Root Productivity in an Amazonian Rain Forest

Abstract

Average rate of root biomass accumulation in the surface root mat of an Amazonian rain forest near San Carlos de Rio Negro, Venezuela was 117 g°m—2°yr—1, and total root biomass increment was 201 g°m—2°yr—1. Root growth was higher in the surface root mat when fresh litter was present. Root growth rates relative to shoot growth rates at San Carlos were similar to ratios for a temperate forest near Oak Ridge, Tennessee, USA. However, turnover rates of roots were higher at the San Carlos site. High turnover rates result in a relatively large proportion of the roots in smaller size classes, which have a large surface area in relation to their volume and thus area efficient nutrient traps. High efficiency of nutrient trapping is important in the nutrient—poor San Carlos forest.