City of Cornwall logo inside tree with bright green leavesWelcome to the Forestry Services section of the City of Cornwall website.

In this area you will find information on a variety of tree and forestry-related matters.

Please scroll down for additional information on the City's efforts to manage the Emerald Ash Borer as well as general tree planting information, the free woodchip and firewood pickup sites and the new commemorative tree planting program.

 Lamoureux Park Arboretum

There's a new attraction in Lamoureux Park that's sure to interest nature lovers.

The Lamoureux Park Arboretum is now open for visitors looking to discover more about Cornwall's urban forest. Located on the Waterfront Trail between the Cornwall Community Museum and the Rotary Eco Gardens, the Arboretum showcases 44 different types of tree species that make up Cornwall's tree canopy in one convenient place.

In the Arboretum, there are two of each species planted in pairs, and each tree has a tag that identifies its name in English, French, Latin and braille.

The full tour of the Arboretum would take about an hour to complete. To make it easier to follow along, a map of the Arboretum is available by clicking here.

 Tree Planting

The City of Cornwall plants a wide selection of tree species during the spring and fall. The tree planting variety list contains varieties best suited to grow in urban conditions. Residents can request to have a specific type of tree planted on the municipal right-of-way in front of their home (see link to species list below). City staff will make the final choice based on tree form, site space, overhead utilities, and the soil type in that particular area (details included on the variety list). The City relies on residents to help with the care of young trees.

Here's how you can help:

  • Residents are encouraged to deeply water the tree once a week in dry weather.
  • Please use caution when using grass trimmers near the tree.
  • Please do not prune or trim the tree.

The City appreciates the help of residents in caring for our trees and our environment. Please click here for a PDF detailing how to care for a tree after it is planted.

 Planting Tree Species List

The most common constraint for tree planting is the size of the area available for the tree, both above and below the ground. Here you'll find a list of the tree the City of Cornwall plants, sorted by size.

Small Trees - less than 10 metres/30 feet

Medium Trees - less than 10-15 metres/30-45 feet

Large Trees for Boulevards - greater than 15 metres/45 feet

Big Trees - greater than 15 metres/45 feet

Narrow Trees - greater than 15 metres/45 feet

Trees are often planted next to residents' property. Please click on this link to learn about how you can promote tree health.

 Commemorative Tree Planting Program 2019-2020

Planning, Development & Recreation is pleased to be able to offer a Commemorative Tree Planting Program. This program may be used as a form of remembrance of a loved one, celebration of a birth, honouring a retiree, or any other event which you feel should be commemorated by a living tribute. A number of locations are available in our City parks for commemorative tree planting in the spring. Forestry staff will gladly assist you in choosing a location that meets your needs and is compatible with the surrounding environment.

Please click here to learn more about the program via PDF.

Please click here to view the Commemorative Tree Planting Order Form.

We offer the following options for Commemorative Trees:

Option 1 - New Tree with a Granite dedication Plaque ($850.00 plus H.S.T.):

  • Choice of 10 tree species (approximately 6' - 8' high, 40mm caliper)
  • Site preparation & planting
  • Personalized dedication message on a black granite cube
  • 16" width x 10" length x 4" thickness with 4 lines - maximum 19, ¾" block gothic letters per line
  • Installation of granite cube
  • The plaque will be installed flush with the ground to reduce vandalism and allow access of maintenance equipment.
  • The City is not responsible for maintenance or replacement of Commemorative plaques
  • 2 year warranty on new tree

Option 2 - New Tree only -no plaque ($400.00 plus H.S.T.):

  • Choice of 10 tree species ( approximately 6' - 8' high, 40mm caliper)
  • Site preparation & planting
  • 2 year warranty on new tree


1. The Municipal Parks Supervisor reserves the right to:

  • Approve any preferred species of tree other than the ten mentioned on the order form.
  • Approve the site for planting and suggest alternative sites.
  • Purchase the tree and deem the tree healthy upon its arrival

2. Tree planting will be conducted in the spring. Orders must be received by March 15th.

3. Once the tree is planted, the tree becomes the sole responsibility of the Planning, Development & Recreation Department, Parks and Landscape section, who will endeavour to keep the tree maintained.

4. The costs are payable to the City of Cornwall and should be received by the Benson Center (800 7th Street West) attention Donna Raymond-Walker, once the application is approved.

All costs may be subject to change.


