Woodipedia Index

Wood Terms that Start with "M"

Lumber Glossary Term Definition


Macassar Ebony
  • Dark brown to black heartwood
  • Mostly straight grain by may sometimes be irregular or wavy
  • Fine and even texture
  • Exceptionally heavy, dense wood
  • Hard to work with hand or machine tools
  • Pre-boring is necessary for nailing
  • Used for cabinet work, walking sticks, musical instruments, billiard cues, and decorative veneers.

The relative ease with which a metal can be shaped by various cutting processes.

Machine Bolt

A bolt typically configured with a hex head, a nut and a blunt end. It is meant to hold two pieces, usually the support structure by pinning them together; the threads hold only the nut and don’t screw into the wood itself.

Machine Burn Burn marks on the surface of converted wood as a result of poor sawing or machining.
Machine Rate

Cost per unit of time for owning and operating a logging machine or some logging equipment. In accordance with engineering practices, the rate is composed of fixed costs such as depreciation, interest, taxes, and license free, and variable costs including fuel, lubricants, and repairs and replacement of components such as tries and wire rope.

Machine Time
  • Machine Availability – Machine availability is expressed as a percent of the scheduled operating time during which a machine is not under repair or service. In other words, it is the percentage of the scheduled operating time during which the machine is mechanically fit and is itself capable of doing productive work. It is expressed by scheduled operating time minus mechanical delay time divided by schedule operating time and multiplied by 100.
  • Machine Down-Time – Time during which a machine cannot be operating in production or auxiliary work because of breakdown, maintenance requirements, or power failure.
  • Machine Utilization – Machine utilization is expressed as a percentage of the scheduled operating time that is productive time. It is computed by productive time divided by scheduled operating time and multiplied by 100.
  • Scheduled Non-Operating Time – Time when no production is scheduled for a machine.
  • Idle Time – Scheduled non-operating time during which a machine is not working, moving, under repair, or being serviced.
  • Out-Of-Shift Repair Time – Part of non-operating time during which a machine is actually undergoing repair. Waiting time is not included here as in the in-shift repair time element.
  • Out-Of-Shift Service Time – Part of non-operating time when a machine is actually undergoing service time. This does not include waiting time.
  • Scheduled Operating Time – Time when a machine is scheduled to do productive work. Time during which a machine is on standby as a replacement machine is not considered as scheduled operating time. When a machine is replaced, the scheduled operating time of the replaced machine is considered as ending when the replacement arrives on the job. Scheduled operating time of the replacement commences when it starts to move to the location of the machine it is replacing. Extension of the regular shift operation into overtime is considered as scheduled operating time.
  • Operating Time – Time during this period can be either productive or delay time. Delay time is the sum of disturbance time, service time, and repair time.
  • Mechanical Delay Time – Part of scheduled operating time spent in repair or service during which a machine cannot work. It does not include replacement of oil filters and spark plugs as scheduled in a preventative maintenance program. Servicing is fueling, lubricating, and doing the work specified in a scheduled preventative maintenance program. When a machine is being serviced while under repair, the time involved is to be classified as repair time, not service time. Repair and service time occur in both scheduled operating and non-operating time.
  • In-Shift Repair Time – Part of mechanical delay time when a machine is actually undergoing repair plus the time during which a machine is waiting to be repaired or for repair parts, mechanics, or facilities. This is the same as repair time.
  • Active Repair Time – Time during which actual repair work is being carried out on the machine itself or a dismantled part of the machine.
  • Repair Time – Sum of active repair time, waiting repair time, and time spent servicing the machine while undergoing repair.
  • Waiting Repair Time – Time during which the machine is waiting for a mechanic, spare parts, or repair equipment. This includes time for transporting the machine to and from the workshop.
  • In-Shift Service Time – Part of mechanical delay time when machine is actually undergoing service plus the time a machine is waiting for service parts, mechanics, or repair facilities. This is the same as service time.
  • Service Time – Time for normal service and maintenance.
  • Non-Mechanical Delay Time – Part of scheduled operating time during which a machine is not doing productive work for reasons other then repair or service. This time may be subdivided by causes; weather or terrain conditions, waiting for another phase of an integrated operation, assisting other machines, and operator talking with visitors.
  • Disturbance Time – Examples are: time spent for logging down, towing, detail planning, talking to supervisor, waiting for wood, and waiting for better weather.
  • In-Shift Moving Time – The part of non-mechanical delay time during which a machine is moving or being transported. Includes the time taking to move or transport the machine between operating sites or between camp and site, assuming the machine is not under repair service. It does not include time spent moving between adjacent working positions on any one site.
  • Operational Lost Time – Time during which production is halted due to things such as operating conditions, non-availability of auxiliary equipment, or using the machine in a non-productive manner to assist other machines.
  • Personnel Time – Part of non-mechanical delay time in which a machine lacks an operator or any other member of the machine crew.
  • P.M.H. – Productive Machine Hour
  • Productive Time – Part of scheduled operating time in which a machine is performing a function for which it was scheduled. Also, time spent in carrying out the task; the sum of actual productive and other productive time.
  • Actual Productive Time – Time spent using the machine to carry out the actual task.
  • Other Productive Time – Time when the machine is carrying out tasks other than those for which are intended.
  • S.M.H. – Scheduled Machine Hour
  • Total Time – Total elapsed time for the period under consideration; total time for a period of 1 week is 168 hours (7 days multiplied by 24 hours per day).
Machine Stress-Rated (MSR Lumber)

