Maintenance and pruning must not compromise the tree development and lifetime. The work must be done in compliance with the most recent norms of the Bureau de normalisation du Québec (NQ 0605-200, IV Entretien arboricole et horticole).
The following injuries inflicted to trees and damaging practices on trees are forbidden. Fines will be levied for infractions.
Soil improvement and fertilization
The ground around your property is generally not the original soil; it is likely backfill. This kind of soil is generally poor or clayish and compacted. Unlike the soil of natural environments (ground litter composed of leaves and of decaying wood residues), backfill does not provide good growing conditions and is nutrient poor.
In an urban environment, nutrient poor soil and general soil structure have to be improved periodically.
Restore the life of the soil
Soil improvements are used to restore soil life by resetting its complexity and its micro fauna, or natural activity of organisms. They provide fertilizing matter and also:
The ground needs organic matter such as:
In general, an annual application of compost on the surface, while doing the spring aeration and top-dressing of ground, can significantly improve the poor, compacted and deficient soil that is so often found in urban areas.
In addition, apply more environmentally friendly techniques by grass cycling. Rather than bagging them, leave grass clippings on the lawn and shred some of the fallen leaves in the fall to mulch and nourish your soil.
There is no need to add synthetic fertilizers to good soil (synthetic fertilizers, sticks, slow-release or regular granules) or to the lawn, since they have no effect on soil improvement. Fertilizers can harm trees by stimulating abnormal growth (aphids). They disrupt the chemical exchange and root absorption of soil nutrients. The excess of synthetic fertilizers released by leaching (watering too often or heavy rain) follows the path of the storm sewers and watercourse and poses environmental problems.
Refer to our GREEN LINE for tips on lawn care without harming trees and other plants.
Protection during work
Do you plan to install a pool, create more parking or redo your landscaping?
Please be advised that in addition to the required permits and certificates, you and your contractor are responsible for the protection of public trees that are located close to or in a work area, including the trees located in the path taken by machinery and workers to reach the said work area.
Avoid destabilization and seriously harming trees and their roots in particular. Root loss, due to roots being ripped out or crushed by machinery, leads to deterioration of the ground conditions and the destruction of the vital environment of the tree. The City has outlined provisions in Bylaw (Chapter VII, p 13-14). Tree protection during construction work or landscaping or permanent lowering of the ground level.
The aerial and underground parts, that is, the branches, trunk and roots, have to be protected during the entire work period.
Anyone who contravenes to the provisions of the by-law commits an infraction and is liable to a fine. The contravener may also be subject to a claim for any damage caused to a tree.
These simple precautions can prevent problems:
According to the regulations, a tree is considered dangerous when it involves an imminent danger. In this case, it is a serious threat and danger for the physical safety of property or persons, and you must immediately take steps to correct the critical situation.
The City may intervene to force the owner to fell the tree or to prune it to correct the unsafe condition. Consult Bylaw R-2007-023, chapter 4, paragraph 6. (p 6-9). You must report such cases to the City by calling 514-684-1034.
A tree can have good appearance and look healthy, but it may present a problem, such as a structural defect, dead branches, a weakness in a fork and more. The structural problems can often be corrected in various ways (tree pruning or guying techniques).
Otherwise, if a structural problem cannot be corrected and if the tree is considered to be hazardous, it should be felled as soon as possible. Contact the Public Works Department at 514-684-1034. Please be advised that these are exceptional circumstances.
To prevent problems, ask an arborist to evaluate the structure of your tree when you carry out its maintenance. In most cases, it is all right to act in time to correct weaknesses and substantially reduce risks.
Ask a forest engineer in specific and complex cases that require further evaluation.
You can obtain a written report from a professional, which could be essential for legal causes or in case of a dispute with neighbours.
Have you received a notice from the City concerning trees? The notice reads:
Please be advised that the City will soon proceed with maintenance work as pruning public trees near your residence.
Please be advised that the City requests you prune obstructive branches of trees that belong to you. You can proceed within 10 days or work out an agreement with the City by contacting the Public Works Department at 514-684-1034.
So as not to interfere with public security, with the work of municipal employees, with the crosswalks and with traffic, each owner is responsible for keeping clear at all times traffic signs and public infrastructures by pruning the branches of his or her trees.
Only the City is authorized to proceed with the pruning of public or common trees.
If a common or public tree needs pruning, please call the Public Works Department at 514-684-1034.
Consult the bylaw, chapter VI, (p 9-10), Rules governing tree maintenance and pruning, to learn more about the regulations concerning the prescribed clearance.
These rules mainly concern:
Myths and realities
The annual growth and the size of large trees can cause concern. The annual growth, called elongation, gradually decreases in mature trees. The tree has its own DNA and can support a genetically predetermined maximum height and the weight of its structure.
Topping is a damaging practice for trees and is forbidden (consult the MISTREATMENT section).
