Facing the difference between how much water plants need, and how much they’ll get
Scientists are looking at climatic water deficit, the water plants need but don't have.
We hear a lot about how climate change will affect rainfall in California, but climate scientists are increasingly looking at a new indicator: water deficit.
“Climatic water deficit” relates to how much water plants need to survive. “It’s the difference between what a plant would use if it had the water and what is actually available,” Alan Flint, research hydrologist with the US Geological Survey, explained on Wednesday at the North America Congress for Conservation Biology.
The value combines temperature, rainfall, the soil’s capacity to hold water and how plants use water. In agriculture, farmers irrigate their crops to make up the water deficit, but plants in the natural world aren’t so lucky. Continue reading
Warmer and wetter weather is good for tree diseases, which is bad news for trees
Susan Frankel/USDA-Forest Service
A patch of tanoak, killed by Sudden Oak Death, in the Los Padres National Forest in Monterey County.
Climate change is likely to wreak havoc on California’s forests. Extreme weather, wildfires and insect outbreaks will all take a toll. Add to those another looming threat: disease. Forest diseases like Sudden Oak Death, which has infected trees in 14 counties in the state, stand to benefit from the effects of climate change, to the detriment, obviously, of the trees.
Trees are big and long-lived. Tree pathogens, mostly fungi and bacteria, are the opposite. They’re mobile, able to blow around on the wind. And they reproduce and evolve rapidly. That’s the crux of the problem, according to Susan Frankel, a plant pathologist with the Forest Service.
“When you look at forest health and the balance between forest trees and the pathogens that attack them, it does seem, given climate change, pathogens get the better end of the deal,” she told me.
Droughts kill trees — but until now scientists didn’t know the root of the problem
Aspens live at high elevations in the Western United States, including in California's White Mountains and Sierra Nevada.
Throughout the West, aspens are quaking for good reason.
About 17% of the aspen in the Colorado Rockies have died in the last decade. That’s about one in every six trees. The widespread die-off, called sudden aspen decline, began after a severe drought and heat wave. So people studying the trees knew that’s what triggered the deaths, but they didn’t know what exactly killed the trees.
William Anderegg, a grad student at Stanford, with help from a team of scientists there and at the University of Utah, has zeroed in on the culprit, and describes the work in a paper published this week. There were two working theories: failures in photosynthesis, which would mean less food for the tree; or damage to the roots, which would mean less water. Anderegg found it was the roots.
Environmental groups are criticizing the Obama Administration’s new proposed rules for managing the country’s nearly 200 million acres of national forest, arguing that they weaken current standards for protecting wildlife and watersheds.
More than 100 organizations, including the Natural Resources Defense Council and Defenders of Wildlife, signed on to a letter sent to Secretary of Agriculture Tom Vilsack on Monday, arguing that the proposal “fails to provide critical, concrete protections for the most precious resources of our forests — water and wildlife,” and that it “weakens the strong standards for safeguarding water quality and wildlife viability first issued in 1982 by the Reagan Administration and currently still in place.”
California's forests provide water, habitat for animals, lumber and tourism dollars, and they sequester carbon. (Photo: Molly Samuel)
For decades the federal government has touted the nearly 200 million acres of national forests and grasslands under its control as a “land of many uses.” But one “use” that’s seldom discussed is as a huge repository for carbon.
But clearly it’s on the minds of officials and scientists as the Forest Service seeks comments on its proposed new planning rule. National Forests and Grasslands are managed individually, but the planning rule guides how those management plans are developed. This new one is replacing a Planning Rule from 1982. Continue reading
As if drought and wildfires weren’t enough, California’s coniferous forests face another climate-related threat
(Photo: Reed Galin/Lone Tree Productions)
In the last decade, tiny forest-dwelling beetles have wiped out pine trees on millions of acres in the Canadian and American West, including Southern California. The rest of the state has been largely spared, but forest ecologists say that’s likely to change.
Reporter Ilsa Setziol recently spent some time tracking these bugs with an entomologist from the US Forest Service. They found beetles at work in Jeffrey pines and coulter pines in the San Bernardino National Forest, east of Los Angeles. Continue reading