On a recent trip to the Northwest I came across the Oregon White Oak tree (Quercus garryana - this species name is similar to its other common name "Garry Oak" Quercus=Oak and garryana=garry). The trees in these images are located on the west side of Portland just off of highway 26 along NW 167 Place near the NW Cornell Road exit. I also saw quite a few of them driving further west on the Sunset highway heading towards the coast from Portland until they petered out by the coastal range.
The acorns of the Oregon White Oak are quite round in shape and almost one inch in diameter.
I also found that on the mature trees there was a lot of dark green moss growing on the top side of the branches. This coupled with the fact that bunches of leaves grow along the length of the branches give the Quercus garryana a distinct look that sets it apart from other oak trees in the area.
The trunk of the tree in the image below must have been close to four feet in diameter. The tree in the top image of this post may have been even bigger at the base.
The leaves of these oak trees were about 4-5 inches long and 2-3 inches wide. Their texture was a bit rough like a fine grain sandpaper. The lobes were quite rounded
Across the road from these trees there was a line of Northern Red Oaks that were already turning color but these Oregon White Oaks were not showing any sign of changing color yet.
The habitat of the Quercus garryana stretches from north to south all the way from B.C. down to Southern California. In Washington State this is the only oak tree species that grows native.