Trees

This program focuses on replacing boulevard trees in the spring and fall seasons.

You may notice markings or flags on the boulevard stump once the locate request is completed. The stump removal and/or tree planting will occur shortly after, and the boulevard area will be restored.

Spring Planting is set to commence in May, 2025. Stump grinding and replacement planting will begin in spring throughout the City and will be completed by our contractor. If you have a tree removed before February 28th, 2025, you should receive your new tree by end of spring planting. If it is removed after this date, it will be placed on the fall planting list for replacement.

Please Note: If you are unsure if you are on the planting list, or want to request a new tree, please contact Service Oshawa.

Since 2018, the woodlot had experienced a steady decline because of Pine Wilt. Staff had responded to numerous service calls, including uprooted or fallen trees due to declining health, resulting in more than 100 tree removals. The trees posed a significant risk to park users and adjacent properties. To address concerns, the City undertook large-scale removal of the woodlot in late November 2021.

In 2022, 150 large caliper trees were planted to begin restoration efforts in this space. The woodlot will see a wide variety of native species planted throughout and create a more sustainable urban forest for the future. 

Ongoing restoration

This has provided the City with a unique opportunity to increase biodiversity and resiliency. Scots pine is not native to Canada will take over an area by shading out native plant species, reducing biodiversity and habitat.

Restoration has included help from City staff, LEAF and volunteers. Over 1600 trees and shrubs have been planted to date and the area will continue to be planted and monitored by the City to ensure its success. Restoration will increase biodiversity, creating a more resilient forest. This will allow the woodlot to withstand the impacts of climate change, severe weather and damage caused by diseases and invasive species.

The restoration process is ongoing so remember to visit LEAF for more information future events both here and around the City of Oshawa.

Your new tree is mulched in a “donut” or ring shape. Adding fresh mulch to the tree over the root ball area to reduce the growth of weeds and retain water in the soil. Be sure to keep mulch approximately 10 cm away from the trunk of the tree. (Free mulch is available at Oshawa Animal Services during the growing season.

Avoid mounding the soil or creating a "volcano" of mulch around the base of the tree. Never cover or bury the trunk flare. Improper mulching can lead to:

• Increased moisture/decay on the base of the tree leading to insect and pest damage
• Girdling roots and shallow root growth
• Lack of water reaching fine tree roots which can limit establishment and growth

City of Oshawa's Forestry Services recommends only mulch and other organic material be used around City owned trees. Alterations around the base of the tree including the use of landscape rings, brick borders, and landscape fabrics can raise/alter the grade and natural environment surrounding the tree and affect the health and longevity of our urban canopy.

Mulching examples

Correct Mulching	Incorrect Mulching

City of Oshawa tree watering:

Community members may notice a green bag around new trees in your neighbourhood. These bags are for watering our new tree plantings throughout the City.

Both City staff and contractors will be out filling these bags to ensure new tree plantings on City boulevards receive adequate moisture. These water bags are designed to slowly release water in the root system to establish deep roots and keep soil moist for longer periods of time between watering.

Your tree will periodically receive watering throughout the growing season but in times of drought or high heat, your new tree may require additional watering. Homeowners are encouraged, but not required to fill these bags. Keeping soil moist and your tree watered in times of high heat or drought will help the new tree establish and thrive in its new environment.

If water is pooling around the tree or the soil is extremely wet after watering, then water less frequently.

Using the water bag:

The bag will be installed by City staff or by our contractor. If you would like to offset City watering in times of heat or drought by filling the bag you can easily do so by:

1. lifting the tag at the top of the to expose the fill opening
2. Insert a garden hose and begin to fill
3. Gently lift the two black straps at top of bah in order to fully expand the bottom
   (Note: Do not hang or suspend bag by straps)
4. Fill to desired level and let drain (Usually 5 to 9 hours)

Staking trees is not always necessary but can sometime aid in stability when exposed to high winds; the soil is shallow, or the root ball is loose when planted. Trees need to develop strong support and reaction wood to stand up to high winds, storms and other environmental factors.

If stakes are used, the city will remove them one to two years after planting.

Keep lawn mowers and string trimmers away from the trunk, which can damage or even kill the tree if bark is removed around the trunk.

• 30 minute consultation in your yard with a LEAF arborist
• 5 to 8 foot tall native deciduous tree OR 2 to 4 foot tall native evergreen tree
• Delivery and full planting service
• Mulch and planting/care guide

• Online educational videos
• 30-minute virtual consultation with a LEAF arborist
• 5 to 8 foot tall native deciduous tree OR 2 to 4 foot tall native evergreen tree
• Delivery (property owner plants)
• Mulch and planting/care guide

Sustainable planting practices

To grow a healthy mature tree canopy, the City is implementing several sustainable planting practices downtown aimed at improving growing conditions that include the:

• review of tree planting locations to limit conflicts with existing infrastructure, services and pedestrians;
• planting of suitable tree species tolerant to urban conditions;
• use of soil cell techniques and suspended paving to support the sidewalk above without compacting the soil below;
• use of rubberized mulch around the base of the tree to allow water to absorb into the soil; and
• installation of watering pipes to be used during times of drought.

How you can help keep our downtown tree canopy healthy

• Do not trim or prune the tree. The City's Forestry Services has qualified arborists who will prune and maintain the trees as they mature.
• To avoid damaging the bark, which can eventually kill a tree, keep the area around the tree free of debris, do not lean, nail or attach anything to the trunks such as signs or bicycles.
• Leave the rubberized mulch at the base of the tree. The mulch is there to protect the tree from damage and reduce water loss.
• If you notice that a City boulevard or park trees is damaged or diseased, submit requests to Service Oshawa online. 

The emerald ash borer 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.

Additional E.A.B. resources

• Ontario Ministry of Natural Resources
• Canadian Food Inspection Agency

Japanese Beetle 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.

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 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.

The City of Oshawa is following the recommendation of the C.F.I.A. (Canadian Food Inspection Agency) and I.S.A.O. (International Society of Arboriculture Ontario) and will not be pruning any Oak species from April to November as a precaution. IF pruning must be done outside this time frame, cuts will be painted with wound dressing.

What can you do?

• Do not prune or wound Oak trees between April and November
• Do not move firewood (of any species)
• Report suspected Oak Wilt to the C.F.I.A.

For more details and information on the signs and symptoms of this disease please visit any of the following links:

• Canadian Food Inspection Agency (C.F.I.A.)
• International Society of Arboriculture Ontario (I.S.A.O.)
• Invasive Species Centre