Portland — the darling of urban planners — is bursting at the seams, and the growth is forcing policy-makers to expand the region’s prized urban growth boundary. Metro, the agency responsible for keeping development within the boundary, already added an unprecedented 18,600 acres for residential and industrial use last year. But the agency says it needs another 2,700 acres for industrial use in the next 20 years.

Now, Metro is studying 68,300 rural acres to find the needed industrial space. The study includes 9,700 acres that Metro has refused to look at in the past because the land is rated as “exclusive farm-use land,” according to Metro’s Lydia Neill, who is overseeing the expansion. Neill says good farmland can also make good industrial land: flat areas, not fragmented by streams or other natural features, and with highway access.

But several nearby towns — including Wilsonville, Tualatin and Lake Oswego — don’t want industry to creep into surrounding rural areas. Wilsonville Mayor Charlotte Lehan says Metro’s criteria-driven approach for “cheap, flat land next to the freeway” is “a way to avoid taking a look at the harder decision, which is: Do we want to allow urban development to continue down the (Willamette) Valley?”