Why are leaves often broader at the bottom of a tree?
its not the case every time.
some trees have broad leaves in top and small in bottom
its cos the bottom leaves are older and the top are younger..
the younger goes the same stage one...
If last year all leaves of young oak were eaten by caterpillars the tree then sprouted leaves at bottom of trunk and this year no leaves on any upper branches again has leaves around base is it dead?
Rain clouds are low, close to the ground, therefore creating high pressure. The air bounces up from the ground and turns the leaves. Take note that it is the leaves towards the bottom of the tree. When the leaves turn, rain is moving in. A tree cannot automatically turn its leaves over. Hope this helps you.