I recently purchased a pretty nice small maple grown from the seed of a Coral Bark Maple from Mendocino Maples down in Ca. Nice tree and he sent along some directions which I actually read. The directions said in part,...."do not use green bark products as amendments Freshly milled bark that has not been composted will slowly rob plants of nitrogen when used as an amendment". Just wondering about this as I buy conifer bonsai soil from BJ's and it has 32% fir in it and I don't think it is composted. Thoughts??