitment and mortality at five-year intervals commenced in 1980.

The Barro Colorado study site (9.15 N 79.85 W) is a broad, flat-topped hill of 1500 ha that protruded 137 m above the man-made Gatun Lake when the Panama Canal was formed in 1914. It is characterised by shallow clay soils, generally less than 50 cm deep, with a climate typical of the lowland moist tropics. 90% of annual precipitation falls in a rainy season from May to December, followed by a marked dry season. Litterfall at Barro Colorado Island is thought to be unusually rich in nutrients, implying high soil fertility.

About half the island is covered by regrowth forest aged 100+ years; the rest has experienced little disturbance over the past 200-400 years, although there is evidence of small hunter-gatherer clearings from about 500 to 1450 A.D. Further details are available through the Web site maintained by the Smithsonian Tropical Research Institute.

Detailed annual litterfall data (5 categories) are available from two sub-sites; 1969-1971 on the plateau and 1973-79 in the Lutz catchment. Average annual leaf litter-fall amounts to about 650 g/m2, with an estimated additional 30 g/m2 of leaf production consumed by ants and 50 g/m2 by other insects. Total litterfall over this 11-year period averaged about 1060 g/m2/year, including leaves, fruit, flowers, twigs and trash. Trash includes some material consumed and excreted by herbivores, so herbivory should not be added to this total; however, twigfall (mean = 157 g/m2/year) may be doubled to take account of dead twigs decomposing in the canopy. Including a minimum estimate of large wood production (100 g/m2/year), total above-ground NPP (ANPP) is therefore at least 1320 g/m2/year.

Average tree mortality from 1982 to 1985 was about 3%, due to a severe 1983 dry season attributed to El Niño; for 1985-1990, mortality was around 2%. Therefore, in order to maintain the stand biomass at around 200 t/ha (20,000 g/m2), wood production is probably closer to 400 g/m2/year, and ANPP correspondingly higher (1620 g/m2/year).

Contact Information

Contacts: Steve Paton, Data Manager; Terrestrial Environmental Science Program
or Dr. R. Condit: or Dr. D. M. Windsor
Smithsonian Tropical Research Institute
Aptdo. 2072, Balboa, Panama
[or: Smithsonian Tropical Research Institute
Unit 0948
APO AA 34002-0948, U.S.A.]

Tel. +507 212-8097
Fax: +507 212-8148
E-mail: patons@tivoli.si.edu / rick@ctfs.stri.si.edu

Alternative Contact: Dr. S. P. Hubbell
Department of Botany
University of Georgia
Athens
GA 30602-7271, U.S.A.

Tel. +1 (706) 542-1809
Fax +1 (706) 542-1805
E-mail: shubbell@dogwood.botany.uga.edu

Click on the following linked phrase to view references and summaries for the Barro Colorado site.