Glossary - Afforestation, Reforestation and Forest Restoration in Arid and Semi-arid Tropics - page 276

designed to calculate stream discharge in terms of the runoff from the tract of land
that forms the catchment of the stream.

Strong coppicer A tree species that coppices vigorously. Such species are ideal for
repeated harvest of small timber and fuelwood.

Strut A structural member that resists compression.

Struts and ties Oblique members in a structure that take on pressure and tension

respectively.

Stump cuttings ⇒ Root-shoot cuttings

Sub-traverses In surveying, a traverse within the main traverse, surveyed with the
purpose of taking more details within the area.

Submersible pump A multistage pump encased in a long thin cylindrical body
with sealed electricals so that it can remain submerged in water while working. Its
position in a well does not have to be adjusted as the water level in the well rises or
falls down.

Subsoil injector A device with a piston and a pointed spout to inject water into
ground subsoil, so that while the roots of the plant will have moisture available, no
evaporation losses take place on the surface of the ground.
Sunken bed

⇒ Bed

Surplussing arrangement In water harvesting, some mechanism, like a drop weir,
by which excess water may safely escape the field without causing soil erosion.

Surveying Measuring distances and angles and determining form, extent, and po-
sitions of different objects (in a tract of land) in order to prepare a map to a given
scale.

Survival The ratio of plants living at the end of a specified period from outplanting,
to the total number of plants originally planted.

Sustainability The quality of a resource, practice, or a phenomenon that persists
over time without getting diminished.

Sustainable use Method of harvesting or using a resource so that the resource is
not depleted or permanently damaged.

Sustained yield Production of a biological resource under management procedures
which ensure replacement of the part harvested, by regrowth or reproduction before
another harvest occurs.

Tachymetric survey Survey conducted using stadia tacheometry.

Tall plants Plants raised specifically over a longer period, usually 2 years or more,
in nursery so that these may survive the harsh conditions of arid climates more
effectively.