Lumber that has been evaluated by mechanical stress rating equipment; each piece is nondestructively tested and marked to indicate the modulus of elasticity. MSR lumber is also required to meet certain visual requirements.

Mahogany An expensive, pink to dark reddish brown hardwood. It is a tropical tree of the genus Swietenia.
Main Line

In cable yarding, the line used to bring logs to the landing.

Main Line Block Block on a spar through which the main line runs.
Main Road

Road that supports a high level of traffic, usually well built and well designed.

  • Pick-red to blood red and red-brown heartwood
  • Straight grain
  • Lustrous and uniform texture
  • Tends to split in nailing, holds screws well
  • Used for furniture, cabinets, turnery, high-class joinery, interior fittings, laboratory benches, boat building and marine plywood.

A tool like hammer with a wooden, rawhide or rubber head.

Managed Harvest

Estimated volume of timber on commercial forest land that could be cut annually for the next ten years while improving tree stocking and bringing about a more even distribution and age classes. Annual managed harvest is considered separate from harvest cuttings and thinnings and is determined by a computer using an area control system that specifies the number of acres to be cut annually.

Managed-Volume Inventory

Computation of pertinent data, such as volume or basal area and increment and mortality of stands, to assess silvicultural opportunities.


Unit of work preformed by one man in one hour.


The producing sawmill sawing lumber from logs.

Manufacturer's Agent

A sales representative for a particular sawmill or several non-competitive lumber manufacturers.

Manufacturing Defects

Includes all defects or blemishes that are produced in manufacturing, such as chipped grain, loosened grain, raised grain, torn grain, shkips in dressing, hot and miss, variation in sawing, mis-cut lumber, machine burn, machine gouge, mismatching, and insufficient tongue and groove.


To select and indicate, usually with paint, trees to be felled in a logging operation and to be left may also be marked.


Selecting and indicating, by a blaze or paint spot, the trees to be cut or left in a timber cutting operation.

Marlin Spike

Iron tool that tapers to a point. This is used to separate strands of rope.

Mason's Line A string that does not stretch, making it useful to establish horizontal lines when laying out the various heights of a deck.

A material with adhesive properties, usually used in relatively thick sections, which can be readily applied by extraction, trowel, or spatula.


A temporary roadway constructed of hardwood lumber.

Mature Timber

A stand of trees that has attained an age or size that satisfies the primary economic goal for which it is managed.


Thousand Board Feet.


Thousand (ft.) board measure.


Moisture Content.


Medium density fiberboard, very stable underlay for counter tops etc. to be covered with laminate.

Mean Annual Increment (MAI) Total increment growth up to a given age divided by that age.
Meandering Line

Survey line at the high-water mark on navigable lakes and streams. This line is where continuous vegetation ends and muddy or sandy shore beings.


The process of dividing the merchantable tree stem into segments of specified length for the purpose of bucking. Measuring a stand begins when a worker begins dividing the first tree into desired lengths and ends when the last tree has been measured.

Measuring Tape

A tape of cloth, paper, plastic, or steel marked off in a linear scale, as of inches or centimeters, for taking measurements.

Mechanical Adhesion

Adhesion between surfaces in which the adhesive holds the parts together by interlocking action.

Mechanical Delay Time Cutting with mechanized equipment, such as the carrier-mounted shear of feller-buncher, instead of by hand with a power saw.
Mechanized Logging

Logging in which most or all of the hand labor is replaced by machines; requires a large outlay of capital.

Medium Density Fiberboard (MDF)

A special type of tempered hardboard characterized by a very fine, smooth finish. MDF is used in cabinet making.

Medium Grain

Wood with 4 to 6 rings per inch.


In forestry, the measurement of both standing and harvested timber.



Merchantable Top

Smallest utilizable top.

Merch Top

Merchantable Top


A tissue capable of active cell division, thereby adding new cells to the plant body.

Metric Tons

Unit of weight equal to 1,000 kilograms. Approximately 2,205 pounds.

Mexican Bocote
  • Heartwood is a dull golden brown with variegated irregular markings
  • Straight grained
  • Medium-coarse texture
  • Works easily with both hand and power tools
  • Moderately durable
  • Resistant to preservatives
  • Used for cabinets, furniture, decorative boxes, boat decking, vehicle bodies, and light construction

Mixed Grain


An extremely narrow bevel along a cutting edge, which increases the sharpness angle for greater edge durability.

Mill Run

Lumber that is in varying grades and widths.


Planed and patterned lumber for finish work in buildings, including items such as sash, doors, cornices, panel work, and other items of interior or exterior trim. This does not include flooring, ceilings, or siding.

Milk Pain

Paint made with milk solids, chemically akin to casein glue, often the original finish on antique furniture.

Mineral Streak

An olive to green-black or brown discoloration of undetermined cause in hardwoods.

Miter-And-Spline Joint

A joint with two mitered surfaces connected by a spline.

Miter Box

An apparatus to guide a saw to make miter joints.

Miter Gauge

A tool that slides into a slot on a power tool such as a table saw, router table, band saw, etc. A miter gauge can be adjusted to different angels and is used to slide the stock past the blade.

Miter Joint

Pieces that are cut on an angle to make a joint.

Mismatched Material

Worked material that does not fit tightly at all points of contact between adjoining pieces or in which the surfaces or adjoining pieces are not in the same plane.

Mixed Car

A railroad car loaded with various kinds, sizes and/or species of lumber.

Mixed Grain

Lumber may be both vertical and flat grain.




Capable of being moved from one location to another.


Theoretical abstraction, usually capable of mathematical manipulation, used to evaluate a problem or a subject of interest.

Modified Wood

Wood processed by chemical treatment, compression, or other means to impart properties quite different from those of the original wood.

Modular Housing

A type of housing in which major components are assembled in a factory and then shipped to the building site to be joined with other components to form the finished structure. The components are usually uniform incremental sizes; permitting some flexibility of design while maintaining the structure of individual elements. Sometimes called “prefabricated’ or “prefab” housing by laymen; these terms are avoided by the industry because of negative connotations.

Modulus of Elasticity (MOE)

The relationship between the amount a piece deflects and the load causing the deflection determines its stiffness.

Moisture Content (MC)

A measure of the amount of water in a piece of lumber.

Molding (Moulding)

A strip of material with a profile cut on the facing edges, used for trimming.

Molecular Weight

The sum of the atomic weights of the atoms in a molecule.


Circle of twisted strands of wire rope used as a temporary line to connect the eye splices of two lines.

Monkey Wrench

A half tool with adjustable jaws for turning nuts of varying sizes.

Mopping Up

Act of making a fire safe after it has been controlled by extinguishing or removing burning material along or near a control line.


Modulus of Rupture

Morse Taper

The standard for the taper on the shanks of drill chucks, drill bits and lathe centers. The different size tapers are designated by numbers, #1 being the smallest, #3 is common for drill chucks.


A rectangular hole cut into a piece of wood to accept a tenon.

Mortise and Tenon

Any joint consisting of a projection (tenon) on the end of one timber and a corresponding slot (mortise) on the other.


Number or sound wood volume of healthy trees that have died from natural causes during a specified period.


A term used to describe various figuring effects, from subtle lacewood to a more velvety figuring.

Moulding (MLDG)

Small shaped lengths of wood used for both interior and exterior trim.

Moulding Stock

Developed in the making of other standard grades; each piece is graded on the basis of the percentage of the area suitable for ripping into strips of a given minimum size and quality.


Machine Stress Rated


Malaysian Timber Certification Council.

Multilevel Deck

A deck that has several discrete areas at different levels. The different levels often are built to conform to a sloping terrain or make a transition from a second story to a ground level.

Multiple Entry

A deck that has several discrete areas at different levels. The different levels often are built to conform to a sloping terrain or make a transition from a second story to a ground level.


Practice of forestry that combines two or more objectives.

Multiple-Use Forestry

Concept of forest management that combines two or more objectives, such as production of wood or wood-derivative products, forage and brown for domestic livestock, proper environmental conditions for wildlife, landscape effects, protection against floods and erosion, recreation, and protection of water supplies.

Multiple-Use Management

Management of land resources with the objective of achieving optimum yields of products and services from a given area without impairing the productive capacity of the site.

Multispan Skyline

A skyline having one or more intermediate supports.


An operation handling two or more stems at the same time.


A strip of metal or wood separating and holding panes of glass in a window or door.


Tract of partly forested peat-land supporting mosses, shrubby plants, and scattered trees.

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