Key points are not available for this paper at this time.
David A. Orwig, David R. Foster, Forest Response to the Introduced Hemlock Woolly Adelgid in Southern New England, USA, The Journal of the Torrey Botanical Society, Vol. 125, No. 1 (Jan. - Mar., 1998), pp. 60-73
Orwig et al. (Thu,) studied this question.