Tree Service Glossary

Glossary Content

As the tree service industry has many terms that the average lay person may not know, our team of tree service experts here at OrangeX Tree Services have compiled this list of search terms for your convenience.

Apple Scab:

This is a common tree disease that affects both the fruit and leaves of apple and ornamental crab apple trees. It creates small, olive-green spots on leaves that eventually turn black as leaves distort, turn yellow and fall in early summer. On fruit, it appears as small, raised, dark areas that become large and corky, causing fruit to crack, distort and fall early.


The study, management and cultivation of trees and other related plants, including shrubs, vines, and other perennial woody plants. Arboriculture includes several practices and techniques, such as selection, planting, fertilization, pest and disease control, pruning, shaping, and removal.

Arborist (Arboriculturist):

A person who practices or studies arboriculture, including the common practices and techniques, as well as related elements like risk management, legal issues, and aesthetic considerations related to woody plants and trees that are maintained in private and public areas.


One of the most common types of trees in south-central Ontario, found commonly in both black and white varieties. Black Ash is found around wet sites in central and northern Ontario, while White Ash is more common in dry areas in Southern Ontario. Ash in general has very hard, strong wood, and as such, is often used to make tools, baseball bats, and furniture. It is also commonly used as pulp and makes excellent firewood.

Ash Anthracnose:

This is a common disease of Ash species that is caused by fungus. Ash Anthracnose appears as water-soaked spots on the edges of young leaves and roots near the base that eventually turn brown and black as the infection spreads from bottom to top.

Balsam Fir:

A softwood species in Ontario that is generally found growing under other species in clumps. Balsam Fir has a tall, narrow profile that tapers to a point, and sticky resin blisters on its trunk. It is traditionally used for pulp, paper, and lumber products.


The outermost layer of a tree; a hard surface that protects the inner layers from fire, disease, and pests, and insulates them against extreme heat and cold.

Black Knot:

A disease that affects some species of fruiting trees, including almond, apricot and cherry. It causes twig and branch swelling, discolouration, dieback, and girdling on branches and occasionally trunks. Black knot appears as a light brown, warty knot on new shoots that eventually turns completely black and encases the limb it's attached to.

Black Spruce:

The most common tree in Ontario. Commonly found in the boreal forests of northern Ontario on dry, sandy areas near wet sites. Black Spruce is slow growing, and long-lived. It is commonly used for pulp and paper, as well as lumber and other solid wood products.


The practice of installing braces—also called thread rods—through unions of weak branches and stems to add support and help them better resist the forces of wind and other types of rough weather in order to reduce the risk of breakages and other damage.

Branch Collar:

The point where a branch separates from a trunk; also referred to as a shoulder or stem tissue. In most trees, there is noticeable swelling and rougher bark around the collar of branches. When pruning larger branches, this is where the final cuts are made to remove the branch. 

Bucket Trucks:

A truck equipped with a hydraulic, extendable arm that has a large bucket at one end. This type of equipment is used for raising workers to elevated areas that would be difficult to access otherwise.


A small bulb, or protuberance, on the branch, trunk, or stem of a tree, or another plant, that will eventually develop into a flower, leaf or shoot.

Buttress Root:

A tree root that projects from the ground and is exposed at its uppermost areas, near the base of the tree. They often appear as large, wide roots on all sides of the base of shallow rooted trees. 


The growing part of a tree trunk, located beneath the bark and phloem, and above the sapwood. A cambium will produce new sapwood and phloem each year, and is the part of the trunk that creates the concentric rings which make it possible to determine the age of a tree.


The practice of installing cables and bolts in the upper crown of a tree in order to limit the movement of branches and reduce the likelihood of damage caused by powerful wind, storms, and other types of rough weather.


Dark lesions and cracked bark patches that may ooze and stain bark. Cankers appear on many species of trees and are caused by both fungal and bacterial infections. They can girdle a tree and make it more vulnerable to other diseases and pests.

Canopy (Crown):

The uppermost part of a tree, made up of branches, stems and leaves/needles. Canopies can vary in size and shape based on the type of tree. Some extend high into the air and far out from the trunk, while others are small and less spread out.


Arborists and tree service professionals who climb into trees for the purpose of performing tree maintenance services like pruning, cabling and bracing, or tree removals.

Conifer Trees:

Large, cone-bearing trees. Most conifers are evergreen and have needles instead of traditional broad leaves. Common conifers include the Fir, Pine, Spruce and Larch species.

Crown Thinning:

A tree pruning technique that involves cutting away live branches in the crown of a tree in order to reduce the density of limbs and leaves and improve the overall air circulation and light penetration around the tree, both to promote healthy growth and reduce the risks of storm damage.

Crown Raising:

A tree pruning technique that involves clearing away the lowest branches of a canopy in order to clear the area below for traffic, nearby structures, or a better view. Raising is a delicate process because a proper balance must be maintained between the trunk and canopy.

