Right now what you can do is cut through the poison oak vines that are climbing up your fir trees. That should stop them from damaging your trees any further. (Be sure to sanitize your tools afterward … it’d be unfortunate to get a rash from your loppers! (See the link for the fact sheet below).

 You can use goats or sheep to browse your poison oak patch, but my understanding is that grazing doesn’t provide long-term control.  As for long-term control, our PNW Weed Management Handbook is a great resource (https://pnwhandbooks.org/weed/problem-weeds/poison-oak-poison-ivy-toxicodendron-spp).  It gives you several options for chemical control of poison oak and also lists the timing for application. From what it says, you’ll want to treat your poison oak next year when it is actively growing; now isn’t the best time to achieve greatest effect. 

 As always, when using chemicals, be sure to read the label carefully and follow the instructions!  Also, because you’re dealing with a plant that you have a sensitivity to (this probably goes without saying), wear gloves and when you take them off to dispose of them, you can pull them off so that your skin doesn’t come in contact with the oils on the outside of the glove … just allow them to turn inside out as you’re removing them.  Have some Technu or other product available to wash with and take extra care with your clothing.

OSU has a great little poison oak factsheet that I think you’ll find very helpful.

http://extension.oregonstate.edu/sorec/sites/default/files/Poison_Oak_Fact_Sheet__06.pdf

If you have more questions, feel free to call, email, or stop by our office.