Part 12

The theory of my rustic friend contains the general results of all that science has yet discovered in relation to the temperature of woods. But the effects of clearing the forest are so different in different situations as to have given origin to a multitude of theories. This diversity of opinion, however, comes from a partial observation of facts, without their qualifying circumstances. On a hot summer’s day we sprinkle our floors with water, for the purpose of cooling the air of the room. But how can it produce this effect, when by evaporation it carries heat from the floor into the very air that is cooled by it? The fact is easily explained. The greater coolness felt when the air of the room is saturated with the moisture evaporated from the sprinkled floor might not be exactly indicated by the thermometer. The sensation of coolness is caused by the increased power of the air to conduct the heat rapidly from our persons,—the effect of its greater humidity. By the same law we may explain why, after a few clear cold days in the winter, if a south-wind arises, we feel as if the cold were greater, because this wind, while it raises the temperature, charges the air with invisible moisture.

The coldness of the atmosphere over grassy meadows when the sky is clear, after the decline of the sun in summer, is a matter of common observation. As this phenomenon is most evident on the clearest nights, it has given rise to the notion that the moon cools the night air. In our rambles after sunset, we have all felt these constant changes of temperature, which are remarkable when walking over an uneven road, the degree of heat corresponding nearly with our altitude. When we occupy high ground, the air is warm and dry; as soon as we descend into a valley, we feel a sudden chill. These differences are not observed on a cloudy night, or when a clear brisk wind is blowing. But in a calm state of the atmosphere, as the lowest stratum of air contains the greatest amount of moisture, its capacity for retaining heat is proportionally diminished. Consequently the heat from the ground is radiated with great rapidity through this damp stratum of air, while the higher strata remain unchanged in their temperature. Indeed, it has been found by experiment that while the greatest heat at noonday in calm summer weather is very near the surface of the ground, yet after dew-fall the highest temperature is several feet above this surface, increasing in altitude for some hours after sunset.

The action of a wood checks this radiation in the early part of the night. Like clouds in the evening, the trees form a canopy of foliage over the ground, and thereby retain the heat many hours after it has escaped by radiation in the open plain. According to these laws of the radiation of heat, a longer time would be required to cool a tract of forest than an equal area of open space, down to a given point. But, on the other hand, a proportionally longer time is required to raise the temperature in the woods to a given point. Hence it is still a question among meteorologists whether the mean annual temperature of a large tract of country is higher or lower when covered with forest than when generally open and cleared. The sun acts with greater force upon an open country; but the radiation of heat is greater in the same ratio during the sun’s absence.

In considering the effects of clearing, travellers have often overlooked the important advantages of protection afforded by woods to agricultural crops. Even if the mean annual temperature of a country be the same after it is cleared as when it was covered, it may at the same time be too cold for certain plants which were formerly its common productions, because there are no woods to protect them from the winds by day or from the cold caused by excessive radiation at night. Palestine, two thousand years ago, was a well-wooded country, and all the fruits of the sub-tropical climates were raised there to perfection by its ancient inhabitants. The date-palm, the fig-tree, and the olive grew there and bore fruit abundantly. Palestine is now a treeless country, and the same fruits are incapable of enduring its climate; yet recent observations have demonstrated that its climate is not colder than it was in the days of the kings of Israel. But as the country has been despoiled of its forests, these sub-tropical fruits are deprived of their natural conservatories, and cannot be raised without great labor and expense in preparing artificial protection for them. Let the forests be restored to the hills and mountains of Palestine, and, though the temperature of its summers were not increased, the fields would be protected by these forests from the winds, and the tender fruits, thriving under their protection, would again become abundant.

The principles involved in these and similar facts form a distinct branch of meteorological science, and would require a volume for their illustration. I have only hinted at some of the general conclusions. It is evident, indeed, that the same objects that serve to protect us from cold may in an equal degree protect us from heat. The woodcutters will continue their labor in a deep forest without discomfort on a winter’s day, when they could not endure the intense cold of the open country. The earliest flowers of spring, however, are found neither in a wood nor in an open meadow, but under the protection of a wood on its southern border, in little openings that are exposed to the beams of the sun.

THE BUTTERNUT.

The walnut includes two species in this country, the Butternut and the black walnut, both trees of considerable note and importance. The Butternut is a well-known tree in the Northern States, cultivated to a great extent in rural villages, but not very abundant in the forest, from which it has probably been extirpated for the beauty and value of its wood in cabinet-work. It is everywhere seen in the enclosures of farm-houses, where it is valued for its fruit and admired as a shade-tree. It is not so tall as the hickory, and differs from it in general shape, as I have already remarked, subdividing itself into several large and equal branches, and seldom extending a central shaft above the lowest point of subdivision. It is a tree of wider spread but thinner foliage than that of the hickory. Its pinnate leaves are long, with a great number of leaflets, and of a light and rather mellow green. It resembles the black walnut in its botanical characters; but the fruit of the Butternut is more elongated, that of the black walnut being nearly globular.

Every one is familiar with the Butternut-tree. Its fruit being more easily obtained than that of the hickory, and ripe at an earlier period, the tree is generally plundered before the time for gathering it. The outer rind is pulpy, and full of a bitter sap that blackens the hands when pressed out by cracking the nuts in a green state; for the kernel is ripe while the shell is still green. This stain may be removed by any fresh vegetable acid; and for this purpose boys generally procure the leaves of sheep-sorrel, with which they rub the stains from their hands, and after washing in soft water it is found to be entirely removed, if no soap has been used. I am not sure that painters would see much to admire in this tree; but to a native of New England it is so pleasantly associated with juvenile feasts of nuts in the early autumn, gratuitously strewed by the green wayside, and with the simplicity of country life, that it is difficult to see in the form of this tree anything we do not admire. If its foliage is thin, its proportions are handsome and symmetrical, and when in its prime there is no tree that better adorns a rustic enclosure. The Butternut puts forth its leaves about a week earlier than the hickory. It is common in all the New England States, especially on the Green Mountain range, from the northern parts of New Hampshire to the Sound.

