The tree. Being raised in the Pacific Northwest I'm used to trees. And hiking and climbing one spends a lot of time intimately connected with trees, and when one has gone above the treeline he has entered a different, much less friendly world.

Driving around the US, when in the desert I know that in a catastrophe I'll die. I don't know how to get along out there, what resources there are or how to access them. If I'm around trees I know I'll be OK for a good, long while.

In an emergency a tree will offer fuel, a basis for shelter, a wind-break and generally indicate there is water someplace not too far away. Since trees often occur in clumps, or forests, there is even more shelter, even more chance for water, survival.

Maybe there is something primordinally comforting about a tree. Dunno, but for me, anyway, it's possible.