Forest Trees and Forest Scenery

by G. Frederick Schwarz

If we look still farther up toward some higher slopes, miles away, we shall see only a uniform and continuous stretch of low brush that appears at that great distance hardly otherwise than a green pasture clothing the barren mountain. As we walk toward it the bluish-green changes to a bronze-green, and then suddenly we recognize the broad sweep of chemisal, with a few scattered scrubby oaks and mountain mahogany in between.

In the account of forest embellishment should be included those humblest plants, the liverworts and mosses and the lichens that so beautifully stain the rocks and color the stems of trees. A close study of all their delicate and tender characters, both of form and color, is always a revelation. Among these lowlier plants it is no uncommon sight in the depth of winter to see a field of fern sending a thousand elegant sprays through the light snow-covering; or half a dozen kinds of mosses, all of different green, but every one pure and brilliant, gleaming in the shadow of some dripping rock. Between the rock and its ice cap, covered by the latter but not concealed from view, there is a fine collection of the most delicate little liverworts and grasses, herbs with tender leaves, and even flowers, it may be, on some earthy speck where the sun has melted the ice—all as if held in cold crystal.

A word also remains to be said about the vines and creepers. As far north as Pennsylvania, and even to the States bordering the Great Lakes, these clambering plants are a conspicuous element in the forest. Virginia creeper, clematis, the hairy-looking poison oak, and the wild grape, are among those that are most familiar. In the woods of the lower Mississippi Valley the wild grapevines often make a strange tangle among the old and twisted trees and hang in long festoons from the boughs. They are not uncommon in some of the northerly States, though less rank and exuberant in growth.

The common ivy is one of the most beautiful of all creepers. It makes a fine setting for the little wood flowers that peep from its leaves. I like it best, however, where it clings to some old oak or other tree and brings out the contrast between its own passiveness and weakness and the strength of the column that gives it support.

III
DISTRIBUTION OF AMERICAN FORESTS

The geographical distribution of trees has been referred to occasionally in the preceding chapters. This distribution, gradually accomplished during the progress of ages, has not been accidental; on the contrary, it has been due to natural causes, and arises out of the special needs and adaptations of each species. The geology of a region, which determines in many respects the character of the physical forces of both the earth and the air, is no small factor in the development of the forest. The character of the climate, the nature of the soil, the degree of moisture in the soil and in the atmosphere, the amount and intensity of the sunlight—in short, the various elements and natural forces that constitute the environment of a tree—are the all-important conditions of its life. On these it depends, and according to its own peculiar nature and its special needs, selects its natural home.

Yet the manner in which this selection is accomplished, though simple in theory, is complicated by many circumstances. Frost, fire, insects, and floods, by destroying the trees or their seeds, may retard the progress of the species. The wind may be unfavorable. The seeds hang upon the trees ready and ripe for germination, but a breeze comes along and carries them to a place where the conditions are ill adapted to their peculiar nature. The following year the wind is propitious and the little trees soon start into life. But presently the seeds of another tree, whose growth is by nature faster, are conveyed to the same spot, and the intruders outstrip the others in rapidity of growth and spread a canopy of foliage that screens the smaller trees from the life-giving sun and dooms them to destruction. Thus only a few of the numberless seeds that are produced each year live, and fewer still are able to maintain or extend the boundaries of the parent tree. Sometimes, too, the frugality or hardiness of a species may be the reason for its exclusive occupation of a certain locality, since other trees may find it impossible to live at high altitudes and on rocky ridges or to subsist upon rough, poor soil. Consequently we shall find some kinds of trees exclusive, gregarious only among themselves, while others mingle freely in the general concourse.

Through the persistency, therefore, of the vital forces of nature, through a suitable climate or situation, through the power of adaptation and the delicate adjustment of many details, the vast armies of trees, like migratory races, have at last accomplished their purpose and found their several homes; and to us the varied aspect of the forests, as we traverse the extended territory of our country, is in a manner explained. There are stretches of land over which the tree growth is dense and uniform; where the forest is given over, it may be, almost entirely to a single kind of tree. In other places the trees may join in varied luxuriance, young and old, familiar and strange, on some fertile, protected plain or well watered mountain side. In still other places they may be seen struggling up the steep slopes and maintaining a precarious existence on bleak, rocky ridges.

While the eastern portion of the United States is, generally speaking, the home of the broadleaf species, and the northern and western portions are similarly occupied by the coniferous forests, these areas may readily be subdivided into specified regions of distinct forest growth. The latter, however, cannot be accurately delimited, since the regions naturally penetrate into one another and overlap, on account of the manner in which forests have extended their bounds.

In the basin of the Great Lakes, where the glaciers of a recent geological age have prepared a light, loose, gravelly or sandy soil, the white pine belt extends through the States of Minnesota, Wisconsin, and Michigan, and penetrates into portions of Pennsylvania, New York, and New England. Once covered with dense tall forests of white pine, interspersed in places with other northern conifers, or broken by smaller areas of broadleaf forests, the white pine belt has now yielded to us its richest treasures. The exacting demands of our modern artificial civilization have drawn ceaselessly upon these resources, and the assiduous ax and the fire that follows in its train have invaded even the most secluded regions. The resulting barren spaces, where they have not become cultivated land, have either reverted to the young white pine itself or have been transformed into oak barrens and open forests of broadleaf trees. Thus the aspect of the region has been altered, though many a limited spot may be found in which the tall majesty of the primeval forest still finds its full expression.