Glossary - Afforestation, Reforestation and Forest Restoration in Arid and Semi-arid Tropics - page 257

Earthen embankment A raised linear structure, usually with a trapezoidal section,
made of compacted earth to hold back water.
EC Emulsifiable concentrate, used to specify concentration of the active ingredient
in pesticide formulations.
Ecorestoration Intervention to control or cut off biotic pressure in a tract of land,
and to enforce other suitable measures, intended to promote growth of the natural
vegetation for restoring vital ecological processes in the area.
Edaphoclimatic conditions Conditions relating to the soils and the climate at a
given place. These are the two crucial elements determining growth of plants, and
therefore are the key considerations in planning an afforestation work in an area.
Endemic species Species of plants characteristically prevalent in a particular place.
As a result of the long process of natural selection the endemic species are best suited
to thrive in that area.
Energy plantation Plantations specifically raised for production of biomass for
conversion into energy. The mode of conversion of biomass into energy can range
from burning fuelwood in households to using sophisticated gasifiers for production
of electricity.
Enumeration Counting of the discrete elements of works to inventory or to verify
these. Enumeration of the pits or plants in a plantation can be quite a difficult task
in rugged and hilly terrain. Marking methods are used for this purpose.
Environmental impact assessment A comprehensive assessment of the impacts,
both positive and negative, of a project on the environment, both physical and human.
Error The difference between the actual and the measured values of a quantity.
Since no physical measurement process can be perfect, there are no observed values
free of errors. It is the magnitude of the error that makes a difference, not error per
se. Often percent error, also called relative error, is more significant value than the
value of error itself.
Error closure In surveying, adjusting or modifying observed values to close a
traverse when a traverse plotted from observed values of angles and distances will
not close on paper. The difference in the position of the last point (which is also the
first point) is the resultant error.
Error closure algorithm In surveying, a step-by-step method for distributing clos-
ing error in a closed traverse. A simple method, when error does not exceed 1 % of
the total perimeter of the traverse, is to shift the position of the point to the mid-point
of the error line when the lengths of the first and the last lines of the traverse are
comparable. If one of these is much larger compared to the other, the longer line
may be redrawn so as to close the traverse. In another method, the angles alone
are changed while keeping distances as observed, since distance measurement in
field has a higher level of accuracy than that of angles. For more accurate work, the