Recovery of Young Balsam Fir Trees Damaged by Balsam Woolly Aphid

After one period of balsam woolly aphid damage, young balsam fir trees resumed normal height growth by the reactivation of inhibited terminal buds on 60% of trees, and by re-orientation of primary internodal and nodal branches on 24% and 16% of trees, respectively. Permanent forks and crooks were formed only infrequently. Height growth loss on damaged trees was small, equalling one to four years growth.