By Alex Devoid, Arizona Daily Star
As the Amazon burns, a bad situation could get worse for forests in Arizona.
“The relationship is very clear,” said Don Falk, a professor at the University of Arizona.
Deforestation in the Amazon accelerates changes in global climate. And these changes eventually affect forests close to home.
They’re driving longer, warmer and more intense wildfire seasons, he said. And they’ve already fueled unprecedented wildfires in Arizona and across the West.
Tropical forests like the Amazon rarely burn when left to nature, but fire has always had a place in the life cycle of forests in Arizona.
Low-intensity fires in Arizona historically cleared the forest floor, limiting the accumulation of wildfire fuel, while leaving mature trees standing.
In the 1880s, people and livestock started interrupting fire’s place in this cycle, Falk said. Then U.S. federal policies suppressed wildfire for decades staring in the 1920s, allowing fuel to accumulate. Changes to global climate dried it out with drought and higher temperatures.
In the worst cases, flames jumped from the ground to the crowns of densely packed trees.
They engulfed old-growth forests, spreading faster and more destructively through more forest than ever before.
In 2002 and 2003, for example, it happened in the peaks above Tucson on Mount Lemmon during the Bullock Fire and then the Aspen Fire. Since then, hundreds of thousands of acres have burnt this way in Arizona.
The Amazon is an important buffer against the warming climate, which has created the conditions for these unprecedented fires. It absorbs around 2 billion of the 40 billion tons of carbon dioxide emitted globally each year.
At least a quarter of the stored carbon on earth is concentrated in tropical forests like the Amazon, which grow on barely 12% of the earth’s land, Falk said.
Forests fires across the globe may contribute to climate change by burning carbon these forests store, according to a 2015 study by researchers from universities across the country.
As the Amazon burns, for example, it absorbs less carbon dioxide.
Meanwhile, more billows from the flames, warming the planet by trapping heat inside the atmosphere.
“It’s a double hit to the global climate system,” Falk said.
By Kirk Siegler
Western towns surrounded by and dependent upon public lands are forced to get creative as federal recreation budgets continue a slow decline. They are boosting local efforts to maintain public access.
It’s the boom times in Mammoth Lakes, Calif., which is wrapping up a winter of record snowfall. Eager to take advantage of it, Donovan Sliman and his two young daughters are lumbering up a snowy trail on the outskirts of town, where the condos give way to National Forest.
“I like to get away from everybody else,” says Donovan. “I like to hear the sound of the wind and the snow through the trees.” “We’re also going to go sledding,” adds Grace, one of his daughters.
Mammoth is completely surrounded by protected federal wilderness or U.S. Forest Service land. Its destination ski resort operates on public land via a federal lease.
The Slimans try to visit the Mammoth Lakes area from their home in Orange County at least a half dozen times a year.
They’re not alone.
Every year, more than 2 million people descend on California’s eastern Sierra region to camp, hike, fish, hunt and ski. This region, often dubbed “the wild side” of the state, only has about 50,000 residents across two sprawling counties roughly the size of Massachusetts.
Across the western U.S., towns surrounded by public lands are facing an increasing bind: They’re seeing a huge surge in visitors coming to play in the forests and mountains surrounding them, which is leading to an economic boom. But, at the same time, federal funding to manage these lands has been drying up.
Hygroscopic aerosols — particles in the air that attract water — could be causing forest decline around the world, according to experiments performed in Germany. Researchers believe that aerosol accumulation on trees enables thin bridges of liquid to form between the leaf interior and the leaf surface, causing the plants to dry out much more rapidly.
“In the atmosphere, aerosols act as cloud condensation nuclei,” says Juergen Burkhardt of the University of Bonn, Germany. “Deposited aerosols on leaf surfaces act almost the same way but attract water from inside the plant.”
Plants have developed sophisticated mechanisms for taking up carbon dioxide from the air for photosynthesis without losing too much water but, as the scientists note, it’s a delicate balance. And one that appears to be upset by rising levels of airborne particles.
“Global aerosol concentrations have roughly doubled compared with natural conditions, and the concentration increase over the continents is even higher,” says Burkhardt. “Our results show that aerosols deposited on leaves interfere with this delicate balance, pointing to a direct mechanism by which air pollution can reduce the drought tolerance of plants.”
Burkhardt and colleagues grew three species of tree — Scots pine, silver fir and common oak — for two years in two greenhouses, one ventilated with ambient air and the other fed with air filtered to remove 99% of aerosols. Seedlings grown under filtered conditions had superior drought tolerance to those raised in ambient air, the team found.
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