Adventitious Shoots: Limbs developing from places other than a meristem tip; adventitious shoots often form around a wound on the tree.
Aeration: A method of increasing water and oxygen into compact soil by creating tiny slices or holes.
Angle of Emergence: The slope between a leading branch and a limb sprouting from it. A tight angle between the branch and a limb results in weakened structures.
Annual: A plant which grows to maturity and dies within one season. Most annual plants are sensitive to frost.
Anvil: The flat blade on a pair of clippers. Proper pruning technique requires that the anvil is positioned on the outboard side of the cut, away from the tree.
Arborist: A person does not need any special training to call themself an arborist. Anyone with a truck and chain saw can say they are an arborist.
Benign Neglect Management System: A method of care which allows a minimal maintenance.
Biennial: A plant which produces a vegetable one season, a flower the next season, then dies, like parsley.
Branch Collar: The point at which a limb joins a leader or a lateral. The branch collar represents the tree’s first line of defense against decay. The final cut is made just outside the branch collar when removing a limb.
Bulb: An underground storage portion of a plant where the stem is covered by scales.
Callous: Hard formation of tissue covering and protecting a wound.
Cambium Layer: The narrow zone of tissue in a stem that produces new cells. The cambium layer also contains the vascular system, which transports water and nutrients within the plant.
Canopy: The uppermost leaves and branches of a tree or group of trees.
Capillary Action: The ability to move liquid through a plant’s structure as a result of surface tension.
Carbohydrates: Organic compounds in living tissues including sugars, starch, and cellulose. They enable the transport and storage of energy and structural components.
Catastrophic Embolism: A blockage of the plant’s vascular system that causes it to lose its ability to transport liquids, often caused when air enters the system through a wound.
Clay: A soil particle that is plate-like, extremely small and may retain nutrients well.
Clean Crown: Generally involves only the removal of dead, dying, and/or diseased stems, branches and stubs from throughout the crown.
Clean Out Interior: Selective pruning to eliminate rubbing and limb crossing, and dead, diseased and/or broken branches.
Clear: Trim trees and plants to prevent damage of paint, gutters, fixtures, etc. or to allow light essential to certain areas of the plant.
Clip Back: Shortening of lateral limbs on a tree.
Clod: A lump of clay that is difficult to break down.
Codit: Compartmentalization of decay in trees.
Compost: A soil product created from decomposed organic material; it is used to add nutrients and encourage growth.
Crown: The leaves and branches of a tree or shrub: the upper portion of a tree from the lowest branch on the trunk to the top of the tree.
Crown Canopy: The upper part of a tree, measured from the lowest branch, including all the branches and foliage out to the end of the longest branch on up to the highest point of the tree.
Crown Raising: The removal of the lower branches of a tree in order to provide clearance.
Crown Thinning: The selective removal of branches to reduce the density and weight of branches and to increase the amount of light penetration and air movement.
Cultivar: A plant variety produced by selective breeding.
Deadwooding: Removal of the dead and dying limbs of a tree.
Decay: Degradation of plant tissue caused by microorganisms.
Deciduous: A plant that looses its leaves in the winter and refoliates in the spring.
Decomposition: The breakdown of plant matter by organisms such as fungi, bacteria, and insects.
Deep Root Fertilize: Injecting dilute liquid fertilizer using a high pressure hydraulic injection method. This type fertilization is primarily used for trees in soils with a poor nutrient status.
Defoliation: The process of plant leaf loss.
De-Sucker: Involves the judicious removal of water sprouts, epicormic growth, or suckers to develop better branch structure.
Dethatching: Removing thatches in grass, commonly with a dethatching machine or a large rake.
Diameter at Breast Height (DBH): The measurement of a tree’s trunk size at a point 54 inches above the base. The diameter or the circumference may be used as the tree’s measurement.
Drainage: The rate that water will pass through the soil.
Drought Tolerance: The ability of a plant to thrive with little water.
Epicormic Shoot: New limbs sprouting from a previously dormant bud.
Evergreen: A plant whose leaves or needles are green year-round and not lost during the fall.
Excise: To cut out with surgical precision, as in sampling or removal of damaging plant tissue.
