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Outdoor Glossary: M

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M
Thousand. Five thousand board feet of timber can be expressed as 5M board feet.

M1
Smaller lunar elliptic diurnal constituent. This constituent, with J1, modulates the amplitude of the declinational K1, for the effect of the Moon's elliptical orbit. A slightly slower constituent, designated (M1), with Q1, modulates the amplitude and frequency of the declinatianal O1, for the same effect. Speed = T - s + h + p = 14.496,693,9 per solar hour.

M2
Principal lunar semidiurnal constituent. This constituent represents the rotation of the Earth with respect to the Moon. Speed = 2T - 2s + 2h = 28.984,104,2 per solar hour. M3: Lunar terdiurnal constituent. A shallow water compound constituent. See shallow water constituent. Speed = 3T - 3s + 3h = 43.476,156,3 per solar hour.

M4
Shallow water overtides of principal lunar constituent. See shallow water constituent. Speed of M4 = 2M2 = 4T - 4s + 4h = 57.968,208,4 per solar hour

M6
Shallow water overtides of principal lunar constituent. See shallow water constituent. Speed of M6 = 3M2 = 6T - 6s + 6h = 86.952,312,7 per solar hour.

M8
Shallow water overtides of principal lunar constituent. See shallow water constituent. Speed of M8 = 4M2 = 8T - 8s + 8h = 115.936,416,9 per solar hour.

macro climate
The general, large scale climate of a large area, as distinguished from the smaller scale micro climates within it.

macro-tidal
Tidal range greater than 4 m.

maelstrom
Famous whirlpool off the coast of Norway in the Lofoten Islands between Moskenesoy and Mosken.

magnetic azimuth
Azimuth reckoned from the magnetic north or magnetic south. See magnetic direction.

magnetic declination
Same as variation.

magnetic direction
Direction as indicated by a magnetic compass after correction for deviation but without correction for variation.

malar streak
Area at the sides of the chin. Synonym(s): whisker, moustache. In picture it is referred to as whisker.

mammary glands
organs in the female mammal that produce milk to nourish the young.

managed retreat
The deliberate setting back of the existing line of defense in order to obtain engineering and/or environmental advantages.

management action
Any activity undertaken as part of the administration of the National Forest.

mandibular ramus
Prong-like, posterior projection from bill.

mantle
Upper surface of the wings and the back.

manual bail
A roller mounted on a revolving cup that picks up the line through the rewinding process

margin, continental
A zone separating a continent from the deep-sea bottom.

marginal coverts
Feathers overlying bases of median secondary coverts. Synonym(s): lesser secondary coverts, shoulder. In picture it is referred to as lesser secondary coverts.

marigram
A graphic record of the rise and fall of the water. The record is in the form of a curve in which time is generally represented on the abscissa and the height of the tide on the ordinate. See tide curve.

marine birds
birds of the open ocean, typically pelagic, and often colonial nesters. Examples include alcids, shearwaters, storm petrels, albatrosses, jaegers, gannets, boobies, and frigatebirds.

marine boundary
The mean lower low water line (MLLWL) when used as a boundary. Also, lines used as boundaries seaward of and measured from (or points thereon) the MLLWL. See coastal boundary.

marker, reference
A mark of permanent character close to a survey station, to which it is related by an accurately measured distance and azimuth (or bearing).

marker, survey
An object placed at the site of a station to identify the surveyed location of that station.

marsh
(1) A tract of soft, wet land, usually vegetated by reeds, grasses and occasionally small shrubs. (2) (SMP) Soft, wet area periodically or continuously flooded to a shallow depth, usually characterized by a particular subclass of grasses, cattails and other low plants.

marsh, diked
A former salt marsh which has been protected by a DIKE.

marsh, salt
A MARSH periodically flooded by salt water.

mascaret
French for tidal bore.

mass movement/wasting
The down-slope movement of large masses of earth material by the force of gravity. Also called a landslide.

mass transport, shoreward
The movement of water due to wave motion, which carries water through the BREAKER ZONE in the direction of wave propagation. Part of the NEARSHORE CURRENT SYSTEM.

mating system
the type of social system a species uses for reproducing (see all monogamy, polyandry, and polygyny).

matrix
The least fragmented, most continuous pattern element of a landscape; the vegetation type that is most continuous over a landscape.

mature timber
Trees that have attained full development, especially height, and are in full seed production.

