More than 3,000 spaces for mobile homes in 56 of Portland's trailer parks could be protected under a proposed city ordinance.

City planners are launching an effort to create zoning specifically for trailer parks. Advocates hope that a code change would preserve such parks from being developed for more lucrative uses. They started agitating for the new zoning after a trailer park called Oak Leaf, in the Northeast Portland neighborhood of Cully, was slated for closure in 2016.

"We have been working since the Oak Leaf was threatened with being shut down," says Cameron Herrington of Living Cully. "Changing the zoning is the baseline that will provide stability for residents."

Under the proposed rules, redevelopment would still be allowed, but property owners would have to apply for a zoning change to switch the use of the park—creating a new hurdle to park closures. The rules would affect some 3,037 mobile-home spaces across the city.

"Manufactured housing plays a small — but important — role in the affordable housing market," the Bureau of Planning and Sustainability draft report notes. "It is often the housing of last resort for households that are struggling to cope with rising housing costs."

Attorney John DiLorenzo, who represents trailer park owners, says the zoning change would set the city up for court claims under state law. "Either the city will have to pay compensation to the owners as a result of the downzoning or will not be able to enforce its rules," he says.

Here's a look at where that new zoning would go.