You can dig the tree when it is dormant or just beginning to break dormancy (swelling buds). This usually is Jan. to Mar. where I live (CA). At that time you probably don't have to worry much about the roots and the tree can be essentially "bare rooted". Pot it up in some very gritty soil with very good drainage and say a prayer. I would do some preliminary branch pruning even severe pruning at the time of the dig in order to sort of set the style and remove some of the canopy to balance with the reduced root system.

ok thanks for the info,but i kinda already dug it up.i planted it in miracle grow and a bag on top so it wont lose moisture.most roots stayed in the rock but three branches of fine roots came up.once it shows signs of new growth i will put it outside to hibernate but it will be in a pot in the ground.i want to make it a mame bonsai and it dident even have a canopy only two leaves about 2cm long.

thanks