From below, this looks like a shrubby deciduous tree. It is really just a Douglas fir, like those around it. All the defoliated thicket growth is overgrown poison oak. It has likely been climbing the fir tree since it was quite young. Poison oak is not very proficient at climbing bare trunks. It typically climbs into lower limbs, and then into higher limbs before the lower limbs are shed.

No one has bothered to cut this poison oak out of the fir tree because it is not within a landscapes area. That dark margin at the top of the picture is the underside of a bridge, from which, not much of the thicket growth below is visible. The area from which this picture was taken is used for piling greenwaste and parking, where no one is concerned about wild vegetation beyond.

However, now that I sometimes park in that…