MBF
Thousand Board Feet ( See board feet.)

mean annual increment of growth
The total increase in size or volume of individual trees. Or, it can refer to the increase in size and volume of a stand of trees at a particular age, divided by that age in years.

mean depth
The average DEPTH of the water area between the still water level and the SHOREFACE profile from the waterline to any chosen distance seaward.

mean diurnal tide level (MDTL)
A tidal datum. The arithmetic mean of mean higher high water and mean lower low water.

mean high water (MHW)
The average ELEVATION of all high waters recorded at a particular point or station over a considerable period of time, usually 19 years. For shorter periods of observation, corrections are applied to eliminate known variations and reduce the result to the equivalent of a mean 19-year value. All high water heights are included in the average where the type of tide is either semidiurnal or mixed. Only the higher high water heights are included in the average where the type of tide is DIURNAL. So determined, MEAN HIGH WATER in the latter case is the same as MEAN HIGHER HIGH WATER.

mean high water line (MHWL)
The line on a chart or map which represents the intersection of the land with the water surface at the elevation of mean high water. See shoreline

mean high water springs (MHWS)
The average height of the high water occurring at the time of spring tides.

mean higher high water (MHHW)
The arithmetic average of the elevations of the higher high waters of a mixed tide over a specific 19-year period. For shorter periods of observation, corrections are applied to eliminate known variations and reduce the result to the equivalent of a mean 19-year interval.

mean low water (MLW)
The average height of the low waters over a 19-year period. For shorter periods of observation, corrections are applied to eliminate known variations and reduce the result to the equivalent of a mean 19-year value.

mean low water springs (MLWS)
A tidal datum. Frequently abbreviated spring low water. The arithmetic mean of the low water heights occurring at the time of spring tides observed over the National Tidal Datum Epoch. It is usually derived by taking an elevation depressed below the half-tide level by an amount equal to one-half the spring range of tide, necessary corrections being applied to reduce the result to a mean value. This datum is used, to a considerable extent, for hydrographic work outside of the United States and is the level of reference for the Pacific approaches to the Panama Canal

mean lower low water (MLLW)
A tidal datum. The average of the lower low water height of each tidal day observed over the National Tidal Datum Epoch. For stations with shorter series, simultaneous observational comparisons are made with a control tide station in order to derive the equivalent datum of the National Tidal Datum Epoch.

mean lower low water line (MLLWL)
The line on a chart or map which represents the intersection of the land with the water surface at the elevation of mean lower low water.

mean range of tide
The difference in height between MEAN HIGH WATER and MEAN LOW WATER.

mean rise interval (MRI)
The average interval between the transit of the Moon and the middle of the period of the rise of the tide. It may be computed by adding half the duration of rise to the mean low water interval, rejecting the semidiurnal tidal period of 12.42 hours when greater than this amount. The mean rise interval may be either local or Greenwich according to whether it is referred to the local or Greenwich transit.

mean rise of the tide
The height of MEAN HIGH WATER above the plane of reference or DATUM of chart.

mean river level
A tidal datum. The average height of the surface of a tidal river at any point for all stages of the tide observed over the National Tidal Datum Epoch. It is usually determined from hourly height readings. In rivers subject to occasional freshets, the river level may undergo wide variations and, for practical purposes, certain months of the year may be excluded in the determination of the tidal datum. For charting purposes, tidal datums for rivers are usually based on observations during selected periods when the river is at or near a low water stage.

