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 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 Rabiu O. Olatinwo, Stephen W. Fraedrich and Albert E. Mayfield III
In recent years, outbreaks of nonnative invasive insects and pathogens have caused significant levels of tree mortality and disturbance in various forest ecosystems throughout the United States. Laurel wilt, caused by the pathogen Raffaelea lauricola (T.C. Harr., Fraedrich and Aghayeva) and the primary vector, the redbay ambrosia beetle (Xyleborus glabratus Eichhoff), is a nonnative pest-disease complex first reported in the southeastern United States in 2002. Since then, it has spread across eleven southeastern states to date, killing hundreds of millions of trees in the plant family Lauraceae. Here, we examine the impacts of laurel wilt on selected vulnerable Lauraceae in the United States and discuss management methods for limiting geographic expansion and reducing impact. Although about 13 species belonging to the Lauraceae are indigenous to the United States, the highly susceptible members of the family to laurel wilt are the large tree species including redbay (Persea borbonia (L.) Spreng) and sassafras (Sassafras albidum (Nutt.) Nees), with a significant economic impact on the commercial production of avocado (Persea americana Mill.), an important species native to Central America grown in the United States. Preventing new introductions and mitigating the impact of previously introduced nonnative species are critically important to decelerate losses of forest habitat, genetic diversity, and overall ecosystem value.
By Michelle Ma
About 450 nonnative, plant-eating insect species live in North American forests. Most of these critters are harmless, but a handful wreak havoc on their new environment, attacking trees and each year causing more than $70 billion in damage.
The problem is, scientists often don’t know which insect will emerge as the next harmful invader.
A team led by the University of Washington, drawing largely on the evolutionary history of insect-plant interactions, has developed a way to understand how nonnative insects might behave in their new environments. The team’s model, described in a paper appearing Oct. 17 in the journal Ecology and Evolution, could help foresters predict which insect invasions will be problematic, and help managers decide where to allocate resources to avoid widespread tree death.
“What makes the bad invaders so special? That has been the million-dollar question, for decades,” said Patrick Tobin, an associate professor in the UW School of Environmental and Forest Sciences and one of the project leaders. “This has the potential to profoundly change how we predict the impact of nonnative species and prioritize limited resources used to mitigate these impacts.”
The new model can quickly evaluate whether a newcomer insect, even before it gets here, has a high probability of killing a population of North American trees. To use the model, all that’s needed is information about the insect’s feeding method (wood, sap or leaf feeder, for example) and what trees it feeds on in its native range. The model will then determine whether any North American trees are at risk of dying from it.
Whether a nonnative insect takes hold and becomes destructive has more to do with the evolutionary history between the new (North American) host tree and the insect’s native host tree from its home region, Mech explained. Molecular tools that allow scientists to construct comprehensive phylogenies (or maps) of how tree species evolved was key to the team’s breakthrough.
For example, if a pine tree in Asia and another in North America diverged tens of millions of years ago, the North American pine likely wouldn’t have retained defenses against an insect that only lives with the pine in Asia. Alternatively, two pines on both continents that share more evolutionary history and diverged more recently might still share similar defenses.
The new model helps identify the evolutionary “perfect storm” for conifers, where the invasive insect still recognizes the new tree as a food source, but the tree hasn’t retained adequate defenses to keep the invader in check.
By Mary Frost
“Today is a great day for our urban forest.”
The insect that threatened to wipe out tens of thousands of the city’s trees has been squashed.
State, city and federal agencies announced on Thursday that the Asian longhorned beetle has finally been eradicated in Brooklyn and Queens, the last two holdouts in the city.
At a celebration in McCarren Park in Williamsburg, cupcakes decorated with pictures of the distinctive black insect were served to jubilant parkgoers and agriculture and horticulture experts.
“Today is a great day for our urban forest as we announce the eradication of the Asian longhorned beetle,” announced Liam Kavanagh, first deputy commissioner of the city’s Parks Department. “It was a bleak day for forestry in New York City when this pest was discovered. Half of the hardwood trees in New York State are susceptible.”
The successful eradication was the result of a decadeslong collaborative effort by multiple city, state and federal agencies, non-governmental organizations and private landowners, officials said.
These include the U.S. Department of Agriculture’s Animal and Plant Health Inspection Service, the state’s Department of Agriculture and Markets and Department of Environmental Conservation, and the city’s Department of Parks.
