Christmas trees are even slower than Christmas, needing up to a decade of growth to reach full size. Yet all that work can suddenly vanish amid disease or bad weather, two problems that increasingly plague U.S. Christmas tree farms from Oregon to Appalachia.

No major Christmas tree shortages are expected in the U.S. this year (turkey, wine and bacon should also be plentiful), but the spread of a deadly water mold and the onset of climate change have nonetheless clouded the outlook for many farms.

Farmers in North Carolina, the country's No. 2 Christmas tree state behind Oregon, are losing $6 million every year to Phytophthora root rot, the Associated Press reports. This genus of oomycetes — weird, fungus-like protists — has a long history of killing crops, earning it a scientific name that means "plant destroyer." Phytophthora is a native pest but can run wild on tree farms, reportedly rendering soil unfit for production once it's there.

"Phytophthora is a problem in most areas where true firs ... are grown," Washington State University plant pathologist Gary A. Chastagner tells the AP. "It's a national problem."

The stakes are even higher in Oregon, according to the AP, where an uncontained Phytophthora outbreak could cost Christmas tree growers up to $304 million every year. No fungicide is known to control the pest on Christmas tree farms.

Meanwhile, other states have lost swaths of tannenbaums to another emerging scourge: extreme weather, which is widely forecast to worsen due to climate change. According to Vermont's Fox44, tree crops in that state and New Hampshire have been battered lately by a spate of severe weather, including a spring heat wave and summer flash floods. "It probably took out as much as half the farm," one Christmas tree farmer says of this year's floods, noting the uncertainty created by wild weather swings. "You get used to 20 to 30 years of how everything works, and now you don't know anymore."

Christmas tree farm Young Christmas trees grow at a West Virginia farm in 2012. (Photo: Robert MacPherson/Getty Images)

Midwestern tree farms have suffered similar die-offs in recent years, points out Emily Atkin of Climate Progress. A brutal drought and heat wave last summer killed an estimated 4,000 young Christmas trees in Michigan and Wisconsin, for example, representing about half of those states' new crops. Major tree deaths were also reported in Iowa, where one farmer described the losses as "by far the worse we've seen" in 32 years.

Recent losses of younger saplings aren't expected to affect Christmas tree supplies or prices this year, but they could in seven or eight years when those trees would have been reaching maturity. Farmers in some states are experimenting with alternative trees like Turkish fir, the AP reports, which is more resistant to root rot but has its own problems, including more vulnerability to hungry deer and late-season frosts than Fraser fir.

Artificial Christmas trees might seem like an easy solution, but they pose a variety of environmental drawbacks. Not only are most imported from China, but they're often made from toxic PVC and can shed lead-based dust. They also have a larger carbon footprint than real trees, each of which can absorb 30 to 400 pounds of carbon dioxide from the air annually. Production of fake Christmas trees requires some 600,000 tons of CO2 emissions per year, or roughly the amount absorbed by 300 square miles of real trees.

"At this time of year, choosing a real Christmas tree is one way that an average person can make a difference in terms of climate change," plant biologist Clint Springer said in a 2012 report from Saint Joseph's University. "[A] 7-foot cut tree's impact on climate is 60 percent less than a 7-foot artificial tree used for six years. So while cut trees are not carbon-neutral, in terms of carbon use, they are better than artificial trees."

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Russell McLendon ( @russmclendon ) writes about humans and other wildlife.

For U.S. Christmas trees, a festival of blights
On top of a deadly soil disease, many Christmas tree farms are reeling from severe weather events encouraged by climate change.