The forests fill an important function in the general economy of the globe, by the influence which they exercise upon the mean temperature and the other meteorological conditions of the regions they shelter. All other things being equal, the temperature of well-wooded countries is perceptibly less elevated and more uniform than that of dry and open districts. The amount of humidity which is retained on the surface of the soil by wide-spread woods is considerable; it results from the lesser evaporation of the waters, the abundant transpiration of the leaves, and the heavy rains which inundate the forests during the tropical summer. Forests, like mountains, seem to attract the clouds. So the plains which lie on their borders are ever better watered and fertile than those whose horizon no obstacle encumbers.
Thus, then, in the forests, in this bright and beautiful world of vegetation, most of the pleasures which man can derive from external nature are garnered up, and most of the lessons he requires are written. All kinds of precious grace and teaching, says Mr. Ruskin,[145] are united in this link between the Earth and the Stars: wonderful in universal adaptation to his need, desire, and discipline; God’s daily preparation of the earth for him, with beautiful means of life. “First, a carpet to make it soft for him; then, a coloured fantasy of embroidery thereon; then, tall spreading of foliage to shade him from sun heat, and shade also the fallen rain, that it may not dry quickly back into the clouds, but stay to nourish the springs among the moss. Stout wood to bear this leafage: easily to be cut, yet tough and light, to make houses for him, or instruments (lance-shaft, or plough handle, according to his temper); useless it had been, if harder; useless, if less fibrous; useless, if less elastic. Winter comes, and the shade of leafage falls away, to let the sun warm the earth; the strong boughs remain, breaking the strength of winter winds. The seeds which are to prolong the race, innumerable according to the need, are made beautiful and palatable, varied into infinitude of appeal to the fancy of man, or provision for his service: cold juice, or glowing spice, or balm, or incense, softening oil, preserving resin, medicine of styptic, febrifuge, or lulling charm—and all these presented in forms of endless change. Fragility and force, softness and strength, in all degrees of aspects; unerring uprightness, as of temple pillars, or undivided wandering of feeble tendrils on the ground; mighty resistances of rigid arm and limb to the storms of ages, or wavings to and fro with faintest pulse of summer streamlet. Roots cleaving the strength of rock, or binding the transience of the sand; crests basking in sunshine of the desert, or hiding by dripping spring and lightless cave; foliage for tossing in entangled fields beneath every wave of ocean—clothing with variegated, everlasting fibres, the peaks of the trackless mountains, or ministering at cottage doors to every gentlest passion and simplest joy of humanity.”
Considered in their physiological aspect, it is evident that the forests have played, from the remotest ages of our planet, a pre-eminently useful part, by absorbing the carbonic acid with which the atmosphere was surcharged, fixing the carbon, and restoring to the air a quantity of oxygen sufficient for the support of animal life, impossible or rudimentary previous to their creation. And they still serve to maintain the chemical equilibrium of the atmosphere, by incessantly refeeding it with the oxygen which the respiration of animals and the phenomena of combustion have transformed into carbonic acid.
Forests formerly abounded in Europe. In Gallia, Germania, Illyria, Sarmatia, whole provinces were covered with immense woods of ancient and patriarchal trees. Civilization has destroyed them in great part, and often without discernment. At the present day few forests in Europe remain untouched. They are rare in Western Asia, in Central Asia, and in Northern Asia; rarer still in the Chinese empire, where the population is denser than in any other country of the world, and where it is the great object of the policy of the State that not a rood of land shall be lost for the culture of plants valuable as food or for industrial purposes. It is only to the south of the Himalaya Mountains, in the still savage and scantily peopled regions of India and Indo-China, that one sees the great vegetables of the Tropical Zone agglomerated in compact masses of considerable extent.
In Africa, forests of any size or density only exist in the mountainous countries and towards the western littoral; as, notably, in the Soudan, the Senegal, in Guinea, at the Gaboon, and on the coasts of Angola and Benguela. In North America, civilization has accomplished, in less than three centuries, the work which in Europe occupied a much longer period. The magnificent forests which spread their awful shades—their vast luxuriance of gloom—over the surface of this continent have fallen before the axe of the pioneer. Only at a few points is realized the fine picture of the poet; only in a few untrodden recesses still flourishes the primeval forest, where—
“The murmuring pines and the hemlocks,
Bearded with moss, and in garments green, indistinct in the twilight,
Stand like Druids of eld, with voices sad and prophetic,
Stand like harpers hoar, with beards that rest on their bosoms.”[146]
When Captain Palliser’s expedition attempted to reach the head waters of the North Thompson from the sources of the North Saskatchewan River, the leader encountered a forest-growth so dense, and so encumbered with fallen timber, that it proved an insurmountable obstacle. Viscount Milton and Mr. Cheadle, in their adventurous journey across the Rocky Mountains to British Columbia, were involved in one of these wildernesses, and with difficulty effected a passage. “No one,” they remark,[147] “who has not seen a primeval forest, where trees of gigantic size have grown and fallen undisturbed for ages, can form any idea of the collection of timber, or the impenetrable character of such a region. There were pines and thujas of every size—the patriarch of 300 feet in height standing alone, or thickly-clustering groups of young ones struggling for the vacant place of some prostrate giant. The fallen trees lay piled around, forming barriers often six or eight feet high on every side: trunks of huge cedars, moss-grown and decayed, lay half-buried in the ground on which others as mighty had recently fallen; trees still green and living, recently blown down, blocking the view with the walls of earth held in their matted roots; living trunks, dead trunks, rotten trunks; dry, barkless trunks, and trunks moist and green with moss; bare trunks, and trunks with branches—prostrate, reclining, horizontal, propped up at different angles; timber of every size, in every stage of growth and decay, in every possible position, entangled in every possible combination. The swampy ground was densely covered with American dog-wood, and elsewhere with thickets of the aralea, a tough-stemmed trailer, with leaves as large as those of the rhubarb-plant, and growing in many places as high as a man’s shoulders. Both stem and leaves are covered with sharp spines, which pierce your clothes as you force your way through the tangled growth, and make the legs and hands of the pioneers scarlet from the inflammation of myriads of punctures.”
Far grander the scene, however—far richer in form and colour—which meets our gaze in the stupendous forest growth still covering the basins of the Amazon and the Orinoco. As a companion to the foregoing picture, we borrow one of this brighter and more wonderful region as painted with equal truth and vigour by Mr. Bates:—[148]