A maple tree grows like a maple tree; an ash tree grows like an ash tree and so on. The tree’s development depends upon its environment. Trees are living organisms that respond to their environment. Everywhere, nature shows survival strategies and adaptation.
For instance, branches develop according to light and space available; root systems compensate in strength to support a trunk leaning toward a light source and they are restricted in development if constrained by a lack of space; crown (all branches and leaves) grows in similar proportions; and so on.
Remember not to fear a tree because of its size, but rather because of its structural defects when left unattended, vulnerable to the elements.
Weaknesses, wood rot or dead wood have to be identified right away; avoid injuries, bad cuts and topping.
The word is prevention. Abnormalities are often corrected during professional pruning maintenance. Look at the structure of the tree early in spring or after the leaves fall. You will be able to react when necessary to request the help of a professional arborist.
There are several misconceptions about roots. Some myths persist about the “force” roots have to cause damage to structures, to crack house foundations or to cause failure of underground pipes. Indeed, if tree roots were capable of such damage, no City would tolerate the presence of trees.
Trees in urban areas share space with the structures and infrastructures. How many trees are located near buildings or along streets and sidewalks, close to the underground utilities, present everywhere in the City? Think about the Hydro-Québec underground cables, the Gaz Metropolitan pipes, the municipal water pipes, the sanitary sewer mains, and so on.
Let us look at the function of roots and how they work. In short, roots are there to support the tree. They provide ground anchor. Remember that trees are living organisms and roots are organs that serve to absorb water, minerals or oxygen and transport nutrients. Roots are located immediately under the soil surface, rapidly diminishing in size as they move away from the trunk.
A greater part is located in the first 30 cm of soil depth. They become scarce in the following 30 cm and rarely exceed 1 m deep. Roots explore surface rather than depth. They extend horizontally over a distance that exceeds the length of the branches if there are no obstacles. They grow by elongation in soil pores, by the extremity of the smallest parts, and only in the direction where the soil does not offer resistance.
Many researchers have studied this issue. Dr. Kim D. Coder (“Root Growth Control: Managing Perceptions and Realities.” Landscape Below Ground II. 1998. p. 57) demonstrates that roots are not strong enough to go through solid materials such as pipes, concrete, plastic or wood. For this reason, roots do not have the ability to cause direct physical damage.
Here are some familiar examples to form your own opinion:
The main objectives of pruning are to maintain trees in good condition and clear of structures.
Each owner is responsible for the maintenance of trees on his or her property. Contact a reputable private contractor for your work.
Maintenance work and pruning must not shorten the tree’s lifespan. Topping is forbidden.
In order for the work to be done in a professional manner and for your trees not to be mistreated (consult the MISTREATMENT section), please ensure your contractor is aware of the City bylaw chapter VI (p 12-13), as well as the norm NQ 0605-200 Entretien arboricole et horticole from the Bureau de normalisation du Québec. Make sure your contractor has liability insurance.
Private common trees
A common tree is any tree whose trunk is partially on another property. The affected owners are responsible for the maintenance of a common tree.
However, in the case of a common tree whose part of the trunk is on public property or any City-owned property, please be advised that only the City is authorized to proceed with the maintenance or pruning of this tree. Consult the bylaw, chapter III, section 2, Rules governing public or common trees. For any tree maintenance, please call the Public Works Department at 514-684-1034.
Consult the MYTH AND REALITY section to learn about the function of roots and how they work.
The root tips offer no resistance against obstacles, whether a small rock, a piece of wood, a foundation wall and even a hard and compacted soil. The elongation of the roots will follow the direction where the ground condition is ideal.
When roots encounter crushed stones, under the parking lot or street, or when they reach the reinforcement of pavement or any other barrier, they grow in another direction.
For the same reasons, a parking lot that has a properly structured foundation under the asphalt, or the paving stones or slabs, will create a barrier against the roots. When construction standards are respected and soil is stabilized to prevent the movements of freeze-thaw cracks, no root damage is possible. If after several years and for different reasons (soil compaction, freeze-thaw, water infiltration or other), the construction deteriorates enough for a root to infiltrate, cut the root and resurface the parking lot.
Research shows that the presence of roots in pipes is due to dislocation or loss of a seal in the connecting joints. This opening permits root infiltration.
The opportunist roots take advantage of water availability, nutrients and oxygen. As long as the conduits are not fixed and impermeable, roots will grow, ramify and colonize the place.
The joint opening is due to a set of defect factors, often combined with age, such as the type of pipe used, the mechanical motion of the soil (packing or freeze-thaw), and the quality of the bedding or of the foundation when installing pipes, the type of filling and the type of connecting joints between the pipes.
Roots take advantage of a weakness or of a default existing in the conduits. Repair of underground pipes solves the problem permanently. (People used to use concrete piping (or clay) of a length of 4 feet; and today, they use PVC plastic pipes or fibreglass FRP in longer sections.)
