terrain follow

Does anyone know what the altitude limit is when using "terrain follow" mode? Lets say I wanted it to stay 100 ft of the ground and there is a fairly steep hill with 70 ft trees on it (not too thick), would the trees interfere with the sensors? Or is it more GPS? Thanks for your replies.

Here are some questions from someone who doesn't own a Mavic yet but likely will in the next few days. Manual: check [multiple times] Youtube: check [reviews, unboxings, stress tests, missions, crashes and compilations] Apologies if any of this is answered clearly in the manual or in a video...