There is a pine bore that kills pines from the top down but generally that deforms the tree and then kills it out right.

I wonder if what you are seeing is the seven yr. cycle that many pines go thru. Some of the needles turn yellowish, then brown and fall off. New growth appears and the tree returns to it's healthy green look.

Other possiblities are acid rain or lack of enough rain to kep the healthy this past summer.

They are hemlocks, and the problem is the wooly adelgid. A search will turn up a lot on the issue.

My hemlocks have wooly adelgid mites. The trees are slowly declining, which is sad - they line one edge of my property line, and I'm not looking forward to having to remove them at some point in the future.

Laurel

Are you sure they are not tamaracks? They are deciduous, and turn bright yellow. I noticed a lot of them in the Adirondacks this year.They really stood out, and I was concerned until I remembered they were deciduous.

Here is a link that might be useful: {{gwi:1329516}}

Mad Gallica. My guess your right.They figure it will desecrate the hemlocks in all the northeast in the near future.I've been to Frost Valley YMCA camp.Thats where I learned of the problem. It's ashame to think that 100 plus tears ago we clear cut hemlock through out the Catskills for the tanning acid.They started a coming back and now we face losing them again.Another native tree dieing off do to a non native.