Some members of the Friends who visited the Arnold Arboretum this spring we surprised to see Hemlock Hill still populated with healthy appearing tall trees free of adelgids. It was particularly surprising because the Arboretum, unlike the Friends, had decided to take no steps to arrest the infestation of the adelgids. Bob Burke made additional inquiry for us, and here is his report:

I finally heard back from the folks at Arnold Arboretum. Two people actually got back to me and their stories were identical and not particularly hopeful. They concurred that the Woolly Adelgid infestation seems to have been halted or at least arrested over the past two years, but they attribute this almost entirely to the very cold, icy winters we have been experiencing.  This has killed off a very significant part of the population. Unfortunately, they do not expect this to continue if future winters return to anything like normal. They have decided not to try and control the problem with any type of chemical substances because it is very expensive and the results would be very uncertain.