Malorie blackman recommendation + book help

[Stoyk]

i was given a book from a friend the uk written by the author Malorie blackman called 'noughts and crosses' it is one of the most powerful books ive read to date, i wont spoil it, just go read it, there are 2 sequels as well.
i will tell you that the basis of the series is the worlds history is completely swapped as in white people are considered inferior race and are subjected to modern racism and slavery
extremely interesting point of view.

now to the help part, i was reading in a bouldering magazine, a canadian climber recomended a book that i cannot remember the title or author, i remember the description though, its about a boy who grew up in a rich family and did not like the way he was being treated so one day he climbed a tree and decided to live in it.
PLEASE HELP!