Trees in urban areas provide benefits for people, including decreased temperatures and improved air quality, according to new research from Washington state.

The Greening Research in Tacoma initiative measured air temperatures across a neighborhood in the city to understand the effects of urban trees.

Ailene Ettinger, qualitative ecologist for The Nature Conservancy in Washington and the study's lead author, said temperatures were as much as 18 degrees lower in areas with trees. Ettinger noted trees are essential to mitigate the effects of climate change.

"They reduce the probability of extreme heat occurring," Ettinger explained. "The kind of heat that can be harmful for human health, and can also just reduce the ability of people to do their work if they're working outside."

The Greening Research in Tacoma initiative is a partnership of The Nature Conservancy in Washington, University of Washington, Tacoma Tree Foundation and Tacoma Urban Forestry program. The study was published in the journal Scientific Reports.

Lowell Wyse, executive director of the Tacoma Tree Foundation, said urban trees are also an environmental justice issue. He pointed out the South Tacoma neighborhood where the study took place has half the canopy coverage of the rest of the city, and is also more racially and ethnically diverse.

"There's a growing awareness that the way the city's designed isn't fair for everybody," Wyse observed. "People that live in this neighborhood really care about making a change on all those fronts - environmental, social and economic."

Wyse added the work has gained greater urgency since the 2021 heat wave in the Northwest, which killed eight people in Tacoma, including one in the neighborhood studied.

"It's kind of becoming a life-and-death issue here to understand the urban heat-island effect, and start making investments in shade and cooling resources in these neighborhoods that are suffering the most from those kinds of events," Wyse stressed.

A Knoxville-based environmental group is raising awareness about increasing U.S. nuclear weapons spending and supporting this week's global effort to ban nuclear arms.

The event, organized by the International Campaign to Abolish Nuclear Weapons, is focused on nine countries, including the U.S., spending more than $90 billion annually on nuclear weapons, the equivalent of more than $173,000 per minute.

Tanvi Kardile, coordinator of the Oak Ridge Environmental Peace Alliance, said the campaign backs the Treaty on the Prohibition of Nuclear Weapons. She stressed this week's campaign, called "No Money for Nuclear Weapons," is a rallying cry worldwide.

"To talk about how much money is being spent on nuclear weapons and how disproportionate it is compared to other facets of society that maybe we aren't putting as much money into," Kardile contended. "Such as health care, education, combating climate change, etc.; things that could actually benefit us as a society."

Besides the tax implications, Kardile pointed out her group is concerned with the ongoing risks closer to home, tied to enriching uranium and other activities at the Y-12 National Security Complex in Oak Ridge.

Kardile argued addressing the humanitarian consequences of nuclear weapons is crucial because in recent years, some global leaders have made threats about using them, amid growing international tensions and discord. She added the production and use of nuclear weapons are environmental hazards.

"I'd say the biggest risk comes from groundwater, and recreational water as well," Kardile emphasized. "Production causes radioactive materials to seep into the waterways, so it's really detrimental to the water we're drinking, the water we're using recreationally."

This month, Gov. Bill Lee announced a nuclear power and renewable energy company based in France is building a uranium enrichment plant in Oak Ridge. The multibillion-dollar centrifuge uranium facility is 750,000 square feet and is expected to employee 300 workers.

By Hunter Fore for Cronkite News.
Broadcast version by Alex Gonzalez for Arizona News Connection reporting for the Solutions Journalism Network-Public News Service Collaboration

On an overcast November morning, volunteers got to work to restore local river flow.

Drought and decreasing water availability have been ongoing problems throughout Arizona. In Tucson, drought along with new land developments are causing decreases in vegetation and wildlife habitat.

Watershed Management Group is a Tucson-based nonprofit that aims to fix this problem. The group aids in local water conservation, land restoration and river flow. It holds regular events to help the environment such as cleanups, workshops, fundraisers and classes. The group has a club called the River Run Network, which includes a biweekly email with invitations to events like creek walks and family education days to help restore Tucson's heritage of flowing rivers.

Watershed Management Group worked to remove an invasive plant from a riparian area in the Tanque Verde community of Tucson on Nov. 18.

The species of grass Arundo donax, more commonly known as "giant reed," is an invasive species in Tucson's riparian ecosystem, the wetland area between a body of water and land. Invasive species in those areas are harmful to the ecosystem, wildlife and the city's groundwater supply.

"Arundo is one of the invasive species that we focus on removing," said Hannah Nuest, a program coordinator for the River Run Network. "It sucks up to three to four times the amount of water that native plants do, which affects groundwater levels and river flow."

Tucson's drinking water comes mostly from the Colorado River, which is experiencing decreasing water levels, and from groundwater. But those underground aquifers are fed with water from natural areas like riparian preserves, and invasive species like arundo compete for that water, cutting into Tucson's water supply

"Invasive species also cause problems for tree canopy coverage," Nuest said. "Trees like the cottonwood and the mesquite need water closer to the surface, so when that water's being used up, the number of trees can decrease, causing habitat loss, less shade, more pollutants and hotter temperatures."

Arundo removal also helps the local ecosystem with flood risk reduction, water quality improvement and increased river flow.

"Arundo comes from the Mediterranean and was brought to the Tucson area around the early 19th century for landscaping," said Jim Washburne, Watershed Management Group's senior project specialist.

When arundo grass is present, nutrients that usually travel downstream are blocked. This prevents other plants from growing along waterways, which increases flood risks and decreases habitat potential.

Complete removal of every arundo plant would be nearly impossible, but removing even a small amount is good for the ecosystem, Washburne said.

"We typically do this every week in Tanque Verde," Washburne said. "This is our most consistent environmental event. It's important for the community to get involved in taking care of the land they live on."

According to Tucson's One Water 2100 Plan, which is a new city plan to improve water delivery methods, riparian preserve restoration not only increases local tree canopy coverage but helps the local economy by helping with cooler temperatures, more trees and more diverse water delivery options.

"Riparian areas are integral to the health of Tucson's water supply and economy," Washburne said.


Hunter Fore wrote this article for Cronkite News.


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Recent extreme wildfires in Wyoming burned nearly 500,000 acres and among those recovering are ranchers and their surviving livestock.

Wildfires burned through large swaths of ranch lands in northern Wyoming and southern Montana last month, including the House Draw Fire, which blazed across nearly 175,000 acres in Johnson and Campbell counties. No homes or human lives were lost, but important ranching resources were, such as hundreds of miles of fencing, winter forage and summer grazing grounds.

Micah Most, agriculture and natural resources educator for the University of Wyoming Extension, said livestock deaths are hard to tally, but the injuries are apparent.

"We're seeing a lot of cattle with injured feet, burned feet, from walking through or over the hot ground as they were escaping," Most pointed out. "A lot of stress just generally on those animals."

Most emphasized the outpouring of support from people in Wyoming and beyond has been "deeply meaningful." The office is coordinating hay donations, locals are helping with livestock relocation and a community network is hosting a drive for fencing supplies. Financial donations can be made to Wyoming Rancher Fire Relief and elsewhere.

Most explained some injured animals may need to be culled from the herd and sold at a discounted price. Extension offices across the state have been revisiting their emergency preparedness and response materials to help people and ranchers deal with increasingly extreme weather events.

"Finding ways to kind of harden your home area, maybe the home ranch place, and limit some of the risk factors," Most stressed.

The fires also burned through important habitat for pronghorn, mule deer and breeding grounds important to the greater sage grouse.