Global Warming Caused Death Rate of Forests in West to Double

The forests of the West, from New Mexico to British Columbia, are becoming one of North America’s most potent signs of global warming. The death rate of old-growth forests across the West has doubled in recent decades, and planting new trees simply isn’t keeping up with the speed at which forests are losing trees to global warming-related causes.

It’s happening at all elevations, in trees of varying sizes and species. Air pollution, crowding and fire suppression impacts have been ruled out as causes, and because mortality increased in young trees, the overall death rate can’t be blamed solely on the aging of large trees.

From MSNBC:

Tree mortality doubled in just 17 years in the Pacific Northwest and 25 years in California. Mortality rates in states farther inland took 29 years to double.

“Regional warming and consequent increases in water deficits are likely contributors to the increases in tree mortality rates,” the researchers said.

Van Mantgem noted that “average temperature in the West rose by more than 1 degree F over the last few decades. While this may not sound like much, it has been enough to reduce winter snowpack, cause earlier snowmelt, and lengthen the summer drought.”

That warming also favors insects like the mountain pine beetle, which has devoured forests in recent years.

This could mean major changes in entire ecosystems, since so many other species rely on these trees for survival. Thinner forests and smaller trees won’t support as many animals. What were once full, lush forests acting as carbon sinks keeping the greenhouse gas from entering the atmosphere could become carbon sources, with all the dying trees emitting CO2, accellerating global warming even more.

If the death rate has doubled just over a few decades, imagine what these areas could look like 10 or 20 years from now. The West could dramatically change in ways that impact every form of life in the area.

Many global warming deniers have claimed there’s a lack of signs to prove that the earth is reacting unfavorably to greenhouse gases – well, here’s your sign, and it’s right in your own backyard. It’s about 100 feet tall and painted in gigantic, red flashing letters.

Link [MSNBC]
Photo credit: Flickr user D & J Huber

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