Although your summary sounded kind of cracky (Harry bonding with a tree branch?) it did intrigue me enough to click on this fic, even though I don’t much like fanon!Draco. (The fact that you borrowed a title from the late, great Arthur C. Clarke didn’t hurt either). This was maybe not truly to my taste but a very original and intriguing fic nonetheless. The mythology of the green man is an interesting topic, and it was cool to see Harry depicted as a wand-maker (or indeed, as anything other than an Auror).
Ollivander's only response to Harry's spluttering outrage was to suggest that the branch might subject itself to being "spruced up a bit." Heh heh. I love puns like this.