Fertilizer: A material added to feed plants rich in nutrients, usually nitrogen, phosphates and potash.
Fescue: A luxury turf composed of soft compact fine-leafed grass.
Fungicide: A chemical used to control a fungus-related diseases.
Genetic Map: The growth pattern associated with the hereditary characteristics of a particular species.
Germination: The sprouting of a seed, spore or pollen grain taking root.
Girdling: An object, staking material or root that encircles a tree, ultimately restricting movement of energy and starches or growth of the tree itself, frequently resulting in the reduced vitality or stability of a plant.
Grading: The process of changing the slope of an area of soil to prepare for better drainage or installation of a building material.
Graft: A shoot inserted into a slit of a growing plant; fruit trees are often developed by grafting a cultivar onto a hardier root stock.
Grind Stump to Below Grade into Mulch: The mechanical grinding of stumps from just below ground level to a maximum of 24″ below grade.
Ground Cover: Plants that are low-growing and create a living blanket over the ground.
Head Back: The shortening of long, lateral branches of a tree to lighten stresses on branch attachment points, to enable access for vehicles, and to prevent limbs from touching structures.
Hedge: A variety of shrubs that when planted close together serve as a wall.
Herbacous: Dying down at the end of a growing season.
Herbicide: A chemical used to control and kill weeds.
Incision: A surgical cut for grafting or examination purposes.
Inorganic Fertilizer: Man-made fertilizer from materials such as natural gas and phosphate rock.
Iron: A mineral that helps to keep grass green.
Irrigation: Watering of plants.
ISA Certified Arborist: A tree care professional who has a minimum of three years experience in the arboricultural field and has passed a rigorous test administered by the ISA (International Society of Arboriculture). A Certified Arborists must complete required continuing education training annually.
Lateral: A shoot or a branch growing from the side of a parent branch or stem.
Leader: A shoot of a plant at the tip of a stem or at the main branch.
Leaves: Leaves take in carbon dioxide and produce oxygen during the process of photosynthesis, thus creating energy for the tree’s survival.
Lime: A source of calcium used to raise the pH in soil.
Macronutrients: Essential elements needed in large amounts for healthy plant growth: nitrogen, phosphorus, calcium, magnesium, and sulfur.
Meristem Tips: The growing ends of shoots and roots that house the tissue that produces new cells in the plant, such as for plant elongation.
Micronutrients: Essential elements needed in small amounts for healthy plant growth: iron, copper, zinc, boron, molybdenum, chlorine, and cobalt.
Morphology: The outward appearance (e.g., physical form, shape, external structure, color, pattern) of a plant.
Mulch: A layer of decaying organic matter, such as leaves and bark, that insulates and enriches the soil, as well as conserve moisture and suppress weed growth.
Narrow Crotching Structure: A shoot or branch with a tight angle of growth from a stem, causing it to have a weak attachment.
Organic Fertilizer: Enriching compounds derived from decomposition of plant and animal products, including include blood meal, bone meal, manure, and sewage sludge.
Osmosis: The diffusion of liquid through a cell wall or membrane by which water and nutrients are transported throughout a tree or plant.
Overhaul: Using all advantageous cultural pruning techniques required for the best health and structure of a tree. It may involve, as needed, crown thinning, endweight removal, correction of structural faults, removal of dead, dying and diseased tussue, and correction of imbalances.
Parallel Leads: Two shoots growing in the same direction and, thus, competing for space in the canopy of a tree or plant.
Parent Branch or Stem: The tree trunk or a large limb from which lateral child branches grow.
Pathogen: A bacterium, virus, or other microorganism that is deleterious for a tree or plant.
Perennial: A plant living for many years.
Pesticide: A chemical used to control a threatening organism.
pH: The alkalinity and acidity of soil.
Photosynthate: A sugar or other substance made by photosynthetic process.
Photosynthesis: The conversion of light energy into chemical energy by living organisms, especially green plants. The raw materials are carbon dioxide and water; the energy source is sunlight; and the outputs are are oxygen and carbohydrates.
Photosynthetic Prime: One of the forces that moves fluids through a tree.
