Tread lightly on the Earth.
(even when you're falling head first into a tree)

Deploy the tree-brake, cap'n, we're goin' in!
Superslide, Wharncliffe Woods, Sheffield
Picture by Antony Hawkins

That pesky mountain biker! Doesn't he realise the damage he's doing by rolling down the hill into that tree? Why, in a hundred years time it might fall over because he damaged the soil over its roots! Someone ought to stop him!

The Superslide claims another victim