By John Tonin
Yukon forests remain healthy according to the 2020 Yukon Forest Health Report, however, there are areas that foresters will be monitoring, said Rob Legare.
The Yukon Forest Health Monitoring Strategy focuses on the 10 forest health agents of greatest concern. The Yukon is divided into five forest health zones.
Each year since 2009, researchers have completed aerial surveys of one of the five zones. But, because of COVID-19, Legare said the aerial study was unable to happen in 2020. Instead, the information provided was an “anecdotal judgement” of what has been known to be occurring.
In 2021 foresters will be back in the air doing aerial monitoring in Zone 3, or the Dawson region.
Aerial surveys will be done in Zone 3 because of spruce budworm. In 2019 and 2020, residents of Mayo reported light defoliation on the tops of spruce trees in the Stewart Crossing area on Ferry Hill.
“When you see it (spruce budworm) in one area, it is very likely that it is in another area,” said Legare.
High budworm populations can result in defoliation ranging from light damage to growing tips to complete tree defoliation, reads the report.
Legare said their forester counterparts in the Northwest Territories have also been reporting budworm on the Yukon side of the border.
“They see it in the Yukon, they are seeing it in the Peel,” said Legare. “We don’t normally fly the Peel Watershed but we are including the Peel so we can start mapping spruce budworm because Northwest Territories’ forest health personnel are seeing it there.”
In the Shallow Bay area, there is “quite a bit of windthrow” said Legare. Windthrow refers to trees uprooted by wind.
“When there is windthrow of conifers that becomes available hosts for bark beetles,” said Legare. “The beetle likes trees that are stressed.
“What the risk is the large amount of windthrow could attract the beetle and populations can build up. We are monitoring those areas right now and doing some removal of host materials.”
Legare said there will be more information on the windthrow situation in the 2021 Forest Health Report.
Perhaps the largest area of concern still remains the territory’s aspen populations.
“The real extent of disturbance in the North is the aspen decline,” said Legare. “People up there have been noticing that the aspen just haven’t looked that healthy.”
Legare said the aspen decline could be attributed to climate change because it’s something that’s occurred in the last 20 years. Climate change can lead to changes in pest distribution, severity and frequency which contributes to aspen decline.
There are two species affecting the aspen decline, the large aspen tortrix and the aspen serpentine leafminer.
Outbreaks of large aspen tortrix have occurred in several places throughout the Yukon including Teslin Lake, Braeburn, Haines Junction, Pelly and Champagne. The tortrix eats the aspen leaves.
The leafminer pest occurs throughout the Yukon range of trembling aspen and also defoliates balsam poplar. The leafminer causes the aspen leaves to turn a milky white.
Although there are some areas of concern, Legare said when the aerial surveys are conducted foresters usually just see rows upon rows of beautiful, healthy trees and rivers.
By Melissa Hale-Spencer
RENSSELAERVILLE — Can a Pacific Northwest silverfly save eastern hemlocks in New York State? The Huyck Preserve in Rensselaerville is leading the way in finding out.
It’s called biological control, and it means putting a natural predator near its prey as a way of managing a pest — in the way that lady bugs killing aphids, or deer mice eat gypsy moths.
The Edmund Niles Huyck Preserve, an accredited land trust with over 2,000 acres and a biological research station, is working with the New York Hemlock Initiative at Cornell University to implement biological control of the hemlock woolly adelgid, a destructive pest of eastern hemlock trees from Asia that was introduced in Virginia in the early 1900s. Since that time, adelgid has killed millions of hemlocks from northern Georgia to Nova Scotia.
The Huyck Preserve is a partner in the Capital Region Partnership for Regional Invasive Species Management, a not-for-profit quasi-governmental agency hosted by the Cornell Cooperative Extension of Saratoga County and funded through the state’s Department of Environmental Conservation via the Environmental Protection Fund.
In 2018, the Huyck Preserve began work on its first invasive-species management and monitoring plan, according to a release from the preserve, and Capital Region PRISM (Partnership for Regional Invasive Species Management) became a significant resource for protecting the lands and waters of the preserve from the harmful effects of invasive species, including forest pests like hemlock woolly adelgid.
The Huyck Preserve undertook its first chemical treatment of woolly adelgid in 2020. But the pest has continued to spread across the nearly 350 acres of hemlocks at the Huyck Preserve. This spring, the New York State Hemlock Initiative released two species of silverflies, Leucopis argenticollis and Leucopis piniperda. These tiny flies are native to the Pacific Northwest of the United States and are specialist predators of the woolly adelgid.
In other words, they feed only on the adelgid and are at very low risk of causing ecological problems. The silverflies feed on adelgid eggs as larvae and are some of their most numerous predators on the western hemlocks of the Pacific Northwest.
This year’s release is part of a long-term study coordinated by the three organizations, and future monitoring will determine the success of establishment of silverfly and control of the adelgid. Only time will tell if the release of a small number of silverflies (compared to the vast infestation of the hemlock wooly adelgid at the preserve) is successful.