Plant Health Care (PHC): To maintain or improve the appearance of a landscape’s appearance or tree vitality, using the most cost-effective and environmentally sound practices and treatments available.
Planter: A defined area, commonly raised and composed of wood or concrete, in plants are grown.
Pollard: A cut that removes the top of a stem, causing new shoots to form around the base of the wound.
Pruning: A method of cutting off parts of a plant to control its size, health and appearance.
Pull Stakes: Removal of supporting tree stakes that are no longer required.
Raise Crown: Removal of lowest lateral branches to enable access or sight lines to remain clear.
Reduce Crown: A method of physical size reduction of the tree crown, leaving a more compact tree.
Refoliate: When a plant grows new leaves after a leafless period, usually in the spring.
Removal: The elimination of an unwanted or dead tree or shrub.
Remove Deadwood/Clean: The removal of the majority of deadwood, dying and diseased branches from a tree’s canopy.
Remove Obvious Surface Roots: The elimination of visible roots in lawns, usually carried out manually with an ax.
Remove to Near Grade: Removal of a tree to as near to ground level as possible.
Resprout: The growth of new shoots from the base of a wound.
Root Crown Shoot: The emergence of an adventitious sprout from the root system.
Root Crown: The top layer of the mass formed by the roots of a plant and the soil surrounding it.
Root Prune: This involves the severance of sections of roots that are causing or are likely to cause damage to hard surfaces, foundations, etc. Root barriers can often be inserted following this mechanical operation to prevent further encroachment.
Root Stock: A plant sometimes just a stump that has an established, healthy root system, used for grafting a cutting or budding from another plant.
Roots: Structural and nutritional support for a plant.
Sap Pressure: Osmotic force that moves the vital fluids throughout a plant.
Scaffold: The trunk and branch structure of a tree.
Selective Pruning: The selective removal of plant parts.
Self Pruning: The process in which a tree sheds unproductive limbs itself.
Shade-out Die Back: Dead structures in the interior of the tree caused by lack of exposure to sunlight.
Shear: The sharp edged blade on a set of clippers; it is placed toward the tree when a cut is made.
Shocking: Describes the wilting and sometimes loss of leaves when a plant is transplanted to a new area.
Single-up: Often trees that have single predominant leaders, will throw out competing leaders or twin forks that result in serious structure problems in later life and can lead to complete tree failure.
Skirt Raise: The pruning of the tips of lower branches frequently done on weeping type trees to enable access or clear sight lines.
Sod: Turf ready for transplant to new locations.
Spray: The control of insects or disease by spraying insecticides, fungicides, etc.
Structural Prune/Formative Prune: The elimination of structural faults, such as tight forks, crossing and rubbing branches, imbalances of crown thus giving the trees a direction for growth.
Stump Grinding: Grinding the remainder of a stump to 12 to 18 inches below the surface.
Target Pruning: The removal of parts that are perilous to a tree’s health.
Temperature Tolerance: The degree to which a plant can tolerate extremes of temperature.
Thatch: The live or dead layer of roots and stems between the turf of a lawn and the soil.
Thin Crown: A preferred method of pruning by removing interior growth and selectively thinning out branch tips.
Thin, Clean, Raise and Reduce Crown by 25%: The process of removing no more than 25% of the total living crown.
Topiary: A decorative style of plant management where growth is controlled by continuous shaping with pruning or shearing.
Topping: The drastic reduction of tree size using indiscriminate cuts without regard to tree health or structural integrity; it is not an acceptable pruning practice.
Transpiration: The evaporation of water through the upper parts of the tree, especially the leaves, enabling enables the flow of nutrients and water from the roots to the shoots.
Transplant: Physically moving a plant from one location to another.
Trim/Shape: The minor trimming of branches to maintain natural shape or form.
Tuck Back: Shortening of lateral limbs but to a lesser degree than heading back.
Turf: A ground cover that can withstand human traffic.
Variegation: A pattern in leaves that contains either white or yellow markings.
Vascular System: The circulatory system of a plant that enables the conduction of water, minerals and nutrients.
Wound: An opening in a plant that could lead to tissue destruction or injury.