That’s due to the one-two punch of two highly destructive insects: hemlock woolly adelgid (HWA) — an aphid-like insect — and elongated hemlock scale (EHS) — an armored insect.

Both are foreign invaders: HWA from Asia and EHS from Japan. Because of this, neither has any natural predators here, so they are free to infect eastern hemlocks without anything to stop, or even slow, them.

Read more: http://citizensvoice.com/sports/under-attack-invasive-species-wiping-out-pennsylvania-state-tree-1.2077510