The Impact of Balsam Woolly Aphid Damage on Balsam Fir Stands in Newfoundland

Abstract

This paper presents data on the effects of balsam woolly aphid damage on the mensurational characteristics of balsam fir trees and stands, and quantitative estimates of changes in merchantable volumes that result from alterations in these characteristics. Average volume losses in damaged semi-mature and mature stands ranged from 2 to 6%, but were as high as 80% or more in a few highly susceptible stands. Strong and consistent relationships were recorded between the incidence and severity of aphid damage and a number of site and stand characteristics, including elevation, soil-moisture regime, stand height and age, balsam fir content and total balsam fir basal area of affected stands, and length of time damage had been present. These relationships were utilized to construct a hazard-rating system for use by forest managers in identifying sites and stands highly susceptible to severe damage, and in scheduling silvicultural control measures.

Temperature and plant hardiness zone influence distribution of balsam woolly adelgid damage in Atlantic Canada

“…Stands ranged in age from sapling to "overmature" and many contained permanent sample plots used to monitor annual changes in spruce budworm density (Hartling 2004). Balsam fir trees were either examined at road-side, within plots or along a transect within each stand for symptoms of BWA attack, which include gouting, drooping branches and flat-topped crowns (Page 1975). All trees classified as damaged by BWA contained gouting, which is only caused by BWA.…”

“…Its lack of wings limits dispersal and infestations build up locally, causing an irregular or spotty distribution of outbreaks (Balch 1952). The most severely affected trees are unsuitable for lumber owing to uneven shrinkage causing warping and splitting, and pulp is of inferior quality to that from normal wood (Page 1975, Milne 1990). Average volume losses in highly susceptible semi-mature and mature stands can be greater than 80% (Page 1975).…”

“…The most severely affected trees are unsuitable for lumber owing to uneven shrinkage causing warping and splitting, and pulp is of inferior quality to that from normal wood (Page 1975, Milne 1990). Average volume losses in highly susceptible semi-mature and mature stands can be greater than 80% (Page 1975). Stem attack can result in growth reductions in excess of 50%, with high populations killing trees of merchantable size within three years (Balch 1952).…”

Recovery of Young Balsam Fir Trees Damaged by Balsam Woolly Aphid

“…Long-term infestation could cause a serious reduction in merchantable volume production through the cumulative effects of damage. However, fir stands in Newfoundland have not yet been exposed t m o such long-term infestation because the aphid is a newly-introduced pest that has been present for less than 15-20 years in most areas (Page 1975).…”

“…Long-term infestation could cause a serious reduction in merchantable volume production through the cumulative effects of damage. However, fir stands in Newfoundland have not yet been exposed t m o such long-term infestation because the aphid is a newly-introduced pest that has been present for less than 15-20 years in most areas (Page 1975).The symptoms of aphid attack include swelling of main stem and branch nodes, inhibition and distortion of the shoots, inhibition of buds, and crown dieback (Carroll and Bryant 1960). On young balsam fir, light aphid damage has little effect on the appearance of the main stem.…”