Apple tree

hi I have hybrid apple tree, probably grown from joining stems together about 18 years ago. all the apples grow on the bottom of the tree , I want to even up the tree if I cut all the branches from the bottom will apples grow on top?, I sometimes get 1 or 2 apples on the top half but they never grow to the same size as the lower ones. The apples are edible and quite sweet, but just too low to the ground. Thanks.