NPP Tropical Forest: Magdalena Valley, Colombia, 1970-1971, R1

This data set contains two NPP data files and one climate data file (ASCI .txt format). The NPP files contain data for above-ground biomass, litterfall, and nutrient content of above-ground vegetation, organic surface layer, and soils measured during an 18-month period in 1970 and 1971 at two contrasting tropical seasonal evergreen forests in Magdalena Valley, Colombia. The climate record provides mean monthly and annual precipitation (1951-1992) and mean monthly and annual average temperature (1970-1997) from Barranca Bermeja (7.00 N 73.80 W) near the Magdalena Valley sites.

One forest stand sits atop a perched water table on a typical valley terrace. It is low in height, basal area (22 m2/ha), and above-ground biomass (18,109 g/m2), but rich in palms with a simple two-layered structure, frequent windthrows and mortality, and few older trees. The contrasting forest stand developed on a lower slope site under more advantageous soil and water conditions. Although number of stems/ha in this forest are smaller and palms less conspicuous, the slope forest shares dominant species of both forests but with taller trees and greater basal area (32 m2/ha) and above-ground biomass (32,581 g/m2). The above-ground biomass and the vegetative bioelement stores were estimated by harvesting sample trees and palms and allometric regressions.

Above-ground net primary production (ANPP) is based on total litterfall accumulation, measured over a 12-15 month period (1,202 g/m2/yr for the terrace forest and 873 g/m2/yr for the slope forest), giving minimum estimates of NPP.