Trees

Urban Forestry facilitated two tree giveaway events in 2022 to residents in the City. Both the spring event (Trees for Canopy Conservation) and the fall event (Environmental and Climate Action Expo or EnviroX) were a success, providing residents with a variety of native potted trees.

Stay tuned for future tree giveaway events as we support residents to enhance our urban canopy. Events are announced through media releases and shared on the City's social media channels and on our website.

Forty fruit trees were planted in five City parks in the spring of 2022 in partnership with GreenUP and Nourish. A team of volunteers formed the Ptbo Community Orchard Stewards and assisted with planting the trees. This stewardship group has committed to maintaining the trees into the future in order to have fruit available and accessible for all.

In 2021, we initiated large-scale volunteer tree planting in the City of Peterborough. Sites were selected that could support planting hundreds of trees in order to enhance and reforest select areas.

Over 1,100 native trees have been planted as of the end of 2022, with Urban Forestry eager to develop more similar projects.

• If a City-owned tree is removed from your property, it will be replaced with a new tree on the same property.
• The Urban Forestry team will determine the best species and location for the replacement tree.
• There is no charge to the property owner for new or replacement trees as they are provided by the City and planted on City property.
• Property owners may request a tree for their residence but may not do so for a property they do not own.
• The City maintains the trees throughout their lives. Homeowners are encouraged to help newly planted trees establish by filling the provided watering bag during the growing season.
• Trees will be approximately 8–10 feet tall when planted.
• One tree will be provided per 30 feet of frontage. Additional trees may be provided on the side of a corner lot.

Urban Forestry staff will look at each request and determine the preferred planting location, any preparation needed, and the best tree species to suit the site.

When a tree is scheduled for planting, an information card will be left for the homeowner with the planting details and tips on how to help care for the tree.

Species and location requests will be considered but cannot be guaranteed.

The Urban Forestry team selects the ideal species of tree for each site as there are many factors that need consideration. Success of an Urban Forest depends on planting the right species in the right place, and planning for the future. The selection process includes planning for:

• Overhead and underground utility conflicts
• Tree species diversity City-wide
• Growing space for the canopy and roots
• Soil type and quality
• Safety requirements and potential future conflicts

Species and location requests will be considered but cannot be guaranteed.

Caring for new trees

Spongy moth is a non-native invasive insect. Spongy moth defoliates trees and over time can cause those trees to die. Caterpillars chew holes in the leaves, and if there are high population levels of LDD moth they can strip tree canopies. The caterpillars of LDD moth selectively attack oak trees, among others, which happen to be especially sensitive to the risks of defoliation. The caterpillars are 5-6 cm long with five pairs of blue dots and six pairs of bright red dots along their back. The female moths are white with dark markings. There are four life stages of development: Egg, caterpillar, pupa and moth.

What can you do?

• Report egg masses to Urban Forestry staff.
• Scrape egg masses off trees where possible and destroy the masses.
• In summer months you can trap caterpillars by wrapping a piece of burlap or cloth around the tree's trunk at chest height, and tying twine or rope around the middle of the burlap. This will provide a place for caterpillars to hide during the heat of the day. Check these bands regularly and scrape caterpillars into a container of soapy water to destroy them.
• Keep your trees healthy and better able to ward off attacks. In urban areas, water trees during dry spells and protect their root zones.

Images courtesy of the Invasive Species Centre of Canada.

The hemlock woolly adelgid (HWA) is a destructive pest that selectively attacks eastern hemlock trees. HWA feeds on plant fluids at the base of the needles and can cause tree mortality in as few as four years.

This pest has not yet been detected in Peterborough, but early detection of HWA is critical for protecting our forests.

Learn more about Hemlock Woolly Adelgid on the Invasive Species Centre web page.

Oak wilt was first detected in Niagara Falls, Ontario in May of 2023. It is a vascular disease, restricting the flow of nutrients and water within the tree. It is caused by a non-native fungus Bretziella fagacearum. Oak wilt affects all species of oak (Quercus sp.), however the red oak family (e.g., northern red oak, black oak, and pin oak) seem to be more susceptible to the disease. Once the tree is infected it often dies within a single season. The white oak family (e.g., bur oak, swamp white oak, and white oak) can also be infected with the disease but appear to have the ability to compartmentalize areas of infection, allowing trees to live longer though there is still a chance of mortality.

What does an infection look like?

Signs and symptoms can vary between the different oak species; however, the following is typically observed:

• Discolouration in the foliage (a bronze or brown colour) starting at the leaf margin and moving toward the midrib. This starts at the top of the tree and moves down
• Wilting and premature leaf fall (during the spring and summer months)
• Fungal mats (grey, black, or white in colour) form beneath the bark and cause outward pressure leading to vertical cracks in large branches and on the trunk of the tree

How does Oak wilt spread?

Oak wilt has several methods of spreading. Sap feeding beetles (family Nitidulidae) are attracted to the sap that secretes from the fungal mats beneath the bark. The fungal spores stick to the body of the beetle which then allows the disease to spread from tree to tree as the beetle enters openings or wounds. Movement of infected firewood or nursery stock can also spread the disease. Root to root contact between infected and healthy trees allows the fungus to spread below ground.

Prevention

The City of Peterborough has over 1000 oaks of various species. The protection of oak trees is vital as they provide many ecological benefits in both the urban forest and natural areas. A decline in oak species could lead to a loss of food and habitat for wildlife as well as impacting social, economical, and cultural values. The following may be done to help slow the spread of Oak wilt.

• Learn the signs and symptoms of Oak wilt
• Do not move firewood or plant materials that may be infected
• Pruning of trees is not recommended between the months of April and October. If pruning is necessary during this time, a pruning paint or latex based house paint can be applied over the wound to protect against infection entry. Storm damage should be addressed in this manner as well
• For those that own private property, observe oak trees closely for any changes and consult with a certified arborist if needed
• Reported sightings of suspected Oak Wilt should be given to the Canadian Food Inspection Agency or the Invasive Species Centre

Resources

For more information, please visit the Invasive Species Centre web page and the Canadian Food Inspection Agency web page. 

Information and photos for this article were sourced from Invasive Species Centre Canada.

Tar spot is a common fungal disease found on the leaves of maple trees, especially Norway maple. It is rarely harmful enough to affect the health of the tree. Heavy infections can cause early leaf drop. The best way to help control the fungus is to rake and destroy leaves in the fall.

Hackberry gall is caused by adult psyllids (tiny sap-sucking insects) laying eggs on emerging leaves of hackberry trees. After the egg hatches, the young psyllid feeds on the leaf, and the leaf responds by growing an abnormal small pocket that surrounds the insect, this forms a "gall" on the underside of leaves. It is very common, and the tree's health is not impacted by the gall.

The eastern tent caterpillar is a leaf defoliator that creates silk-like tents in the branches of trees. It is sometimes confused with the LLD moth due to its similar appearance. The caterpillar commonly attacks fruit trees, but may also defoliate other hardwood trees, including ash, birch, hawthorn, maple, oak, poplar and willow. Eastern tent caterpillar is more of a nuisance than detriment to tree vigour. Feeding does not seriously damage healthy, mature trees; the damage is primarily cosmetic, with trees appearing ragged or unsightly. Even if completely defoliated, most trees will leaf out again within two or three weeks, since caterpillar feeding generally ends during vigorous leafing activity.