Our plan for productivization of the mountainous part is, firstly, the regeneration of 

 the severely destroyed climax vegetation in the mountains and on certain sandy plains, 

 which could provide about 4-5 months pasturage a year following regeneration. One may 

 also assume a certain degree of self- sufficiency of the settlers in respect to grain, 

 vegetables, and fruit, if measures are taken to utilize the torrential winter floods in the 

 wadis. The latter problem is more technical, the former is purely geological. In this 

 area, which has been suffering from over- grazing for thousands of years, the theoretical 

 reconstruction of the climax associations depends in the first place on the finding of 

 good fodder plants, especially those rare species in inaccessible places. 



Another important task is the determination of the palatibility of the various spe- 

 cies, since those of highest palatability are of course most in danger of total extenction. 

 On the other hand, unpalatable plants should also be studied in order to ascertain the 

 reason for their being shunned by grazing animals. Finally, the competitive power of 

 these plants must be evaluated and compared. 



It would be helpful if small areas of such destroyed pasture regions that occur in 

 the Orient and in Africa, could be fenced off and protected from grazing for a time. In 

 a very few years important changes indicating the tendency of the natural succession 

 could be observed. 



I should like to bring you another example from the Negev. The small shrub Arte - 

 misia herba alba is scorned by all animals. Consequently it has been able to conquer 

 large areas including all the mountains above the altitude of 450- 500 metres. As soon 

 as we eliminate grazing, however, the previously rare tall feather grasses multiply 

 rapidly, indicating a trend towards the actual climax condition, in which good fodder 

 grasses such as Slip a barbata, Stipa Szowitziana, certain Aristida spp., and others 

 dominate. It is clear that the vigorous fibrous root systems of these bunch grasses can 

 compete with the much weaker roots of Artemisia herba alba. The seeds of Stipa find 

 good conditions for germination in the bushes of Artemisia, and if they are not devoured 

 at an early age, may eliminate the Artemisia within a matter of years. Such studies of 

 succession lead to the reconstruction of the climax association, and only on the basis 

 of this can one begin to make serious plans for the conversion of man-made desert and 

 semi-deserts into pasture land. 



In the days of the Palestine Mandate I had the opportunity to wander through these 

 remote areas on camel -back and I have therefore been able to observe their develop- 

 ment for a number of years. The most striking phenomenon is the increase of good fod- 

 der plants after the cessation of grazing. In the Tureibe region, a sandy area of about 

 30,000 acres, together with my assistant, Mr Tadmor, I carried out an exact statistical 

 study of their development. The unpalatable species remained constant in their popula- 

 tion density, while the highly palatable ones have increased in density approximately 

 ten times during the past five years, while there has been no grazing. I am referring 

 principally to Aristida plumosa, Danthonia forskahlei. Convolvulus lanatus, Argyrolo- 

 bium uniflorum, etc. Calligonum comosum, a large and valuable fodder bush, has not 

 multiplied during this time. As is the case with many trees and bushes, it apparently 

 needs one or more years of favourable conditions in order to germinate and to multiply 

 naturally. However, multiplication by the means of cuttings is within the range of eco- 

 nomic possibility. 



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