Plagues Devastating Forests Across the U.S. West – ‘We’re talking millions of trees killed, whole mountain sides dying’





A mysterious disease has ravaged the US’s only rainforests – and just one of the plagues that are devastating American forests across the west.



 
A forest ecologist named at the University of Hawaii named Friday, started getting calls from concerned landowners in Puna, which is on the eastern tip of Hawaii’s big island, in 2010. Their seemingly ubiquitous ohi’a trees were dying at an astonishing rate. The leaves would turn yellow, then brown, over just a few weeks – a startling change for an evergreen tree.



“It was like popcorn – pop, pop, pop, pop, one tree after another,” Friday said. “At first people were shocked, now they are resigned.

“It’s heartbreaking. This is the biggest threat to our native forests that any of us have seen. If this spreads across the whole island, it could collapse the whole native ecosystem.”

Almost six years later and nearly 50,000 acres of native forest on the big island are infected with rapid ohi’a death disease. Rumors abound as to its origin: did it emerge from Hawaii’s steaming volcanoes? A strange new insect? Scientists still aren’t sure of where it came from or how to treat it.

Forestry officials and scientists are increasingly alarmed, and say the essential role of trees – providing clean water, locking up carbon and sheltering whole ecosystems – is being undermined on a grand scale.

California and mountain states have suffered particularly big die-offs in recent years, with 66m trees killed in the Sierra Nevada alone since 2010, according to the Forestry Service.

In northern California, an invasive pathogen called Sudden Oak Death is infecting hundreds of different plants, from redwoods and ferns to backyard oaks and bay laurels. The disease is distantly related to the cause of the 19th-century Irish potato famine, and appears to have arrived with two “Typhoid Marys”, rhododendrons and bay laurels, said Dr David Rizzo, of the University of California, Davis.





“We’re talking millions of trees killed, whole mountain sides dying,”
Rizzo said.

Five years of drought in the west have not only starved trees of water but weakened their defenses and created conditions for “insect eruptions” across the US, said Diana Six, an entomologist at the University of Montana. Bark beetles and mountain pine beetles, usually held in check by wet winters, now have more time to breed and roam. The latter have already expanded their range from British Columbia across the Rockies, to the Yukon border and eastward, into jack pine forests that have never seen the bug.

The outbreak is “something like 10 times bigger than normal, I would argue a lot more than that,” Six said. “Basically a native insect is acting outside of the norm, because of climate change, and become an exotic in forests it’s never been before. We haven’t seen very good outcomes of exotics moving into native forests.” 


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Plagues Devastating Forests Across the U.S. West – ‘We’re talking millions of trees killed, whole mountain sides dying’ Plagues Devastating Forests Across the U.S. West – ‘We’re talking millions of trees killed, whole mountain sides dying’ Reviewed by Admin on 00:12:00 Rating: 5
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