330 TEEES OF SOUTHEKIS' EUROPE. 



admit of cultivation, or of tlie growth of grass among tliem, are 

 but an inadequate substitute for the thick and shady wood ; bat 

 they perform to a certain extent the same offices of absorption 

 and trans23iration, they shade the surface of the ground, they 

 serve to break the force of the wind, and on many a steep de- 

 chvity, many a bleak and barren hillside, the chestnut binds the 

 soil together vdth its roots, and prevents tons of earth and gravel 

 from washing down upon the fields and the gardens. Fruit- 

 trees are not wanting, certainly, north of the Alps. The apple, 

 the pear, and the prune are important in the economy both of 

 man and of nature, but they are far less numerous in Switzerland 

 and Northern France than are the trees I have mentioned in 

 Southern Europe, both because they are in general less remu- 

 nerative, and because the climate, in higher latitudes, does not 

 permit the free introduction of shade trees into grounds occu- 

 pied for agricultural purposes.* 



* The walnut, the chestnut, the apple, and the pear are common to the bor- 

 der between the countries I have mentioned, but the range of the other trees 

 is bounded by the Alps, and by a well-defined and sharply drawn line to the 

 west of those mountains. From some peculiarity in the sky of Europe, cul- 

 tivated plants will thrive, in Northern Italy, in Southern France, and even in 

 Switzerland, under a depth of shade where no crop, not even grass, worth 

 harvesting, would grow in the United States with an equally high summer 

 temperature. Hence the cultivation of all these trees is practicable in Europe 

 to a greater extent than would be supposed reconcilable with the interests of 

 agriculture. Some idea of the importance of the olive orchards may be formed 

 from the fact that Sicily alone, an island scarcely exceeding 10,000 square 

 miles in area, of which one-third at least is absolutely barren, has exported to 

 the single port of Marseilles more than 2,000,000 pounds weight of olive-oil 

 per year, for the last thirty years. 



According to Cosimo Ridolfi, Lezioni Orali, vol. ii., p. 340, in a favorable 

 soil and climate the average yield of oil from poorly manured trees, which 

 compose the great majority, is six English pounds, while with the best cultiva- 

 tion it rises to twenty-three pounds. The annual production of olive-oU in the 

 whole of Italy is estimated at upwards of 850,000,000 pounds, and if we aUow 

 twelve pounds to the tree, we have something more than 70,000,000 trees. 

 The real number of trees is, however, much greater than this estimate, for 

 in Tuscany and many other parts of Italy the average yield of oil per tree 

 does not exceed two pounds, and there are many millions of young trees not 

 yet in bearing. Probably we shall not exaggerate if we estimate the olive 

 trees of Italy at 100,000,000, and as there are about a hundred trees to the 

 acre, the quantity of land devoted to the cultivation of the olive may be taken 

 at a million acres. Indeed this estimate is far too low according to the Italia 



