2220

ARBORETUM AND FRUTICETUM.

PART III.

menced his operations in the Gulf of Gascony, in 1789. The downs there arecomposed of drifting sands, covering 300 square miles. Bremontier comparesthe surface of this immense tract to a sea, which, when agitated to fury by atempest, had been suddenly fixed, and changed to sand. It offered nothing tothe eye, but a monotonous repetition of white wavy mountains, perfectly de-stitute of vegetation, in times of violent storms of wind, the surface of thesedowns was entirely changed ; what were hills of sand often becoming valleys,and the contrary. The sand, on these occasions, was often carried up intothe interior of the country, covering cultivated fields, villages, and even entireforests. This takes place so gradually (by the sand sweeping along the sur-face, and thus raising it, or falling from the air in a shower of particles, sofine as to he scarcely perceptible), that nothing is destroyed. The sand graduallyrises among crops, as if they were inundated with water; ar.d the herbage andthe tops of trees appear quite green and healthy, even to the moment of theirbeing overwhelmed with the sand, which is so very fine as to resemble thatused in England in hour-glasses. After three chapters of preliminary matterof intense interest, M. Bremontier, in his fourth chapter, gives an account ofthe manner in which he proceeded, not only to fix this sea of sand, but torender it productive of timber, resin, and other articles. This process is asremarkable for its simplicity as for its complete success. It consists in sowingon the surface seeds of the common broom, mixed with those of Pinus Pi-naster ; commencing on the side next the sea, or on that from which thewind generally prevails, and sowing in narrow zones, in a direction at rightangles to that of the wind ; the first-sown zone being protected by a line ofhurdles, this zone protecting the second, the second the third, and so on, til]the whole breadth of the downs in that locality is covered with plantation.From 4 lb. to 5 lb. of broom seed, and from 1 lb. to 2 lb. of pinaster seed,are sown per acre, and immediately covered with branches of pines, or ofother trees, with the leaves on, brought from the nearest woods, in order toshelter and protect the seed, and, by the help of the hurdle fence, to retainthe sand. These branches are laid down in a regular manner in the directionof the wind, and overlapping one another, so as to produce a sort of thatchingto the surface; and, in places very much exposed, rods are laid across them,and firmly hooked down. In a word, wherever seeds are sown, the surface ofthe downs, as far as the sowing extends, may be said to be carefully thatched;branches of evergreen trees being used instead of straw. In six weeks or twomonths, the broom seeds have produced plants 6 in. in height, and whichattain three or four times that height in the course of the first season. Thepines do not rise above 3in. or 4 in. the first year; and it is 7 or 8 years beforethey completely overtop the broom, which often attains, in these downs, from12 ft. to 16 ft. in height. At the age of 10 or 12 years, the pines have, in agreat measure, suffocated the broom, and they are then thinned, the branchescut off'being used for the purpose of thatching downs not yet recovered, andthe trunks and roots cut into pieces and burned, to make tar and charcoal.In about 20 years, the trees are from 20 ft. to 30 ft. in height ; and they arenow prepared for producing resin, which process is carried on, in the mannerhereafter described,for 10 or 12 years; when the trees are cut down, and theirbranches applied, as before, for thatching, and their trunks and roots for makingtar and charcoal; the self-sown seeds having furnished the surface with a pro-geny to succeed them. In 1811, a commission appointed by the French go-vernment made a report on the downs, and announced that about 12,500acres of dowms had been covered with thriving plantations, and that it wasfound a thatching or covering of any kind of vegetable herbage, such as straw,rushes, reeds, sea-weed, &c., might be used instead of branches, and was evenpreferable. Another improvement w hich had been tried, and found very suc-cessful, was the substitution of a fence of boards for that of wattled hurdles, asmore completely excluding the wind. (See Diet, lies Eaux et Forets, tom. i.p. 810.) These plantations, and others in the Landes of Bordeaux, and be-