The City of Newport recognizes the value of trees within the community (described at right). As such, Newport’s goal is to, at minimum, maintain the existing tree canopy cover (amount of city covered by trees when viewed from above) at the current 33%, while working to improve the quality and health of the current canopy as well as equalize the tree canopy cover between neighborhoods - all while maintaining public safety.
The City has taken a number of steps to work toward the tree canopy goals described above:
Though a proactive care program can take time to implement properly, the city is taking steps to transition into proactive care. Each year a small section of the public trees will be re-assessed and re-inventoried, and appropriate proactive care performed later that year.
This is considered the best practices for care of public trees, and will both reduce risk and in the long term will increase canopy and save the city money.
Multi-Year Phased Removals of Infested, Dying Ash Trees.
As of 2017, the City of Newport manages around 120 ash trees on public land (mostly along streets), many of which are in severe decline from the Emerald ash borer (EAB). The time has come to start to remove these infested trees to maintain public safety.
For budget reasons and to avoid dramatic losses of canopy, the City will not remove all the dying ash at once. It will instead be done in phases over the next few years. The largest concentration of these trees is in the East Row neighborhood, mostly along Washington Avenue (a reminder of why it is a poor practice to plant only one species along street segments).
In 2018, the 35+ ash trees in the worst condition or causing the highest risk to public safety were removed.
All remaining ash will be re-evaluated in spring 2019 for the next round of removals.
Thankfully we have a number of trees that are not showing signs of any infestation, as well as some trees that are being treated by the adjacent property owner on an ongoing basis. Please note that no healthy ash trees will be removed.
Figure 1: Location of all ash trees in Newport under public management as of 2017.
Figure 2: 2018 Removals. Map of all publicly-managed trees in Newport (green), with ash trees removed in 2018 (in orange).
1. Why isn’t the City treating any ash trees? There indeed are treatments available for management of ash trees, though treatment must be applied every two years in perpetuity. Because of this need for ongoing applications, treatment is often expensive. Additionally, once an ash is showing signs of infestation, the treatments then only prolong the life of the tree by a few years and removal is eventually required regardless.
Cost of treatment is based on the inch of trunk diameter. Newport currently has a combined total of approximately 1,200 inches of ash trunk diameter. This would equate to over $15,000 in treatment expenses every two years. This would use up a significant percent of the annual budget allocated to tree care in Newport.
Many municipalities have chosen the removal and replacement as the best long-term management option. The City of Cincinnati opted for this management approach and has removed most of its ash trees since damage started within the last decade. You can read more about their approach here. The City of Indianapolis is also not treating street trees for EAB and are in the process of removing dying ash now. Read more about Indianapolis approach here.
However, Newport’s approach is not to remove all ash trees in entirety – only those showing damage and causing a safety issue. There are approximately 10 ash that are showing no damage and thus are not slated for removal. Trees will be assessed annually on need for removal.
2. Stumps left don’t show any decay – were they really unhealthy?
Ash trees suffering from EAB infestation die back starting from the top. Here’s how the pest damages the tree:
Adult beetles lay eggs on the bark of ash trees. When the eggs hatch, the larvae bore into the bark and feed on the tissues on the outer most section of the trees – this is the tissue that transports water and sugars up and down the tree. The damage the larvae causes disrupts the movement of nutrients and water within the tree, girdling it and causing tree death.
Therefore, damage will not be evident in the stumps left behind. It is seen in the outer most rings of the tree, as shown in Figure 4 at right.
3. They don’t look sick to me - why are they being removed? As explained above, EAB-infected ash trees die by drying out because the tissue that carry moisture and nutrients to the branches is destroyed. For this reason, the dead limbs that first appear become brittle much earlier than the point the entire tree fully dies off (Figure 5 below). Because this dead wood is very brittle, a decaying ash along a street should not be left standing, as it becomes a safety hazard. Limbs can break, endangering people and causing property damage. Additionally, removal costs rise the more removal is delayed. The larger percentage of dead tree the risker it becomes, and riskier trees are more expensive to remove. Additionally, the national standard of tree risk assessment involves not just assessing the probability of failure (limbs falling, etc.) but the likelihood of damage caused from that failure. For this reason, busy streets with dying ash are a higher risk than others that have less traffic.
Figure 5: EAB damage starts from the top of the tree.
4. Does the city have plans to replant? In any given year, the city has funds to remove 10-15 trees on average. As there are over 100 that need to be removed in the coming years (knowing we will not remove healthy ash) there are no additional funds for replanting at this time. The City will, however, continue to fully support community planting events and can revisit planting efforts after this ash management priority work is complete.
We will continue to remove ash that are dying as it is required in order to maintain public safety in the coming years.
In cities across the country, there are many residents who lament the presence of urban trees, citing a number of problems. The most common of which are that they are messy, damage sidewalks and are sources of potential property damage from falling limbs or total tree failure. However, thanks to new technology and modeling tools, trees have now been proven as valuable city infrastructure and critical to vibrant communities because of the benefits they provide, with benefits shown to outweigh the maintenance related work associated with trees.
Urban trees have proven to be an effective tool across multiple city management areas, including planning, economic development, public health, and sanitation. They have been proven to alleviate water and air pollution, improve public health, increase property value, and enhance the success of business districts.
On an annual basis, cities often see a strong return on investment related to tree costs and benefits. A recent five-city study found that cities accrued benefits ranging from $1.50–$3.00 for every dollar invested in trees (U.S. Environmental Protection Agency 2015).
Unlike man-made systems, trees are the only urban infrastructure that actually increase services and value over time. As trees mature, benefits increase exponentially, unlike more traditional city infrastructure such as roads and bridges that deteriorate with age.
The emerald ash borer (EAB) is a pest from Asia that has been killing ash trees in the US since it was found in 2002 near Detroit, MI. By 2009 it had migrated to our area (largely through sale of infested firewood). See the Figure 6 for the latest infestation map. Once infected, an ash tree can die within just 4-5 years, and often become extremely brittle and lose limbs well before death. Though treatment options do exist, they are expensive and must be reapplied regularly. To learn more about the emerald ash borer, visit: UK College of Agriculture.