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Categories All categories Arboriculture Terms
p
- pulleydevice consisting of a rotating. grooved wheel between two side plates or cheeks. Used to change the direction of pull in a line. as a fair lead to guide a line or as part of a mechanical advantage system (compare to block).
- pupa (pl. pupae)resting stage of an hemimetabolous insect just prior to transforming to an adult. Stage at which adult morphology is acquired.
- pustulessmall. confined blister-like raised area on a leaf surface.
- PUWERPosition and Use of Work Equipment Regulations
- PWPpermanent wilting point
q
- QTRAquantified tree risk assessment
- qualified line-clearance arboristan individual who. through related training and on-the-job experience. is familiar with the equipment and hazards in line clearance and has demonstrated the ability to perform the special techniques involved.
- quick-release fertilizera fertilizer that is immediately available to a plant (contrast with slow-release fertilizer).
r
- radial aerationsee radial trenching.
- radial transportlateral movement of substances. perpendicular to the longitudinal axis of the tree or stem.
- radial trenchingtechnique for relieving soil compaction and improving rooting conditions around a tree by digging or excavating trenches in a spoke-like pattern radially from the trunk. then backfilling. Often performed with air excavation equipment to minimize root damage (see trenching).
- raisingselective pruning to provide vertical clearance (see crown raising).
- ram's hornsinward curling formation of wound wood resembling the horns of a ram.
- raspingScraping. as in the rasping mouthparts of an insect
- ratcheting bollardBallard-type lowering device equipped with a mechanism for lifting loads.
- rayparenchyma tissues that extend radially across the xylem and phloem of a tree and function in transport. storage. structural strength. and defense.
- RCAASCA Registered Consulting Arborist
- RCEroot collar examination
- reliability-centered management. replacement cost method
- RCXroot collar excavation
- reaction forceforce of equal magnitude exerted in the opposite direction of a force acting on a body.
- reactive forceforce generated in response and opposite to another force. Important concept for safely operating a chain saw.
- recycled waterwastewater that has been recovered and/or treated for potable or non-portable use.
- redirectI) v. changing the path of a climbing or rigging line to modify the forces on. or the direction of. the line. 2) n. a system installed to change the path of a climbing or rigging line.
- reductionpruning to decrease height and/or spread of a branch or crown.
- reduction cutpruning cut that reduces the length of a branch or stem back to a lateral branch large enough to assume apical dominance. Pruning method that reduces the height and/or spread of a plant. using reduction cuts and branch removal cuts.
- reduction pruningpruning method that reduces the length of a branch or stem back to a lateral branch.
- regenerationtissue restoration or new growth produced by an organism. In forestry. establishment of new trees. either naturally or planted.
- reiterationan asexual reproductive strategy of trees such as aspen (Populus spp.) and willow (Salix spp.). which produce new trees or groups of trees by root suckering (see Slicker).
- reliability-centered management (RCM)in an electric utility system. scheduling of preventive maintenance (including utility arboriculture and IVM) to maximize electric service reliability and cost efficiency.
- removal cutcut that removes a branch just outside the collar at its point of origin. Collar cut.
- replacement cost method (RCM)method to appraise the monetary value of trees considered replaceable with nursery or field-grown stock. Based on the cost of replacement with the same or a comparable species of the same size and in the same place. subject to depreciation for various factors (contrast with trunk formula method).
- rescue kitclimbing gear and emergency equipment that should be sent out on every job site and made available to a worker conducting an aerial rescue or applying first aid.
- rescue pulleylight-duty pulley used in light rigging operations.
- resinSolid or semisolid natural organic flammable substance formed by plant secretions that are typically not water-soluble
- resistance1) in plants. the tendency to withstand certain pests. disease. or fungal problems; pest resistance. 2) in insects. the ability to withstand certain insecticides; survival of just a few genetically resistant insects that reproduce can lead to populations that are resistant.
- resistance-recording drillsee micro drill resistance testing.
- resistant varietiesplant varieties that are tolerant of. or not susceptible to. certain disease or pest problems or abiotic disorders.
- Resistographbrand name of a device consisting of a specialized micro-drill bit that drills into trees and graphs density differences that are used to detect decay. Invented and trademarked by Frank Rinn of Heidelberg. Germany.
- resonance testingnondestructive means of determining the soundness or structural integrity of an object or material by determining the rate at which magnetic. sound. or other waves travel through it.
- resource allocation1) in plant physiology. distribution and use of photosynthates for various plant functions and processes. 2) in management. distribution of materials or other assets to accomplish objectives.
- resource assessmentin urban forestry. an evaluation of trees based on inventory. canopy assessment. and/or sample surveys; may also consider factors affecting the urban forest such as soils. hydrology. water quality. temperature extremes. and wind.
- resource conservationactions and plans that protect and sustain natural plant and animal communities. soil. water. and ecosystems.
- respirationin plants. process by which carbohydrates are converted into energy by using oxygen.
- response growthnew wood produced in response r to loads to compensate for higher strain in outermost fibers; includes reaction wood (compression and tension) and woundwood.
- restoration1) pruning to improve the structure. form. and appearance of trees that have been vandalized. damaged. or improperly trimmed. 2) management and planting to restore altered or damaged ecosystems or landscapes. 3) replacement or reproduction of damaged or destroyed plants.
- retreat pathpredetermined escape route away from a tree that is to be felled. Should be a 45-degree angle back and away from the direction of the falling tree and clear of obstruction (see escape route).
- retrenchment1) natural process during which a mature tree reduces its crown and increases its girth to consolidate resources and increase longevity. 2) the deliberate process of reducing tree height to mimic natural processes.
- RFPrequest for proposal
- RFSRoyal Forestry Society