Insect threatens Fairfield’s ash trees
Fairfield will implement an Urban Tree Plan perhaps with more urgency than previously anticipated, because of the local presence of the emerald ash borer discovered at the beginning of August.
Fairfield City Council’s Environmental & Franchise Utilities Committee met Tuesday with two state representatives who traveled from Des Moines to talk with city representatives.
Emma Hanigan, Department of Natural Resources state urban forestry coordinator and Robin Pruisner, an Iowa Department of Agriculture state entomologist, along with Ray Lehn, DNR district forester and Emily Swihart from Trees Forever, impressed upon the committee the serious threat the emerald ash borer is to the community and county.
“If it spreads, it could take out every ash tree. We could see a total loss of all species of ash trees in three to five years,” said Michael Halley, committee and city council member.
“The emerald ash borer threat is serious; it’s as serious as Dutch elm disease was last century. We’re looking at a changed landscape in our future.”
Halley does not want to sound as an alarmist, but the state representatives told committee members it is up to each community to educate the public.
According to a press release issued by the Iowa Department of Agriculture in August, “EAB kills all ash species and is considered to be one of the most destructive tree pests ever seen in North America.”
The emerald ash borer doesn’t move very fast.
“Most of our ash trees do not have symptoms of disease yet,” said Halley. “The easiest way to spread the disease is to transport infected ash wood.”
Even though an official quarantine is not yet in place, Halley recommended not taking ash tree limbs to the city yard waste site because it is not a secure area and someone else may unknowingly pick it up for use as firewood and transport it out of the area.
“We haven’t placed any restrictions yet,” said Pruisner today. “We are working on a regionalized concept for a quarantine [Des Moines County identified a presence of emerald ash borer in July]. A multi-county quarantine on the movement of ash wood as firewood, limbs, mulch, etc., will allow movement of wood within the quarantined region.”
The purpose of such quarantine is to contain high-risk material, such as infected ash wood, to slow the spread of the disease, she said.
“The state is working with wood mills to educate the mill workers, and we’ll be educating our community,” said Halley.
The state doesn’t manage every individual who moves firewood, so the city and county will need to educate citizens on what to do with infested ash wood.
As long as ash wood is ground smaller than one inch in all dimensions the chips are safe to use for mulch, and larger pieces are suitable for firewood only within the quarantined area.
“Pam Craff, director of city parks, estimates 70 percent of the trees in both Central Park and O.B. Nelson Park are ash,” said Halley.
Public Works Superintendent Darrel Bisgard estimates that 20 to 30 percent of the trees in the city right of way are ash as well.
It’s possible that up to 25 percent of all trees within Fairfield city limits are ash and are all at risk, Bisgard said.
Chemical treatments exist that can protect healthy trees, but they are expensive and must be continually administered for years, said Halley. The chemicals can pose health risks to surrounding areas.
“For those reasons, the city will most likely not pursue treatment and not encourage citizens to do so either,” said Halley.
Hanigan suggested the city conduct an inventory and health assessment of each tree belonging to the city.
Fairfield Sustainability Coordinator Scott Timm will research funding options and/or partnerships with Iowa State University Extension to complete an inventory soon.
Swihart will help the city secure grants to replant trees.
Mayor Ed Malloy will appoint members to a Tree Advisory Committee at the next city council meeting. The committee will help guide the city’s tree policy, including updating the list of appropriate trees to plant in the right of way and educating citizens about the emerald ash borer quarantine.
The Tree Advisory Committee also will work with local nurseries to ensure nurseries keep a variety of tree species in stock of various sizes for ongoing communitywide tree planting.
A Fairfield Tree Ordinance can include a preservation clause designed to protect healthy, mature trees from being removed from private property.
Current city policy to replace all trees cut down from the city’s right of way with two new trees can be formalized in the ordinance.
Public Works crews can receive periodic training in tree care and pruning.
“The Environmental & Franchise Utilities Committee will continue to work with state agencies, local tree specialists and city employees to develop a viable urban tree plan, including an updated tree ordinance and advisory committee,” said Halley.
“Our concern about our trees also includes the oak wilt which caused 50 oak trees being removed from Chautauqua Park and the stress of extreme weather,” said Halley. “The city will create an Urban Tree Plan, which will include an updated Tree Ordinance, formation of an Arbor Commission by the mayor, and ongoing replanting efforts in the years to come to assure that Fairfield continues to offer a rich and diverse tree population for future generations.”
Iowa State University Extension and Outreach has information online at www.extension.iastate.edu for identifying ash trees diseased by the beetle, a list of chemical treatments and protocol and contacts to call or email with questions.
The website includes this information:
“Although the adult stage causes minor feeding damage to ash foliage, the larval stage feeds beneath the bark and disrupts water and nutrient flow within the tree, which leads to tree death. Larvae are actively feeding from early summer through fall.”
And from a 2012 study published by the University of Minnesota, available online at emeraldashborer.info, symptoms of emerald ash borer infestation include: Thinning of tree’s foliage or crown dieback; possible epicormic (new growth of small limbs in bark) sprouting on declining trees; damage from woodpeckers as small patches of bark are stripped away when the birds search for EAB; D-shaped emergence holes, approximately 3 millimeters in diameter; larval galleries, typically S-shaped, meandering and packed with EAB frass (debris or excrement produced by insects.).