The beaver is the largest rodent in North America. In Ontario, they have been known to eat almost every tree and shrub species available but they prefer poplars and willows.
Beaver dams help create wetland and reduce erosion. They also benefit rivers and streams and the fish population. These good aspects make their presence desirable despite the damage they do.
Reduce beaver activity by:
Beavers like running water. Consult professionals to construct culverts to reduce the water flow.
Trapping is not effective. No matter how many are trapped and removed, others will take their place.
Bees are important pollinators and honey producers. Wasps and hornets are considered beneficial insects because they feed on a large number of insect pests.
Bees, wasps and hornets nest in trees but don’t typically damage the tree.
Bees, wasps and hornets are important for the environment.
If you see a nest on a City-owned tree, call 311. Don’t disturb the nest! The City will investigate. Unless the nest threatens public safety, the nest won’t be removed.
If you see a nest on your own property, don’t disturb the nest! Contact a professional to help with removal.
Keep bees, wasps and hornets away by:
Galls are unusually-shaped formations that grow on plants including trees. Galls are caused by bacteria, fungi, mites and more. Wildlife like birds and butterflies can help control the spread of galls. Plant flowers and other plants that attract them.
Most galls don’t harm trees and are only cosmetic.
Black knot of cherry is destructive and can kill a tree.
Galls should be tolerated since they don’t cause problems for the tree.
Branches can be pruned:
Girdling roots are roots that grow around other roots or around the main stem of a tree.
Girdling roots restrict the movement of water and nutrients within a tree.
Species that commonly have girdling roots:
Mechanical injuries are one of the most common causes of damage to trees in an urban environment. Even the smallest of damage can allow pests and diseases to enter the tree. Trees can be damaged by::
De-icing salt used in winter to provide safe road and walking conditions can cause significant damage to trees and other vegetation.
Some tree species are very sensitive to salt:
You can also choose trees that are tolerant of salt:
Water is vital to trees. Without water, a tree cannot maintain its physiological functions and will die.
Too little water:
Too much water:
Wood decay is a process of wood disintegration that is caused by fungi or other micro-organisms.
Wood decay affects the structure of a tree and can kill it. Trees with decay could drop branches or the whole tree might fall.
In an urban environment, this can cause damage to property or to members of the public.