Part 4 of 4 in a series, "Our changing cities."

The Twin Cities area continues to attract more residents, but the addition of new park and recreation space is not keeping pace the way it has in the past.

That's raising questions among park officials who want to ensure that residents have ample recreational space, and to cement the region's top-tier reputation among urban outdoor enthusiasts.

"We don't feel that we have the land and acres yet to really satisfy the seven-county metro area," said Emmett Mullin, the Met Council's manager for regional parks, which account for a third of the parkland in the metro area.

Since 2010, the seven-country metro area has averaged one-third as much new park and recreation land annually as during the previous two decades, according to new Metropolitan Council data analyzed by the Star Tribune. The region boasts more than 200,000 acres of parkland, but the amount per resident has dropped slightly.

Parks advocates are trying parse what the lagging numbers mean. They attribute the slowdown to increasingly complex and expensive land buys, a larger focus on new trails, the closure of golf courses, and the pattern of cities growing up instead of sprawling out after the recession.

Boe Carlson, superintendent of Three Rivers Park District, said the agency serving west metro suburbs is focusing on amenities, like snow-making at Elm Creek Park Reserve, which began in 2012.

"We're not adding parkland, necessarily," Carlson said. "Now it's the point of developing it and getting opportunities for people to come out and recreate within the parks."

Others pointed to the link between new parks and new housing, which often brings in development fees that cities use to pay for new parks.

"A lot of local and regional park acquisition is done on the back of new development projects," said Kris Larson, executive director of the Minnesota Land Trust. "So with the slowdown during the recession, you also just didn't have as much development that also coincidentally fuels some of that acquisition."

Trails, however, have expanded rapidly. The metro area has 131 more miles of regional trails than it did in 2009, according to Met Council data. At 362 miles, the trail system is now large enough to reach from Minneapolis to Milwaukee if it were connected end-to-end.

"The trails are notable, in the sense that that's where a lot of emphasis is going in the regional parks system," Mullin said.

The Met Council takes aerial photos of the seven-county metro area every five to seven years to determine how every inch of land is being used, aided by property assessment records. It isn't perfect — the analysis relies on human judgment, sometimes correcting past imperfections. The data reflected big parkland gains in Lake Elmo and Afton, for instance, due to fixes to old maps.

Still, cities across the region use the detailed maps and data to plan for the future. The Star Tribune compared the Met Council's 2016 survey with its last flyover in 2010.

The park and recreation land measurement includes a wide array of outdoor areas, from local and regional parks to wildlife refuges, soccer fields and golf courses. It even captures some open land that is preserved during the creation of new subdivisions.

So which cities saw the biggest gains in parkland?

Acreage-wise, the city of Columbus in Anoka County led the metro area for new park and recreation land with expansions at Rice Creek Chain of Lakes Park Reserve and the Carlos Avery Wildlife Management Area. Rice Creek is one of the largest regional parks in the metro area at more than 5,000 acres, offering space to canoe, bird watch, hike and otherwise enjoy the outdoors.

Other places that saw big gains include Woodbury, with 100 acres of new sports fields and outdoor space near HealthEast Sports Center, and Empire Township, home to a new aquatic management area and the expanded Vermillion Highlands Wildlife Management Area.

In St. Paul, the standout was the Trout Brook Nature Sanctuary, which uncovered a stream that had been buried underground.

We'd like to hear about what's happening in your neighborhood. Use our interactive map to look at land use changes in your area. Then share what you found in the comments below or on Facebook, Twitter or other social media platforms. Copy the URL from the map (while zoomed to your location) and paste it with your comments, as well.