Apple tree size classes number from one to ten in increasing height and breadth. A "1" is a dwarf which can be productive and as short as with proper pruning. A "10" is the standard sized tree with no dwarfing and will grow to tall and wide or more, dependent upon the variety chosen. In general the class range is (1) 10-20% of full size, (2) 20-30%, (3) 30-40% and so forth to size 10 which is 100% of full size.