A good analysis by the local paper from this summer:
“2010 Census shows that Oregon’s densest tract shifted from the area around Northwest 21st Avenue to downtown, specifically the area centered on Portland State University. What do all these numbers mean? Portland’s 1972 Downtown Plan created in response to suburban flight continues to exert influence decades later.
“As the city has grown, so has the share of people who want to be close to downtown,” said Charles Rynerson, a demographer at PSU’s Population Research Center. “So there’s a lot less resistance to high density. You can’t build a 20-story tower everywhere in Portland. But where you can build one, and where people want to build one, it can be done.”
There’s still quite a bit of resistance to densification throughout Portland, which is strange because popular support for urban growth boundaries is contradicted by the resistance to densification. The president of Metro, the area’s regional government stated that there is still a great deal of resistance to infill development in the city of Portland.