To get started pruning your newly-planted fruit tree, the essential tool for pruning a young fruit tree is a pair of sharp hand pruners. You should be certain to use “bypass” and not “anvil” type pruners. Bypass pruners are safe to use on living wood, whereas anvil pruners are meant to be used only when cutting up deadwood or kindling. If you’re working with branches that are too big to be cut easily with hand pruners, you can graduate up to either loppers or a saw. Hand pruners are generally useful for branches up to 1/2″ or so in diameter, loppers are effective for branches between about 1/2″ and 2″ or so, and then a folding saw becomes useful for addressing any cuts larger than about 2″. It’s up to your preference which tools you use, so get out there and try as many as you can to inform your decision when it comes to acquiring tree tools of your own.