By Peter Fimrite
It is the forgotten killer when compared to our increasingly frequent climate calamities, but the virulent pathogen known as sudden oak death remains active and is spreading death so fast it could destroy California’s coastal forest ecosystem, UC Berkeley scientists reported Thursday.
The deadly microbe has now established itself throughout the Bay Area and has spread along the coast from Monterey to Humboldt County, according to a study of 16,227 trees in 16 counties in Northern California.
Millions of coast live oak and tan oak trees have withered and died over the past quarter century, leaving acres of kindling for wildfires, but the outbreak this year was one of the worst. Oak trees have historically been abundant in California and southwestern Oregon, with hundreds of millions of them stretching all the way to Baja California.
The rate of trees infected almost doubled in 2019 — from 3.5% to 5.9% — and was 10 times higher in some places compared with the 2018 survey, said Matteo Garbelotto, the director of the UC Berkeley Forest Pathology and Mycology Laboratory, which tested leaf samples taken by 422 volunteers.
Infections were found in all the well-known hotbeds, like Marin and Sonoma counties, the East Bay, Big Sur and the Santa Cruz mountains. But the 12th annual survey detected more of the pathogen this year in virtually every location. That’s mainly because the disease spreads faster in the kind of wet weather that hit California last winter, Garbelotto said.
“There was a significant increase in infection rates over last year, but that’s not totally surprising because we had a lot more rainfall,” Garbelotto said. “But it was a surprise to see them all at once. It’s telling us we are entering a different phase of the disease, where the organism isn’t really establishing itself in new areas, but is showing itself more when weather conditions are favorable.”
Sudden oak death is an exotic disease that was discovered in Mill Valley in 1995. It now exists in forests and wildlands in 14 California counties and in Curry County, Ore., just across the state border.
It kills oak trees, including California’s signature tree — the live oak — and there are 107 susceptible host plants, including such common garden ornamentals as camellias and rhododendrons. Although some hosts are sickened, they do not always die from the fungus-like ailment. Instead, these plants, bushes and trees help spread the deadly spores.
By Will Brendza
Jeremy Altdorfer’s day of delivery was hectic, but successful. All day on Saturday, Oct. 5 he was zipping around Boulder in his car, which was loaded to the brim with white pine saplings; making one delivery after the next, dropping off the baby trees wherever they’d been requested. Meanwhile, his brother and other partners from Experience Dental, opening Oct. 30, were doling out more trees at several different locations throughout the county.
Their goal: to plant 1,000 trees in Boulder County in a day. Or, at least, to give out 1,000 ready-to-plant trees to individuals, businesses and schools that wanted and needed them. In part, Altdorfer wants to reduce his own business’ carbon footprint, and in part, he wants to help save Boulder’s threatened canopy of trees.
“I thought we were crazy, trying to do 1,000 in a single day,” Altdorfer says. But by the end of the day, they’d met their goal — all 1,000 trees had been distributed.
Altdorfer’s 1,000 white pines are going to help offset what the City of Boulder is calling the “Tree Crisis of 2019.” Boulder’s trees are currently under threat, and while the City’s forestry department plants about 500 new ash trees a year, Altdorfer’s contribution of 1,000 white pines in a single day is a welcome offering and a much-needed addition.
“Planting new trees is crucial to maintaining our urban tree canopy,” says Kathleen Alexander, a forestry worker with the City of Boulder’s forestry department.
According to Alexander, Boulder is projected to lose some 70,000 ash trees to the emerald ash tree borer (EAB), an invasive insect from Asia, over the next 10 years. By 2035, she says, the EAB could destroy 25 percent of Boulder’s urban tree canopy.
It’s why the City is urging residents and the community to take action and plant trees to replace those being killed, and to protect existing trees. It’s why the City has planted more than 2,500 trees on public property since 2013, and why it’s provided more than 3,900 trees to residents for planting on private property.
Having an assorted mix of tree species around the City and throughout Boulder County means the urban canopy is less vulnerable to any one stressor.
“A diversity of tree species is going to help make the urban forest more resilient long-term,” Alexander says.
White pines are good options because they grow fast, they grow large (so they sequester a lot of carbon) and they aren’t at risk from EAB.
By Andy Eckardt and Yuliya Talmazan
HAINICH, Germany — As forester Dirk Fritzlar walks through thick woodland on a sunny September morning, it starts to “rain” spruce needles.
