Glossary M-Z

This page contains definitions of forestry terms beginning with the letter M through the letter Z.

Glossary M - Z

Mast - Fruits or nuts used as a food source by wildlife. Soft mast includes most fruits with fleshy coverings such as persimmon, dogwood seed or black gum seed. Hard mast refers to nuts such as acorns, beech, pecans and hickory nuts.
McLeod - A scraping tool for line construction used in areas where duff is common.
Mill site - Place where forest products are stored, altered or processed.
Mineral soil - Soil with properties predominantly of mineral matter and usually less than 20 percent of organic matter.
Mop up - Extinguishing or removing burning material near control lines, felling snags in areas that have burned to make it safe or to reduce residual smoke.
Mulch - Any material placed on the surface of the soil (i.e. wood chips, shredded bark, leaves) to conserve moisture, control weeds and moderate surface soil temperature.

Native species - A species that is a part of the original fauna or flora of the area in question.
Natural barrier - Any area where lack of flammable material obstructs the spread of wildfires.
Natural soil - A soil having a pH value between 6.6 and 7.3.
Nomex - Fire-resistant synthetic material used in the manufacture of flight suits, pants and shirts used by firefighters.
Nonpoint source pollution - Pollution of diffuse origin not resulting from any discernible, confined or discrete conveyances or readily identifiable source.
Nutrients - Mineral elements such as nitrogen, phosphorus or potassium that are naturally present or may be added as fertilizer or a fire retardant.

Organic matter - Plant and animal residue in the soil in various stages of decomposition.
Organic soil - Soil containing greater than 20 or 30 percent organic matter (depending on clay content).
Overhead Team - Personnel assigned to supervisory positions, including incident commander, command staff, general staff, branch directors, supervisors, unit leaders, manager and staff.

Percolation - The downward movement of water through the soil.
Perennial stream - See "stream."
Permeability - The ability of a soil horizon to allow air or water to move through it. A whole soil's permeability may be limited by one layer of impermeable horizon, even though others are permeable.
Persistence - Ability of a pesticide to remain active over a period of time.
Pesticides - A chemical used to kill pests including insecticides, herbicides and rodenticides.
Personal protective equipment (PPE) - The equipment and clothing required to reduce or eliminate the risk of injury from exposure to hazardous conditions encountered during the performance of duty (such as fire fighting). PPE includes but is not limited to, fire resistant clothing, hard hat, flight helmets, shroud, goggles, respirators, hearing protection, chainsaw caps and fire shelters.
pH Value - A numeric designation of acidity and alkalinity in soil. Soils are either acid (pH value less than 7), neutral (pH value 7) or alkaline (pH value greater than 7).
Phloem - Inner bark tissue through which the tree moves sugars produced in the leaves to other plant parts.
Photosynthesis - A process by which plants make sugar for energy by using the pigment chlorophyll, light energy from the sun, carbon dioxide from the air and water. This process produces sugar and gives off oxygen.
Pollution - Presence of substances that impair or render harm to life, health and the productivity of the environment or are offensive to the senses.
Prescribed fire - Controlled application of fire to wildland fuels in either their natural or modified state, under specified environmental conditions that allow the fire to be confined to a predetermined area. The application produces the fire behavior and fire characteristics required to attain planned fire treatment and resource management objectives.
Presuppression - Activities in advance of fire occurrence to provide effective suppression response. Includes planning, organization, recruiting and training, procuring equipment and supplies, and maintaining fire equipment and fire control improvements.
Pruning - The removal of branches from a tree, typically done for safety, health or aesthetic reasons.
Pulaski - A fire line building tool with a blade that is a combination of an axe and a hoe.

Reburn - A fire may sometimes pass through an area without burning all materials there. These remaining materials, dried by the first fire pass, can reignite, and the area may "reburn."
Red card - Fire qualifications card issued to fire-rated persons showing their qualifications and their training needs to fill specified fire suppression positions in a large fire suppression or incident organization.
Red flag warning - Term used by fire weather forecasters to alert forecast users to an ongoing or imminent critical fire weather pattern.
Regeneration - Process of replacing old trees with young through harvest or other means.
Residual trees - Live trees left standing after harvesting is completed.
Resource order - The form used by dispatchers, service personnel and logistics coordinators to document the request, ordering or release of resources, and the tracking of those resources on an incident.
Retardant - A substance dropped on fires from air tankers to reduce flammability of fuels.
Rill erosion - An erosion process where numerous small channels, only several inches deep, are formed. Occurs mainly on disturbed and exposed soils.
Riparian - Pertaining to the banks of a stream, river or pond.
Riprap - Relatively large stone placed on erodible sites to reduce the impact of rain or surface runoff.
Root collar - The transition zone between the stem and the root, sometimes recognized in trees and seedlings by the presence of a slight swelling just above the roots of a tree.
Root feeder - A device for fertilizing and watering trees and shrubs. It has a wand that goes into the ground 12 inches or less to place water or fertilizer in the area of root growth and to bypass the roots of turf.
Runoff - Portion of precipitation that flows from a drainage area or in open channels.
Ruts - Depressions in roads and trails from repeated passage of wheeled vehicles.

Safety zone - An area (usually a recently burned area) used for escape in the event the fire line is outflanked or in case a spot fire causes fuels outside the control line to render the line unsafe. In firing operations, crews progress so as to maintain a safety island close at hand, allowing the fuels inside the control line to be consumed before going ahead. Safety islands may also be constructed as integral parts of fuelbreaks; they are greatly enlarged areas that can be used with relative safety by firefighters and their equipment in the event of a blowup in the vicinity.
Sapwood - The active xylem (wood) found right under the cambium that stores water and carbohydrates and transports water and nutrients.
Seedbed - Soil prepared by natural or artificial means to promote germination of seeds and seedling growth.
Seedling - A small, young tree, less than 3 years old.
Selection method - Removing mature timber as scattered individual trees or in small groups in relatively short intervals. Encourages continuous reproduction and uneven-aged stands.
Sheet erosion - Removing a fairly uniform layer of soil by water runoff.
Shelterbelt - One or more rows of trees and shrubs planted upwind of an area or building to protect it from winter winds and blowing snow. Shelterbelts are also commonly known as windbreaks or hedgerows.
Silvicultural activities - All forest management activities, including logging, log transport and forest roads (EPA's interpretation).
Site preparation - Readying an area prior to reforestation.
Skid trail - Temporary path used to drag or transport felled trees or logs and other material to a landing.
Skidding - Transporting felled trees or logs by dragging them behind heavy equipment to the log deck.
Slope - Degree of deviation of a surface from the horizontal, measured as a numerical ratio (2:1, first number is the horizontal distance--run, and second number as the vertical distance--rise), percent (a 2:1 slope is 50 percent) or degree (the angle from the horizontal plane. 90 degrees is the vertical maximum and 45 degrees being a 1:1 slope).
Slash - Debris left after logging, pruning, thinning or brush cutting. It includes logs, chunks, bark, branches, stumps and broken understory trees or brush.
Slow-release fertilizer - A fertilizer that is available to plants over a long period of time in comparison to those that dissolve quickly and are immediately available to plants.
Slurry - Another name for retardant used on fires.
Smokejumper - Specially trained firefighter who parachutes to fire sites.
Snag - A standing dead tree or part of a dead tree from which at least the leaves and smaller branches have fallen.
Soil - Unconsolidated mineral and organic material on the immediate surface of the earth, serving as a natural medium for the growth of plants.
Soil conservation - Protecting and using the soil within the limits of its physical characteristics.
Soil productivity - Capacity of soil to produce a specified plant or sequence of plants under a specific system of management.
Soil texture - Relative proportion of various size groups of individual soil particles.
Spoil - Excess material removed as overburden (cut) or generated during construction (road or land) that is not used as fill.
Stream - A body of concentrated flowing water in a natural low area of land. 1. "Ephemeral stream" means a stream that flows only during and for short periods following precipitation and flows in low areas that may or may not have a well-defined channel. 2. "Intermittent stream" means a stream that flows only during wet periods of the year (30 percent to 90 percent of the time) and flows in a well-defined channel. 3. "Perennial stream" means a stream that flows throughout a majority of the year (greater than 90 percent of the time) and flows in a well-defined channel.
Streamside management zone (SMZ) - Area along both sides of perennial and intermittent streams and perennial water bodies where extra precaution is used in carrying out forest practices to protect water quality.
Streambanks - Usual, not flood boundaries of a stream channel. Banks are named left and right facing downstream.
Stub - An undesirable short length of branch remaining after a break or incorrect pruning cut is made.
Sucker - A vigorous shoot arising at or below the graft union or groundline of a tree.
Sunscald - Injured, usually cracked, bark caused by sudden changes in temperature. This happens to thin-barked trees like maples in the early spring when a warm, sunny day is followed by a rapid drop in temperature after the sun goes down.
Switchback - A 180-degree change in a trail or road for climbing steep slopes.

Thermal pollution - Temperature rise in a body of water sufficient to be harmful to aquatic life in the water.
Thinning - Cutting or removing certain trees to allow those remaining to grow faster. Usually a commercial operation in younger stands that brings an income to the landowner while improving a forest.
Timber stand - A group of trees.
Timber stand improvement (TSI) - Improving the quality of a forest stand by removing or deadening undesirable species or trees to achieve desired stocking and species composition. TSI practices include applying herbicides, burning, girdling or cutting.
Topping - Cutting off branches to stubs. Cuts made without consideration of the location of side branches. Acceptable practice in arboriculture, sometimes called tipping, round over, heading, shaping, capping or pollarding.
Topsoil - The upper part of the soil, which is the most favorable material for plant growth. It is ordinarily rich in organic matter.
Toxicity - The relative degree or severity of being poisonous or harmful to plant or animal life.
Trenching - Digging trenches on a side slope to catch any burning or other materials that might roll across fire control lines.
Turnout - (1) A widened space in a road to allow vehicles to pass one another. (2) A ditch that drains water away from roads.

Uneven-aged or all-age management - The practice of managing a forest by periodically selecting and harvesting individual trees or groups of trees from the stand while preserving its natural appearance. Most common in hardwood forests. A forest stand composed of trees of different ages and sizes.
Utility - An entity that delivers a public service such as electricity or communication.
Utilization - Branch of forestry concerned with the operation of harvesting and marketing the forest crop.

V-crotches - Branches with pinched bark between the trunk and the branch that have no collar and no branch bark ridge.
Values at risk - Term used to describe the value of an area that is threatened by fire. For example, an area that has high-quality timber will have a higher value verses an area that has scrub timber (poor quality) or areas with and without structures will have varying values when comparing fire risk.

Waste - Materials and substances usually discarded as worthless to the user.
Water bar - Diversion ditch and/or hump across a road or trail on the uphill side for carrying storm water runoff to vegetation, forest floor, ditch or dispersion area, preventing increased volume and velocity that causes soil movement and erosion.
Water body - Natural or man-made basin that stores water. Does not include jurisdictional wetlands or beaver ponds.
Water control structure - Any structure used to regulate surface water levels.
Water pollution - Harmful or objectionable material added to water in concentration or sufficient quantities to adversely affect its usefulness or quality.
Water quality - Describes the chemical, physical and biological characteristics of water in respect to its suitability for a particular purpose.
Watershed - Area within which all runoff collects into a single stream or drainage system, exiting through a single mouth or outlet.
Water spout - A vigorous shoot arising from the trunk or branches of a tree. Water spouts arise above the graft union or soil line. See "Sucker."
Wildfire control - Actions taken to contain and suppress uncontrolled fires.
Wildfires - Uncontrolled fires occurring in forestland, brushland and grassland.
Wildland/urban interface - The line, area or zone where structures and other human development meet or intermingle with undeveloped wildland or vegetative fuels.
Wound - The opening that is created any time the tree's protective bark is damaged, cut or removed. Pruning a live branch creates a wound, even when the cut is properly made.

Xylem - Wood tissue; sapwood contains active xylem; heartwood contains inactive xylem.