Nav: Home

Forest loss in one part of US can harm trees on the opposite coast

May 15, 2018

Large swaths of U.S. forests are vulnerable to drought, forest fires and disease. Many local impacts of forest loss are well known: drier soils, stronger winds, increased erosion, loss of shade and habitat. But if a whole forest disappears, new research shows, this has ricocheting effects in the atmosphere that can affect vegetation on the other side of the country.

A University of Washington-led study published May 16 in Environmental Research Letters shows that forest die-offs in specific regions of the United States can influence plant growth in other parts of the country. The largest impacts seen were from losing forest cover in California, a region that is currently experiencing dramatic tree mortality.

"These smaller areas of forest can have continental-scale impacts, and we really need to be considering this when we're thinking about ecological changes," said first author Abigail Swann, a UW assistant professor of atmospheric sciences and of biology. Such far-off effects are accepted in the atmospheric sciences community, Swann said, but the idea is only beginning to be accepted by ecologists.

A 2016 study from the same UW group looked at what removing trees from larger areas, like western North America or the entire Amazon rainforest, would mean for worldwide plant growth. This study took the same approach on a regional scale.

The project divided the mainland U.S. into the 18 regions used in the National Ecological Observatory Network. Researchers then ran a climate model to look at what removing the existing forest cover from the 13 most-heavily-treed regions would mean for growing conditions across the country.

Of all the regions, the Pacific Southwest region, which covers most of California, has the smallest total area of tree cover. But removing those trees had the biggest influence on growing conditions nationally, by reducing vegetation in the Eastern U.S.

The precise mechanisms would require further study, Swann said, but in this case it seemed to make Eastern summers slightly warmer, which was harmful to plant growth.

"Forest loss is disrupting or changing the flow patterns in the atmosphere that is leading to a slightly different summertime climate in the eastern part of the country," Swann said. "It's very analogous to El Niño or 'the blob,' something that's occurring that causes the atmosphere to move around, which causes these warmer or cooler conditions, or wetter and drier conditions, somewhere else."

Compared to an El Niño cycle, Swann said, "the changes we made here were smaller and over land, but it's very analogous."

The results also showed other Western regions, such as the Northern Rockies and the Great Basin region, as having negative effects on plant growth in the eastern half of the country. These regions are currently losing tree cover: California forests have lost more than 130 million trees since 2010, largely due to the combined effects of drought, warm temperatures, insects and disease.

"In some case trees may be killed by drought, but in many cases they're being weakened by the drought and then being finished off by the beetles or other stresses," Swann said.

The study suggests that current forest loss in Western regions is big enough to trigger changes in plant growth, though it might not be possible to detect these small changes over large areas of the country.

"There's some pretty extensive, widespread forest loss going on," Swann said. "The changes we made in the model are bigger, but they're starting to converge with things that we're actually seeing.

"These results show that we need to start thinking about how altering vegetation in one place can affect plants elsewhere, especially in the context of climate change."
-end-
The research was funded by the National Science Foundation. Other co-authors are Marysa Lagu?, a UW doctoral student; Elizabeth Garcia, a former UW postdoctoral fellow now at Seattle Public Utilities; Jason Field, David Breshears, David Moore, Darin Law and Scott Saleska at the University of Arizona; Scott Stark and David Minor at Michigan State University; and Juan Villegas at the University of Antioquia in Colombia.

For more information, contact Swann at aswann@uw.edu or 206-616-0486.

University of Washington

Related Climate Change Articles:

The black forest and climate change
Silver and Douglas firs could replace Norway spruce in the long run due to their greater resistance to droughts.
For some US counties, climate change will be particularly costly
A highly granular assessment of the impacts of climate change on the US economy suggests that each 1°Celsius increase in temperature will cost 1.2 percent of the country's gross domestic product, on average.
Climate change label leads to climate science acceptance
A new Cornell University study finds that labels matter when it comes to acceptance of climate science.
Was that climate change?
A new four-step 'framework' aims to test the contribution of climate change to record-setting extreme weather events.
It's more than just climate change
Accurately modeling climate change and interactive human factors -- including inequality, consumption, and population -- is essential for the effective science-based policies and measures needed to benefit and sustain current and future generations.
Climate change scientists should think more about sex
Climate change can have a different impact on male and female fish, shellfish and other marine animals, with widespread implications for the future of marine life and the production of seafood.
Climate change prompts Alaska fish to change breeding behavior
A new University of Washington study finds that one of Alaska's most abundant freshwater fish species is altering its breeding patterns in response to climate change, which could impact the ecology of northern lakes that already acutely feel the effects of a changing climate.
Uncertainties related to climate engineering limit its use in curbing climate change
Climate engineering refers to the systematic, large-scale modification of the environment using various climate intervention techniques.
Public holds polarized views about climate change and trust in climate scientists
There are gaping divisions in Americans' views across every dimension of the climate debate, including causes and cures for climate change and trust in climate scientists and their research, according to a new Pew Research Center survey.
The psychology behind climate change denial
In a new thesis in psychology, Kirsti Jylhä at Uppsala University has studied the psychology behind climate change denial.

Related Climate Change Reading:

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Moving Forward
When the life you've built slips out of your grasp, you're often told it's best to move on. But is that true? Instead of forgetting the past, TED speakers describe how we can move forward with it. Guests include writers Nora McInerny and Suleika Jaouad, and human rights advocate Lindy Lou Isonhood.
Now Playing: Science for the People

#527 Honey I CRISPR'd the Kids
This week we're coming to you from Awesome Con in Washington, D.C. There, host Bethany Brookshire led a panel of three amazing guests to talk about the promise and perils of CRISPR, and what happens now that CRISPR babies have (maybe?) been born. Featuring science writer Tina Saey, molecular biologist Anne Simon, and bioethicist Alan Regenberg. A Nobel Prize winner argues banning CRISPR babies won’t work Geneticists push for a 5-year global ban on gene-edited babies A CRISPR spin-off causes unintended typos in DNA News of the first gene-edited babies ignited a firestorm The researcher who created CRISPR twins defends...