I grew up in a neighborhood without any playground but with plenty of trees for children to climb. There were many reasons for me and my playmates to climb trees, among them were to pluck ripe fruits and shake the branches to dislodge June beetles, but most of the time we climbed them just forfun.
My son is growing up in a community with several playgrounds to choose from and lots of trees to climb. He has autism and I am encouraging him to climb trees for gross motor skills development. He is not yet interested in having playmates and I rarely see children here climb the trees so he always does it alone. Most of the time he's not sure which branch to cling to and which branch to step on, but he kept on trying and he does not whine. I guess he is also having fun.