mean sea level
The average height of the surface of the sea for all stages of the tide over a 19-year period, usually determined from hourly height readings (see sea level datums).

mean steepness
The ratio of the MEAN DEPTH to the horizontal distance over which the MEAN DEPTH was determined.

mean sun
A fictitious sun which is assumed to move in the celestial equator at a uniform speed corresponding to the average angular speed of the real Sun in the ecliptic, the mean sun being alternately in advance and behind the real Sun. It is used as a reference for reckoning mean time, noon of mean local time corresponding to the time of the transit of the mean sun over the local meridian. See equation of time and mean time.

mean tide level
Same as HALF-TIDE LEVEL.

mean time
Time based upon the hour angle of the mean sun as distinguished from apparent time which is based upon the position of the real Sun. The difference between apparent and mean time is known as the equation of time.

mean water level (MWL)
A datum. The mean surface elevation as determined by averaging the heights of the water at equal intervals of time, usually hourly. Mean water level is used in areas of little or no range in tide.

mean water level line (MWLL)
The line on a chart or map which represents the intersection of the land with the water surface at the elevation of mean water level.

mean wave period
The mean of all individual waves in an observation interval of approximately half an hour.

mechanical brake
A mechanism that stops the release of line through the spool

median line
Stripe through the crown.

median secondary coverts
Feathers overlying bases of greater secondary coverts

mend
The act of repositioning the fly line on the water in order to achieve a drag-free drift, control the action of the fly in the water or control the depth of the fly in the water column.

mergansers
ducks with long, narrow serrated-edged bills, feeding primarily on fish.

meso-tidal
Tidal range between 2 m and 4 m.

metapopulation
a group of subpopulations each isolated in a patch of habitat. The persistence of the metapopulation is dependent on the persistence of the subpopulations and movement of animals among subpopulations to exchange genes.

meteorological tides
Tidal constituents having their origin in the daily or seasonal variations in weather conditions which may occur with some degree of periodicity. The principal meteorological constituents recognized in the tides are Sa, Ssa, and S1. See storm surge.

metonic cycle
A period of almost 19 years or 235 lunations. Devised by Meton, an Athenian astronomer who lived in the fifth century B.C., for the purpose of obtaining a period in which new and full Moon would recur on the same day of the year. Taking the Julian year of 365.25 days and the synodic month as 29.530,588 days, we have the l9-year period of 6,939.75 days as compared with the 235 lunations of 6,939.69 days, a difference of only 0.06 day.

Mf
Lunar fort nightly constituent. This constituent expresses the effect of departure from a sinusoidal declination Al motion. Speed = 2s = 1.098,033,1 per solar hour.

micro climate
The climate of a small site. It may differ from the climate at large of the area due to aspect, tree cover (or the absence of tree cover), or exposure to winds.

micro-tidal
Tidal range less than 2 m.

mid-extreme tide
A plane midway between the extreme high water and the extreme LOW WATER occurring in any locality.

middleground
A term used the management of visual resources, or scenery. It refers to the visible terrain beyond the foreground where individual trees are still visible but do not stand out distinctly from the stand.

middleground shoal
A shoal formed by EBB and flood tides in the middle of the CHANNEL of the LAGOON or ESTUARY end of an INLET.

migratory birds
all birds listed under provisions of the Migratory Bird Treaty Act and published in the Federal Register.

mineral
A naturally occurring, inorganic, crystalline solid that has a definite chemical composition and possesses characteristic physical properties.

mineral soil
Soil that consists mainly of inorganic material, such as weathered rock, rather than organic matter.

minimum fetch
The least distance in which steady state wave conditions will develop for a wind of given speed blowing a given duration of time.

minnow
(1) A small fish used by fishermen to catch other fish. (2) Another name for some Killifish

MIS (management indicator species)
A wildlife species whose population will indicate the health of the ecosystem in which it lives and, consequently, the effects of forest management activities to that ecosystem. MIS species are selected by land management agencies. (See "indicator species".)

