 |
|
| |
View previous topic :: View next topic |
| Author |
Message |
GTG
Was lost but now am found
Joined: 30 Dec 2002
Posts: 2387
Location: Peoria, Arizona, originally from Rocket City, USA
|
 Posted: 10/12/2005, 3:50 pm Post subject: Bark beetles took advantage of weather, invaded dry pines |
 |
 |
|
|
From today's Arizona Republic - A very interesting article about something we've had to read about too much in the past few years.
http://www.azcentral.com/news/articles/1012deadtrees12.html
| Quote: |
Bark beetles took advantage of weather, invaded dry pines
Shaun McKinnon
The Arizona Republic
Oct. 12, 2005 12:00 AM
High temperatures fueled the bark beetle invasion that ravaged Arizona's forests in recent years, researchers said, adding to evidence that even subtle changes in climate can leave lasting damage on the environment.
Drought weakened millions of piņon and ponderosa pines across the state, but the researchers said it was heat that allowed the swarms of bark beetles to deliver the knockout punch, in some cases killing every tree for miles.
The new findings suggest events like the infestation could become more common if temperatures continue to climb as they have in recent years in Arizona and elsewhere on the planet.
The consequences of such events are severe: Scientists say many of the areas hit by the beetles may not recover for generations, if at all. That could trigger a domino effect of ecological changes. Wildlife that depended on the trees will move to new homes or die, forcing other species to leave as well. Their old habitats could evolve into a more arid landscape.
"Scientists are concerned about how fast vegetation will respond to climate change, but we don't have many examples to test our ideas," said University of Arizona Professor David Breshears, research team leader. "Here we've clearly documented a case that shows how big and fast the die-off can be."
Breshears, with team members Neil Cobb from Northern Arizona University and Paul Rich, a research scientist at the Los Alamos National Laboratory in New Mexico, published their findings this week in the online edition of the Proceedings of the National Academy of Sciences.
The study supports theories that rising temperatures can worsen a drought or other events, Breshears said, but it wasn't meant to point to the dead trees as specific victims of global warming. Instead, the researchers found what they believe is a link between climate change and ecosystems.
"The simplest message is droughts can really whack these systems hard and cause a big, fast change," he said. "Hotter droughts may be able to whack even harder, and we ought to be concerned about this."
Because Breshears and others had studied pine trees in the past, the team looked at pine forests in Arizona, New Mexico, Colorado and Utah, where as many as 80 percent of piņon pines died during the height of the beetle attack in 2002 and 2003. Far fewer trees died during the region's last severe drought during the 1950s, so the research team compared conditions during the driest years of that period, 1953-56, and the driest of this one, 2000-03. The difference was the heat.
The average temperature from 2000 to 2003 was anywhere from 1 to 2 degrees higher in some areas to as much as 5 to 10 degrees higher in others when compared with the 1950s drought.
"By any measure we looked at, the recent drought was hotter," Breshears said.
The drought clearly drained the trees of moisture needed to produce sap to fight off the infestation. That, combined with the dry conditions, stressed the trees enough to let the beetles spread, chewing through so many trees that the die-off was quickly visible from satellites.
The researchers used those satellite images to study the advance of half a dozen varieties of the pine beetle.
The forests paled in color as the attacks worsened, turning from barely green to brown before the trees dropped their needles, Breshears said.
The beetles infected more than 2 million acres of Arizona forests from 2001 through 2003, according to the UA Cooperative Extension.
The insects killed 50 million piņon trees on about 2 million acres in Arizona and New Mexico and 20 million ponderosa pines on 1 million acres in the two states.
Among the hardest hit areas: the Apache-Sitgreaves National Forests east of Phoenix, a swath of trees near Crown King in the Prescott National Forest and forests in the higher elevations of the Navajo Reservation.
The infestation slowed in 2004, according to UA, with the number of acres affected dropping significantly. Wet winter conditions gave trees a better shot at recovering this year, but dry, windy weather in the spring and the monsoon's late arrival still left trees vulnerable to attack, scientists said.
Because the trees grow slowly, "we aren't going to have woodlands of this type back in this area for decades," Breshears said.
The effects will be felt immediately. The loss of piņon nuts, for example, will rob wildlife of a food source and cut off supplies to nearby residents, who collect and sell the nuts.
The forests' long-term fate depends on climate and weather conditions, said Rich, of the Los Alamos lab.
"If it's wetter, the trees may come back," he said.
"If not, we'll probably see shifts to species from drier ecosystems."
|
GTG
_________________
Good things come to those who walk. |
|
| Back to top |
|
 |
GeorgAz
Joined: 04 Jan 2003
Posts: 815
Location: Scottsdale
|
| Posted: 10/13/2005, 9:18 am Post subject: |
|
|
|
|
| There was just a program on Animal Planet with Rudd, the Bug Guy about the flourishing bark beetles in Alaska due to global warming, which is finally being recognized. |
|
| Back to top |
|
|
|
Back to top
|
|
|
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
|
|
Home
Board
AZH Gear
FAQ
Search
Members
Articles
Calendar
Gallery
Register
Profile
Log in
Hosted by Gartman
Technical Services.