In Hennepin County, homes within 200 feet of a park, natural area or greenway get an average property value boost of $16,300 because of their proximity to open land, a study has found.

The benefit of large parks extends even further. Open areas of 50 acres or more lend increased value of 3 to 4.8 percent to homes up to a half-mile away, the study says.

These are the findings of a property value analysis by Embrace Open Space, a program of The Trust for Public Land, a St. Paul-based land conservation advocacy group.

"We are interested in raising public awareness of the benefits of conserving natural areas," said Jenna Fletcher, program coordinator for Embrace Open Space.

With funding from the McKnight Foundation, Three Rivers Park District and others, the study used census data, home sale and other information to conclude that Hennepin County's "total increase in property values due to the presence of open space is $3.6 billion." That value generates $36 million in tax revenues a year, the study calculates.

Embrace Open Space said it chose to study Hennepin County because of "its rapid population growth and degree of unprotected natural resources."

Addressing common questions about how conserving land affects tax revenues, the study says that tax revenues lost by keeping land as open space can be "offset in part if homes adjacent to open space have greater value and produce higher property tax revenue."

"We are trying to build the arguments for why should cities and counties and townships invest in parks and natural areas," Fletcher said.

Not only does the study show the benefit to properties close by, but it also shows that all properties benefit "just because there is open space in a city," she said. "If a city increases its investment in open space, we can predict the increase in home values."

Embrace Open Space plans to present the study to selected cities this summer. Hennepin County will use the information in discussions with developing cities about saving critical natural areas, said Rosemary Lavin, assistant director of environmental services for the county.

"There is a view that the county has a fair amount of open space, but we've got continuing development that is occurring throughout the county," Lavin said.

The open space study gives cities an economic reason, in addition to the natural environmental benefits, to balance land preservation with development, she said.

The study found that 18 percent of Hennepin County is open space and about a third of that is the parks, trails and natural lands in the Three Rivers Park District.

The study estimates that Three Rivers park lands and natural areas have increased home values by $369 million -- a figure that translates to $3.5 million a year in property tax revenues for Hennepin County.

Three Rivers contributed $10,000 to the study to get that kind of detail about "what it is we bring to the community," said Three Rivers Commissioner Marilyn Corcoran.

"It helps to confirm that the trails and the open space combined are important to people, important to their quality of life, and we can validate that claim isn't just a hollow comment," she said.

Some people are "truly skeptics as to the value of a trail and open space," Corcoran said.

Boe Carlson, Three Rivers' governmental relations administrator, said, "I think everybody feels that parks are a good thing." What the study shows is they are also "a good investment of public dollars."

Laurie Blake • 612-673-1711