The Lorax is a loser.
If we want to conserve water, solve our drought issues and save the Great Salt Lake, what we need to do is cut down some of those pesky trees that are guzzling all our precious liquid.
I’ll admit, when I heard that pitch recently from Salt Lake County Councilwoman Dea Theodore and a group of Republican lawmakers to Gov. Spencer Cox and legislative leaders, it seemed laughable.
Elsewhere it was reported without a second thought or scrutiny, and with such simple logic: If trees are simply straws slurping water out of the ground, fewer straws will mean less water gets sucked up before it gets to our lakes and reservoirs. Indeed, since the unconventional theory was posited in 1967, it has become the conventional wisdom for a generation of foresters.
It’s also wrong.
Or, at the very least, evidence is accumulating that the relationship is nowhere near that simple, especially as it applies to arid climates like Utah’s.
That’s what I learned while talking to several biologists who have studied the issue — University of Utah professors Paul Brooks, the director of the hydrology and water resources graduate program, and Bill Anderegg, with the school of biological science, and Sara Goeking, a researcher with the U.S. Forest Service.
Most of the research that led to the “cut-trees-to-save-water” philosophy was done in wetter, cooler parts of the country, Goeking told me. But in two recent peer-reviewed papers, she notes the results can vary significantly depending on the climate and elevation of the forest.
When she looked specifically at the drier, more arid climates in the West, including Utah, she found that removing trees can actually reduce the amount of water that makes it out of the mountains.
“In recent years, especially following mortality due to drought and some of the mountain pine beetle epidemics and then some fire disturbances, too, we’ve found that in drier environments … that the amount of water that you get out of that forest watershed might not change or it might even decrease,” she said.
There are several reasons for that. Fewer trees result in less shade, so snow falls to the ground, melts faster and evaporates. And, where old trees stood, new trees sprout and use more water.
When Goeking looked at results from 67 forests around the West that had been disturbed, either by cutting or natural events, more than half saw stream flows decrease, with lower streamflows most common in drier, hotter areas.
Brooks said there are some parts of Utah where thinning could yield more water. The area around Snowbird and Alta ski resorts, for example, have high elevations, cooler temperatures and the slopes face northeast, so they get less direct sunlight. But the increased flow would be negligible and, without regular upkeep, short-lived.
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Given the amount of water needed to reverse the decline of the Great Salt Lake — as much as 700,000 acre-feet, or roughly 228 billion gallons of additional water making it to the river each year — Anderegg said the small amount that forest thinning might yield would be negligible, a drop in the proverbial bucket.
“Sure, there are some places where it makes ecological sense and could bring some additional water,” Anderegg said, “but it’s not going to solve the lake problem on its own and it’s going to be that big of a ticket item.”
To be clear, none of the three scientists I spoke with advocate for a hands-off approach to forest management.
“There are other very, very good reasons to thin the forest: for fire protection, for carbon sequestration, for ecosystem health and habitat,” Brooks said. “There are a lot of good reasons to do a better job of managing our forest, but supplying large amounts of water is not one of them.”
Brooks said when the letter came out advocating cutting trees, it caused “heartburn” among local hydrologists — and I think I understand why.
As I see it, the disappearance of the Great Salt Lake, and the environmental and economic consequences that come with it, is a critical issue for our state. It demands a massive response and serious solutions — not agenda-driven elected officials pushing for ideas that simply don’t hold water.
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