Our winter was tough on a lot of trees in our open spaces. The heavy snowfall in February and the strong windstorms this winter have brought down a great number of trees. It seems that the poison ivy vines have weakened many trees like to one pictured. In the picture is a tree with the vines growing to the top. A couple of years ago a very large tree next to this one came down after being weakened by the vines. I have tried to control the vines in my yard that seem to love poplar trees. The vines leave the beech trees alone probably because of the smooth bark of the beeches.
I tried to pull the vines off the trees years ago after we moved into our house. Unfortunately I didn’t take enough precautions to cover exposed skin on my arms. These vines are extremely poisonous and my arms had a bad reaction with blisters. I have since chopped the roots off with an axe and poured vinegar on the remaining roots. That seems to stop their growth.
I am not sure if CA is trying to do anything to the vines on open space land but it seems to be growing uncontrolled in many open space areas. I would hope that these vines would not continue to destroy the trees along many of our paths.