16.32.010 DEFINITIONS
The following definitions will apply for terminology used in this chapter. If a definition is not listed in this chapter, the definition in Title 19 will apply. Where definitions are not provided in this chapter or Title 19, their normal dictionary meaning will apply:
“Arbor Day/Week” means a day/week designated by the City to celebrate and acknowledge the importance of trees in the urban environment.
“Arboriculture” means the practice and study of the care of trees and other woody plants in the landscape.
“Canopy” is the layer of leaves, branches and stems of trees that cover the ground when viewed from above. Canopy cover is measured as the proportion of a fixed area of the ground covered by tree crowns.
“City” means the City of Milwaukie.
“City Engineer” means the City Engineer of the City of Milwaukie or designee.
“City Manager” means the City Manager or the City Manager’s authorized representative or designee.
“Council of Tree and Landscape Appraisers (CTLA)” means the publishers of the Guide for Plant Appraisal.
“Crown” means area of the tree above the ground, measured in mass, volume, or area extending from the trunk and including the branches, stems, leaves, and reproductive structures.
“Crown area” means the average area in square feet that the tree crown covers (Figure 16.32.010-1).
Figure 16.32.010-1
Measuring Crown Area
“Cutting” means the felling or removal of a tree, or any procedure that naturally results in the death or substantial destruction of a tree. Cutting does not include normal trimming or pruning but does include topping of trees.
“DBH” means the diameter at breast height.
“Dead tree” means a tree that is dead or has been damaged beyond repair or where not enough live tissue, green leaves, limbs, or branches exist to sustain life.
“Diameter at breast height” or “DBH” means the measurement of mature trees as measured at a height 4.5 feet above the mean ground level at the base of the tree (Figure 16.32.010-2A). The DBH may be determined by measuring the circumference of the tree trunk 4.5 feet above the mean ground level at the base of the tree and dividing by 3.14. Trees existing on slopes are measured at the lowest point of ground at the base of the tree (Figure 16.32.010-2B). When the trunk branches or splits less than 4.5 feet from the ground, measure the smallest circumference below the lowest branch and divide by 3.14 (Figure 16.32.010-2C). For multi-stemmed trees, the size is determined by measuring all the trunks, and then adding the total diameter of the largest trunk to 1/2 the diameter of each additional trunk. A multi-stemmed tree has trunks that are connected above the ground and does not include individual trees growing close together or from a common root stock that do not have trunks connected above the ground (Figure 16.32.010-2D).
Figure 16.32.010-2
Measuring Diameter at Breast Height
“Drip line” means the perimeter measured on the ground at the outermost crown by drawing an imaginary vertical line from the circumference of the crown, straight down to the ground below.
“Dying tree” means a tree that is diseased, infested by insects, deteriorating, or rotting, as determined by a professional certified in the appropriate field, and that cannot be saved by reasonable treatment or pruning, or a tree that must be removed to prevent the spread of infestation or disease to other trees.
“Hazardous tree” means a tree or tree part the condition or location of which presents a public safety hazard or an imminent danger of property damage as determined by an ISA Qualified Tree Risk Assessor, and such hazard or danger cannot reasonably be alleviated by treatment or pruning.
“Invasive species” means a tree, shrub, or other woody vegetation that is on the Oregon State Noxious Weed List or listed on the City of Milwaukie Invasive Tree List in the Public Works Standards.
“ISA” means the International Society of Arboriculture.
“ISA Best Management Practices” means the guidelines established by ISA for arboricultural practices for use by arborists, tree workers, and the people who employ their services.
“Major tree pruning” means removal of over 20% of the live crown, or removal of or injury to over 15% of the root system during any 12-month period.
“Master Fee Schedule” is the schedule of City fees and charges adopted by City Council for the services provided by the City.
“Minor tree pruning” means the trimming or removal of less than 20% of any part of the live crown, or less than 15% of the root system during a 12-month period.
“NDA” means Neighborhood District Association.
“Noxious weed” means a terrestrial, aquatic, or marine plant designated by the State Weed Board under ORS 569.615.
“Owner” means any person who owns land, or a lessee, agent, employee, or other person acting on behalf of the owner with the owner’s written consent.
“Park tree” means a tree, shrub, or other woody vegetation within a City park.
“Person” means any natural person, firm, partnership, association, social or fraternal organization, corporation, estate, trust, receiver, syndicate, branch of government, or any other group or combination acting as a unit.
“Public agency” means any public agency or public utility as defined in ORS 757.005, or a drainage district organized under ORS Chapter 547.
“Public tree” means a tree, shrub, or other woody vegetation on land owned or maintained by the City, but does not include a tree, shrub, or other woody vegetation in the right-of-way.
“Right-of-way” means an area that allows for the passage of people or goods. Right-of-way includes passageways such as freeways, pedestrian connections, alleys, and all streets. A right-of-way may be dedicated or deeded to the public for public use and under the control of a public agency, or it may be privately owned. A right-of-way that is not dedicated or deeded to the public is usually in a tract or easement.
“Shrub” means any plant with multiple woody stems that does not have a defined crown and does not grow taller than a height of 16 feet.
“Street tree” means a tree, shrub, or other woody vegetation on land within the right-of-way. When any portion of the trunk of a tree crosses a public right-of-way line at ground level, it is considered a street tree.
“Street Tree List” is the list of tree and shrub species approved by the City for planting within the right-of-way.
“Topping” means a pruning technique that cuts branches and/or the main stem of a tree to reduce its height or width.
“Tree” means any living woody plant characterized by one main stem or trunk and many branches, or a multi-stemmed trunk system with a defined crown, that will obtain a height of at least 16 feet at maturity.
“Tree Board” means the City of Milwaukie Tree Board.
“Tree Canopy” means the aggregate or collective tree crowns.
“Tree Fund” means the Tree Fund as created by this chapter.
“Tree removal” means the cutting or removal of 50% or more of the crown, trunk, or root system of a plant, the uprooting or severing of the main trunk of the tree, or any act that causes, or may reasonably be expected to cause the tree to die as determined by an ISA Certified Arborist.
“Urban forest” means the trees that exist within the City.
“Urban Forester” means the Urban Forester of the City of Milwaukie, or designee.
“Urban Forest Management Plan” is the management plan adopted by City Council for the management of the City’s urban forest.
“Utility” is a public utility, business, or organization that supplies energy, gas, heat, steam, water, communications, or other services through or associated with telephone lines, cable service, and other telecommunication technologies, sewage disposal and treatment, and other operations for public service. (Ord. 2216 § 2, 2022; Ord. 2197 § 1, 2020; Ord. 2141 § 1, 2017; Ord. 2116 § 1, 2016; Ord. 1836 § 1, 1998)