The Northwest Pacific forests will be less vulnerable to drought and fire during the next three decades than those of the Rocky Mountains and Sierra Nevada, computer modeling by researchers from the Forest State School of Oregon State University.
The conclusions, published today in Spain Biology of global change, represent an important tool for scientists and land managers because forests throughout the western United States are under increasing stress due to the accelerated drought-related mortality rates related to global climate change and caused by human beings.
In addition, Northwestern Swan, Douglas and forest have a tremendous potential to neutralize climate change through their carbon sequestration capabilities, which means that policies that promote the management of these forests are critical, scientists say.
"The last prolonged droughts and catastrophic forest fires in the West have raised concerns about forest mortality and how it can affect the forest structure and ecosystem services and also the economic vitality of nearby communities," said the corresponding author Polly Buotte of the Department of Ecosystems and Forest Society of OSU. "Western forests maintain diversity of tall species and some Northwestern forests are among the densest forests of carbon dioxide in the Earth."
Beaumont and College of Forestry colleagues, Beverly Law, led a partnership that shaped 13 different types of major forests throughout the United States, taking into account the climatic conditions and atmospheric carbon dioxide levels in the next 30 years.
The model was of high resolution from the spatial point of view, which broke the forests in networks of 16 square kilometers and also because it considered the specific responses of species to the environmental variables.
"The model has calculated multiple biophysical and biogeochemical processes, including superficial heat fluxes, photosynthesis, evaporation, perspiration, carbon-to-tissue allocation, decomposition and nitrogen cycling," said Buotte.
Researchers, who also included David Rupp of the OSU Earth Sciences, Oceans and Atmospheric Sciences, have developed vulnerability indicators to prolonged and prolonged drought in the short term.
"The projections show that the limited water forests in the Rocks, in the southwest and in the Great Basin will be the most vulnerable to the future mortality related to drought," said Buotte. "We expect the vulnerability to future fires to be the highest in the Sierra Nevada and portions of the Rocky Mountains. The forests of the Pacific coast and the Western Western regions, where there is a great rainfall, are the least vulnerable to drought or fire."
Stress caused by drought causes trees to spill leaves, limiting their ability to photosynthesis; Insect infestations also make life difficult for the trees affected by drought.
"Our analyzes indicate a strong potential for the continuing levels of forest mortality related to drought in the ruins of the south and southwest in the next decades, since forests are likely to suffer from climate change," said Buotte.
The researchers point out that there is a great spatial variability in the future vulnerability. And this vulnerability against fires is not the same as the intensity of fire.
"We do not imply that marked areas of high vulnerability will burn or become inflamed will burn with high intensity, but they will be at greater risk in the coming years than they have historically been," said Buotte.
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Polly C. Buotte et al. The forest vulnerability near the future drought and fire varies throughout the west of the United States, Biology of global change (2018). DOI: 10.1111 / gcb.14490