Critical Root Zone – Generally a circular region measured outward from a tree trunk representing the essential area of the roots that must be maintained or protected for the tree’s survival. Critical root zone is one foot of radial distance for every inch of tree diameter measured at 4.5 feet above ground level, with a minimum of eight feet. For significant trees, the formula changes to 1.5 feet for every inch of tree diameter measured at 4.5 feet above ground level, with a minimum of 12 feet.

Crown – the leaves and branches of a tree or shrub; the upper portion of the tree from the lowest branches on the trunk to the top. May also be referred to as “canopy.”

DBH – Diameter-at-breast-height is tree trunk diameter measured in inches at a height of 4.5 feet above the ground. If a tree splits into multiple trunks below 4.5 feet, the trunk is measured at its most narrow point beneath the split.

Downtown Tree Zone – Street trees located within an area bounded on the north by Fifth Street, on the south by First Street, on the east by Johnson Street and on the west by Adams Street.

Downtown Tree – A public street tree planted within public rights-of-way within the Downtown Tree Zone.

Drip Line – A vertical line extending from the outermost edge of the tree’s original canopy to the ground.

Hazardous Tree – A tree or part thereof growing on private or public property which endangers, obstructs or impairs the free and full use of a public area, including utilities within these areas or is afflicted with or weakened by a disease or injury.

Historic Tree – Selected trees placed on an inventory based on the age, species, location, and historic significance.

Major Pruning – Removal of over 20 percent of the tree’s canopy, any tree topping, or disturbances of over 10 percent of the root system.

Public Tree – A tree located within a public right-of-way or on public land, such as a city park.

Repeated or Excessive – Two incidents within any three year period requiring removal or repair of a public sidewalk.

Significant Trees – Selected trees placed on an inventory based on the age, species, and location.

Street Tree – A living, standing woody plant typically having a single trunk at least 1-1/2 inches in diameter at a point six inches above mean ground level at the base of the trunk, that is located within the street right-of-way.

Topping – The severe cutting back of limbs to stubs three inches in diameter within the tree’s crown to such a degree so as to remove the natural canopy and disfigure the tree.

Tree – Any woody plant having a trunk five inches or more in diameter 4.5 feet above ground level at the base of the trunk. If a tree splits into multiple trunks below 4.5 feet, the trunk is measured at its most narrow point beneath the split.

Tree Board – An appointed citizen committee formed for the purpose of hearing concerns and making decisions regarding trees. The McMinnville landscape review committee currently serves in this capacity.

Tree Establishment – Includes watering, initial pruning, and replacement of trees, if necessary, for a period of three years from the date of planting. (Ord. 4816 §2, 2004; Ord. 4654-B §1, 1997).