Pacific Northwest Trees Dying as Climate Warms

A new study conducted over a 50 year period in the coniferous forests of the American West, reports that forest trees are dying at a rate twice as fast as they were 17 years ago. The scientists are blaming this phenomenon on warming temperatures.

The data was gathered at multiple sites over Oregon, Washington, California, Colorado, Arizona, New Mexico, and southwestern British Columbia. All the sites under study were over 200 years old, and suffered rising mortality rates across the board. The main species studies were pines, firs, and hemlocks, with pines suffering the highest rise in mortality rates. Most of the data was collected from rudimentary tree counting.

The scientists ruled out other causes like ozone pollution, fire prevention, and forestry management, because the mortality rates went up across the board in the old growth forests.

Rising temperatures mean less snowpack, thus bringing an earlier summer drought. Warmer climate can also encourage harmful insects and invasive species, which cause more damage to the already drought-stressed population. Species like the bark beetle are known for attacking trees that are already weakened by environmental factors.

Some scientists believe the trees will migrate to cooler areas if necessary, but the question remains if they can do this quickly enough to save the species.

The report is disconcerting because forests have the potential to be carbon sinks, as they take in carbon dioxide to produce oxygen. If the trees are dying they can no longer perform this function, therefore further increasing carbon dioxide levels in the atmosphere.