OR Landscape Contractor flashcards

32 cards. Read the term and the definition here. The deck at the top of this page is optional.

Oregon Landscape Contractors Board

The Oregon state agency that licenses landscape contracting businesses under ORS Chapter 671, adopts rules in OAR chapter 808, and investigates complaints against licensees.

Limited landscape contracting license

An Oregon LCB license that authorizes only specified specialty work, such as irrigation installation or landscape maintenance, instead of the full scope of landscape contracting.

Landscape contracting under ORS 671

Work performed for compensation that involves planning, installing, constructing, planting, or maintaining landscape and its appurtenances for another person, which requires an LCB license.

Root flare

The widened zone where trunk tissue transitions to root tissue; it must sit at or slightly above finished grade, because a buried flare girdles and kills the tree.

Balled-and-burlapped stock

Nursery trees and shrubs dug with a soil ball wrapped in burlap and secured with twine or a wire basket; remove at least the top half of the wrapping before backfilling.

Right plant, right place

Selecting species by matching site conditions such as hardiness zone, light, soil moisture and drainage, mature size, and maintenance budget to the plant's known requirements.

Leaf arrangement

The pattern of leaves along a stem, either alternate, opposite, or whorled, and one of the primary keys used with leaf type, margin, buds, and bark for identification.

Precipitation rate formula

Precipitation rate in inches per hour equals 96.25 times the zone flow in gallons per minute, divided by the irrigated area in square feet.

Matched precipitation rate

Design practice of keeping only heads with equal precipitation rates on the same zone, so every part of the area receives uniform water and none is over- or under-irrigated.

Reduced pressure zone assembly

A backflow preventer with a differential relief valve that discharges if pressure is lost, used on high-hazard connections such as irrigation with chemical injection, and tested annually.

Cycle-and-soak irrigation

A controller method that runs a zone in several short cycles separated by soak pauses so water infiltrates clay soil instead of running off the surface.

Gross margin percentage

Revenue minus direct job costs, divided by revenue; it measures what remains from each sales dollar to cover overhead and profit on a project.

Labor burden

The cost above base wage for payroll taxes, workers' compensation insurance, benefits, and paid leave, typically adding 25 to 40 percent to the hourly rate.

Break-even revenue

The sales volume at which total revenue equals total costs, calculated as annual fixed overhead divided by the company's gross margin percentage.

Quantity takeoff

Systematic measurement of every material and labor item from the plans, such as area, length, count, and volume, producing quantities to which unit costs are applied.

Oregon construction lien deadline

In Oregon, a construction lien must be recorded within 75 days after completion of the improvement in order to preserve the claimant's right to lien the property.

Change order

A written, signed amendment to the contract that defines a change in scope, price, or schedule; changed work should not proceed until the document is executed.

Soil textural triangle

A chart used to name soil texture from the percentages of sand, silt, and clay in a sample; loam falls near 40 percent sand, 40 percent silt, and 20 percent clay.

Compaction and bulk density

Compaction presses soil particles together, raising bulk density and lowering pore space and air, which restricts root growth and infiltration; it happens when wet soil is trafficked.

French drain

A subsurface drain of perforated pipe set in washed gravel and wrapped in filter fabric, laid at a minimum one percent fall to carry groundwater to an outlet.

Paver base thickness

Compacted aggregate base is typically 4 inches for pedestrian pavers and 6 to 8 inches for vehicle areas, topped with 1 inch of bedding sand.

Retaining wall batter

The deliberate backward lean of a segmental retaining wall, about 1 inch per foot of height, which improves stability by keeping the wall's weight over its base.

Concrete control joint

A sawed or tooled groove forming a weakened plane so concrete cracks there rather than randomly; typical spacing is 8 to 10 feet in a 4-inch slab.

One-third mowing rule

Remove no more than one-third of the grass blade height at any single mowing; cutting more shocks the plant, thins the stand, and invites weeds.

Thatch layer

The layer of dead stems, roots, and crowns between the soil surface and green grass; when it exceeds about one-half inch, core aerification or dethatching is needed.

Deep and infrequent irrigation

Watering turf heavily but rarely so moisture penetrates the full root zone, encouraging deeper roots and greater drought tolerance than light daily sprinkling.

Economic threshold

The pest population level at which the cost of control equals the damage the pest causes; integrated pest management treats only when monitoring shows it is reached.

Restricted-entry interval

The label-specified period after a pesticide application during which workers may not enter the treated area without required protective equipment; it appears on every agricultural label.

Mode-of-action rotation

Alternating pesticides from different IRAC, FRAC, or WSSA groups so a pest population is exposed to different chemistries and resistance is less likely to develop.

Call 811 before digging

Oregon's free utility locate service; a contractor must notify it at least two business days before excavation and wait for buried lines to be marked.

Excavation protective system

Sloping, benching, shoring, or a trench shield required for excavations 5 feet or deeper; soil type sets the maximum allowable slope, from 0.75:1 to 1.5:1.

Hearing protection threshold

Oregon OSHA requires hearing protection and a hearing conservation program when noise exposure reaches 85 decibels averaged over eight hours; use double protection above 100 dBA.