Street Trees and Tree Care

Newly planted trees along Lakeview Park

Street trees are an important part of the City's streetscape. Trees add value to your property and provide beneficial services to us like reducing runoff and improving air quality. They also benefit our mental health and can even reduce stress and anxiety.

Tree Ownership

Oshawa Forestry services plant and maintain City trees on boulevards, parks and green spaces.

To determine if a tree is located on your property or on City property, review the property lines on your home survey. Generally, City trees are planted within two metres of the curb or within one and a half metres from the sidewalk on the boulevard side.

Private trees

If you have an issue with a tree within your property lines, please contact a qualified tree service company.

Forestry requests

Tree pruning

Proper care of our street trees helps maintain the tree's structure, maintain good visibility and prevent conflicts with the built environment. Street tree maintenance is completed on a 10-year cycle or by request.
Request tree pruning

Tree removal

All trees are inspected and assessed by a certified Arborist before a decision is made to remove them. We remove trees affected by pests and disease, or ones which pose a safety risk to residents.

Create a service request

Tree planting

We are committed to growing our tree canopy. You can request a new tree for your boulevard and Forestry staff will inspect and determine if it is possible. All trees removed on City property go on the stumping and planting list to be replaced.

Tree Planting page

Stump removal

When we remove a tree, it will be cut low to the ground and placed on our stump and replace list. Occasionally, a ‘peg' will be left standing to be removed at a later date with other Forestry equipment.

During the stump removal process, the stump will be grinded out and the area left with dirt and wood fibre present on the affected area. This will be left until the tree is planted and the affected area is restored with fresh soil and grass seed.

Pest management and tree disease

We actively monitor and assess our tree canopy health but we do not spray for any pests or diseases.

Emerald ash borer (E.A.B.)

Is an invasive beetle that feeds on all ash (Fraxinus) species in Ontario, including green, red, white, black and blue ash, as well as some non-native species such as European black ash (Fraxinus excelsior). Mountain ash is not a true ash tree and is not effected by the beetle.

The metallic green beetle emerges in early summer and will grow to be 8.5 to 13.5 mm long with a flattened head, large black compound eyes on the sides of the head, and short antennae. They lay 60 to 90 eggs one at a time in bark crevices on ash trees. Once the eggs hatch and become larvae, they tunnel under the bark to feed. These tunnels stop the flow of water and nutrients causing, the ash tree to die.

Identifying an ash tree

Bark is tight, rough and often has a distinct diamond pattern
The leaves are compound and contain five to eleven finely toothed leaflets
The seeds of the leaf are oar shaped and hang down in clusters

Signs of infection

Signs of E.A.B. usually only become clear once a tree is heavily infested. However, the following are signs and symptoms your ash tree may be infested with the E.A.B.:

leaves in the top third of the ash tree lose their green colour, thin and die back
galleries girdle the ash trees and foliage will wilt or turn yellow
branches begin to grow from the low trunk or roots
shallow meandering “S” shaped tunnels under the bark with abrupt turns and “frass” (refuse left behind by boring insects) or sawdust will be evident in tunnels
the bark begins to split
there are small “D” shaped exit holes 4 to 5 mm across on the bark of infected trees
increased woodpecker activity on the tree resulting in large holes

Lakeview Park and E.A.B.

Lakeview park has over 300 ash trees that are treated for E.A.B. every year by City staff
The City uses a systemic insecticide called TreeAzin to treat Lakeview Park. It is approved by Health Canada's Pest Management Regulatory Agency. Trees showing signs of 30% or more dieback of their branches will not be treated
Understory tree planting continues in the park to help offset canopy loss and create a more sustainable park canopy for the future

Woodlots and green-spaces

While natural regeneration will account for most of the regrowth in our woodlands, portions of select sites have been identified for enhanced and/or intensive regeneration and replanting.

City trails and rural road right of way areas will be planted with small container stock trees starting this Fall, 2024 as part of restoration planting and canopy enhancement.

