Glossary - Afforestation, Reforestation and Forest Restoration in Arid and Semi-arid Tropics - page 265

Mathematical model A set of variables cast into a formula—or a set of formulae—
so that they predict behaviour or characteristics of a real system. A model helps in
studying performance of a system without incurring the costs of physically carrying
out experiments or building the physical system.

mdeq ⇒ Man-day equivalent

Mean annual increment Average annual increment in the biomass averaged over a
stand of trees, better known in its abbreviated form MAI. The MAI of a plantation or
forest is a measure of its biological productivity and characterises the soil, climate,
and species composition of the plantation. Artificially raised plantations composed
chiefly of fast-growing multipurpose species usually can have an MAI many times
that of a natural forest. In relation to the age of a plantation, the MAI varies according
to the usual logistic (S-shaped) curve. The point of time when it achieves its peak
value and then starts declining is called the rotation age of the plantation. Based
purely on yield considerations, this is the desired age when the plantation should be
harvested.

Measurement topic A topic for serially recording work measurements, as work
progresses at a site. It usually is kept separately for each work. Each bill of work is
entered into it in entirety.
mEq

⇒ milli-equivalent

mho Unit of conductance, equal to the reciprocal of an ohm. It has now been
replaced by siemens as the standard unit of conductance in the SI system of units.

Microclimate The characteristic climatic conditions occurring over a small local
area or habitat. A distinct microclimate can be created by the presence of a water
body or a large and dense population of trees in the area.

micron A unit of measurement of length equal to one-thousandth of a millimetre.
It is often used in measuring thickness of thin films.

Microplan A developmental plan covering a small area and addressing local issues
of development.

Micro-windbreaks Small palisades erected in a dense line of brushwood to obstruct
wind and check movement of sand. These windbreaks are erected on the active
portions of sand dunes in sand dune stabilisation plantations.

milli-equivalent Amount of a chemical substance equal to one-thousandth of a
gram-equivalent which is equal to the number of grams of substance equal to its
molecular weight.

millisiemens Unit for measuring electrical conductance, abbreviated as mS. It is
equal to one-thousandth of a siemens.

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