Many affordable-housing activists have fought the rising rents and property values that tend to come with new construction because, they say, they tend to push the poor out of the neighborhood.

Experts disagree about whether this “gentrification” makes the city a better place or creates low-density pockets of poverty and crime.

Steve Belmont, a local architect and author of “Cities in Full,” said Friday the activists’ fight fans the flames of transportation costs and urban crime.

The focus should be getting the middle class – and the density – back into the inner city, Belmont said. Belmont spoke to a group of community activists, builders and students at the Center for Urban and Regional Affairs’ monthly housing forum held at the Carlson School of Management.

Low-cost housing advocates often create crime-ridden pockets of poverty, Belmont said, and they tend to build low-density housing in the inner city, which hurts the city economically. The more spread out development is, the more crime is concealed in the empty spaces between and behind buildings, Belmont said.

Belmont, who is also the founder of the Great Cities Alliance, a Minneapolis-based nonprofit urban planning policy advocacy group, criticized the popular “smart growth” movement.

Smart growth supporters believe new urban construction should be built in dense points along suburban transit stations. Belmont called smart growth a “suburb-centric agenda” that would be better-known as “dumb growth.”

“The land at the heart of the metropolis is grossly underutilized, and that’s why we have a transportation crisis,” Belmont said.

Edward Goetz, who directs the Urban and Regional Planning Program at the Humphrey Institute of Public Affairs, said smart growth is a better idea than Belmont made it sound.

“His argument is a bit overstated,” Goetz said. “I agree with the part of his argument that calls for greater density in cities. But I think that we also have to come to grips with the fact that suburbanization has taken place to a great extent and that most metropolitan areas are what we call ‘polycentric.’ “

That means the Twin Cities metro area, like many others, has several center-points and that people tend to commute to and from the nearest center from their homes. But according to a Great Cities Alliance report, many people drive longer distances to a center farther from home.

Belmont blamed the smart growth agenda on the urban political climate.

“It’s a Metropolitan Council agenda under Ted Mondale,” Belmont said. “I think there’s an ideological and political compatibility between Ted Mondale and the political leaders of the core cities. And the political leaders of the core cities resist meaningful change.”

The Great Cities Alliance said in a report that the first step in fighting urban crime is to regain the lost residents and keep building until the city is saturated with higher density – and land prices.

“It’s appropriate to develop suburbs the way (smart growth advocates are) proposing once the land at the core reaches a state of optimal utilization,” Belmont said.

Belmont said he wants to focus on building denser core cities, and Goetz said we should combine that with transit-oriented suburban development.

“Smart growth is being pushed by people who believe that there are real costs to sprawl,” Goetz said. “Costs to the environment, costs to people in terms of time and money spent in commuting and costs to governments for creating infrastructure to stretch over the miles that are necessary to cover growth.”