“It is not normal for the trees to shed so many needles. It is far too dry. Many spruce trees are dying,” Fritzlar said as he peeled off a piece of bark. He quickly finds a colony of bark beetles that are a major threat to the spruce — a common species in German forests.
In the last two years, Germany has experienced long summer droughts and rising temperatures, both of which are putting the country’s woodlands in peril.
The potential fate of this forest and millions of German trees shows the danger climate change and changing weather patterns pose to biodiversity and raises questions of how states and citizens should protect their local green spaces.
In 2018 alone, 110,000 hectares (about 272,000 acres) of forest area in Germany were damaged and 33 million cubic meters of wood — equivalent in volume to 12 Great Pyramids of Giza — were declared dead, researchers at the country’s Thünen Institute of Forest Ecosystems said.
A preliminary assessment for 2019 shows at least the same amount of damage.
German researchers and foresters have told NBC News the damage is the result of high temperatures and lack of rain drying out the trees, and in the case of the spruce, weakening its defenses against pests such as the bark beetle.
During a heat wave that hit much of Europe in July, Germany was one of several countries to break records, recording temperatures as high as 42.6 degrees Celsius (108.7 F).
WELZOW: Germany’s forests have long been treasured by its people, so the country has reacted with alarm and dismay as a beetle infestation has turned climate-stressed woodlands into brown ecological graveyards.
After two unusually hot summers in a row, vast patches of the forests mythologised by medieval fairytales, Goethe’s writings and Romantic painters have turned into tinder-dry dead zones.
Given the scale of the threat to the one third of German territory covered by trees, Chancellor Angela Merkel’s government convened a “national forest summit” on Wednesday.
There Agriculture Minister Julia Kloeckner pledged 800 million euros (about $880 million) in federal and state funds over four years to restore the 180,000 hectares of forest destroyed by drought and pests as well as storms and fires — the equivalent of 250,000 football pitches.
The chief culprit has been the tiny bark beetle, which has gone on a rampage as trees in water-starved habitats have lost their natural defences.
In vast parts of Germany, like Welzow forest 100 kilometres (60 miles) south of Berlin, once healthy trees have become defoliated skeletons, their trunks marked by tell-tale networks of tiny tunnels.
“The insect eats the bark and lays eggs inside,” said forest ranger Arne Barkhausen. “The larvae then start to eat the trunk and block the nutrient pathways of the tree, which dies in about four weeks.”
By Sam Lounsberry, Boulder Daily Camera
Even as Boulder County foresters press on in their fight against the invasive emerald ash borer harming the local tree population, officials acknowledge it is a losing battle.
But it is one lovers of ash trees don’t have to walk away from empty-handed, even as sickened trees are in line for removal or have already been sawed to stave off the infestation.
Woodworkers like Evan Kinsley, who started the Boulder-based business Sustainable Arbor Works several years ago, have turned to ash trees to supply their furniture and art crafting practices as a way to maintain the local benefit provided by the species slated for a countywide death at the hands of the insect. Emerald ash borer has already dramatically altered the composition of forests across the middle and eastern regions of the country.
“It’s a privilege to be able to work with a local hardwood like ash,” Kinsely said.
When he first learned of the 2013 detection of emerald ash borer in Boulder — it has since spread to Longmont, Lafayette, Lyons and Superior, but until last month, when it was first detected in Broomfield, Boulder County remained the only area in the Mountain West with a confirmed presence — Kinsley and his now-business partner Aaron Taddiken looked at each other and said, “We have to do something.”
The solution was to build a wood kiln to speed up the drying process for felled trees, and now Kinsely focuses on harvesting trees removed from the urban landscape, a large proportion of which are ash due to the pesky beetle’s invasion, and reusing them for wholesale lumber slabs and designing and building custom furniture.
“It used to be most of this time, that a lot of woodworkers got their wood from big wood suppliers. That would come from all over the country, all over the world,” Kinsley said. “It’s not a new thing to use local lumber. But it was a new idea for smaller woodworkers, smaller lumber mills to start working with tree (removal) companies.”
Supporting Kinsley’s living is not the life cycle he prefers for the trees, but he feels he is making the best out of a bad situation…
While the city and Boulder County continue treating public ash trees to keep them alive as long as possible using pesticide applications, tree adoption programs and biological weapons, enforcement against declining ash trees on private property continues to ramp up.
