November 22, 1893.] 



Garden and Forest. 



481 



GARDEN AND FOREST. 



PUBLISHED WEEKLY BY 



THE GARDEN AND FOREST PUBLISHING CO. 



Office : Tribune Building, New York. 



Conducted by Professor C. S. Sargent. 



ENTERED AS SECOND-CLASS MATTER AT THE POST OFFICE AT NEW VOKK, N. Y. 



NEW YORK, WEDNESDAY, NOVEMBER 22, 1893. 



TABLE OF CONTENTS. 



PAGE. 



Editorial Articles: — The Desolatitin of Central Tunis : Was it Caused by the 



Destruction of Forests? 481 



Fences. — 1 482 



Is the Woodpecker Useful ? (With figures.) Professor John B. Smith. 483 



New or Little-known Plants :—Fiaxinus rhyncophylla. (With figure.) C. S. S. 4B3 



Foreign Correspondence : — London Letter W. Watson. 484 



Cultural Department : — Diseases of Raspberries and Blackberries, 



Fred. W. Card. 486 



Cactus and Show Dahlias W. E. Endicott. 487 



Laclienalias K. O. O. 488 



Nerine roseo-crispa J. N. G. 4^8 



Correspondence : — The Boston Public Garden A'. 488 



Chrysanthemums for E.xhibition J. N. Gerard. 488 



Exhibitions: — The Chicago Chrysanthemum Show Fanny Copley Seavey. 489 



Notes 490 



Illustrations: — Fraxinus rhyncophylla. Fig. 70 485 



Stem of White Oak sapling, showing work of a woodpecker. Fig. 71 487 



The same stem sawed through the centre. Fig. 72 '. 487 



The Desolation of Central Tunis : Was it Caused 

 by the Destruction of Forests? 



THAT portion of Tunis which is included between the 

 two branches of the great south Algerian mountain- 

 range, which cross it from west to east, is a high arid 

 plateau — a barren and inhospitable country, which affords 

 meagre pasturage to a few miserable, half-starved tfocks. 

 That this region once supported a large and prosperous 

 population, the ruins of cities like those of El Djem, the 

 ancient Thysdrus, the principal city of Byzacene, with its 

 noble amphitheatre, of Cillium and of Thelepte, with their 

 populous suburbs, bear abundant witness. In this region, 

 where hundreds of thousands of human beings once lived 

 in plenty, now a few hundred sheph^ds are barely able to 

 keep themselves from starving. The remarkable change 

 in the character of this region has been explained by the 

 nature of the Arabian occupation, which, in destroying the 

 forests which have been supposed to have covered it at 

 one time, prepared the way for the erosion of the soil and 

 produced a radical change of climate. This has been the 

 accepted view of travelers and historians who have dis- 

 cussed the physical condition of Tunis. Monsieur Paul 

 Bourde, in a learned and valuable report upon the culti- 

 vation of the Olive-tree in Tunis, which has lately ap- 

 peared, takes a different view, however, and his conclusions 

 are not only of great historical interest, but have a direct 

 bearing upon the future of other warm arid regions like 

 many parts of the Mediterranean basin, southern Califor- 

 nia. Lower California and northern Mexico. Here are some 

 of his facts and inferences : 



