The root systems of 28 Douglas fir (Pseudotsuga menziesii (Mirb.) Franco) in four stands, aged 10, 25, 40, and 55 years, were excavated hydraulically to determine the rooting characteristics of trees in different crown classes at various ages. The extent, depth, configuration, rooting density, and mycorrhizal component of root systems were examined. The significance of the characteristics observed is discussed in relation to silviculture, nursery practice, and forest pathology.

No abstract

Basal scarring, a conspicuous abnormality of western white pine (Pinus monticola Dougl.) and its associated species in the Interior region of British Columbia, was found to be chiefly attributable to injury by bears, infections of Armillaria mellea (Vahl ex Fr.) Quél., fire, mechanical wounding, and the pole blight disease. Diagnostic characteristics, which facilitated classification of scars, even those of advanced age, were found and described. The implications of the various types of scarring are considered.

Hail, bane of the agriculturist and insurance adjuster, is rarely noted as a cause of damage to forest trees. Yet, when severe hailstorms occur, damage to forest vegetation may be both dramatic and serious. We report here on the immediate effects of one hailstorm on recently planted white spruce (Picea glauca (Moench) Voss) and lodgepole pine (Pinus contorta Dougl. var. latifolia Engelm.) trees near the village of Upper Fraser in central British Columbia. ObservationsA drop in temperature from 65OF to 45°F immediately preceded the storm which occurred at 1630 on 23 July, 1972. Hailstones from one to one-and-a-half inches in diameter, driven by strong southwest winds, pelted down continuously for about 10 minutes causing. substantial damage to aluminum roofs and other property in Upper Fraser. The swath of the storm was over 5 miles wide; its length was undetermined.The opportunity to make the observations and comparisons reported here resulted from the "mixed blessing" of having Canadian Forestry Service regeneration research plots directly in the path of the storm. The plots contained planted spruce and pine trees of three ages: 4-year-old transplants (2-1 stock planted in fall, 1970). 3-year-old seedlings (2-0 stock planted in spring, 1971 ) and 2-year-old seedlings (2-0 stock planted in spring, 1972). The plots had received various site preparation treatments and covered a range of site types. In some plots, the seedlings had been stratified into three size classes at the time of plantingsmall, medium and large.The plots were inspected immediately after the storm, and in mid-September the degree of defoliation, presence of stem lesions and death of terminal buds or leaders were assessed. Defoliation was assessed as heavy if the loss was greater than 50% for pine or 30% for spruce. (The different criteria were adopted because of greater defoliation on pine. The effect is to exaggerate the defoliation of spruce compared to pine and to under-emphasize the difference between them. In retrospect, 50% should have been adopted as the criterion for both species.) Lesions were recorded only if they were on the main stem and were greater than 3-cm long. Over 1500 trees of each species were assessed.Ground vegetation was flattened by the storm and within a week. dead and wilted leaves resembled the effect; of autumn frosts. However, within a month, the shrubs had made a vigorous recovery. Defoliation, stem lesions and broken branches and leaders were evident on most smaller trees and the litter of twigs covering roads adjacent to mature standing timber showed that large trees had not escaped damage. Damage to leaders in a 5-year-old spruce plantation was similar to that resulting from a serious outbreak of spruce weevil.Of 3122 trees examined, 14% were undamaged and 2 % were killed by hail; the rest suffered varying degrees of damage. Typical damage was defoliation, stem lesions which were confined to the windward side of stems, and dead leaders usually caused by extensive wounding of the bark (Figs. 1 and 2). ama age t...

Trees per acre Basal area (sq. ft. per acre) Volume (cu. ft. per acre) Tsuga heterophylla Av. height, dom. and codom. (ft.) Av. diam., dom. and codom. (in.) Av. age, dom. and codom. (years) Trees per acre Basal area (sq. ft. per acre) Volume (cu. ft. per acre) Thuja plicata Av. height, dom. and codom. (ft) Av. diam., dom. and codom. (in.) Av. age, dom. and codom. (years) Trees per acre Basal area (sq. ft. per acre) Volume (cu. ft. per acre) Shrub Layer (Line interception) Gaultheria shallon