Why use wood?

If you can hit with wood you can hit with aluminum. 

Stories of players picking up a wood bat and showing great improvement the next season are becoming more and more common.  Wood bats have a smaller sweet spot.  Using a wood bat makes players concentrate on pitch location and proper hitting technique.  Wood bats also provide negative feedback on poor swings.  

There is also a difference of weight.  Modern youth players swinging a -11 oz bat when they are 8 years old will need to transition to -3 oz bats by the time they play high school baseball at age 13-14 years old.  Young hitters that wait too long to transition to heavier bats will struggle to perform with the heavier bats they will be forced to use when they are older.  Using wood bats as a practice tool will increase strength and allow an easier transition to high school play.  

Baseball seems to be the only sport in which the amateur players use different equipment than the professionals.  It seems crazy that a college player can be drafted, sign a professional contract, and has never even used the tool with which he is expected to earn his livelihood.

Youth players using wood bats will benefit with better pitch recognition, quicker/stronger hands, and more time at the plate to decide on their swing.  

Search for yourself and you will find a ton of data supporting the use of wood bats.