Unless it's a % of the wood gained, the higher trees give more wood per chop, so they would also give the highest apples per chop. If it was 10% of the wood value, then you'd not get apples unless it was at least a level 3 or 4 tree (depending on rounding rules).
And even if it's a flat rate on a per tree basis, if you could be chopping level 10 trees instead of level 1 trees, you'd be sacrificing at least half your wood production to try and get more apples. Unless the apple drop rate approached 50% I doubt it'd be a sacrifice worth making.
And even if it's a flat rate on a per tree basis, if you could be chopping level 10 trees instead of level 1 trees, you'd be sacrificing at least half your wood production to try and get more apples. Unless the apple drop rate approached 50% I doubt it'd be a sacrifice worth making.