I used to climb trees as a kid. Still do, on occasion. This is cheating:
There’s also a lift. It’s got glass sides and is easy to miss, though you’re looking right at it in this picture.
The Xstrata [that’s a mining company by the way] Treetop Walkway lift has proved unreliable since it was brought into service. After exhaustive investigation it has been decided that an alternative solution to the current lift will need to be found. Investigations are underway as to what the options are.
My vote goes for a trebuchet, and I suppose a net to satisfy Health & Safety. Warwick Castle has one. The action starts about a minute in: