I have a 150 ft wall of 20 ft high hemlocks that act as a fence and privacy buffer between myself and the neighbors yard. In certain areas we have had trees die and others get very thin. A few years back we had a tree company come out and they treated for wooly adelgid. Did not seem to help much but hard to judge as who knows what it would look like with no treatment. I do think adelgid are present as from what I read they are everywhere in this area. Very expensive to treat and neighbor and I are thinking of doing it ourselves. Would also like to do something for tree health but the line runs to lake so we will not use anything that may cause harm. Any suggestions on products, methods, best time of year.... I did find a place that sells a type of Beatle that feeds on these things. That seems interesting.
https://www.treesaverspa.com