I’ve posted pictures of tree roots before, most notably in:

Tree Roots (at Little Stony Point)
Tree Roots (at Roaring Brook Lane)
Wasteland off the lake (last picture)
A few black and whites from the West Point Foundry Preserve (fifth picture)
Rock Formations (last picture)

Here are some more. I like their gnarled appearance and the way they seem to reach out towards you – almost like tentacles. If you stayed in one place for long enough they’d get you eventually too (I’ve seen tree roots growing through stone in the temples at Angkor Wat and check out the last link above). Of course you’d have turned to bleached bones long before this happened.