Successful Biological Methods for Combating Desertification at Degraded Areas of China - Combating Desertification in Asia, Africa and the Middle East - page 55

Fig. 3.2 Planting trees in the swales where soil water relations are better is a good way to flatten
dunes over a period of several years as sand is transported downwind

like Elaeagnus angustifolia , which is drought tolerant, survives as dwarf shrubs.
Some trees species like Ammopiptanthus mongolicus and shrub, semi-shrubs like,
Amorpha fruticosa, Artemisia halodendron have been buried by shifting sands or
survived with poor growth.
It can be concluded from long-term experiments that the choice of good or
pioneer species for binding sands depends on the following criteria:

• Tolerant to hot temperature, aridity and infertility of soil.

• Fast growing, strong germination and ability to survive burying by sand.

• Well-developed root system and potential capability of the horizontal lateral roots

to fix dunes and to hold moisture in sands.

• Easy to establish and self-reproducing.

The following species have been selected as the pioneer species from long-
term experiments since the 1950s: Hedysarum scoparium, H. fraticosum, Caragana
microphylla, Calligonum arborescens, C. caput-medusae, Atriphaxis bracteata,
A. pungens, Salix flavida, Artemisia ordosica, and A. sphaerocephala .

4.1.2 Arrangement, Density and Spacing

Attention should be paid to the suitable arrangement and suitable density, which
are essential to the survivorship and vigor of the selected pioneer plants. The plant