In Catonsville, a forest between a neighborhood and a highway clogged with mattress outlets and car dealerships could be paved for a parking lot.

Closer to Woodlawn, an Annapolis-based developer is looking at building a 122-acre complex of housing and offices in an area currently preserved.

And in Owings Mills, a proposed nursing home might expand into a mix of offices and senior housing.

In each case, though, zoning designations would have to be changed to allow for businesses to expand, and for houses and shopping centers to be built.

Baltimore County is in the midst of its comprehensive zoning map process - better known as the CZMP - done every four years. A series of public hearings on the proposed changes begins this week.

"It gets the community talking before everything is submitted as a development plan," said County Councilman Stephen G. Samuel Moxley, a Catonsville Democrat. "There's nothing worse than when the plan is already submitted, and the community says, 'Oh, wait a minute!'"

By then, it's hard to stop the development, county elected officials and community activists say.

The March hearings, before the county Planning Board in each of the seven council districts, are followed by another series of hearings in June before County Council members, who ultimately decide the designations that guide land use. The final vote by the council is in September.

"It's probably the most significant responsibility of the council," said Council Chairman Kevin Kamenetz, a Pikesville-Ruxton Democrat.

Countywide, more than 570 requests have been made by council members, developers and property owners who are seeking changes in zoning designations.

Among them is a plan by Ribera Development to change rural conservation zoning on more than 100 acres near Patapsco Valley State Park and Interstate 70 to a designation that permits office and residential development.

Community activists say they try to review the proposals carefully.

"You can't just look at what they're saying now," said Steve Duffy, vice president of the Patapsco Falls North Homeowners Association.

His Catonsville neighborhood group has been told that a nearby parking lot is planned. But the real estate holding company that owns the nearly 6 acres is looking to change the residential zoning to "business-roadside," the most permissive commercial designation in the county.

"The first and most obvious concern is that property values will take a hit, no matter how well concealed it is," Duffy said.

Because of better notification about zoning changes, community groups are becoming increasingly active in the process, county officials say.

"It is also a recognition that the county is fairly well built-out," Kamenetz said. "The last remaining tracts become that much more controversial."

In Owings Mills, residents have had two town hall meetings, including one last week, about a proposal by The Associated: Jewish Community Federation of Baltimore, to change zoning on a 55-acre parcel, formerly part of the Rosewood Center, from a residential designation that allows one house to be built per acre to one that would permit office and commercial buildings and up to 10.5 residential units per acre.

"After traffic and safety, the concern is that this doesn't fit the rural character of the area," said Jim Angelone, one of the founders of the new Greater Greenspring Association.

Matthew Freedman, chief planning officer for The Associated, issued a statement, saying that the requested zoning "would be consistent with the nursing home use that was approved for the property."

"As with all senior housing facilities, amenities needed to meet the needs of residents will be considered for inclusion on the property," he wrote.

laura.barnhardt@baltsun.com

The Planning Board hearing on CZMP requests in the 1st District, which includes Catonsville and Arbutus, will be at 7 p.m. Tuesday at Lansdowne High School, 3800 Hollins Ferry Road.

The hearing on the requests in the 2nd District, which includes Pikesville and part of Owings Mills, will be at 7 p.m. Thursday at Pikesville High School, 7621 Labyrinth Road.

For the hearing schedule or more information about other requests: www.baltimorecountymd.gov/Agencies/planning/zoning/2008czmp/index.html.