How to Identify Ash Trees and Detect Emerald Ash Borer Infestation
Introduction
Our Ash trees in Manchester are under attack from a destructive pest called the Emerald Ash Borer (EAB), a metallic green beetle native to Asia that was accidentally introduced to North America in the 1990s and first appeared in Massachusetts in 2012. EAB larvae feed on the inner bark of ash trees, disrupting the flow of water and nutrients and eventually killing the tree. EAB has killed millions of ash trees across the United States and Canada, and poses a serious risk to the health and diversity of our forests and communities. Many of Manchester's Ash trees have already died or are dying, but we are fighting back!
In this blog post, we will show you how to identify ash trees and how to recognize the signs of EAB infestation. By learning how to spot these trees and pests, you can help protect them from further damage or request the Manchester DPW to remove any public street trees that have already died or are dying. Finally, you will learn that the Friends of Manchester Trees is treating a number of public Ash trees that have been deemed healthy enough for preservation.
How to Identify Ash Trees
Ash trees belong to the genus Fraxinus, which includes about 65 species worldwide. In North America, there are 16 native species of ash, and they are mostly found in the eastern and central regions. Ash trees are deciduous, meaning they lose their leaves in the fall, and they typically grow to 50-80 feet tall. They have opposite branching, meaning the branches and buds are directly across from each other on the stem. This is a distinctive feature that can help you narrow down your search, as only a few other trees have opposite branching, such as maple, dogwood, and buckeye.
Notice in the photograph above that the branches are noticeably directly across from one another.
The leaves of ash trees are compound, meaning they are composed of several leaflets attached to a central stalk. The number of leaflets varies by species, but most ash trees have 5-11 leaflets per leaf. The leaflets are usually lance-shaped, with serrated edges and pointed tips. The leaflets are also slightly offset from each other, creating a feather-like appearance. The leaves are green in the summer and turn yellow, purple, or red in the fall, depending on the species and environmental conditions.
Ashes have compound, lance-shaped leaves.
The bark of ash trees also varies by species, but it is generally gray or brown, with furrows and ridges that form a diamond-shaped pattern. The bark becomes more rough and corky as the tree ages. The twigs of ash trees are smooth or slightly hairy, and often have a white or grayish color. The buds are usually black or brown, and shaped like a cone or a dome. The flowers of ash trees are small and inconspicuous, and they appear in clusters in the spring before the leaves emerge. The fruits of ash trees are winged seeds, called samaras, that hang in bunches and are dispersed by the wind. The seeds are flat and oval, with a long, narrow wing that extends from the tip.
How to Detect Emerald Ash Borer Infestation
Emerald Ash Borer (EAB) is a small, metallic green beetle that measures about half an inch long and one-eighth of an inch wide. The adult beetles emerge from the bark of ash trees in late spring or early summer, and feed on the leaves for a few weeks. They then mate and lay eggs on the bark, usually in crevices or cracks. The eggs hatch into larvae, which bore into the bark and create winding tunnels under the surface. The larvae feed on the inner bark for one or two years, cutting off the flow of water and nutrients to the tree. The larvae then pupate and transform into adult beetles, which chew their way out of the bark and leave D-shaped exit holes. The cycle then repeats, and the infestation spreads to other trees.
EAB infestation can be hard to detect in the early stages, as the symptoms may not be visible or noticeable. However, as the infestation progresses, the tree will show signs of decline and stress, such as:
·        Thinning or dying of the crown, starting from the top and moving downward
·        Yellowing, wilting, or browning of the leaves
·        Increased woodpecker activity, as they feed on the larvae under the bark
·        Formation of epicormic shoots, or sprouts, along the trunk or branches
·        D-shaped exit holes on the bark, about one-eighth of an inch in diameter
·       Â
Dying Ash tree on Pleasant Street. Notice that the entire crown is leafless, even though the lower branches are still producing leaves. This tree is dying and will be marked for removal.
If you suspect that your ash tree is infested by EAB, you should do the following:
If it's a public tree  (within 11 feet of a public road), you should request that the DPW remove the tree. Link to Tree Removal Form: https://www.manchester.ma.us/226/Trees. The Manchester Tree Warden, Tom Henderson, will assess the tree to see if it needs to be removed or if it can be treated for EAB.
If it is not a public tree, you should contact your local arborist for confirmation and advice. Depending on the extent of the damage and the location of the tree, there may be treatment options. However, many infested trees may be too far gone to save, and may pose a hazard to people and property. I
Manchester's EAB Treatment Program
Ash trees are an important and beautiful part of our natural and urban landscapes,and we would like to save as many as we can. This year, Friends of Manchester Trees has partnered with the Manchester DPW to treat Ashes that are healthy enough to be preserved. By learning how to identify Ash trees and how to detect EAB infestation, you can help protect these trees and report any problems to the DPW. You can also join (if you not already a member) Friends of Manchester Trees, to support our efforts to plant, care for, and advocate for trees in our city. Together, we can make a difference for our environment and our community.
The graceful, beautiful canopy of a healthy public Ash tree on Old Neck Road. This tree is being treated for EAB, under the new FOMT/DPW program.
The EAB treatment consists of injecting the tree with a systemic insecticide that kills EAB larvae and adults and protects the tree for up to two years. The treatment is safe for people, pets, and wildlife, and does not harm other insects or plants. The program will also monitor the treated trees and evaluate their response to the treatment.
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