Estimate of nitrogen fixation on leaf surfaces of forest species in Minnesota and Oregon

Abstract

Leafy branches from 52 tree or shrub species collected from Minnesota forests during July and August, 1976, and (or) May and September, 1977, were tested for their ability to fix nitrogen. Seven species were similarly sampled in western Oregon during November, 1976. Nitrogen fixation was assessed by the acetylene reduction method. Little, if any, acetylene reduction was detected on branches without epiphytes. The upper limits of possible nitrogen fixation on the leaf surfaces were below amounts important in the nitrogen economy of the stands.