SPRUCE BUDWORM DAMAGE TO BALSAM FIR IN IMMATURE STANDS, QUEBEC

A study was made of the effect of the 1945-1957 spruce budworm infestation on 1,800 acres of spruce-fir and spruce-fir-hardwood forest logged for pulpwood about 15 years prior to the infestation.The number of fir trees was reduced 64 per cent between 1951 and 1961 in the main cover type representing 69 per cent of the forest; fir was reduced from a major stand component of 45 per cent by volume to a minor component of 11 per cent. The basal area reduction of fir varied directly with the fir basal area at the time of the outbreak. Losses were very high in stands containing over 20 sq. ft. of fir per acre.These young stands did not exhibit the degree of resistance to damage often observed in young stands elsewhere. But in spite of heavy losses through all diameter classes, the amount of spruce and fir regeneration that survived to 1961 is believed adequate to produce a pulpwood crop within 60 years.