I have two mature trees that seem to be dead and dying. One did not leaf out at all this spring, and the other one is now losing large limbs. One limb came down yesterday. These are established trees in my backyard landscape in Hillsboro, Oregon. I do not know what kind of trees they are but they have dark purple foliage. Just wondering how I would go about figuring out what is going on. thank you so much; Lara Martin