Lev Lafayette's journal

Would a land tax be levied annually on the value of land, or only levied at the point of sale? The latter seems more reasonable to me as taxing unrealised income seems a bit dubious - but most of the arguments you link to are to the former. Wouldn't this force people to e.g. borrow against or sell their land or assets if they were caught in a boom and had to pay a large tax on only a notional value increase? Or is that the idea? (I'm aware that part of the purpose of the tax is to reduce the likelihood of booms, but what I get from chaos theory is that booms are an inherent part of any complex system).