Module 2.) Levels of Assessment Flashcards
categorization of the breadth and depth of analysis used in an assessment
Level(s) of assessment
a visual assessment from a specified perspective such as a foot, vehicle, or aerial (airborne) patrol of an individual tree or a population of trees near specified targets to identify conditions or obvious defects of concern.
Limited visual assessment (level 1)
a defined set, group, or collection of trees.
Tree population
a limited visual inspection, usually from one side of the tree, performed as the tree risk assessor walks by the tree(s)
Walk-by (assessment)
limited visual inspection from only one side of the tree, performed from a slow-moving vehicle. Also may be called a windshield assessment.
Drive-by (assessment)
overflights of a utility right-of-way, large areas, or individual trees in a defined area to record the location of trees that are likely to fail and cause harm.
Aerial patrol
a remote sensing method that uses laser technology to measure tree size and location in relation to the target of concern.
LiDAR
Light Detection and Ranging
detailed visual inspection of a tree and surrounding site that may include the use of simple tools. It requires that a tree risk assessor inspect completely around the tree trunk looking at the visible aboveground roots, trunk, branches, and site.
Basic assessment (level 2)
a measuring tape scaled such that when it encircles a tree trunk, the width can be read directly.
Diameter tape
instrument used for measuring the height of a tree or other structure.
Clinometer
a broad headed hammer made of wood, plastic, or resin used for “sounding” a tree.
Mallet
a stiff, small-diameter rod, stick, or wire that is inserted into a cavity or crack to estimate its size or depth.
Probe
an assessment performed to provide detailed information about specific tree parts, defects, targets, or site conditions. Specialized equipment, data collection and analysis, and/or expertise are usually required.
Advanced assessment (level 3)
inspection of the upper tree parts not readily accessed from the ground; typically done by climbing or from a lift.
Aerial inspection
an instrument or tool developed to detect decay in tree parts.
Decay-detection device
degradation of the ability to withstand mechanical stress.
Strength loss
a device consisting of a specialized micro-drill bit that drills into trees and graphs resistance to penetration; used to detect internal differences in the wood, such as decay.
Resistance-recording drill
a process of measuring wood density, or other mechanical properties, using an instrument that transmits, receives, and records the velocity of sound or electric waves through wood.
Sonic assessment
use of multiple sensors placed around a trunk of limb to record sound or magnetic waves traveling through the wood, with measurements resulting in a picture of internal density characteristics. Typically used in arboriculture to measure the extent of decay in trees.
Tomography
roots at the base that help support the tree and equalize mechanical stress.
Buttress roots
process of removing soil to expose and assess the root collar (root crown) of a tree.
Root collar excavation (RCX)
a nondestructive device that uses radar pulses to image the subsurface.
Ground-penetrating radar
in advanced tree risk assessment, pulling tests to measure or observe the amount of inclination and/or deformation to assess stability.
Load testing
a load test that involves installing a line in a tree, and the pulling and releasing the line several times to move the tree or branch. Most commonly used in a pre-work inspection, but can be used as part of an advanced tree risk assessment.
Hand pull test