Nitrogen-fixing plants in a cut-over lodgepole pine stand of southern British Columbia

Abstract
The acetylene reduction assay was used to estimate amounts of nitrogen fixed by Lupinusarcticus Wats. (1.97 kg•ha−1•year−1) and Shepherdiacanadensis (L.) Nutt. (0.78 kg•ha−1•year−1) in a regenerating lodgepole pine (Pinuscontorta Dougl.) stand in southern British Columbia. These amounts appear to be significant, as lodgepole pine ecosystems are generally highly deficient in nitrogen. Thinning of excessively dense pine stands may provide an added growth benefit by increasing nitrogen fixation activity of understory vegetation.