Crown Reduction:

A tree pruning method meant to control growth and promote the growth of new branches by cutting old branches back to the lateral branch supporting them.

Crown Cleaning: 

Also sometimes referred to as dead-wooding, this is a tree pruning method that involves removing all old, dead, damaged, and diseased limbs in order to prevent the spread of disease and infestations, reduce the risks of damage and breakage, and improve the overall structure and appearance of the tree.

Deciduous Trees:

Flowering trees that lose their leaves during fall, and which are often grown for their attractive, decorative features, such as their colour-changing leaves, their flowers, and their fruit. Common species of deciduous trees include Ash, Larch, Maple, and Oak.

Deep Root Fertilization:

A tree care technique that involves injecting liquid fertilizer deep into the soil around the base of a tree in order to increase the amount of nutrients in the soil and promote healthy growth. Deep root fertilization is often used in urban areas where soil is less nutrient-rich.


A condition in which a tree will begin to deteriorate and decay from the tips of its leaves or roots back into its trunk, often as a result of environmental stressors, diseases and infestations.

Dutch Elm Disease:

A disease carried by beetles that affects most Elms in North America. The primary symptom is the gradual yellowing and wilting of leaves, which progresses continually until a tree is left completely bare.

Eastern Filbert Blight:

A fungal tree disease found throughout North America that causes dieback and small cankers that appear in gradual rows each year until the branches and tree eventually die.


Oval and egg-shaped deciduous trees found in Ontario and many other parts of North America. Elm trees are not native to North America but were planted frequently during the 19th and 20th century as ornamental trees. Many North American Elms have perished as a result of Dutch Elm Disease.

Emerald Ash Borer:

An invasive species of beetle that has spread to Ontario and caused the destruction of many Ash trees. The signs of an Emerald Ash Borer infestation include wilting leaves, small "D" shaped holes left in bark, and S-shaped pathways left behind by the larvae as they chew their way through bark.

Epicormic Shoots:

A shoot growing from beneath the bark, stem, trunk or branch of a plant. In trees, epicormic shoots often sprout near the base of the trunk in response to stress and are a common sign of problems with the tree, such as poor soil conditions, damage, or infections.

Fire Blight:

A serious disease that affects many trees and plants, including pear and apple trees. Fire blight causes leaves to turn brown, wilt, and curl. It can also cause droplets of ooze to appear, create cankers, shrivel fruit, and leave trees looking as though they are burnt.


A process whereby a root, branch, shoot or other growth wraps completely around the branch or trunk of a tree, inhibiting further growth and sometimes causing other issues. Girdling often occurs as a result of a pre-existing infection.


The innermost layer of a tree; the strongest and oldest layer of bark, located at the center of the tree.


A common tree found across the Great Lakes-St. Lawrence region of Ontario. It is commonly found growing near Birch and Maple species, on cool, moist soils near water. Hemlock often attracts white-tailed deer during winter and its wood is used for lumber and railway ties. Hemlock is often planted as an ornamental tree.

Jack Pine:

A common tree found throughout Ontario, but primarily near sandy or rocky sites in northern Ontario. Jack Pines have short needles that are sharp, slightly curved, and grow in pairs. Their cones are curved and will open after a forest fire. Jack Pines are commonly used for lumber, pulp, and paper.

Lateral Branch:

A secondary branch that grows off the main trunk, including the main arms of the structure, which are also sometimes called scaffold branches.

Larch (Tamarack):

A coniferous tree found throughout Ontario, but more commonly in northern Ontario. Larches have needles that turn yellow and fall off in autumn. They grow naturally in many areas, but prefer wet soils. Larches have tough, flexible wood that is used for lumber, pulp, poles and snowshoes.

Leaf Blotch:

A leaf disease caused by fungi that is not a serious threat. Leaf blotch first appears as water-soaked spots that turn reddish and merge over time. 


A common hardwood species in south-central Ontario that is known for its large crown and distinctive leaves. Ontario has many species of native Oaks, including red, white and black. Oak trees produce acorns that attract many animals, and their wood is highly valued for use in trim, flooring, and furniture.

Oak Anthracnose:

A fungal disease that causes the leaves of Oaks to turn brown, develop deformations and eventually die. Although Oak Anthracnose causes dieback, it is not serious in most cases, and can be easily controlled by not watering leaves and by pruning affected branches.

Oak Decline:

A syndrome that affects mature Oaks as a consequence of many stressors interacting at the same time which eventually causes affected Oaks to die.

Oak Wilt:

A fungal, vascular disease that affects all Oak species and is spread by sap-feeding beetles. Oak wilt is a serious disease that kills many species of Oaks, although White Oaks do show some resilience to the infection. Common symptoms include leaves turning colour, early leaf drop during summer, and fungal mats found under bark, which can cause bark to split.


