The _second_ zone ranges from about 2000 feet to between 5000 and 6000 feet above the level of the Mediterranean, the climate corresponding with that of the central districts of France. The temperature is, however, very variable, and its changes are sudden. Frost and snow make their appearance in November, and often last for fifteen or twenty days together. It is remarked, that frost does not injure the olive-trees up to the level of about 3800 feet; and snow even renders them more fruitful.
The chestnut appears to be the characteristic feature in the vegetation of this zone. Thriving also among hills and valleys of a lower elevation, here it spreads into extensive woods, till at the height of about 6000 feet it is exchanged for the pine, and Marmocchi says[14], I think incorrectly, _cède la place_ to the oak and the _beech_. We certainly found the oak, both evergreen (ilex) and deciduous, growing very freely and in extensive woods in close contiguity with the chestnut at an elevation far below the limit of the _second_ zone, as well as mixed with the pine in the forest of Vizzavona, also below that limit. But, from my own observation, I should class the oak of both kinds among the trees belonging to the second zone, though the chestnut is its most characteristic feature; and should much doubt its flourishing at the height of between 6000 and 7000 feet above the sea-level,—still more the beech. The highest point at which we found the beech was the Col di Vizzavona, on the road from Vivario to Bocagnono, 3435 feet above the level of the Mediterranean, and I was surprised to see it flourishing there.
While the principal cities and towns in Corsica stand within the limits of the first zone, it is in the second that by far the greatest part of the population live,—dispersed, as we have often had occasion to remark, in valleys and hamlets placed on the summits or ridges of hills. The choice of such positions is a necessary condition of health, as in this region, no less than in the former, the valleys are notorious for the insalubrity of the air.
The _third_ zone, ranging from an elevation of about 6000 feet to the summits of the highest mountains, is a region of storms and tempests during eight months of the year; but during the short summer the air is said to be generally serene, and the sky unclouded. This elevated region has, of course, no settled inhabitants, but during the fine season the shepherds occupy cabins on its verge, their sheep and goats browsing among the dwarf bushes on the mountain sides. The vegetation is scanty. Even the pine cannot thrive at such an elevation, and the birch, which one generally finds, though dwarf, still higher up the mountains, I did not happen to see in Corsica, though it is mentioned in _Marmocchi's_ list of indigenous trees.