The City recommends the following parklands for commemorative tree planting:

  • North End: Silver Cross Park, Terry Fox Park, Optimist Park
  • West End: Riverdale Park, St. Theresa Park
  • East End: Mattice Park, Menard Park, Reg Campbell Park
  • Downtown: Horovitz Park, Lamoureux Park
  • Centretown: Broadview Park

The following trees are preferred: Ivory silk lilac, European hornbeam, Ironwood, Hackberry, Red oak, Ginkgo, Sugar maple, Native red maple, Shagbark hickory, and White pine.

 Woodchips, Compost and Firewood

Woodchips and compost are available for pickup at Optimist Park and Guindon Park. You can take as much as you wish. Bring a shovel and your own buckets, bags, or a pickup truck to load it up!

Firewood is also intermittently available at the wood chip bins. It is very popular and tends to disappear quickly.

Freshly cut firewood is not ready to burn. Firewood needs to be cut and split and left for a year to season as it is too wet to burn. If you burn unseasoned wood, you are at great risk of having a chimney fire.

No chain saw or axe use is permitted on City property. Picking up wood chips and firewood is done at your own risk.

Please click here for a map of wood and woodchip pickup locations.

 Insects and Diseases 

From time to time, the presence of various insects and diseases can cause questions and concerns for residents.

Boxelder Bug

Boxelder bugs (Boisea trivittata) are named for their primary host, the boxelder tree. One of the less destructive agricultural pests, boxelder bugs do infrequent damage to apples, peaches, grapes, strawberries, plums and non-fruiting trees including maple and ash. A bigger nuisance to homeowners, they seek and enter houses in colonies of hundreds, even thousands of insects as cold weather approaches, congregating in walls and warm basements, making themselves at home all through winter and occasionally emerging into kitchens, living rooms, bed rooms and other human-inhabited spaces.

Boxelder bugs, though mostly scentless, give off a pungent odour when disturbed or crushed. Also offensive: the accumulation of excrement and dead bugs that fall from the colonies inside walls and other hard-to-access places.

Adults, the stage most often seen in homes, are dark with three distinct orange or red stripes, the first centred behind its head, the other two running along the sides of its body. The adult's abdomen is also orange. About 1/2 inch long, its dark wings cross along its back. Eggs, found on leaves, the seed pods of boxelder trees, and in ground vegetation, are yellow and clustered in groups that begin to redden as the nymph develops. Nymphs go through five stages, continuing to turn red as they mature. Adults are sometimes mistakenly identified as stink bugs, which they generally resemble.

Life Cycle
Adults survive the winter sheltered beneath loose tree bark, in plant debris, or in homes, garages and out-buildings. They emerge as the weather warms in spring. Staying close to the ground, they feed for two weeks on boxelder seeds and other vegetation before starting the mating cycle. Female bugs fly up female boxelder trees and lay eggs on seed pods and the undersides of leaves. They will also leave eggs on stems and branches. Eggs take 10-14 days to hatch. During the summer, all stages of the boxelder can be found in and around host trees. While nymphs continue to develop into the fall, only adults survive cold weather.

Box elder bugs are sap suckers, penetrating plant tissue with their considerable proboscis and using secretions to make it consumable. They almost exclusively feed on the acer family of maple trees and vines that includes the boxelder and its spinning "helicopter" seed pods, but have also been known to feed on fruit during dry summers. Infestations on box elder trees may cause its leaves to yellow and curl or leave spots on stems and new growth. Most trees survive. Damage to grapes, peaches, and other soft fruits is mostly cosmetic, appearing as depressions, sometimes as bruises. While a nuisance, boxelder bugs do relatively little damage to fruit crops, preferring to feed and procreate in its namesake tree.

Indoors, the bugs can be a major problem. While they don't normally cause structural damage to homes or contaminate food sources, they can be a source of filth, odor and displeasure due to their sheer numbers. Warm weather or an increase in home heating may convince individual boxelder bugs that spring has arrived and they will enter a family's living space in search of a way outside. In late summer and autumn, then they gather in groups much like swarms of bees on the sun-facing, preferably white side of homes and garages where their sheer numbers will discolour the building's side if allowed to stay.

Indoor and outdoor boxelder control are interrelated. Destroying boxelder colonies outdoors means few bugs looking for a way into our home come fall. Denying places in your home for boxelders to overwinter means fewer numbers laying eggs in your trees next spring and summer.

Most outdoor boxelder damage is minor and, most years, won't require treatment most years. Some years will produce more boxelder bugs than others. Dry years may encourage the bugs to seek out fruit. Wind plays a great role in the dispersal of flying boxelder bugs.

Chemical pesticides are a poor option for boxelder infestations. Their use indoors can pose a hazard. Dusting of colonies may kill thousands of bugs but will only encourage other insects and rodents who feed on the dead bodies. The common and troublesome carpet beetle is attracted to dead boxelder remains. There it feeds and lays egg, guaranteeing another generation of increased numbers to damage in your home.

