Golden State Bonsai Federation Collection North
Located in Lakeside Park at Lake Merrit in Oakland, CA (www.gsbf-bonsai.org)
This is collection of trees that were mostly donated over the years. Open to the public year round.
These pictures are from my visit on 5/13/07.

(click image for larger view)
They said this oak was a gift to President Lincoln in the 1860's.