400 THE FUTURE OF ARID LANDS 
used for the breeding of either perennial or drought-resistant 
watermelons, or both. 
Selection of Woody Desert Plants for Various Purposes. (25) 
Woody species find their uses in deserts: (a2) for shade, which 
is so essential to the well-being of livestock in the scorching noon- 
day desert sun; (4) for permanent dune fixation by plants which 
resist oversanding and blowing out; (c) for shade and beauty 
wherever human beings settle. 
A good local candidate, but not yet used on a practical scale, 
is Haloxylon persicum which is to be found as remnants of former 
larger ‘“‘desert-forests” in Nahal Arava. It is a good “fodder-tree”’ 
and represents the dominant plant of a climax association. 
“Large-scale artificial reestablishment in its original area of dis- 
tribution is highly recommended” (Q). 
The local Tamarix species represented a special problem. This 
is one instance where considerable financial loss was experienced 
when trying to proceed empirically without proper scientific 
preparation. In the earliest stages of this work Tamarix was 
planted indiscriminately on a large scale. It was found that the 
species used was ecologically the wrong one, and the whole plan- 
tation failed in one year’s time. Nine species with widely diverse 
ecological requirements are to be found in Israel, but their tax- 
onomy is most difficult, as everybody knows who ever tried to 
identify the different closely related species. The thorough taxo- 
nomic survey, which is the first precondition for their proper use 
in desert afforestation, is now being undertaken. 
Local Retama and Pistacia species are at present also being 
studied taxonomically as only after determining the subspecies 
and varieties which differ much in their respective ecological am- 
plitude can they be profitably propagated. 
Of the introduced species, Eucalyptus rostrata may be impor- 
tant. Fourteen years ago a big plantation was made in the Negev 
on a locality with 1oo mm yearly rainfall. Only few specimens 
survived, apparently representing a drought-resistant strain. 
They are now being propagated. 
