How To "Talk Trees"

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
Dripline – 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.
Parkstrip – 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 parkstrip between the sidewalk and street
Topping – Removing the top or sections of large branches with no regard for how the tree will recover. See link for more details
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