NPP Tropical Forest: Kade, Ghana, 1957-1972


[PHOTOGRAPH]
Photograph: Forest after clearing of secondary growth at the Kade site (click on the photo to view a series of images from this site).

Data Citation

Cite this data set as follows:

Nye, P. H., and D. J. Greenland. 1998. NPP Tropical Forest: Kade, Ghana, 1957-1972. 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

Biomass and nutrient content of different vegetation components and soil for a secondary tropical forest were determined in the late 1950s at the Kade Agricultural Research Station of the former University College, Ghana. Net primary production (NPP) was estimated on the basis of standing biomass accumulation and litter fall. Later studies on litter and wood fall and decomposition were made in the early 1970s, and NPP was recalculated.

The Kade study site (6.15 N 0.92 W) was situated near the town of Kade, 100 km northwest of Accra or about mid-way between Accra and Kumasi. It consisted of moist semi-deciduous forest characterised by the Celtis-Triplochiton association, typical of old secondary forest, and had probably not been cultivated since around 1915-1925. Tree basal area measured in 1957 was quite high at 145 square feet per acre (33.7 m2/ha); measurements in 1968 of a plot a few hundred metres away gave 30.6 m2/ha.

Detailed data are available for a single clear-felling made in 1957, including biomass and nutrient content (N, P, K, Ca, Mg) for lianes, trash (leaves/twigs), branches, large wood, standing dead wood, stumps (above and below ground), litter and roots. Total live + dead biomass was 36,102 g/m2, of which 5,414 g/m2 (15%) was below-ground, and 23,568 g/m2 was above-ground live biomass. Monthly litter fall is available for 26 months, 1970-72, with a single 6-month estimate of timber fall and decomposition rates for various litter categories.

Total annual NPP was estimated for the late 1950s at about 2400 g/m2, based on litter fall of 1054 g/m2 and rough estimates of timber fall (1070-1121 g/m2) and root production (258 g/m2). In the 1970s, NPP was recalculated at 2200-2500 g/m2. Additional detailed data is available in the literature on botanical composition and root size distribution, plus root distribution by depth in 15-year and 50-year undisturbed plots. Diurnal microclimate data at different positions in the canopy and soil are available for several stations along a catena.

In the absence of certain long-term climate data (temperature) for this site, an additional climate data set is provided for Kumasi, Ghana (6.72 N 1.60 W).

Contact Information

Contact: Dr. P. H. Nye
Hewel Barn
Common Road
Beckley
Oxfordshire OX3 9UR
U.K.

Telephone/fax: +44 (1865) 351607
E-mail: not available

Alternative Contact: Dr. D. J. Greenland
Low Wood
The Street
South Stoke
Oxfordshire RG8 0JS
U.K.

Telephone/fax: +44 (1491) 873259
E-mail: dgreenland@cwcom.net

Click on the following linked phrase to view references and summaries.