Being a good neighbor and the civil code
Sometimes tree branches or roots encroach on your neighbour’s land. In that case, your neighbour can ask you to cut said branches and roots. If you refuse to comply with his request, he may obtain an injunction granted by the Court, providing he has sent a written notice first.
Finally, if your tree is threatening to crash into the neighbour’s property, he may similarly require you to fell or straighten it.
Send a written notice to as the owner to consent to correct a situation that seems dangerous to private or public property, or cause prejudice according to the intent of the law. (Source: Justice Québec pamphlet.)
(It is recommended that you send your request by registered mail.) If your neighbour, owner of the tree, after having received the formal request, refuses or fails to take the necessary steps to correct the situation, you can take your case to court to obtain a Court judgment. You are not authorized, in your sole discretion, to take action on the property of others, not even cut a single branch within easy reach, without prior consent from the owner.
Roots by K.D. Coder
When can you plant?
The planting period easily extends from the spring thaw until late in the fall. However, wait until the right moment and avoid working on poachy ground. Also avoid planting in summer drought conditions, because it requires more precautions, care and more watering is necessary. Whatever the time of year, please respect the City’s watering restrictions.
How to choose the right tree?
For the best results, choose a tree:
and one that:
and, above all one that:
The tree has to benefit from sufficient sun exposure (some trees require lots of sunshine; others tolerate half-shade).
Provide your tree with ideal growing conditions to ensure longevity and prevent possible problems, such as diseases and undesirable insects. Consult our suggestions. LIST OF TREES
How to plant a tree
The planting method is a controlling factor to ensure the survival of the tree. It is imperative to know the appropriate planting techniques and to allow for a large hole. Please refer to the norm NQ 0605-100, VIII, Aménagement paysager à l’aide de végétaux, pp. 89–101 as well as the WATERING section.
Please consult the Montreal Botanical Garden’s “Carnet horticole et botanique.”
Before you plant a tree, test the soil drainage by filling up half the hole where you intend to plant. If after several hours, the water has not drained out of the hole, you have slow-draining soil. Roots need oxygen and root asphyxiation will kill your tree. You may opt for a better spot to plant your tree.
Slow-draining soil solutions
If you install support stakes, place them away from the root ball to avoid root damage. The stakes can be used to protect a tree exposed to prevailing northwest winds, for instance, but they must not be used to straighten a tree.
Stakes are not necessary in most cases and are often responsible for trunk, root and branch damage. The spreading of the roots should be fast enough to support a young tree. If you install stakes, remember to remove them the next year. Monitor and prevent tree injuries when removing them.
Wires are essential when planting or relocating any large tree. They help to stabilize it, since the root ball is small compared to the height of the tree and considering the rooting will take longer. These wires will be kept much longer than stakes.
In order to prevent damage caused by snow removal (especially to conifers), it may be wise to install a snow fence and jute around plants. For conifers, remove the protection on cloudy days in the following spring, to avoid the burning of leaves by the sun.
Similarly, before winter, protect the trunk of young trees and fruit trees to prevent damage to the bark caused by small rodents and rabbits. Install a protective sleeve or tube or a wire fence around the trunk. Firmly tamp and compact the snow around the trunk to prevent the formation of tunnels through which small rodents can move.
t is important to provide good irrigation when planting young trees and to monitor the early years. An application of about 50 litres of water is ideal. The formation of a water retention basin is desirable in the first year, and sometimes the second, to direct the flow of irrigation water to the roots. During the development, the roots will gradually move away from the trunk. It will then be unnecessary – and even inadvisable – to water near the trunk and to keep a basin.
It is recommended to place mulch all around the tree at approximately 2.5 cm away from the trunk. Mulch conserves moisture and has several benefits for the soil. You will have to water less if mulch is installed. Further, it provides protection against injuries to the trunk by keeping the cutting tools away – many trees are damaged when the lawn is mowed. Tree injuries often lead to serious problems later and are an important cause of mortality in trees.
Respect watering restrictions issued by the City. A young tree can easily be watered by hand, which is always allowed.
There is no need to fertilize a newly planted tree.
Mature trees (15 years and older)
If rainfall is insufficient, water the soil surrounding the tree from time to time, up to a distance beyond the end of the crown: where the roots have developed (and not near the trunk). In general, if they have adapted to their environment, trees will manage. Remember, it is better to water at low frequency (two or three times throughout the season) but deeply to promote good root development. Frequent superficial watering promotes development of surface roots, which are sensitive to temperature and humidity variations, with harmful results to the tree and to other plants.
Since the roots are fragile, pay special attention to grass surface irrigation. Change bad watering habits to better manage water usage and improve the performance of your plants and lawn.
A period of summer drought can cause a state of dormancy in a tree (and in a lawn), which will limit its need to be watered and restrict its need of water and nutrients. However, you may have to compensate after the drought by watering deeply.