Coupled isotopic and process-based modeling of gaseous nitrogen losses from tropical rain forests

Isotopic evidence for large gaseous nitrogen losses from tropical rainforests.

The nitrogen isotopic composition (15N/14N) of forested ecosystems varies systematically worldwide. In tropical forests, which are elevated in 15N relative to temperate biomes, a decrease in ecosystem 15N/14N with increasing rainfall has been reported. This trend is seen in a set of well characterized Hawaiian rainforests, across which we have measured the 15N/14N of inputs and hydrologic losse...

Tropical Rain Forests

Consequences of Nitrogen Additions for Soil Processes and Solution Losses from Wet Tropical Forests

Wet tropical forests growing on highly weathered soil, depleted in rockderived nutrients, yet rich in nitrogen (N), may respond quite differently to anthropogenic N inputs than those growing on younger soils low in N. We evaluated the effects of firsttime and long-term N additions on the pattern and regulation of hydrologic N losses from wet tropical forests located at the extreme ends of a soi...

Modelling Selection Harvesting in Tropical Rain Forests

VANCLAY, J.K. 1989. Modelling selection harvesting in tropical rain forests. Long term yield estimates for natural forests require a harvesting model to enable future yields to be estimated reliably. The model should predict the felled stems, the proportion of these which are merchantable, and any damage to the residual stand. Regression analyses was used to develop a model of current logging p...

Controls Over Leaf Litter and Soil Nitrogen Fixation in Two Lowland Tropical Rain Forests

Global com parisons suggest that rates o f N fixation in tropical rain forests m ay be am ong the highest on earth. However, data supporting this contention are rare, and the factors th a t regulate N hxation w ithin the biom e rem ain largely unknow n. W e conducted a full-factorial (N X P) fertilization experim ent in two lowland tropical rain forests in C osta Rica to explore the effects o f...