In reply to jonathan shepherd:
There wasn't a tree I hadn't climbed in the wood behind the houses on my street by the time I was 11. Mind you I went up a tree recently and got to the top before I started to realise the danger I had been in back in the 1950s. Sometimes I wake up screaming... but that's mostly to do with the hand over hand descents into coal mine shafts on a piece of old brown hawser lay cable somebody had got hold of. God knows how we secured it at the top. Or the explorations of sewerage drainage pipes; or the merry games down in the goods yard... or the swimming expeditions round the flooded sand quarries.
Lucky days and lucky to have survived.
If you want to climb a tree, climb one.