In 2018, Read said the city sent 182 letters to private property owners asking them to address declining ash trees posing safety hazard; in 2017 the number was 118, in 2016 it was 82. This year he expects to send a significantly larger number of such letters. The growing number of letters aligns with the advance of the beetle infestation. Tree owners who receive such a letter will have to show the city a good-faith effort is being made to remove trees considered dangerous.
But work to preserve ash trees still free of the emerald ash borer goes on, even as replanting species that won’t be affected by the invasive bug remains the focus of foresters for the future of Boulder’s canopy. The city’s Tree-Imagine campaign launched this spring is pushing city residents to collectively plant 25,000 new trees by 2025.
The county this summer introduced a swarm of a non-stinging, parasitic member of the wasp family on the Mayhoffer open space property in Superior, and also has enlisted 159 participants in its adopt-a-tree program for ashes slated for removal from public places. Program participants can choose to commit to pay for treatment to keep the trees alive.
“A lot of these ash trees are old and they’ve been with the community a long time,” Kinsley said. “Trying to protect them in every way is a valiant effort.”
By Jacob Jones
Atop a low ridge in the heart of Oregon’s Blue Mountains, Michael McWilliams pushes through brittle branches and scrambles over toppled logs and decay. Bare trunks tower overhead, but the U.S. Forest Service pathologist focuses low. He’s searching for something that lurks underfoot, hidden despite its immense size.
A sickly fir tree is where he finally stops and kneels. He begins raking at its roots with the curved adz blade of his wood-handled Pulaski. The tool clinks and scrapes, revealing a cream-colored film beneath the bark. It’s an inches-long glimpse of what is likely to be the world’s largest single living organism, a fungus thousands of years old yet still capable of strangling an entire forest.
“Yeah, baby,” McWilliams says, scraping away. “This is a tree killer.”
Dubbed the “Humongous Fungus,” the honey mushroom officially classified as Armillaria ostoyae spreads underground through trees’ root systems. It fruits an edible honey-brown cap just a few weeks each year, typically after the first fall rains. The rest of the year it’s elusive, its presence subterranean.
But what a presence that is: Researchers estimate that the colony here covers 3.7 square miles and may weigh a collective 35,000 tons.
“If you can expand your perception of what a mushroom is,” McWilliams says, “you can see it everywhere.”
Another Forest Service scientist first noticed the widespread die-off of local tree stands in 1988. Greg Whipple linked the problem to armillaria, then worked with others to map samples across hundreds of acres. The teams eventually confirmed that many shared the same DNA.
Whipple, now retired, remembers how his early attempts to limit the damage by clearing out infected areas drew death threats. Timber wars were raging between loggers and environmentalists, upending federal forest management in the Pacific Northwest.
“It was my lesson into politics,” he says.
Decades later, the killer fungus carries on, growing 1 to 3 feet a year. In satellite images of the Malheur National Forest in Eastern Oregon, rusty streaks of dead canopy and the pale, crisscrossed skeletons of downed trees now litter the infestation areas.
Researchers believe part of the colony could date to 6600 B.C. “It’s one of those things that makes you realize mankind is pretty insignificant,” Whipple says. “You realize just how small of a blip we are on the landscape.”
Root disease kills more trees in this region than bugs or beetles, but it moves slowly, picking winners and losers over generations. The fungus remakes the forest as it expands, choking off fir or pine while sparing more tolerant larch. Stunted saplings turn orange as the fungus takes hold. Trees often keel over to reveal roots completely eaten away.
By Chrissy Sexton
Professor Matthew Evans from the University of Hong Kong created a computer model to estimate how ash dieback disease may affect the UK’s 125 million ash trees.
Human-induced changes to the environment are increasing the rate at which pests and diseases are introduced, which is severely threatening to native species. Long-lived species that reproduce slowly, such as forest trees, are particularly susceptible to new pathogens.
It is estimated that in 2015, 100 million hectares of forest were affected by pests and diseases around the globe. However, the subsequent impacts to any given forest ecosystem cannot be detected for years, so experts use computer models to predict future outcomes.
In a recent study, Professor Matthew Evans from the University of Hong Kong created a computer model to estimate how ash dieback (ADB) disease may affect the UK’s 125 million ash trees.