Replanting trees can provide:

Benefits to our health, the environment and the economy
Improved air quality and provides habitat for wildlife
Reduced heating and cooling costs of a home
Increased property value

Private Property

Please remember that private property owners are responsible for trees on their property. If you suspect your Ash tree may have E.A.B., you are encouraged to consult a professional arborist as soon as possible. You should choose an arborist certified with the International Society of Arboriculture or registered with the American Society of Consulting Arborists. Doing nothing may put you and your property at risk.

We encourage residents to also become stewards of our urban forest, which provides many environmental and ecological benefits and encourage all to consider planting more trees on their private property, where suitability exists.

Additional E.A.B. resources

Japanese Beetle

Japanese Beetles are Leaf Skeletonizers, which eat the soft outer tissues of foliage while leaving behind a skeletal network of veins. When a tree is skeletonized, it does not mean it has died. A tree will often respond by producing new leaves by the end of the season. Japanese beetle is not a serious tree health concern unless infestations occur repeatedly and severely on the same tree.

The City will not put out traps for this insect. Although the pheromone and floral lures sold with the traps are very effective and attract many beetles each day, the traps attract more beetles than are caught. This results in other species of trees or plants being at risk of suffering damage from this insect.

Lymantria Dispar Dispar (L.D.D.) moth

Identifying L.D.D. moth

Overwinters in the egg stage, often on the bark of trees.
Eggs hatch in the spring, and larvae ascend the trees to feed on the new foliage.
Feeding occurs during the day, but as the caterpillars mature, feeding occurs mainly at night.
Mature caterpillars are 50 mm long, dark coloured, hairy, with a double row of five pairs of blue spots, followed by a double row of six pairs of red spots.
Feeding finishes by August.
Male moths are light brown and slender-bodied, while females are white and heavy-bodied.

Life Cycle

The L.D.D. moth has four distinct developmental stages in its life cycle similar to other moths and butterflies:

1. Egg (Late August to early May)

L.D.D. moth egg mass

2. Caterpillar (Early May to mid-July)

L.D.D. caterpillar

3. Pupae or Cocoon (Mid-July to early August)

L.D.D. cocoon

4. Moth (Late July to late August)

L.D.D. Gypsy Moth

Infestation

L.D.D. moth outbreaks can occur every seven to ten years.

Caterpillars chew holes or devour entire leaves.
In late July, you can find spongy egg masses on the trunks and branches of infected trees.
During severe outbreaks, trees and shrubs are defoliated over large areas. Despite the trees' ability to produce a new crop of leaves in the same season, the damage can be harmful to the tree and makes it more susceptible to secondary pests, drought, or poor growing conditions.

Management tips

Visit the Government of Ontario website for best practices and management strategies when dealing with L.D.D. both in your community and on private property.

Frequently asked questions

Will the City spray for L.D.D.?

No. The City of Oshawa does not currently spray for L.D.D. The City's Integrated Pest Management (IPM) Plan focuses on other strategies for management of pests and diseases that do not involve the use of pesticides.

What do I do if I see L.D.D.?

You can report sightings or infestations to Service Oshawa, or:
- EDDMapS Ontario, 1-800-563-7711
- Canada-wide: Invasive Species Centre

How can I help reduce the L.D.D. population?

CAUTION: Please ensure you are wearing proper hand protection when dealing with L.D.D. as contact is known to cause skin irritation or allergic reactions.

My tree has been defoliated. Is it dead?

No. Although the tree may have been defoliated, it is very unlikely to die. The tree will work to flush out a second set of foliage in the same season. Repeated defoliation can cause severe stress if sustained over many years. This could lead to the tree's decline; but it is rare for the tree to succumb to L.D.D. moth in one season.

Tar Spot

Tar spot is a fungal disease that does not harm the tree and only affects the appearance of the leaves. It begins as small yellow spots that become larger and turn black as the season progresses. To reduce or prevent this, rake up leaves and dispose of them immediately instead of placing them in a compost pile. The disease can over-winter on the ground in fallen leaves and is very hard to get completely remove from an area.

Oak Wilt

Oak Wilt was recently detected in Ontario and it is important to be aware of the signs and symptoms of the disease. It is a fungal disease spread naturally through root systems or by beetles carrying the fungal spores. Oak wilt is not a threat to humans or wildlife.

Please visit the Canadian Food Inspection Agency website to learn more and to report possible cases.