Fjölrit RALA - 05.12.1999, Blaðsíða 119

RajivK. Sinha etal.
117
aneura, A. salicina, Colophospermum mopane, Dichrostachys glomerata, Brasiletta
millis, Schinus molis and Prosopis juliflora have emerged very promising for the In-
dian desert. Of all the exotic species tried, ‘Acacia tortilis’’ from Israel has been ad-
judged the best ‘fuel-cum-fodder species’ for the desert. Since its introduction, it has
found a ‘niche’ not only in Rajasthan desert but also in other States of India. Acacia
tortilis which has shown performance in growth and survival equal to or better than
the indigenous Acacia senegal, is very promising (Muthana and Arora 1973). How-
ever the desert dwellers are not happy. They want Acacia senegal to be planted on
large scale. This species of Acacia senegal is of great socio-economic value for them.
Besides yielding fodder and fuel it also gives a valuable ‘gum resin’. They are also
somehow linked with the chain of the great Indian majestic bird of the Thar desert
called ‘godawan’ which is threatened with extinction. Godawan feeds on the insects
which thrive on the gum resins of Acacia senegal.
Stabilization ofshifting sand-dunes
In low-rainfall areas (150 mm to 400 mm), huge shifting sand dunes are commonly
found, particularly near human habitations. Techniques of afforesting the shifting
dunes were standardized after 10 years of experimentation. These techniques consist
of: (i) protection against biotic interferences; (ii) treatment of shifting sand-dunes by
fixing barriers in parallel stripes or in a ‘chess-board’ design, using the local shrub
material starting ffom the crest of the dunes to protect the seedlings from burial or ex-
posure by the blowing of sand; (iii) afforestation of such treated dunes by direct seed-
ling and planting. The two species commonly used for erecting ‘brush-wood barriers’
(micro-windbreaks) are Zizyphus nummularia and Crotalaria burhia (Kavia and
Harsh 1993).
The indigenous and exotic species which have proved successful in sand dune sta-
bilization are: trees - Acacia senegal, Prosopis juliflora, Albizzia lebbeck, Cordia
rothii, Dalbergia sissoo (in regions with mean annual rainfall of 250 mm) and Zizy-
phus jujuba', shrubs — Calligonum polygonoides, Cassia auriculata, Ricinus communis
and Zizyphus nummularia; grasses - Lasiurus sindicus, Panicum turgidum and Eri-
anthus munia. Among exotic species, Eucalyptus oleosa (Australia), Acacia tortilis
(Israel), Parkinsonia aculeata and Acacia victoriae (Australia), Acacia albida (Middle
East) were found to be very promising, especially as these species were found to be
frost resistant. Acacia albida was used to stabilize 60,000 hectares of sand-dunes in
the Thar desert (Anonymous 1988).
Phog (Calligonum polygonoides) needs special mention. It is a very useful species
of the Thar desert. It is a naturally growing shrub on the sand dunes. It has a massive
network of underground root which works as effective ‘sand binder’. Other species
occurring on sand dunes are Aerva psuedotomentosa, Leptadenia pyrotechnica, Ci-
trullus colocynthis, Lasiurus sindicus, Calotropis procera, etc. Other suitable species
for planting on sand dunes are Colophospermum mopane and Prosopis cineraria.
Shelterbelt plantations to reduce wind velocity
Shelterbelts and tree-screens consisting of a row of trees viz. Acacia tortilis, Tamarix
articulata and Azadirachta indica flanked by two rows (one on each side) of smaller
trees like Acacia senegal, Prosopis juliflora etc., with two rows (one on each side) of