Arboriculture Glossary of Terms
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- palmmonocotyledon plant of the Palmacea family. With some exceptions. it has an unbranched trunk; its leaves are spirally arranged around the terminal bud; and the vascular bundles are scattered.
- palmatetype of compound leaf with veins or leaflets radiating in a fanlike pattern (contrast with bipinnate and pi11nate).
- Pandanus pygmaeus Pandanus pygmaeus
- Pandanus tectorius Pandanus tectorius
- PARphotosynthetic active radiation
- parasiteorganism living in or on another living organism (host) from which it derives nourishment to the detriment of the host (contrast with epiphyte and saprophyte).
- parasitoidorganism living in or on another living organism during its immature stage. killing& sterilizing. and/or consuming the host when it emerges (see parasite; contrast with epiphyte and saprophyte).
- parenchyma cellsthin-walled. living cells capable of dividing and essential in photosynthesis. radial transport. energy storage. and production of protective compounds.
- parent branchlarger branch or stem from which a smaller. lateral branch arises.
- parent materialsoil bedrock or base material from which a soil profile develops.
- Parthenocissus himalayana Parthenocissus himalayana
- particulatessmall solids suspended in air that are generated by combustion of fossil fuels. construction and demolition. industrial processes. soil tillage and erosion. and complex reactions between sunlight and gaseous pollutants. Associated with respiratory and cardiopulmonary diseases and cancer.
- patented plantplant cultivar for which exclusive rights are granted to a breeder. Only the patent holder may commercially propagate or sell the cultivar. Contrast with trademarked cultivar.
- PBZpaclobutrazol
- peaveylever with an adjustable hook and a sharp spike instead of a blunt end. Used for handling a11d rolling logs.
- peenthe act of bending. rounding. or flattening the fastening end of through-hardware for the purpose of preventing a nut from backing off." "
- Peltophorum pterocarpumYellow Poinciana
- penetrometera device for assessing soil compaction; can be dynamic or static.
- PERCFederal Energy Regulatory Commission
- perched water tableaccumulation of water in an upper soil layer above the actual water table. resulting when drainage in ru1 area is impeded by an impem1eable layer. such as rock or heavy clay. or when the interface between soil layers bas become stratified (i.e.. with sharp contrast in soil pore sizes) (see water table).
- percolationmovement of water through the soil (contrast with infiltration).
- perennialplants that live for more than two growing seasons (compare to annual and bien11inf).
- performance budgetingbudget format that identifies what programs will accomplish with the expenditures; includes mission statements and objectives along with performance measures. Compare with program budgeting.
- performance evaluationassessment of an employee's work quality and competence in performing the job duties. description of problems that need correcting. and identification of objectives for the future.
- performance measurementquantifiable evaluations of specific outcomes and outputs and progress toward goals.
- performance standardsdescriptions of expected work quality. behaviors. and outcomes for specific duties on which employee performance is evaluated.
- peridermthe outer layers of tissue of woody roots and terns consisting of the cork cambium and the tissues produced by it. such as bark.
- permanent branchesin structural pruning of young trees branches that will be left in place often forming tbe initial scaffold framework of a tree (contrast with temporary branches).
- permanent wilting pointpoint at which a plant cannot pull any more water from the soil and suffers permanent damage (compare to available water. field capacity. gravitational water. and saturation point).
- permeableallowing liquids or gases to pass through. as with a membrane or material.
- permitwritten order granting permission to conduct a specified task or action.
- personal protective equipment(PPE) personal safety gear such as hard hat. safety glasses. hearing protection. and leg protection. including chaps.
- personal protective equipment (PPE)personal safety gear such as helmet. safety glasses. hearing protection. gloves. and leg protection. including chaps.
- perviouspenetrable; allowing passage through; often used to describe surfaces.
- pestorganism (including. but not limited to. weeds. insects. or fungi) that is damaging. noxious. or a nuisance.
- pest preventionan approach to pest management that encourages favorable plant development conditions and discourages favorable pest development conditions.
- pest resistancein plants. the tendency to withstand or to not develop certain pest problems.
- pest resurgenceincrease in the population of a pest following a reduction in the population of natural predators or parasites of that pest. Usually the result of a nonspecific pesticide or unfavorable environmental condition.
- pest suppressionan approach to pest management that reduces the pest
- pesticideany chemical used to control or kill unwanted pests such as weeds. insects. or fungi.
- pesticide resistanceability to withstand certain pesticides; survival ofjust a few genetically resistant pests that reproduce can lead to populations that are resistant.
- petiolestalk ofa leaf or portion ofa leaf between the stem and the blade.
- petiolulestalk of a leaflet.
- PGRplant growth regulator
- pHunit of measure that describes the alkalinity or acidity of a solution. Negative log of the hydrogen ion concentration. Measured on a scale from 0 to 14. Greater than 7 is alkaline. less than 7 is acid. and 7 is neutral (pure water) (see acidity and alkalinity).
- phasein an electric utility system. a single primary line affixed to a pole or cross arm. Technically. phase refers to the synchronized movement of electrical energy and pertains to common designs of electric supply lines such as single phase (one primary conductor). two phase (two primary conductors). or three phase (three primary conductors).
