If you're an Eastern Grey Squirrel, and through some accident of history now live in southern British Columbia, your lot in life can be greatly improved if through other accidents of history oak trees--of which many species share the squirrel's ancestral range-- have been planted nearby.
The heavy trunks and spreading branches are the heart of this rodent's 3-dimensional world. (Avatar is really about squirrels.)
In autumn, acorns are hoarded, along with hickory nuts, beechnuts and Christmas lights, none of which are native here but are relatively easy to find in suburban parks and yards.
Back to oak: in spring, the dangly catkins of oaks are eaten, which I didn't know until I saw this one doing so.