By Teri Greene
The study, “Using ICESat-2 to Estimate and Map Forest Aboveground Biomass: A First Example” in the journal Remote Sensing, shows how NASA’s Ice, Cloud and land Elevation Satellite-2, or ICESat-2, can be used to estimate aboveground biomass, or AGB, of forests and map its distribution.
Narine said limited information on the three-dimensional structure of forests has contributed to uncertainties in determining carbon budgets. However, ICESat-2 can capture this information using a laser-based lidar (light detection and ranging) instrument.
Lidar facilitates direct three-dimensional structural measurements, and using this technology from a space-based platform translates to exciting possibilities for assessing forest resources up to global scales, Narine said.
Knowing the capabilities of ICESat-2 allows for a better understanding of the satellite’s capabilities and limitations for characterizing vegetation.
“With ICESat-2 providing elevation measurements globally, a plethora of indicators of ecosystem health and function — including a key surrogate measure of forest AGB — can be potentially estimated to support sustainable management of forests,” Narine said.
The ICESat-2 mission was primarily designed to capture ice measurements, but its capture of data over vegetated areas offers investigators broader insights into ecosystem structure and the potential to contribute to the sustainable management of forest ecosystems.
By Japan News-Yomiuri
Cherry and peach trees across Japan are dying at the hands of invasive beetles, and one expert warns that in the worst-case scenario, there may be no cherry blossoms to view a few decades from now.
The first report of damage by the kubiakatsuya kamikiri (red-necked longhorn beetle) came in 2012 in Aichi Prefecture. Now, 11 prefectures have been hit, with cherry trees dying in parks and schools, as well as peach trees in orchards.
The beetle, native to China and Mongolia, was designated an invasive species in 2018. It may have arrived in Japan in wooden packing materials.
“No matter how many times we get rid of them, they just keep coming back,” said the office manager at Tatebayashi High School in Tatebayashi, Gunma Prefecture, while pointing out a tree that suffered holes in its trunk.
There were once 29 cherry trees fronting the school gate. They were popular among students and residents.
In July 2015, the trees started to die at the hands of the beetle. The school tried to fight off the bug with pesticide and covered tree trunks with protective nets. But swarms of beetles kept returning. By August, the staff was battling the bugs hands on and killed 350.
But since then, seven trees have been chopped down, and six stand dead. The remaining 16 are blooming poorly, and because large branches can suddenly fall off trunks, the school has given up. By the end of next year, all the trees will be gone.
The beetle’s high fertility and mobility make it especially threatening. While a Japanese long-horned beetle lays 100 eggs at most, the red-necked longhorn can lay more than 500 eggs and travel more than a mile by riding the wind.
With no natural enemies, its population abounds, and the fact that it prefers peach and cherry trees only exacerbates the problem. So far, there is no definitive method for eradicating the bug.
In Tatebayashi, the government is paying residents about 50 cents per beetle killed. Last year, citizens killed 6,249 beetles. Yet the number of damaged trees grew.
“If we don’t act now, we may not be able to enjoy cherry blossom viewing 20 to 30 years from now,” said Ryutaro Iwata, a specialist in forest entomology. “The central government must establish a system to forcibly cut down, crush and burn the damaged trees.”
by Seth Truscott
Washington State University scientists seek help from residents of the Pacific Northwest in tracing the worrying die-off of an iconic forest tree, the western redcedar.
A distinctive, useful, and beautiful giant, the western redcedar has historically provided Native American tribes with much of the materials for practical objects and culture. Valued for its natural beauty and soft, red timber, which resists decay and repels insects, redcedars can reach nearly 200 feet in height and live for more than a thousand years.
Western redcedars are found throughout the Northwest due to their tolerance for shade, flooding, and poor soils, thriving where other trees cannot.
Over the last few years, however, scientists have observed an increasing number of dead and dying trees. Mortality begins with dieback, in which the tops and branches die from the tips. Some specimens survive, but the condition can also kill.
Joseph Hulbert, postdoctoral fellow in WSU’s Department of Plant Pathology, founded the Forest Health Watch program to enlist citizen scientists in understanding and preventing dieback.
Researchers believe the problem is spurred by longer, hotter droughts in the region. But it’s unclear if precipitation, temperature, consecutive dry days, or other environmental factors are the main factor.
Launched in 2020, Forest Health Watch seeks answers. Citizens help by logging and photographing sites where trees are healthy, dead or dying back. People can also identify sites and conditions where trees may be vulnerable, and watch for signs of disease or pests.
“Anyone can be a community scientist,” Hulbert said. “All you really need is a camera for this project.”
Hulbert launched the Western Redcedar Dieback Map on the iNaturalist citizen science website to allow citizens to easily log their sightings.
“Once we have a strong understanding of the areas where trees are vulnerable, we can begin to explore options for keeping trees healthy in those areas,” he said.
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.”