Jamieson, Fausset and Brown on Leviticus 19:23-25

23-25. ye shall count the fruit thereof as uncircumcised; three years ... it shall not be eaten of--"The wisdom of this law is very striking. Every gardener will teach us not to let fruit trees bear in their earliest years, but to pluck off the blossoms: and for this reason, that they will thus thrive the better, and bear more abundantly afterwards. The very expression, 'to regard them as uncircumcised,' suggests the propriety of pinching them off; I do not say cutting them off, because it is generally the hand, and not a knife, that is employed in this operation" [Michaelis].