Here’s The Oregonian’s weekly look at the numbers behind the state’s economy. View past installments here.

Of the many ways to measure economic activity, garbage piles have to be among the most intriguing. And the Portland area is producing a nearly record amount.

University of Oregon economics professor Tim Duy tallies the state’s trash every month as a component of his Index of Economic Indicators, a barometer of the state’s economic outlook. He began incorporating trash volumes in his index several years ago, in the aftermath of the Great Recession, observing that the state produces more refuse in good times and less in bad times.

“It does seem to follow the (business) cycle,” Duy said.

On a seasonally adjusted basis, the area served by the regional government Metro produced more than 122,000 tons of trash in December. That’s just a shade below the all-time record in January 2018.

It makes sense, when you think about it. A healthy economy means people are buying more and building more. And that means a lot more waste – everything from construction debris to the plastic cushioning nestled around packages ordered from Amazon.

Trash volumes in the Portland area plunged by nearly a third between 2007 and 2012 with the onset of the Great Recession. The rebound was even faster, with trash volumes making up all their lost ground by 2016.

In the last few years, though, trash production has flattened as both construction and household waste leveled out.

“I’m not sure what to make of that,” Duy said.

One possibility is that people are recycling more and producing less trash. But Joel Sherman, senior solid waste planner for Metro, says recycling rates in the Portland area have been pretty steady for the past decade.

So Duy and Sherman agree that the trash slowdown reflects a broader economic slowdown across the metro area. By that measure, then, the fact that trash remains near an all-time high may underscore that the regional economy remains healthy – though perhaps not as robust as in the past few years.

Household waste has been pretty solid (so to speak) these past couple years, Sherman said, while construction waste has fallen off a bit as the industry has slowed down. He said Metro’s current outlook calls for that trend to continue for the foreseeable future.

“We’re projecting pretty flat tonnage over the next couple years,” he said.

-- Mike Rogoway | mrogoway@oregonian.com | twitter: @rogoway | 503-294-7699

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