“A gaffe is when a politician tells the truth — some obvious truth he isn’t supposed to say.”

Or she.

Salt Lake County Mayor Jenny Wilson suffered through a brief outbreak of truth the other day when she was heard to say that Olympus Hills, the 931-acre mega development eyed for the southwestern corner of the county, is going to be approved.

Of course it is. In some form.

The demographic and economic pressure to build a house, an office building or a 7-Eleven on every square inch of the Wasatch Front is more than any mere mortal mayor could overcome.

Not everyone is happy about that, though, and with some reason.

What many people who love living in the various communities of Salt Lake County most fear is that somebody is going to come along and build more communities that look like Salt Lake County.

Central planning, whether by government or by the private sector, is understandably derided as regimented, dull, soul-killing. But a lack of planning — most critically for transportation — is certain to lead to an unsustainable mess of traffic jams and red air days.

The Hot New Thing in urban planning is rolling out in Minneapolis. There, the city turned its back on a century of municipal thinking and did away with the idea that residential areas should be strictly zoned for single-family here, duplexes there and multi-unit apartments over yonder.

By allowing future development — or redevelopment — to include an evolving, market-driven hodge-podge of houses, triplexes and, along transit corridors, apartments, city leaders have a reasonable hope of easing their housing crunch, their traffic woes and a legacy of land-use law that was basically designed to fence out undesirables. Black people, poor people, students, Democrats.

The idea that a man’s home is his castle can no longer include the notion that my single-family home on a third-acre lot can only be within sight of other single-family homes on third-acre lots.

Look around, people. Yes, these things swing in trends. But the most popular place to live — as measured by the fact that you can’t afford to live there — is no longer White Pickett Fence Ville. It’s Haight-Ashbury. It’s the East Village. It’s the Avenues.

That, ideally, is what Olympus Hills would be. A thousand acres of Avenues. Little houses. Big houses. Small lots. Low-rise apartment buildings. Cozy cafes tucked into neighborhoods so discreetly that you need a GPS to find one and, having found it, don’t want to leave.

Of course, designing an Avenues, a Village, an East Nashville, an Austin’s South 1st Street is practically an oxymoron. These things aren’t really planned, by government or by big-time developers. They just sort of happen.

Also, neighborhoods like that thrive not just because of what they are, but also what they are next to. In the case of the Avenues and the pricier Federal Heights, that’s the University of Utah and downtown Salt Lake City.

But there are some nudges we could employ.

First, take the popular image of suburbia out back and shoot it. No cul de sacs. A downright radical mix of housing sizes, styles and price ranges. Built from the ground up with public transit embedded, on a grid system that more efficiently handles traffic of every kind.

A mix of residential, commercial and office, so there is at least reason to hope that people will spend most of their time close to home, living, working and playing.

A whole new regime of impact fees. Every housing unit created must pay for the infrastructure it will demand. Streets and transit. Schools. Public safety. Paid up front.

As Ike might say, every housing tract laid out, every old tree felled, every NIMBY appeased, signifies, in the final sense, a theft from those who cannot afford a place to live, those whose schools are obscenely overcrowded, those who are stuck in traffic breathing toxic fumes.

And if the mental image of a new Avenues seems odd, just add trees. Lots of trees.

A new report from a gaggle of Swiss scientists posits that the cheapest, least disruptive thing we could do to curb the damage done by climate change would be to plant a few trees. Maybe a trillion of the carbon-sucking things all over everywhere.

Utah’s share of a trillion trees, apportioned according to our percentage of global gross domestic product, might be about 2 billion. Or, as a percentage of world population, a more manageable 42 million.

Olympus Hills, the old prison site in Draper — and the land that will be available once we kill the stupid inland port — would be great places to start.

(Francisco Kjolseth | The Salt Lake Tribune) Tribune staff. George Pyle.

George Pyle, editorial page editor of The Salt Lake Tribune, is grateful to his wife for teaching him how to plant a tree.

gpyle@sltrib.com

Twitter, @debatestate