Here are several techniques to control boxelder bugs:

  • Preventing boxelders from entering your home is the single most important defense. Seal around window frames, where utilities enter the house, cracks in the foundations and under eaves. Make sure doors are weather stripped at the bottom, leaving no space. Screen off vent pipes and other roof openings with fine screen to prevent the bug's entry.
  • Repair any loose siding which, like loose bark on a tree, allows the bugs to get behind the siding and against the house. Patch any cracks in plaster or stucco- sided houses.
  • Eliminate wood piles, landscape debris and other places boxelder bugs will gather to survive the winter.
  • Boxelders found in clusters on trees or the sunny side of houses can be sprayed away with a garden hose. A hard spraying is sometimes enough to convince the surviving bugs they should go somewhere else.
  • Hot water between 160-180˚F will kill the bugs but, at these temperatures, can also burn the sprayer. Use extreme caution if you have a source of water this hot to use and do so only outside.
  • Sometimes your best weapon when facing colonies of boxelder bugs is a shop-vac. Vacuum colonies from the sides of houses and around window sills into a bag-less, wet-dry vac canister with a quarter to half inch of soapy water in the bottom which will suffocate the bugs. If you find and can access boxelder colonies behind walls, remove them with the vacuum.
  • Because it's the chosen habitat and breeding ground of the bug, female boxelder trees are sometimes removed to decrease the insect's number. This seems a rather radical move and is a mostly fruitless one as well, especially in areas where boxelder trees are numerous. The insects' eggs disperse on seed pods -- the "helicopters" produced by boxelder trees -- and adults will fly as far as two miles seeking new sources of food and breeding grounds.
  • Tree removal is not recommended, unless yours is the only boxelder tree for miles around and the bugs have been a persistent problem.



  • Aphids are found on almost all types of plants and a few species can cause plant injury.
  • Aphids are more active during hot, dry, weather at the end of summer.
  •  Some aphid species can curl the new leaves of some types of plant.
  • Natural enemies of aphids include lady beetles, flower fly larvae, lacewing larvae, and parasitic wasps. Strong rainfalls will flush the aphids from trees.
  • Aphids feed by sucking sap from plants. When the number of aphids on a plant is very high for an extended period, their feeding can cause wilting and sometimes even dieback of shoots and buds. Some aphids can cause leaf curling when the insect infests emerging leaves.
  • Sometimes problems with aphids do not primarily involve plant injury but instead their production of sticky honeydew. Honeydew is the waste material excreted by aphids.  It may cover leaves, branches, sidewalks and anything that lies beneath a infested plant material.  Gray sooty mould grows on the honeydew, further detracting from plant appearance. Ants, wasps, flies, and bees are usually attracted to plants that are covered with honeydew.
  • During heavy Aphid population, not parking vehicles etc under the tree is recommended.
  • Exposed aphids can be controlled with a strong jet of water or water mixed with a mild soap solution. 
  • Due to the cosmetic pesticide ban in Ontario, City of Cornwall cannot spray for Aphids.
  • Pruning will allow air flow which will reduce the population of Aphids.
  • The City of Cornwall does not remove trees due to Aphid problems but will where possible trim the tree to allow air flow to help reduce the population.  A garden hose where possible to spray tree with water to reduce Aphid populations.
 Emerald Ash Borer 

The Emerald Ash Borer beetle is a non-native invasive insect that attacks and kills most varieties of ash trees.

Adult EAB beetles lay their eggs on ash trees in the summer. When the eggs hatch into larvae, they tunnel under the tree's bark to feed. The tunnels prevent the flow of water and nutrients, causing the tree to die. As larvae, they are located between the bark and sap wood. As adults, EABs eat ash tree leaves. Both of these actions, including the fact that EABs do not have any natural predators, lead to infestation and eventual death of the tree (in approximately 1 to 4 years).

In order to deal with the threat posed by EAB, the City of Cornwall's EAB management plan (see below) involves a combination of monitoring, treatment, ash tree removal and replacement, and public education.

Tree removal: Ash trees in the community that have been marked with an orange line on the trunk and an information sign posted on the tree will be removed. When the tree is removed, all limbs will be chipped and wood will be removed off site. The stump will be removed at a future date and if space permits, a new tree will be planted. 

