I have a few acres of white birch trees that I need to "harvest" (to make room for planting Christmas trees).

I would like to sell the branches to wholesalers (they're used for craft / decorative purposes) and the larger parts of branches to sell as decorative firewood. Any idea when I need to do this harvesting (particularly for the small branches for decorative purposes) and what to do with them after they are cut (do they need to be dried a special way and/or packaged a special way?). Location is upstate NY.