http://buildengineer.com/www.paulbirch.net/CritiqueOfGeorgis...
Key points are in section 7-8. Key paragraphs:
>The form of land-use towards which the single tax pushes us is one in which the countryside is randomly dotted with perpendicular towers (tapering wastes land), 200 metre or so on a side, 2000 metre or so high, each tower a complete small town of 50,000 or so, inclusive of apartments, shops, offices, services and factories, but paying no more tax than a single suburban house. The internal economy of those towers will have some similarities to Type III market Georgism, but with the crucial distinction that no one who wishes to cease renting a unit when the current lease expires has any further liability; finding a new tenant is the responsibility of the tower owner. Most of the surrounding countryside will be abandoned or common land and thus effectively exempt from taxation.
>That doesn't mean that existing towns would just disappear — there is too much already invested in them — though dereliction would tend to set in over much of the urban area over the course of a century or so as abandoned properties reverted to common ownership. ...
>The problem here is that although buildings and other on-site improvements are supposed to remain purely private property, there is no easy way a landholder can remove his property without destroying it if he is outbid in the annual auction. A competing bidder might therefore risk paying considerably over the odds in the reasonable expectation of getting free use of the buildings until the following year, when the original owner may end up paying the market rental on the full property value, not merely the site value, in order to guarantee access to his own property. A sufficiently cheeky tenant could even demand rent from the property owner for allowing the property to remain on the tenant's rented land!
[1] of the British Interplanetary society; found just now that he passed in 2012.