Navigation Links
Tree deaths have doubled across the western US
Date:1/22/2009

Tree death rates have more than doubled over the last few decades in old-growth forests of the western United States, and the most probable cause of the worrisome trend is regional warming, according to a U.S. Geological Survey-led (USGS) study published in Science on January 23.

The study found that the increase in dying trees has been pervasive. Tree death rates have increased across a wide variety of forest types, at all elevations, in trees of all sizes, and in pines, firs, hemlocks, and other kinds of trees.

Regardless of the cause, higher tree death rates ultimately could lead to substantial changes in western forests, said Phil van Mantgem, a USGS scientist and co-leader of the research team. Such changes, the team noted, can have cascading effects, such as by changing forest suitability for wildlife species. Additionally, increasing tree mortality rates mean that western forests could become net sources of carbon dioxide to the atmosphere, further speeding up the pace of global warming.

"The same way that in any group of people a small number will die each year, in any forest a small number of trees die each year," said van Mantgem. "But our long-term monitoring shows that tree mortality has been climbing, while the establishment of replacement trees has not."

The result is that forests have begun to lose trees faster than they're gaining them, said van Mantgem.

The study's authors ruled out a number of possible sources of the increasing tree deaths, including air pollution, long-term effects of fire suppression, and normal forest dynamics. In contrast, increasing regional temperature was correlated with tree deaths.

"Average temperature in the West rose by more than 1 F over the last few decades," said van Mantgem. "While this may not sound like much, it has been enough to reduce winter snowpack, cause earlier snowmelt, and lengthen the summer drought."

The lengthening summer drought could be stressing trees, leading to higher death rates, he said. Warmer temperatures also might favor insects and diseases that attack trees. Some recent outbreaks of tree-killing bark beetles in the West have already been linked to warming temperatures.

"Tree death rates are like interest on a bank account the effects compound over time," said Nate Stephenson, also with the U.S. Geological Survey and research team co-leader. "A doubling of death rates eventually could reduce average tree age in a forest by half, thus reducing average tree size."

In some cases, increasing tree deaths could indicate forests vulnerable to sudden, extensive die-back, similar to forest die-back seen over the last few years in parts of the southwestern states, Colorado, and British Columbia. "That may be our biggest concern," said Stephenson. "Is the trend we're seeing a prelude to bigger, more abrupt changes to our forests?"


'/>"/>

Contact: Phil van Mantgem
pvanmantgem@usgs.gov
707-825-5189
United States Geological Survey
Source:Eurekalert

Related biology news :

1. Stroke Belt deaths tied to non-traditional risk factors
2. Fewer deaths with preventive antibiotic use
3. New technology aims to reduce maternal and neonatal deaths
4. Study shows rise in Cornwalls dolphin, whale and porpoise deaths
5. Human deaths from shark attacks hit 20-year low last year
6. Earlier bites by uninfected mosquitoes boost West Nile deaths in lab mice
7. Small-scale fishing in Mexico rivals industrial fisheries in accidental turtle deaths
8. Warmer climate causing huge increase in tree mortality across the West
9. Effects of climate change vary greatly across plant families
10. Healthy Minds Across America features 48 public forums on mental health research, Sept. 14
11. Scientists find a fingerprint of evolution across the human genome
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:2/2/2017)... , Feb. 2, 2017  EyeLock LLC, a market ... new white paper " What You Should Know About ... of ensuring user authenticity is a growing concern. In ... of users. However, traditional authentication schemes such as username/password ... Biometric authentication offers an elegant solution to the ...
(Date:2/1/2017)... IDTechEx Research, a leading provider of independent market research, business ... new report, Sensors for Robotics: Technologies, Markets and Forecasts 2017-2027 ... ... Revenues of ... for Robotics: Technologies, Markets and Forecasts 2017-2027: Machine vision, force sensing ...
(Date:1/30/2017)... , Jan. 30, 2017   Invitae Corporation ... growing genetic information companies, today announced that it will ... and provide 2017 guidance on Monday, February 13, 2017, ... that day at 4:45 p.m. Eastern / 1:45 p.m. ... team will briefly review financial results, guidance, and recent ...
Breaking Biology News(10 mins):
(Date:2/23/2017)... SAN FRANCISCO , Feb. 23, 2017 /PRNewswire/ ... and Beyond Type 1, a not-for-profit advocacy and education ... announced a grant from Beyond Type 1 to support ... 1 and other insulin-requiring diabetes.  For ... stem cell-derived cell replacement therapies with a focus on ...
(Date:2/22/2017)... (PRWEB) , ... February 22, 2017 , ... Park ... free AFM Luncheon for all SPIE attendees and Park customers ... just one block from the San Jose Convention Center. The luncheon will feature ...
(Date:2/22/2017)... ... February 22, 2017 , ... ProMIS Neurosciences ... treatments for neurodegenerative diseases, today announced it has issued a scientific white paper ... one of a series of commentaries from ProMIS’s scientific team offering insight into ...
(Date:2/22/2017)... -- Origin (Origin Agritech, LLC, a subsidiary of Origin Agritech Ltd.) ... Arcadia (Arcadia Biosciences, Inc., NASDAQ: RKDA), a ... traits and nutritional products, today announced their collaboration to achieve the ... China to the United States ... ...
Breaking Biology Technology: