Glossary of Tree Care Terms: A Resource for Eugene, OR Residents

Caring for trees is a rewarding endeavor, but the specialized language used by arborists can be confusing. Whether you're a homeowner with a few trees on your property or a community member interested in the urban forest, understanding tree care terminology is essential for making informed decisions and ensuring your trees receive the best possible care.

Urban Arbor Care, the leading tree service provider in Eugene, OR, is here to help you navigate the world of tree care terms. This comprehensive glossary will define key concepts, explain common practices, and empower you to communicate effectively with arborists and tree care professionals.

A

• Abscission: The natural process of a tree shedding leaves, flowers, fruit, or other parts.
• Aerial Root: A root that grows above ground, often providing support or absorbing moisture from the air.
• Arborist: A professional who specializes in the care and maintenance of trees. Arborists are trained in tree biology, identification, pruning, planting, and other aspects of tree care.
• Aspect: The direction a slope faces, influencing sunlight exposure and microclimate.

B

• Bark Ridge: A raised line of bark where two branches or stems join.
• Branch Collar: A swollen area at the base of a branch where it attaches to the trunk.
• Branch Union: The point where two branches or stems join.

C

• Cambium: A thin layer of tissue between the bark and wood responsible for tree growth.
• Canopy: The upper portion of a tree, consisting of branches and leaves.
• Chlorosis: A condition in which leaves turn yellow due to a lack of chlorophyll.
• Codominant Stems: Two or more stems of similar size and vigor growing from the same point on a tree.
• Crown: The entire top of a tree, including branches, twigs, and leaves.
• Crown Cleaning: The removal of dead, diseased, or weakly attached branches from the tree's crown.
• Crown Raising: The removal of lower branches to increase clearance for buildings or vehicles.
• Crown Reduction: The selective removal of branches to reduce the size or density of a tree's crown.
• Crown Thinning: The removal of a portion of smaller branches to increase light penetration and air circulation.

D

• Deciduous: Trees that shed their leaves annually.
• Defoliation: The loss of leaves from a tree, which can be caused by pests, disease, or environmental stress.
• Dieback: The progressive death of twigs and branches, often starting at the tips.

E

• Espalier: A pruning technique that trains trees to grow in a flat, two-dimensional form against a wall or trellis.
• Evergreen: Trees that retain their leaves year-round.

F

• Fastigiate: A tree form with upright branches that create a narrow, columnar shape.
• Flare: The widening of the trunk at its base where it meets the roots.

G

• Girdling Root: A root that encircles the trunk, potentially constricting growth and causing tree decline.

H

• Heading Cut: A pruning cut that removes the terminal portion of a branch, stimulating lateral bud growth.
• Heartwood: The non-living, central wood of a tree, often darker in color.

I

• Internode: The section of stem between two nodes (where leaves or branches are attached).

L

• Lateral Branch: A branch that grows outward from a main stem.
• Leader: The dominant, central stem of a tree.

M

• Meristem: A region of active cell division responsible for tree growth.
• Mulch: A layer of organic material spread around the base of a tree to retain moisture, suppress weeds, and regulate soil temperature.

N

• Node: A point on a stem where leaves or branches are attached.

P

• Phloem: The inner bark tissue that transports nutrients throughout the tree.
• Pollarding: A pruning technique that removes all branches from a tree, leaving stubs from which new shoots will grow.
• Pruning: The selective removal of branches or parts of a tree to improve its health, structure, and appearance.

R

• Root Collar Excavation: The process of removing soil around the base of a tree to expose the root flare and improve root health.
• Root Crown: The area where the trunk transitions into the roots.

S

• Sapwood: The living, outer wood of a tree, often lighter in color.
• Scaffold Branches: The main structural branches of a tree.
• Thinning Cut: A pruning cut that removes an entire branch at its point of origin.
• Topping: A harmful pruning practice that involves cutting the top of a tree.

T

• Transplanting: The process of moving a tree from one location to another.
• Tree Removal: The process of cutting down and removing a tree from a site.

W

• Water Sprout: A vigorous, upright shoot that grows from latent buds on the trunk or branches.
• Whorl: A ring of three or more branches or leaves growing from the same point on a stem.

X

• Xylem: The wood tissue that transports water and nutrients from the roots to the rest of the tree.

FAQs: Your Tree Care Questions Answered by Urban Arbor Care's Certified Arborists

1. What is the difference between an arborist and a tree trimmer? An arborist is a trained professional with expertise in all aspects of tree care, including pruning, planting, disease diagnosis, and risk assessment. A tree trimmer typically focuses on basic pruning and removal tasks.
2. Why should I hire a certified arborist? Certified arborists have the knowledge and experience to provide proper tree care, ensuring the health, safety, and longevity of your trees. They also adhere to industry standards and best practices.
3. When is the best time to prune my trees? The optimal time for pruning depends on the tree species and the desired outcome. In general, late winter or early spring, when trees are dormant, is a good time for most pruning. However, some trees may require pruning at other times.
4. Is tree removal always necessary? Tree removal is a last resort.  In many cases, tree pruning, bracing, or other treatments can save a tree. Consult with a certified arborist to determine the best course of action.
5. How can I protect my trees from pests and diseases? Regular inspection, proper cultural practices, and timely intervention can help prevent pest and disease infestations. If you notice any signs of problems, contact a certified arborist for diagnosis and treatment.
6. What should I do if a tree falls on my property during a storm? Do not attempt to remove the tree yourself. Contact Urban Arbor Care for emergency tree removal services. Our team is available 24/7 to respond to storm damage and ensure your safety.

Contact Urban Arbor Care Today!

We hope this glossary has demystified the language of tree care. If you have further questions or need professional tree services in Eugene, OR, contact Urban Arbor Care today. Our team of certified arborists is dedicated to providing the highest quality tree care to help your trees thrive.

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