Pronounced “Flow-em”, this is a layer of cells between the bark and cambium that carries sugars from the leaves to the rest of the tree. As phloem dies, it becomes part of the outer bark.

Poplar (Aspen):

A common species throughout all of Ontario that is often the first to grow at a newly disturbed site. Poplars have light, soft wood that is commonly used in composite products, pulp, and paper.

Powdery Mildew:

A common cosmetic disease that doesn't kill the affected plant. Powdery mildew appears as a white powder on the upper surface of leaves, often as a result of increased moisture due to poor air circulation.

Red Maple:

The less common species of Maple found in the Great Lakes-St. Lawrence region of Ontario. Red Maples are known for their bright red leaves that appear during autumn. They are often planted as an ornamental tree and are an important source of food for wildlife.

Red Pine:

A common species throughout south-central Ontario that has long, dark, sharp needles. Red Pine is commonly used to make poles and lumber, and has strong, pale reddish-brown wood.

Root Ball:

The mass of roots at the base of a tree. When relocating trees, this is the part that will be replanted below the surface in the new location. 

Root Pruning:

The process of cutting roots to protect the connected plant from damage as a result of nearby excavation or construction, or in preparation for transplanting a large tree.


An inner layer of bark, below the cambium, that carries water and nutrients from roots to leaves. As new layers develop, sapwood dries out and becomes hardwood.


Any new, leaf-bearing stem or above-ground growth on a plant.

Stump Grinding:

The process of using specialized equipment like a mechanical grinder to break a stump down and grind it into wood chips. Stump grinding is a fast, efficient and safe way to remove a stump. .

Stump Removal:

The method of digging up a stump and removing it with heavy machinery. . Traditional stump removal ensures that the entire root system is removed, but it takes much longer than grinding, results in more damage to your yard, and often requires access and space for large expensive machines like tractors, backhoes or excavators.

Sugar Maple:

The most common Maple species in Ontario's Great Lakes-St. Lawrence region. It is the leaf of the Sugar Maple that is found on the Canadian flag. Sugar Maples supply the sap used to make maple syrup and have a hard, white wood that is used for furniture, flooring and firewood.

Tar Spot:

A fungal disease that affects Red Maples and Sugar Maples. It does not cause permanent damage. Tar spot makes leaves turn colour over time, causing them to develop spots that grow darker and darker until they look like spots of tar.


The process of rapidly trimming the entire crown of a tree by cutting away its uppermost sections. Topping has the potential for many serious consequences and is often only done as a last resort on trees that are becoming a hazard because of their proximity to nearby structures or power lines.

Tree Pruning (Trimming)

Sometimes called structural pruning or selective pruning, tree pruning is the process of cutting away dead and living branches on individual trees through methods like thinning, reduction and raising that improve the overall appearance of the structure and promote healthy growth.

Tree Removal:

The process of removing hazardous trees so that they do not cause damage or other issues. Tree removal is often done for older, dead trees in Simcoe County, but may also be necessary for mature trees that are developing substantial issues, or for trees that have become a hazard due to their growth patterns or the development of infestations and infections. 

Verticillium Wilt:

A vascular disease caused by a soil-borne fungus that enters roots through injuries and other types of damage. Verticillium wilt causes wilting leaves and dieback, and is serious enough to cause a tree to die in just a single season.

Water Sprout:

Shoots that develop on the trunks and branches of trees as a result of stress, weather and poor pruning. Water sprouts should be pruned as soon as possible, as they can sap the nutrients and energy from the root tree, making it more vulnerable to other issues.

White Birch:

A common species found throughout Ontario. White Birches have smooth, white, paper-like bark and are often used for firewood, veneer, pulp, paper and specialty products like hockey sticks.

White Cedar:

A common species in Ontario that generally prefers swampy, wet sites. Cedars are often planted as ornamental additions for hedges and their rot-resistant wood is often used for shingles, fence posts, lumber, and boats.

White Pine:

This species is Ontario's provincial tree and is common throughout south-central Ontario. It has long, soft needles that grow in bunches of five. It is traditionally used for trim, furniture and lumber and has a light white, knotty wood.

White Spruce:

This species is found throughout Ontario but is more common in the boreal forests. It has short needles that are bluish-green in colour, and it is one of the most popular choices for Christmas trees. White Spruce is also commonly used for lumber, pulp and paper.

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About OrangeX

OrangeX was founded by three professional firefighters who share a passion for service, excellence and trees. Our fresh approach to tree care is shaking up the industry. By applying the same levels of professionalism and service excellence that we learned in the fire service to the tree care industry, we've set ourselves apart and quickly earned a reputation as a name you can trust.

We believe in putting our people first. Our employee-centered approach means we offer the best pay and enforce the highest safety standards, which allows us to hire and retain the best in the industry. Our customers love it, because they know that when they hire OrangeX Tree Services, they are getting best.

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