So far as concerns the forests, the fact appears to have 

 escaped general attention that Tunis possesses only two trees 

 of large size — the Cork Oak and the Zcen Oak — and that these 

 trees, excessively particular as to the composition of the soil 

 in which they grow, flourish in the sands of the north, i)ut do 



not grow at all on the limestone mountains of the central and 

 southern portions of the country. In these are found only 

 species ot small size, the Everi^Tcen Oak, the Aleppo Pine, the 

 Thuya and the PluL-nician Juniper, which are rather large 

 shrulis than trees, rarely growing to a greater height than 

 twenty feet and rarely producing trunks. Unless we can sup- 

 pose in ancient tunes the existence of other species of trees, 

 since disappeared, it must be acknowledged that there has 

 never been in the country high, continuous forests. With 

 regard to water-supply, the irrigation works, still to be seen in 

 most ruined cities, indicate what part they played in the ancient 

 civilization of the country. At Thelepte, at Cillium and at 

 Siiffetula, for example, the capacity ot these canals was calcu- 

 lated for the volumes of water which are practically the same 

 as those which the actual springs yield at present. When 

 springs have decreased in volume or disappeared it is because 

 they had become choked up, as has been seen at Gafsa and 

 at Ferriana, where they have been restored. Water is always 

 in the ground, and there is every reason to suppose that there 

 is no appreciable difference between the quantity of rain which 

 tell formerly and that which falls to-day over this region. 



Monsieur Bourde has reached the conclusion, and his 

 readers, after they have examined the facts which he has 

 collected, will be inclined to agree with him, that there has 

 been no notable change of .climate in Tunis since the time 

 of the Romans. To the proof of direct observations he joins 

 the testimony of Latin and Arab authors. The description 

 which Sallust gives of the country between Thula and 

 Gafsa is as true to-day as when it was written. The country 

 is, as in the time of Sallust, dry, uninhabited and horrible. 

 Nevertheless, between the desert traversed by Marius and 

 the desert of to-day there has existed a period of success- 

 ful cultivation and of great prosperity. In the eleventh 

 century, El Hekir saw two hundred flourishing villages in 

 the neighborhood of Gafsa. What is the secret of a coun- 

 try uninhabited in the time of Sallust, covered with cities 

 and villages at the time of the Arab invasion, and to-day 

 again uncultivated and uninhabited.? INIonsieur Bourde is 

 the first to answer these questions and has shown that this 

 country, so barren in appearance, is eminently fit for the 

 cultivation of fruit-trees of the warm temperate zone — the 

 Olive, the Grape, the Fig and the Almond. In no other part 

 of the world does the Olive so flourish or produce such crops. 

 The soil being very loose, and the surface drying rapidly, 

 it cannot support herbage, and is not suitable for the cultiva- 

 tion of annual crops, although the rain-water is stored up in 

 the subsoil, which is always cool .and moist. If cereals 

 are sown in this soil, four years out of five they will not 

 find in the upper layer sufficient humidity to insure 

 their ripening, while trees will send their roots down to 

 reach the waters of the subsoil and flourish. The 

 Romans seem to have understood this, and here is the 

 secret of their colonization of this country — a secret which, 

 up to this time, the savants, who have studied the matter, 

 apparently have not hit upon. Monsieur Bourde states the 

 matter tersely : 



The cause of the contrast of extreme prosperity and of ex- 

 treme misery which is found in the history of such a country 

 is not doubtful. It is not necessary, in order to e.xplain it, to 

 suppose modifications of soil and climate — the truth is simpler. 

 The country is exceptionally favorable for one kind of culture 

 and is not at all suited to another. Before the Roman invasion 

 this cultivation was unknown and the coimtry a desert. The 

 Romans introduced it toward the end of the first century, and 

 became rich ; the Arabs destroyed it in the eleventh century, 

 and the country has become a desert again. The truth of this 

 statement is so striking, when the territory itself is examined, 

 that it is possible to fix approximately in figures the results of 

 the Roman colonization and the immensity of the catastrophe 

 which has destroyed them. In central Tunis there are about 

 3,200,000 acres suitable for the cultivation of fruit-trees. Aban- 

 doned to pasturage, this land is worth four francs an acre ; 

 planted in Olive-trees, it is worth at the very lowest estimate 

 three hundred and twenty francs an acre. So it would appear 

 that the Roman colonization had improved the country from a 

 condition where the land was worth al)out thirteen millions of 

 francs to one where it was worth more than a thousand mil- 

 lion francs, and that the Arab invasion has reduceil it again to 

 its former misery and poverty. 



