Botanical features of the Algerian Sahara

by William Austin Cannon

Commercially speaking, the cork oak is at present the most important species in Algeria. It occupies about 600,000 acres, and the yearly yield is valued at nearly $1,000,000. It may be seen along the railroad between Tunis and Constantine and east of Algiers. When old the species has a peculiarly gnarled appearance, with a short, stout bole, usually hollow, which may become 10 feet in diameter, with irregular, straggling branches. It is less symmetrical in nature than under cultivation, as in the Santa Clara Valley and Santa Barbara, California, where a few specimens may be found. Another species of oak, Quercus ballota, of no great commercial importance, provides the source of the acorns in general use among the natives for food. The acorns are found in all markets, even (as in Ouargla and Ghardaia) where transportation for considerable distance is necessary; they are less astringent and hence more pleasant than those of most species. Although Q. ballota appears not to be planted for its fruit, it has been stated (Kearney and Means, loc. cit.) that the Kabyles preserve such selected trees as have superior fruit, which would perpetuate the best-liked varieties. It may be remarked in passing that the seeds of the pine are also in common use among the Arabs as a food, although not employed so generally nor in so many ways as the acorn.

The cedar (Cedrus atlantica), the most beautiful tree in Algeria, is found in high altitudes only and on mountains separated from one another, but always in the more northern Atlas ranges. In the following mountain groups are to be found the main cedar forests, namely: Ouarensis, Teniet, Blida, Babor, Maadid, and the Aurés. The forest seen was that near Batna, near the western base of the most important range in Algeria, the Aurés. Somewhat below the lower limit of the Batna cedar forest is an open forest of oaks (Quercus mirbeckii), Juniperus oxycedrus, and J. phœnicea, mingled with which are shrubs suggesting those of the desert, such as Acanthyllis numidica and Retama sphærocarpa, as each genus is represented south of the Saharan Atlas on the open desert. These species are mainly confined to the southern facing, and hence on the side of the mountains opposite the beginning of the cedar. By the roadside are to be seen also several specimens of Juniperus oxycedrus badly infested with the mistletoe (Arceuthobium oxycedri). In one instance the unusual condition was observed of a mistletoe group remaining alive on a host branch which appeared to be dead for several inches below the point of attachment.

The first representatives of the cedar forest were encountered as stragglers in the dry wash at the north base of the mountain on which the forest is situated. In part these trees were shapely, with a taper summit, and in part they were short, with a summit broad and flat, in effect like an inverted cone. When the main forest was entered the trees were mainly of the type first characterized, with widely reaching lower branches and slender summits. In exposed places or in older parts of the forest the trees of the second type were often seen; and on the crest of the mountain the most bizarre shapes (induced by wind action), the trunks nearly parallel to the ground and the branches hugging the ground. In the upper portion of the forest the trees were more widely separated than in the lower portion, and here and there we met with really large specimens, which must have been very ancient. One of the large trees had a bole which 1 meter above the ground was about 5 meters in circumference. The trees were fruiting freely, but we did not see many seedlings. Why, was not apparent. There were no indications that fires had swept over the mountain recently.

THE HIGH PLATEAU.

The vegetation of the High Plateau, taken as a whole, is sparse, due in part to rather light annual precipitation, but largely to the lack of efficient drainage, for which reason large areas are so heavily charged with salts as to be inimical to most plants. Halophytes form an important element in the flora of this region. In the most intense salt areas no plants are to be found at any season. Along the oueds such shrubs as species of Tamarix and Zizyphus occur, and juniper may be seen in the more elevated places, such as near Guelt-es-Stel or further toward Djelfa.

The route followed across the High Plateau ran from Boghari to Ain Ossera, Guelt-es-Stel, and Djelfa, which is in the midst of the Saharan Atlas, and from thence to Laghouat.

BOGHARI TO LAGHOUAT.

Boghari, situated at the place where the Oued Chelif, having come across the High Plateau, enters the Tellian Atlas on its way through them to the Mediterranean, lies on the northern edge of the High Plateau and in what appears to be a fairly arid region. The oued at this place is rather narrow and has low banks. In its bed, in October, were a few pools of water. On either side is the flood-plain of the oued, several meters in width, sometimes partly under cultivation. Tilled fields are to be seen to the west and not far from the town. From the low mountains immediately to the west of the town the steppes stretch unbroken (save by low hills) to mountains bounding the southern horizon, possibly 100 miles straight away. The mountains are the Dj. Sahari, the Saharan Atlas, beyond which lies the desert.

The vegetation in the neighborhood of Boghari is at present meager in amount and of small size. Along the banks of the Chelif are a few tamarisks, and on the plain not far from the oued are a few specimens of Zizyphus vulgaris and Pistacia lentiscus and other low-growing shrubs. Owing to the large number of sheep, goats, and camels which are driven through the pass of the Chelif, or which are kept in the neighborhood by their Boghari owners, few plants thereabouts fail to exhibit indications of being eaten. In fact, at Boghari the effects of grazing were first noticed, though afterwards repeatedly seen. Only such plants as are poisonous, distasteful, or heavily armed survive the predatory attacks of the countless numbers of domestic animals.

The habitat of Pinus halepensis, which thus extends to the very edge of the steppes, is to the east and west of the town. To the west it forms an open forest and is associated with Quercus ballota, growing on the crest and on the northern slopes of the low mountains. Its abundant fruit, together with acorns, is gathered assiduously by the Arabs for food. Juniperus oxycedrus and J. phœnicea also occur.