Fencing/ Screen Planting
Fences are used to keep animals in or out of an area. They can be made from a wide variety of materials, depending on terrain,
location and animals to be confined. Most agricultural fencing averages about 4 feet (1.2 m) high, and in some places, the height
and construction of fences designed to hold livestock is mandated by law. It may be a hedgerow or a shelterbelt (windbreak) or a
refugee for native plants. If not too narrow, it acts as a habitat corridor.
The earliest fences were made of available materials, usually stone or wood, and these materials are still used for some fences today. In areas where field stones are plentiful, fences have been built up over the years as the stones are
removed from fields during tillage and planting of crops. The stones were placed on the field edge to get them out of the way. In time, the piles of stones grew high and wide.
In other areas, fences were constructed of timber. Log fences or split-rail fences were simple fences
constructed in newly cleared areas by stacking log rails.
The Industrial Revolution brought the first barbed wire (also "barbwire" or just "barb") fences, which were widely used after their
introduction in the mid-19th century. This technology made it economically feasible to fence rangeland for the first time.
Smooth wire fencing is often used as an inexpensive material to safely contain horses and other animals that run a high risk of
entanglement, usually in conjunction with a line of electric fence. Smooth wire is also used in securing fence-post braces and
other uses where barbed wire is not recommended.
High tensile (H-T or HT) fencing is a special hard, springy steel wire that was introduced in the 1970s and has slowly gained
acceptance. The wire may be a single strand plain or barbed wire, or woven mesh, and is capable of much higher tension than mild steel.
Woven wire is more costly to purchase and time-consuming to install than is basic wire, but is often safer and less expensive than wood, pipe, or other materials.
Electric fencing became widely available in the 1950s and has been widely used both for
temporary fences and as a means to improve the security of fences made of other materials.
A fence charger places an electrical pulse from ground to the wire about once per second. The pulse is narrow and usually around 5-20 kV. Animals receive an uncomfortable but harmless shock when contacting the wire, and learn to stay away from it.
