Most varieties of apples must be thinned when the fruitlets are still small, otherwise the apples will remain small, red apples won't colour well, and crowded apples will rub against each other and leave unsightly marks. Also leaving too many apples can cause branches to snap. Bunches are usually thinned from bunches of four or five down to singles or doubles, mainly depending on the crop load, but sometimes also depending on market fruit size requirements. The thinned apples are left on the ground to rot, as they are of no value. It seems like such a waste seeing so many apples on the ground, but it is neccesary in order to produce a crop of good sized, good quality apples.