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.
Jeff Mulhollem, Pennsylvania State University
Genes in green ash trees that may confer some resistance to attacks by the emerald ash borer express themselves only once the tree detects the invasive beetle’s feeding, according to Penn State researchers.
Knowing this, geneticists may be able to selectively breed trees to strengthen them and perhaps move the resistance response earlier to ward off the beetles’ onslaught, explained John Carlson, professor of molecular genetics.
Green ash, an ecologically and economically valuable tree species native to eastern and central North America, is under severe threat from the rapid invasion of emerald ash borer, a wood-boring beetle native to Asia. Penn State scientists and others are trying to save the species.
Prior observations in a green ash provenance trial—an experiment to see how plants adapt—planted at Penn State in 1978 by Kim Steiner, professor of forest biology and director of The Arboretum at Penn State, and colleagues in the U.S. Forest Service, show that a very small percentage of ash trees survive emerald ash borer infestations, seemingly because their tissues do not nourish and perhaps even sicken the beetles.
“Emerald ash borer probably entered the provenance trial unnoticed around 2008 and trees started showing symptoms of attack by 2012,” Carlson said. “All but eight or nine of the approximately 1,800 trees that Kim planted have subsequently been killed by the beetles.”
Ash trees succumb after adult beetles lay eggs on their bark. When the eggs hatch, the larvae bore into the bark and feed on the transportation tissues of the tree. This disrupts the movement of nutrients and water within the tree, girdling it and causing death.
“To better understand the response of green ash trees to emerald ash borer, we compared gene expression data for resistant versus susceptible green ash genotypes exposed to attack by the beetles,” said Carlson, director of Penn State’s Schatz Center for Tree Molecular Genetics. “By comparing RNA-sequence data from stems attacked by emerald ash borer to multiple tree tissues under other stresses, we could identify differences in the gene expression profiles specific to emerald ash borer resistance.”
By Grace Neumiller, Keller Leet-Otley, and Tommaso Wagner
Brown ash trees, also known as black ash, are critically endangered throughout the state of Maine. The emerald ash borer, a parasitic beetle that has already killed ash trees across the United States, was first detected in Maine last May — several years before it was anticipated. Faced with these ongoing threats, the Wabanaki tribes — Mi’kmaq, Maliseet, Passamaquoddy, and Penobscot — have been leading the defense of brown ash trees in Maine.
Native to wetlands, but often planted in New England towns, brown ash trees play a critical role in basket-weaving practices, particularly to those of the Wabanaki.
Jennifer Neptune, a member of the Penobscot Nation, director of the Maine Indian Basketmakers’ Alliance, and co-curator of an upcoming art exhibition at Colby College, says that brown ash wood is integral to indigenous basket weaving traditions. Not only does the wood possess flexibility and strength, but the brown ash is also considered to be the source of life in Wabanaki creation stories, central to Wabanaki culture. Under threat of local and global extinctions, brown ash tree endangerment jeopardizes the livelihoods of basketmakers and cultural practices of the Wabanaki.
The emerald ash borer is known by entomologists by its acronym: EAB. If you’re an insect aficionado or a tree lover, you likely already know this name. For the rest of you, it’s a name you will know soon enough. It is the cause of arguably the most catastrophic current tree death events in the history of North America.
By Josephine Marcotty
As Minnesota’s ash trees fall to the invasion of emerald ash borer in the next decade, the forest that borders the 72-mile stretch of the Mississippi River in the Twin Cities metro area is expected to lose one-fifth of its canopy.
Turns out that’s not all bad.
Conservation groups that work in the 54,000-acre Mississippi National River and Recreation Area are using that environmental disaster to thwart a much larger one on the way — climate change.
By replacing ash with other kinds of trees, as well as bushes and other plants, they hope to establish a forest that is more likely to thrive in a future of higher average temperatures and much more erratic precipitation.
State and federal entomologists believed the destructive pest would show up near the New Hampshire border, not hundreds of miles to the north.
By Deanna Weniger
The emerald ash borer has proved an elusive foe to conservationists. It hides in the tree tops and its larvae stow away under the bark of the ash tree, making early detection difficult.
Scientists have tried a host of methods — purple sticky boxes, yellow pan traps and bark stripping — in a desperate effort to stop the destruction of the invasive wood boring beetle that has killed tens of millions of ash trees in over 20 states.
While the beetle can hide from humans, it’s not as good at hiding from natural predators, such as the smoky-winged beetle bandit, also known as Cerceris fumipennis.
The University of Minnesota Extension office is looking for volunteers to locate and monitor these harmless wasps that build their nests in sandy soil.