Tree injection: Ash trees in the community that have been marked with a green dot at the base of the trunk are candidates to be treated with TreeAzin to protect it against the EAB. TreeAzin is a systemic insecticide injected into the tree's bark to kill EAB larvae feeding on the tree's tissues. It does not pose any health risk to people, pets or wildlife and degrades naturally. It is injected in the tree every year for 2 years than skip a year, then injections for the next 2 years. This is the latest updated change for injections.

Please click here to see the Ash Tree Removal Notice.

Please click here to see the City of Cornwall Tree Planting List.

Please click here to see the March 24, 2014 Report to Council.

Please click here to see the Emerald Ash Borer Management Plan.

Saving your trees from salt damage

Parks and Landscaping often gets questioned in the spring about why trees along roadways have brown leaves or needles and how this can be avoided. While tree damage from road salt usage doesn’t become obvious until the spring, now is the time to consider ways to minimize damage over the winter.

Approximately five million tonnes of road salt are released into the environment in Canada each year. The most commonly used road salt is the same salt that is used on food – sodium chloride.

Although road salt assists with keeping pavement dry and safe during the winter and has little negative effect on human health, its widespread use can cause damage to trees, shrubs and other plants along roadways.

How salt damages plants

Road salt can damage plants in two ways. The first is through an airborne spray that kills dormant buds by penetrating leaf scars. The second occurs when salt accumulates in the soil where it breaks down into its two components, sodium and chlorine, both of which act differently to affect the plant.

In extreme cases, chlorine ions in the soil are taken up by the tree in early spring, where they enter the sap and concentrate in shoots, preventing bud openings. Eventually, the chlorine is transported to actively growing leaf margins where it causes leaf scorch, curling and death.

Sodium ions in the soil follow the same route as the tree’s nutrients, blocking magnesium and potassium, both of which are necessary for the production of chlorophyll. Again, in extreme cases, this can result in a potassium deficiency that may inhibit the tree’s resistance to drought and disease.

Salt accumulation in the soil can also cause a physiological drought. Salt solution near tree roots is more concentrated than the tree’s sap, impeding osmosis and preventing the tree from taking up water through its roots.

In general, the primary long-term damage to salt-weakened plants is a result of their increased susceptibility to insects, pathogens, and the environmental stress of drought, wind and ice. Tree death from road salt is less common.

Symptoms of salt damage

Salt damage to conifers is most noticeable in the spring. Branches closest to the road get yellow and brown needles that drop off. This colour change starts at the tips of the needles and progresses to affect the whole needle.

By summer, trees have usually recovered and have new green growth. Damage due to salt spray is usually short-term, with long-term damage occurring where the tree is under other stress.

Deciduous trees damaged from road salt may have many twigs densely clustered together, called witches’ brooms, near the ends of branches as a result of terminal buds killed by salt spray. Other symptoms include unopened flower buds, twig dieback, sparse, stunted or yellow foliage, and leaf scorch.

Young trees are more susceptible to salt damage because they have fewer roots than older ones.

Preventing salt damage to your trees

There are several ways that you can reduce the damaging effects of salt on your trees.

  • Avoid the use of de-icing salts. Use coarse sand to help make driveways and sidewalks less slippery. If salt must be used, use as little as possible, lower the throwing distance, and apply before the area freezes.
  • Keep your trees and shrubs healthy. A healthy plant is better equipped to survive salt spray and accumulation in the soil.
  • Plant salt-tolerant trees near roadways and walkways. Some salt-tolerant native species include red pine, red oak, birches and poplars. Salt-intolerant species, such as white pine, sugar maple, eastern hemlock, basswood, and spruce, should not be planted near areas where salt is used.
  • Use barriers to protect sensitive species from salt damage. Barriers may include plastic fencing, snow fencing, or burlap.
  • Improve the drainage around trees or adjust the grade so salt is easily leached away from the trees.
  • Flush the soil with water in the spring when it thaws so salts are sent beyond the trees’ root zones.

Until a cost-effective alternative to the use of conventional road salts is developed to keep our roads safe in the winter, reducing the amount of salt applied and minimizing salt damage to our trees and our watersheds is the best course of action. 