mission (of the USDA Forest Service)
"To Care for the Land and Serve the People". As set forth in law, the mission is to achieve quality land management under the sustainable multiple-use management concept to meet the diverse needs of people.

mist
Water vapor suspended in the air in very small drops finer than rain, larger than FOG.

mitigation
Actions taken to avoid, minimize, or rectify the impact of a land management practice.

mixed current
Type of tidal current characterized by a conspicious velocity difference between the two floods or two ebbs usually occurring each tidal day. See also MIXED TIDE.

mixed stand
A stand consisting of two or more tree species.

mixed tide
Type of tide which the presence of a DIURNAL wave is conspicious by a large inequality in either the high or LOW WATER heights with two high waters and two low waters usually occurring each tidal day. In strictness, all tides are mixed, but the name is usually applied without definite limits to the tide intermediate to those predominantly semidiurnal and those predominantly DIURNAL.

mixed-condition
A piece of clothing that is more water-resistant and less breathable

MM
Million

Mm
Lunar monthly constituent. This constituent expresses the effect of irregularities in the Moon's rate of change of distance and speed in orbit. Speed = s - p = 0.544,374,7 per solar hour.

MMBF
Million Board Feet ( See board feet.)

modified epoch
See kappa prime and epoch (1).

mole
In coastal terminology, a massive solid-filled structure (generally revetted) of earth, masonry or large stone.

monitoring and evaluation
The periodic evaluation of forest management activities to determine how well objectives were met and how management practices should be adjusted. See "adaptive management".

monochromatic waves
A series of waves generated in a laboratory, each of which has the same length and period.

monofilament
A single strand of nylon

monogamy
is a mating system in which each male mates with one female only.

monsoon current (Southwest Monsoon Current)
An Indian Ocean current setting in a generally eastward to southeastward direction off India and Ceylon. It replaces the North Equatorial Current, reversed by wind stress of the south-west monsoons, in August and September.

month
The period of the revolution of the Moon around the Earth. The month is designated as siderial, tropical, anomalistic, nodical, or synodical according to whether the revolution is relative to a fixed star, vernal equinox, perigee, ascending node, or Sun. The calendar month is a rough approximation to the synodical month.

moraine
An accumulation of earth, stones, etc., deposited by a glacier, usually in the form of a mound, ridge or other prominence on the terrain.

morphodynamics
(1) The mutual interaction and adjustment of the seafloor topography and fluid hydrodynamic processes, seafloor morph-ologies and sequences of change.dynamics involving the motion of sediment. (2) The coupled suite of mutually interdependent

morphology
River/ESTUARY/lake/seabed form and its change with time.

mortality
Trees that were merchantable and have died within a specified period of time. The term mortality can also refer to the rate of death of a species in a given population or community.

mosaic
Areas with a variety of plant communities over a landscape, such as areas with trees and areas without trees occurring over a landscape.

mountain pine beetle
A tiny black insect, ranging from 1/8 to 3/4 inch in size, that bores through a pine tree's bark. It stops the tree's intake and transport of the food and nutrients it must have to stay alive, thus killing the tree.

moustache
Area at the sides of the chin. Synonym(s): whisker, malar streak. In picture it is referred to as whisker .

mouth
Cavity bounded by the bill. No picture yet.

MSf
Lunisolar synodic fort nightly constituent. Speed = 2s - 2h = 1.015,895,8 per solar hour.

mu (?)
Variational constituent. See lambda. Speed = 2T - 4s + 4h = 27.968,208,4 per solar hour.

mud flat
A muddy, low-lying strip of ground by the shore, or an island, usually submerged more or less completely by the rise of the tide.

multiple tide staff
A succession of tide staffs on a sloping shore so placed that the vertical graduations on the several staffs will form a continuous scale referred to the same datum.

multiple use management
The management of all the various renewable surface resources of National Forest lands for a variety of purposes such as recreation, range, timber, wildlife and fish habitat, and watershed.

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