- phase-to-groundin an electric utility system. the electrical potential between an energized conductor and the ground.
- phase-to-neutralin an electric utility system. the electrical potential between an energized conductor and the neutral wire.
- phase-to-phasein an electric utility system. the electrical potential between two energized conductors or between an energized conductor and a neutral conductor.
- PHCPlant Health Care
- phellemthe outer portion of the bark that often exfoliates in plates or peels as it sheds from the tree.
- Phellinus noxiusPhellinus noxius (有害木層孔菌) is a white simultaneous rot fungus that causes Brown Root Rot(BRR) disease (褐根病), which could result in rapid health and structural deterioration of trees and may lead to tree failure.
- phellodermthe inner portion of the outer bark generated by the cork cambium that stores energy and may photosynthesize.
- phellogenmeristematic tissue located in the bark and that generates the phelloderm on the inside and the phellem on the outside. Cork cambium.
- phenological stagea biological stage of development of an organism that may be associated with other biological events such as insect hatching.
- phenologyrelationship between the climate and biological events. such as flowering or leafing out in plants.
- phenology calendara calendar that correlates pest activity or development with readily observable. seasonal events such as plant budding. flowering. or fruiting.
- phenolsnaturally produced organic alcohols. One of several chemical defense compounds in trees.
- pheromonechemical substance produced by an animal (usually in reference to insects) that serves as a method of communication with other individuals of the same species.
- Philodendron bipinnitifidumPhilodendron bipinnitifidum
- Philodendron bloodred Philodendron bloodred
- Philodendron selloum Philodendron selloum
- Philodendron XanaduPhilodendron Xanadu
- Phoenix robellenii Phoenix robellenii
- photoperiodlength of daylight and/or darkness required for certain developmental processes and growth in plants.
- photosynthategeneral term for the sugars and other carbohydrates produced during photosynthesis.
- photosynthesisprocess in green plants (and in algae and some bacteria) by hitch light energy is used to fom1 glucose (chemical energy) from water and carbon dioxide. "
- photosynthesizeto form sugar (glucose) from water and carbon dioxide using the energy of light (see photosynthesis).
- phototropisminfluence of light on the direction of plant growth. Tendency of plants to grow toward light.
- Phyllanthus emblicaMyrobalan - Emblic Leaf-flowered
- Phyllanthus myrtifolia Phyllanthus myrtifolia
- phylum (pl. phyla)primary taxonomic group within kingdom.
- physiological disorderin plants. a disorder not directly caused by an insect. pathogen. or injury.
- physiologyin arboriculture. the study of the life function of a tree (contrast with anatomy. morphology. and taxonomy).
- phytochromeplant pigment that is sensitive to certain wavelengths of light. Plays a role in plant responses to light.
- phytotoxictend to describe a compound that is poisonous to plants.
- phytotoxicityquality of being phytotoxic.
- pigmentsubstance that appears colored as a result of the reflection of certain light wavelengths.
- pin locksee notch gate.
- pinchingthe equivalent of heading performed on a very young tree or plant (see heading).
- pinnatetype of compound leaf. with leaflets along each side of a common axis (contrast with bipinnate and palmate).
- pitch tubestubular structures created by insects on the bark around entrance holes; can be made of resin. boring dust. and/or frass. Usually associated with conifers.
- piththe central core of a stem. Often is a lighter color than surrounding tissue.
- PLANETProfessional Landcare Network
- plant growth regulatorcompound effective in small quantities that affects the growth and/or development of plants. May be naturally produced (hormone) or synthetic (see plant hormone).
- Plant Health Care(PHC) comprehensive program to manage the health. structure. and appearance of plants in the landscape.
- Plant Health Care (PHC)comprehensive program to manage the health. structure. and appearance of plants in the landscape.
- plant hormonesubstance produced by a plant that. in low concentrations. affects physiological processes such as growth and development. often at a distance from the substance's point of origin (see plant growth regulator).
- plantinginstalling a plant in the landscape.
- planting pithole dug in the soil to plant a tree or other plant.
- planting sitelocation chosen to plant a tree. including its surroundings.
- planting specificationsdetailed plans and statement of particular procedures. requirements. tools materials. and standards for planting.
- plasmodesmatajunctions through cell walls that connect the cytoplasm of adjacent plant cells. forming a circulatory and_ communication system connecting the cells in plant tissue.
- pleachingspecialty technique of pruning and training branches or vines. generally horizontally and where they may be interwoven. often to form an arbor. wall~ or arching tunnel.
- Plumeria rubraFrangipani - Red Fragipani - /
- Plumeria rubrum Plumeria rubrum
- plunge cutusing the tip of a chain saw to cut into or through the middle of a piece of wood. Back-cut technique in which the hinge is established by cutting through the stem behind the notch then cutting back away from the hinge. Bore cut.
- Podocarpus macrophyllusBuddhist Pine - Kusamaki
- pole1 in utility systems. vertical structure (often made of wood) used to support utility line above the ground. 2) a long too] handle u ed to work at a distance. In tree care and removal operations. poles are made of non-conductive materials such as wood or fiberglass. Consumer poles are sometimes made of conductive aluminum.
- pole chain sawa small chain saw mounted on a pole and used to cut branches from a distance.