I like trees and would support anything that would help the world we live in.
However I fail to notice how it relates to web hosting.
Sure I would support a scheme to plant more trees and / or protect the environment or help it any other way - but tying it in with web hosting?
And buy a "Carbon Neutral Hosting company" do you mean that you want Mark to go out and plant a tree for every sign up eUKhost has
.