Emerald Ash Borer Frequently Asked Questions

 What is the Emerald Ash Borer (EAB)?
The EAB beetle is a non-native invasive insect, that attacks and kills most varieties of ash trees (white and green ash). Adult EAB beetles lay their eggs on ash trees in the summer. When the eggs hatch into larvae, they tunnel under the tree's bark to feed. The tunnels prevent the flow of water and nutrients, causing the tree to die.
 Where did EAB come from? 
The EAB beetle originated in Asia, and is believed to have come to North America in the early 1990's, via the transportation of ash wood materials. It was first detected in Canada in 2002 in Windsor, Ontario. It has since killed and infested over 70 million ash trees.
 How does EAB spread? 
The most common way for the emerald ash borer to spread is through people moving infested materials such as firewood. To prevent the spread of EAB, don't move firewood, and buy wood locally. Scientists in Canada and the United States have concluded that the emerald ash borer cannot be eradicated. In light of this the Canadian Food Inspection Agency (CFIA) adopted a "slow-the-spread" approach. To help limit the spread, ministerial orders have been put in place to regulate areas infested by the pest. The CFIA is the federal governing body responsible for exotic insects.
 How does EAB impact ash trees? 
EAB kills ash trees by eating their nutrients. As larvae, they are located between the bark and sap wood and eat the trees nutrients. As adults, EABs eat ash tree leaves. Both of these actions, including the fact that EABs do not have any natural predators lead to infestation and eventual death of the tree (approx. 1 to 4 years).
 What has EAB been found?
EAB has been confirmed through out the City of Cornwall. However, EAB beetles can fly long distances up to 8 km.
 Possible signs of EAB infestation 
There are a number of possible signs that could indicate a possible EAB infestation.




Dead branches or discoloured foliage which can be observed during late summer. Feeding by the larvae kills branches and eventually the trees (approx. 1-4 years). See Figure 1.

Epicormic shoots: These shoots are also called suckers, water sprouts or witches broom and are produced on the tree trunk and roots when the tree is under stress. They can sometimes be found in the tree crown, on stems and on larger branches. Not all trees attacked by the Emerald Ash Borer develop epicormic shoots. However, under the right conditions and intensity of attack by the beetle, they can develop and grow quickly. See Figure 2.

Woodpeckers feed on the larvae under the bark. Look for increased Woodpecker feedings or signs of their robing in the bark. See Figure 3.

Close examination of the bark may reveal D-shaped holes. When new adults emerge from the tree they create this hole to leave the tree. These holes are approximately 3.4 to 4 mm wide. See Figure 4.

Vertical splits of the bark of 7 - 10 cm are often present over larval galleries. These are often more noticeable on young trees that do not already have splits from growth-related expansion. See Figure 5.

If the bark is peeled back S-shaped tunnels may be visible. This is from the larva feeding between the bark and sap wood. See Figure 6 and 7.

 What chemical controls are available? 
TreeAzin™ is a systemic insecticide injected into the tree's bark, directly into the conductive tissues, and moves upward with the flow of water and nutrients. It kills EAB larvae feeding on the tree's tissues by regulating growth and disrupting normal molting. It does not pose any health risk to people, pets or wildlife and degrades naturally. To be effective, it is injected into the tree every year for 2 years, then skip a year, then injected for the next 2 years.
 How will EAB impact the Urban Forest in Cornwall?
Ash trees make up approximately 25% of the town's urban forest, on public property and 25-30% on private property. The Urban Forest has an inherent value and provides us with numerous benefits - helping clean the air we breathe, shading us from harmful UV rays, beautifying our city and many others. Untreated ash trees are expected to be impacted or killed by EAB over the next 10 years.
 What is the City of Cornwall doing about EAB? 
The City is currently implementing its EAB Management Strategy, which aims to reduce the significant aesthetic, environmental and financial impacts of the EAB. This is being done through a combination of monitoring, treatment, ash tree removal and replacement, and public education. Private property owners are responsible for trees on their property.
 What should I do if I have an ash tree on my property? 
Property owners are responsible for the care of privately-owned trees. The City of Cornwall recommends you monitor the condition of your tree and look for signs of infestation. If you see signs that your ash tree is dead or dying, you should contact a professional tree care company. If an Emerald Ash Borer infestation is detected early, you may consider asking your tree care company to assess whether the tree may benefit from injections.
 What should I do if an ash tree on my property is infested?
Property owners who suspect an EAB infestation are encouraged to contact a professional arborist. Private property owners are responsible for trees on their property.
 What will happen to the City-owned ash tree on or near my property? 
City staff require your assistance to monitor the health of City trees in your neighbourhood. If a City tree appears to be in decline, please advise the Parks and Landscaping Section at (613) 930-2787 ext. 2264. The tree will be assessed by a certified arborist and appropriate best arboricultural practices will be applied to maintain the urban forest.

For more information, please contact:

General Parks Inquiries:

Acting Parks & Landscaping Supervisor
City of Cornwall
613-930-2787 ext. 2264

Horticulture and Trees:

Emil Booyink
City arborist
613-930-2787 ext. 2272

Weed and Grass Complaints:

Larry Legue
Parks and Landscape Subforeperson
613-930-2787 ext. 2282

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