Fencing Work - Afforestation, Reforestation and Forest Restoration in Arid and Semi-arid Tropics - page 80

step, pitching in stones may be laid so that when water cascades over it, no erosion
is caused. The height and number of steps, or the interval, can be so regulated that a
step does not have a fall of more than 0.30 m. Accordingly, the horizontal length of
the steps will vary with the slope of the ground.
Where slope of the ground is negligible (less than one-half percent) the ditch
need not be excavated in terraced form, but obstacles to flow of water, or baffles,
should be kept by leaving certain sections of the ditch half-dug. A baffle having
a width of 0.45 m may be provided at every 100 m of the fence. This will prevent
water from running long distances and causing erosion. Instead of leaving out soil
undug, building partitions of masonry in mud or lime mortar, or fixing stone slabs
as obstructions to water flow, may also be considered. Loose stone checkdams can
also be laid to slow down the flow of water.
The ditch should not be dug in sections where it is running across a stream draining
the area. No ditch will survive the flow of water, hence it is better to leave these
sections undug and close the sections using other methods of fencing such as barbed
wire or stone wall.
Correct section of the fence must be maintained all along its length. Any portion
with poor section will attract animals, tempt them to cross it, and once that is crossed
they will not fear crossing all other sections. A wooden frame the size of the correct
section may be made and run all along the fence to quickly check the adequacy of
the section. Similarly, it must be ensured during quality control inspection that the
bund has been formed with proper side slopes and is of effective height.
Maintenance of a ditch fence should be a continuous operation. The ditch will
get damaged, especially during the rainy season. It may also be damaged by animals
and human activities, whether intentional or unintentional. Immediate re-digging is
necessary to protect the plantation. Therefore, constant watch over integrity of the
fence and constant maintenance is essential for the success of a ditch fence.

4.3 Barbed-Wire Fence

A barbed wire fence (Figs. 4.3 and 4.4 ) suits all sites when the cost of fence and
employment generation are not a consideration. However, rare is the afforestation
programme where these two considerations are absent. Consequently, barbed wire is
the last alternative to be considered. It is unavoidable in sandy areas where none of the
other two methods of fencing, namely, stone wall and ditch-cum-bund, are feasible.
A barbed wire fence poses another problem—that of being susceptible to theft. It is
also easier for humans and animals to damage, destroy, or violate it. A really effective
barbed wire fence is likely to be much more costly compared to other fences.
Alignment of the fence is marked in whitewash by drawing a line and marking
positions of the posts. The positions of the posts with supports—tripods or ties—
should be clearly marked for both the intermediate and for the corner posts. Support
tripods or struts are welded prior to being brought to the site, and should be used at
the points so marked.