For those of us who’ve lived in Portland for more than a year or two, the urban landscape has already changed quite a lot. We’ve watched Southeast Division Street grow from an overlooked neighborhood drag dotted with diners and mini marts into the Pacific Northwest’s most scrutinized dining street. We can tell stories about when artists still lived in the Alberta Arts District, sharing space with working class families who’d been there since the days when we still built Liberty Ships.

A Liberty Ship — the SS William Clark — being launched from Oregon Shipbuilding Corp, 1942. Image via kaiserpermanentehistory.org

Some of us even remember when the South Waterfront was just a barren stretch of brownfield, wedged between two traffic-thronged bridges. It’s been a busy decade for Stumptown, no doubt.

So when I say that the next five years are going to transform the streets and buildings of central Portland more dramatically than at any time in living memory, you’re forgiven for thinking it’s hyperbole.

It’s not.

A look through the real estate stories in local newspapers, business journals and the Portland Monthly makes this much clear: there’s a construction boom going on in the city, and for the first time in a generation, it’s producing buildings that are truly, enthusiastically, sometimes ill-advisedly new. As Randy Gragg points out in that article series above, the boom is not unprecedented in size; the number of building permits issued in the city in 2013 is still well below the peak of the hot-burning early 2000s. But what’s being permitted this time is different. Instead of more two-story homes with lawns, punctuated by the occasional condo, now we seem to be making almost nothing but urban buildings. City buildings. Buildings for people who walk fast and ride the streetcar and take taxis, and stay up late and order takeout.

A few of the sites where major apartment projects are being constructed. Image via oregonbusiness.com

This shift is the result of two inter-playing forces, both of which have been around for years, but have only recently combined in a way that’s visible at street level.

The first is Portland’s shifting demographics. The city has been getting younger, more transient and more educated for years — at least since the turn of the millennium — and this means tremendous growth in the demand for rentals, especially rentals near downtown or the commercial strips of the east side. It’s a marked shift from Portland’s residential identity through most of the 20th century, when it was defined by families looking to buy their slice of the American Dream, front porch and backyard included. This long history, upset suddenly by an influx of young new residents, is the main reason Portland has one of the lowest rental vacancy rates in the nation — occasionally the lowest, with a market that’s tighter at times even than San Francisco’s or New York’s.

Accessory Dwelling Units, which can be anything from basement conversions to tiny outbuildings like this, are abundant in Portland, largely because of recent changes in regulation. Image (cc) via Flickr user Tammy Strobel

The other force at play is the region’s long allegiance to close-knit urbanism and smart growth. Greater Portland’s Urban Growth Boundary dates back to 1973, and policies encouraging infill development and increased density have been popping up ever since, in the form of tax breaks, zoning adjustments and simplified permitting processes. The current rush to build Accessory Dwelling Units, for example, is a direct result of the city’s decision to waive system development fees; a decision in 2002 to suspend parking minimums for apartment buildings in transit-dense areas has spurred more than a dozen projects into life.

Independently, either of these trends would give the city a gradual push towards taller buildings, clustered around transit and pedestrian-friendly streets, that embrace the sidewalk rather than shying away from it. Taken together, though, their impact is more rapid, and more dramatic. Take Northeast Multnomah Street, for example: the half mile or so that this broad arterial spends in the Lloyd District has been defined for decades by parking lots, parking structures and curbside parking. The Northeast 7th stop on the city’s MAX light rail, a block south on Northeast Holladay Street, was one of the city’s least utilized and most perplexing (why did it even exist, I wondered, when you could chuck a rock in either direction and hit the next stop?).

The Hassalo on Eighth under construction, with the temporarily closed NE 7th MAX station in the foreground. Photo by Flickr user ProTram, used with permission.

But then came the Milano, a tidy little bike-themed, bike-oriented block of small apartments at the western edge of the District, which did surprisingly well in the struggling economy. Then came the transformation of Northeast Multnomah itself, with one of the city’s first separated cycletracks. Now everything seems to be happening at once. The Hassalo on Eighth, which covers nearly a full city block between Multnomah and Holladay, will be the largest apartment development in the history of Oregon when it opens a few months from now, and promises to create something no one could have imagined for the area until recently: a street life. Less than a year after that, the Lloyd Mall just up the street is billed to cut the ribbon on a dramatic redesign, replacing a pedestrian-repelling parking structure with a series of storefronts designed expressly with foot traffic in mind (though the mall itself will retain much of its existing parking).