The practice of the state growing trees to sell to the private sector is said to be sustainable. In ecology or physics, a system would be described as sustainable if that which flows into it is balanced by that which flows out. If taxpayers pay government to grow and harvest trees, and then buy them back, it appears that money is flowing one way, from citizens to government. It would be analogous to a person paying a gardener to tend to his yard, and then, if he wants to eat a carrot or some beans, paying the gardener again. Somebody doing a flux analysis might predict that money will flow into government until government’s boundaries can no longer expand to maintain a pressure balance, and then it will explode.