Birch Forest Update

Some ideas to improve the Birch Forest based on official concept art. Birch trees should have branches and yellow leaves, making them more distinct from oak and adding a new foliage color. Mushrooms could also generate on the sides of Birch Trees. This could either be a new type of mushroom or just a new ability of mushrooms to be placed on the sides of blocks. Finally, hollow logs could generate in Birch Forests. Hollow logs would come in all wood varieties and be crafted from eight logs providing eight hollow logs. These new additions would improve Birch Forests and all forests in general.