i am sure you would like a more out of the box explanation
but could it be that you feel more motivated and happy in the trees (whatever reason that is?)
i personally feel the other way
i also feel motivated walking without a route when backpacking
i love cities, museaums and buildings
i love archeology and pyramids
i love to see what humans create and what we are capable of
i just dont care that much about rivers, mountains, volcanos, forests and stuff like that.. i get bored hiking in those places
its just not my thing.