“It’s been a long, hard road,” USDA’s Samantha Simon said. “We knew that if it became established, the Asian longhorned beetle would threaten billions of dollars’ worth of timber [and] the maple syrup industry.”
The insect attacks maple, elm, willow, horse-chestnut, mulberry, birch, green ash, sycamore and London planetrees.
It’s been 23 years since the invasive beetle (technically not a bug) was first detected in Brooklyn. Experts believe it entered the country on wooden pallets shipped to Greenpoint.
The USDA calculated the speckled insect, about the size of a waterbug with antennae as long as its body, has wiped out more than 24,000 New York trees, and 180,000 nationwide. Thursday’s announcement marks the end of a six-year quarantine in northern Brooklyn and Queens.
To eliminate the beetle, APHIS regulated the movement of trees, firewood and woody debris and carried out surveys to find and remove infested trees. In total, APHIS removed 5,208 infested trees and treated 67,609 at-risk trees.
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 Bruce Scruton
MIDDLE SMITHFIELD, Pa. — Three species of a small wasp that can attack the eggs of the emerald ash borer were released by National Park Service biologists within the Delaware Water Gap National Recreation Area this past weekend.
The borer, an invasive beetle from Asia, is capable of killing a full-grown ash tree within a couple of years and has been found in several locations in Sussex County in the past two years.
The release was in the Mosier’s Knob area, just below the Walpack Bend of the Delaware River and across the river from Worthington State Forest where the New Jersey Department of Agriculture recently released its own biological agents to stem the invasion of the pest.
Kara Deutsch, chief of resource management for the park, said the emerald ash borer has been found on both sides of the river. The choice of Mosier’s Knob for the release came at the recommendation of regional NPS experts.
The wasps, known in scientific circles as “parasitoids,” were supplied by the United States Department of Agriculture’s Animal and Plant Health Inspection Service (APHIS) and came from the Plant Protection and Quarantine (PPQ) EAB Parasitoid Rearing Facility in Brighton, Mich.
There were three species of wasps released — one release was of adults and the others were pupae of separate species.
The three are themselves invasives, native to the Asian areas where the emerald ash borer are native. The borer was imported to this area first identified in the area around Detroit and believed to have arrived in 2002 inside of wooden packing material.
In less than two decades since, the borer, a type of beetle, has been found in the U.S. from the Atlantic Coast (except Forida) as far west as Colorado and has spread throughout the eastern two-thirds of Canada.
The wasp parasites — the adults are about the size of a mosquito and don’t sting — get the borer in both egg and larval states.
The adult Oobius agrili female will lay her own egg inside the egg of an ash borer and there are two life cycles of the wasp for one life cycle of the borer. In experiments and observation, more than half an emerald ash borer’s eggs became victims of the wasp.
The other two wasps attack the larval stage of the borer and it is that stage that causes the damage to ash trees.
By Michael MacDonald
HALIFAX — An invasive insect from Asia is expected to kill almost every ash tree in Canada, but Donnie McPhee has a plan to preserve the species.
Co-ordinator for the National Tree Seed Centre in Fredericton, McPhee is asking Canadians to help him find mature stands where seeds can be gathered and later stored for future generations in the centre’s deep-freeze vaults.
“We’re looking to protect the genetic diversity of the species,” McPhee said in an interview. “We’re looking for natural stands of trees that are in seed …. We want Canadians to be our eyes — to let us know they’re out there.”
And the time is right to start the search because the white ash and black ash — two of the most common species — are expected to produce a bumper crop of seeds this fall. The centre’s website provides details on what to look for, but seed collecting should be left to experts.
“We’ve already had people showing up with big bags of ash seed … but it’s too early in the season,” McPhee said.
Larvae of the emerald ash borer, a small beetle with an iridescent green hue, have already killed millions of trees in Canada and the United States, and the pest’s population is still growing.
The larvae make tunnels underneath the tree’s bark, cutting off nutrient flow to the canopy, which eventually kills the tree.
“The reports I’ve seen suggest that within 50 years, there might not be any ash trees anywhere in the country,” McPhee said.
McPhee’s long-term plan is to have the centre retrieve the collected ash seeds from cold storage in about 40 or 50 years, when the ash borer population has dwindled and safe planting can begin.
“The population of the insect will drop way down because the food supply isn’t there,” he said. “At that time, we want to go in and put the genetic diversity of the population back to where it came from.”