ADB disease, which is caused by a fungus native to East Asia, was introduced to the UK seven years ago. This incurable infection leaves diamond-shaped scars on the bark and causes the leaves to fall off of the trees.
About one in every 100 ash trees is able to resist the fungus and avoid infection. This is likely due to a genetic advantage which allows the trees to shed their leaves earlier to prevent the fungus from establishing itself.
Professor Evans found that at the current level of resistance, 95 percent of the UK’s ash trees could be wiped out by the end of the century. He determined that breeding more ash trees with resistance will prevent millions of deaths.
In 2001, forest pathologists in Oregon discovered what was killing trees in Curry County in southwest Oregon – a devastating disease known as sudden oak death. Almost 20 years later, sudden oak death hasn’t spread beyond the county’s borders.
Although the initial goal was eradication, limiting sudden oak death’s spread proved to be a success, said Everett Hansen, a now-retired Oregon State University professor who helped spearhead the effort to contain the spread of the disease.
“From day one, we invoked legal machinery to mandate the destruction of diseased trees,” Hansen said. “Every time we found a diseased tree we cut it down as fast as we could. We were going full bore. So, we went through all these years without any published data to suggest what we were doing was working.”
In a new study published in the journal Forest Pathology, Hansen and colleagues at the Oregon Department of Forestry and U.S. Forest Service highlight the successes of the two-decade effort to manage and reduce the spread of sudden oak death in Oregon.
In 2001, federal, state and local agencies marshaled their resources to manage the outbreak. They quarantined areas where the trees had been infected and cut down and burned sick trees.
“We focused on local treatments instead of landscapes, sometimes by design but sometimes out of necessity,” said Hansen, lead author on the study. “If it was one tree and we cut it down and all the surrounding trees for a mile we might well have eradicated it. But we never had that chance. We didn’t have enough chainsaws.”
However, the researchers found that these treatments did demonstrably reduce the infestation. They concluded that eradication of sudden oak death is difficult — the pathogen that causes the disease may survive in soil for several years – but not impossible.
By Dean Mosiman
Threatened by infestations, climate change and competing demands for space, Madison’s tree canopy will shrink with “potentially disastrous results” unless the city invests more in its trees, a new report says.
After nearly two years of study, the city’s Urban Forestry Task Force is making a series of recommendations — some with potentially significant price tags — to nurture and dramatically increase the area covered by trees from 23% to 40% of Madison’s 80 square miles.
Already, the city has had to deal with infestation by the emerald ash borer that’s forcing the removal of thousands of trees, as well as disease, climate change, loss of mature trees to development, road salt, and cramped space for planting and growth in the public right of way.
On private property, where most of the trees in the city are located, uneven care is also affecting the urban canopy, the report said.
The task force, created by the City Council on Aug. 1, 2017, has offered a 25-page report and recommendations aimed at elevating the importance of trees in the city’s planning, investments and operations and creating a new city role in expanding the canopy on private property.
“We have a quality urban forest in the city,” parks superintendent Eric Knepp said. “However, there are many opportunities to improve it.”
The 46 recommendations call for a preservation ordinance to protect mature trees; a yet-to-be defined grant program for planting trees on private property; focusing attention on neighborhoods that need trees; written standards for how to care for trees; hiring a forestry outreach and education specialist; revisiting old sites that don’t require much landscaping, such as parking lots at big shopping malls, and bringing them up to current standards; and planting more trees in parks than needed to replace those that are lost.
By Scott Buffon
The U.S. Forest Service in Washington D.C. changed its national policy on the price of selling Forest Service timber in a way they hope will help forestry projects clear cut timber off of its thinning areas.
Across the country, Forest Service officials are now able to sell bundles of logs for a new minimum price that applies to trees regardless of its diameter — 25 cents per CCF. As 5 CCFs can fill a log truck, the new metric means a truck could be carrying a load worth only about $1.25 in areas with low-value lumber. John Crockett, Deputy Director of Forest Management, Range Management and Ecology at the Forest Service in Washington D.C., expects the change will not impact areas where trees are sold at high value, and will only help areas that are struggling to remove unhealthy swaths of trees.
The Four Forest Restoration Initiative (4FRI) works across four national forests and offers timber sales and stewardship contracts to clear unhealthy forests around northern Arizona. The new minimum rate will help 4FRI lower the cost of the wood, in the hopes that a business might be able to save money on the wood and afford the costs of removing it from the site.