The best idea about clearings I have heard is as follows ...

The folks way back then had to create a home base to stay in and go a-hunter-gathering from. The image most people have of them being permanently on the move is wrong. When then returned to these clearings a year or two later they noticed that these clearing were now occupied by young juicy sapplings, which attracted deer etc, because the new leaves were within reach. So, naturally some clearings started to be made just for this purpose.

There is some evidence that some of these clearings may have been deliberately cultivated so that thorns and brambles populated the perimeters. This implies an actually trap so that animals could be lured in and caged up.

Farming may have started earlier than we all think!