Also dont know the proper answer!!!..... but I recently lifted a couple of bulbs from a friends mixed native woodland (under the canopy)and have transplanted into the same. It seems to do really well in hedgrows, so I'm suspecting it likes dappled sun. My experience of beech woods is that not a lot grows in the understory as the canopy gets so dense, but as garlic is so early, it might be OK? If youve got some, might be worth putting more in the margins/edge of wood. Mine is not looking comletely happy but is flowering - possibly I was a bit late transplanting. Good luck