Canadian Forest Service Publications
Lodgepole pine response to nitrogenous fertilizers applied on and off snow, and to associated damage by small mammals. 1992. Marshall, V.G.; Barclay, H.J.; Hetherington, E. Forest Ecology and Management 54: 225-238.
Issued by: Pacific Forestry Centre
Catalog ID: 3142
CFS Availability: Order paper copy (free)
The effects of two nitrogenous fertilizers, applied on bare ground in October and on 70 cm of snow in February, were studied in a 15-year-old lodgepole pine (Pinus contorta Dougl. var. latifolia Engelm.) stand near Spillimacheen, B.C. Fertilizers were applied at three stocking levels: 16 000, 2500 and 800 stems ha-1. Urea (300 kg N ha-1) was applied on bare ground and on snow, whereas ammonium nitrate (300 kg N ha-1) was applied only on snow. Over a 3 year period, height growth was not significantly affected by any treatment. Absolute volume growth was significantly (P<0.001) increased by thinning. Absolute volume growth was also significantly increased (P<0.05) by ammonium nitrate in moderately thinned stands (2500 stems ha-1), and diameter at breast height (DBH) growth was increased by ammonium nitrate and urea in heavily thinned (800 stems ha-1) plots, but differences between these fertilizer forms were not significantly different. Urea applied on snow showed a slight advantage over urea applied on bare ground. Fertilized trees that were damaged by snowshoe hare (Lepus americanus Erxleben) and red squirrel (Tamiasciurus hudsonicus Erxleben) also increased significantly (P<0.05) in volume growth compared with unfertilized controls.