STAND IMPROVEMENT WITH WHITE SPRUCE PLANTED WITH CONCURRENT DYBAR (FENURON) HERBICIDE TREATMENT

Three ½-oz. spot applications of Dybar (pelleted fenuron: 3-phenyl-1, 1-dimethylurea) were given in 1960-61 to competing vegetation around each planted white spruce (Picea glauca (Moench) Voss) in an overmature boreal mixedwood. The herbicide was applied at distances from 1 to 7 feet from the spruce concurrently with planting, in fall, spring and summer. Survival of white spruce, 75 per cent in 1963, was not affected significantly by any of the treatments. A highly significant relationship was found between total live canopy in 1963 (X, not greater than 75%) and height growth of spruce in 1963 (Y):[Formula: see text]Significance of regression was not increased by the inclusion of either initial canopy or height of stock at planting. The study shows that the non-selective Dybar can safely be used at the time of planting to aid the establishment of white spruce, and that subsequent growth of the spruce is largely dependent on the density of total live canopy.