Below is a glossary of terms commonly used by Urban Forestry and in the tree care industry:

Absorbing Roots – Non-woody roots that absorb water and nutrients

Broadleaf – Trees that have broad, flat leaves as opposed to needles. Also often called “hardwoods”

Buds – Leaves contained in protective tissue through the winter

Caliper – Diameter of the tree measured at the ground. Only used for nursery trees below 6 inches

Cambium – Thin layer of cells that produces new wood

Canopy – The layer made up of all tree crowns in a specified area

Certified Arborist – An arborist that is certified by the International Society of Arboriculture to possess technical skills and knowledge through experience and training to manage or provide expertise on the management of trees

Conifer – A tree with needles instead of leaves. Most are evergreen, however some are deciduous

Critical root zone – An area near the trunk of the tree where the large anchoring roots are located

Crown – The branches and leaves at the top of the tree

Diameter at Breast Height (DBH) – Diameter of the tree measured at 4.5 ft above the ground

Deciduous – Trees that lose their leaves each year. These are usually broadleaf trees, but several conifers are deciduous

Drip line – The horizontal edge of the tree crown

Drought-tolerant – Trees that are more adapted to withstand extended dry periods when they are mature. ALL TREES STILL NEED WATER, but especially young trees. Drought-tolerant does not mean you don’t have to water the tree.

Girdle – To cut through the cambium all the way around the tree

Girdling root – A root that has grown to encircle the main stem of the tree and girdles the tree

Hanger – A large branch that is broken and hanging in the tree

High-voltage transmission lines (HVTL) – Utility wires that transmit power throughout the electrical grid. These require high clearance and are different than cable or other small electric lines that do not require large clearances. Trees near HVTL need to be pruned by utility companies and must have large clearances.

Park strip – Area of landscaping between the sidewalk and street

Pruning – An intentional process of cutting tree branches to promote tree health/safety. Pruning is not randomly cutting branches with no clearly defined end-goal

Public right-of-way – City-owned strip of land extending from the center of the street to a defined distance

Removal – Work done by professionals to safely take a tree out of the landscape. Urban Forestry removes trees due to safety issues or the health of the tree is beyond remediation

Street tree – City-owned trees growing in the park strip between the sidewalk and street

Topping – Removing the top or sections of large branches with no regard for how the tree will recover.

Tree – A plant that forms woody tissue with a single trunk and extending to heights above 15 ft

Tree Protection Zone – A Fenced-off area around existing trees during construction activity

Trunk – Main stem of the tree

Vascular System – The structures in a tree that carry water and energy throughout the tree