One study ignores the role of environmental protection in enhancing land value, but another study does better

I probably shouldn't completely condemn the study because I haven't finished reading it.  Still, I have problems with this Harvard study of Massachusetts land values that appears to conclude that environmental protections, such as ones that keep development away from floodplains and increased septic system requirements, caused an artificial land scarcity and forced up the cost of housing.  The problem is that what I've read doesn't address how environmental improvements reduce negative externalities that harm the land value of the broader community.  Keeping development out of flood plains and keeping septic systems from failing in particular are hugely beneficial to the broader community.  So is the increase in cost due to artificial scarcity, or is it just a reflection of increased environmental benefits?  Maybe this is addressed somewhere in the study, but I've missed it.

Much more promising is a Stanford study showing that conservation efforts didn't substantially reduce the housing stock in Silicon Valley:

It's no secret that the San Francisco Bay Area, where the median house price is $350,000, is home to expensive real estate. Developers have often blamed conservationists for the high costs by arguing that making land off-limits for new construction shrinks the area's housing supply and drives up prices.

But Stanford researchers say that argument holds little water. Only 51,000 more homes would have been built in the southern Bay Area's Silicon Valley if land had not been set aside by nonprofit groups and the government, they say.

In a study conducted by the university's Bill Lane Center for the American West, executive directorJon Christensen, sociology graduate student Carrie Denning and landscape ecologist Robert McDonald analyzed whether land conservation efforts in Silicon Valley – which has about 116,000 acres of protected parks, forests, waterfronts and wildlife refuges – have hurt housing development.

Their findings, published online in the journal Biological Conservation, suggest that land protection may not have much of an impact on the number of housing units available in the region. That's because most of the protected land isn't suitable for development, they say.

-Brian