There are many consequences of sprawl - the unconstrained expansion of city limits into greenfield sites. The name itself suggests a lax and flabby urban form - the couch potato of cities. It is certainly easy tp increase housing by loosing the belt. But the costs...

By creating new infrastructure to support the new greenfield developments is also created a new liability for future generations to maintain. This is costly as the low density of sprawl suburbs means there are few houses to support the maintenance - effectively the denser parts of the city are subsidising the diffuse hinterland.

Such spread out, cul-de-sac developments are car centric. There are few local amenities and those that exist assume people will drive to them. New towns are filled with huge mega-centres surrounded by carparks. This is inherently carbon intensive development.

And the change of use of the land, from productive farmland to dead and breathless concreted over suburbia is a tragedy that should be prevented. There are obvious tensions between landowners and farmers who wish to cash in on the value of their land should they sell to developers, and the need for society to have locallay grown food. A recent article - Auckland’s insatiable urban sprawl - focuses on this dynamic.

Patumahoe is part of what's known as the Pukekohe Hub, 4359 hectares of some of New Zealand's most fertile and productive land. According to Auckland Council's Climate Action Framework released last year it generates $327 million a year, which is the equivalent of 26 percent of NZ's total domestic value of vegetable production.

From 2002 to 2016, vegetable-growing land across the country was reduced by 30 percent.

This is staggering and upsetting. Surely we should be preserving this land as a resource for future generations - let alone current ones. We need fruit and vegetables to survive... and we need the opposite of sprawl - dense walkable neighbourhoods - in order to thrive. Sprawl being the opposite of walkable we're dooming our youth to a poverty of fewer fruits and vegetables, and the ill-health of an inactive lifestyle.

I've joked previously that future children might sue their elders, and retired town planners, for allowing and enabling the drop in life quality caused by ill-considered planning changes.

Fortunately this situation is being addressed. The National Policy Statement for Highly Productive Land will hopefully set out protections for land. A clear demarcation will give certainty to landowners that their land is protected, and that rapacious towns and cities will not threaten them.

But. This is a complicated dynamic. Unless there is adequate land for development housing prices will increase. Already we have experienced huge price increases for housing - and this is mostly due to the change in the value of the underlying land. And ironically, intensification and densification drives up house prices. Because if you have a single house on a piece of land zoned for multi-family homes, then the land will be valued at the development potential. So land zoned for single family homes in greenfield sites is cheapest and when made more available reduces pressure on house prices.

And this may be evident in the cost comparison between Christchurch and Auckland where the former has released a lot of greenfield sites for development. It is a hard problem to square - but certainly a balance can be created that protects the very valuable horticultural land from development while enhancing mechanisms for infill, and densification.

A good article on this dynamic at play.on the Greater Auckland blog - - Of Trees and Housing - which is itself a commentary on another article - In Thrall to the Sprawl - by a developer explaining the balance that needs to be strike.

Tightening our greenbelts, and building up taller, will prove to be better for the environment, the economy, our well-being, and our health. We should not have to put our productive land at risk in order to live well and cheaply. In a nutshell this is what Hab3 wishes to engage on... the processes we can use to come to that better future.