THE BLACK WALNUT.

The Black Walnut is common in all the United States below the latitude of Long Island. It is especially abundant in Pennsylvania, and is also found singly and in small scattered groups in New England. It is a larger and more hardy and rapid-growing tree than the English walnut, but it bears an inferior fruit. This tree does not differ from the butternut in general characters, but it is of greater height and more majestic in appearance. It has very long pinnate leaves, of a pure untarnished green and a warmer look than the darker foliage of the hickory. Both trees produce an elegant wood for cabinet-work, but that of the Black Walnut is preferred, though the wood of the butternut is nearer the color of mahogany.

THE WHORTLEBERRY PASTURE.

Thoreau relates that he once thought of whortleberrying as an occupation for a livelihood. This was said in a quaint and paradoxical humor, but there are multitudes who can sympathize with the feelings that prompted his remark. As a quiet outdoor amusement, it is not surpassed either by angling or botanizing; and I cannot see why the whortleberry field should not have its Izaak Walton as well as the lily-pond or the trout-stream. The freedom enjoyed in the open pasture, the simple and honest people whom we meet there, the tiresome, but still agreeable and emulative task of picking the fruit, are only a fraction of our enjoyments. The chirping of various insects, and their constant sportiveness among the bushes; the motions of birds and the plaintive melody of the wood-sparrow, which is tuneful nearly the whole month of August,—prepare us to be cheerful and delighted with all things. The cattle feeding carelessly upon the hillsides, the scattered groups of trees and the cool shadows they cast upon the green turf, the sweetness of the air, our unrestrained rambling, the precipitous rocks that intercept our way only to disclose a bower of raspberries protected by their walls, the mossy seats under umbrageous pines, the countless wild flowers on every knoll, the pleasant sensation of rest after weariness and of coolness after the heat of exercise and weather, all combine to render the whortleberry pasture a field of delight surpassing all that is written of gardens of orange and myrtle.

The whortleberry is peculiarly an American fruit; though a few species are common in Middle and Northern Europe, they are in no part of the world so abundant as in North America. The whortleberry tribe of plants form a conspicuous feature of New England landscape, especially near the coast. No single species has been domesticated, though any one of them would well reward the labor of the cultivator if the fruit could not be obtained from the fields. Their fruit is well known to the inhabitants of the Eastern States. Very little has been written upon it, and few persons are aware of its importance to the inhabitants of North America. Botanists make no generic distinction between the whortleberry and the blueberry; but we may distinguish the two at once by their different flavor, and not by their color. The whortleberry is less acidulous, less mucilaginous, and contains a harder seed than the blueberry. The flowers of the two species differ as widely as their fruits: those of the blueberry are large and white; those of the whortleberry are greenish, tipped with red, smaller and more contracted in the mouth. There is no family of plants that runs into a greater number of varieties in a wild state; but I have never seen one that seemed to possess the characters of the blueberry and whortleberry combined. With regard to their colors it may be remarked, that while there are blueberries which are black, there is no whortleberry which is purely blue.

It may truly be asserted that if the cherry and the whortleberry, with all their varieties, were to become extinct, the want of the latter would be most painfully felt by the mass of our population. We were not taught by the Europeans to appreciate the value of our wild fruits. “In Scotland,” said one of a company of Scotch girls whom I met in a whortleberry field, “we have no wild fruits. All our fruits are in gardens.” In this country, where whortleberries are so common as to be found in all wild lands that are not densely wooded, their fruit constitutes one of our staple productions, of greater value to us than even the cranberry, except as an article of export. During about three months, from the first of July to the last of September, millions of bushels of whortleberries are consumed in this part of the country. People are often deceived by measuring the importance of any article according to its commercial value. Hence the whortleberry pastures are called “waste lands.” But were these lands deprived of their products of wild fruit, the want of it would be a grievous affliction to the community. How many poor families earn their livelihood in summer by gathering whortleberries for the market! How many delightful excursions does this fruit-gathering annually afford to the children and youths of our land! The robin, the waxwing, and other birds that consume our cherries, would be diverted from the orchard and the garden by a good supply of fruit from the bushes of an adjoining field; and our cultivators might prevent their depredations by planting the different species by the sides of their fences and in all open situations which are not adapted to tillage.

As an object in the landscape and a field for the botanist and student of nature the whortleberry pasture is worthy of study and full of attractions. This scenery, with all the spontaneous mapping of its beds of shrubbery, its groups of trees, its tussocks of mosses and ferns, its little green hollows spangled with flowers, and its projecting rocks covered with brambles, all intersected widely by the smooth greensward, is peculiar to New England. In the Southern States the whortleberry-bushes are more promiscuously scattered, and are not seen in this delightful grouping, forming with the trees, fruits, and flowers a true symbol of the beneficence of nature. A genuine whortleberry pasture is one of the most beautiful of gardens,—a modern Vale of Tempe, a true Eden,—inasmuch as it is without culture; and abounds from early spring till waning autumn in the most interesting shrubs and flowers of our clime; in August and September sparkling with clusters of shining black and azure berries, and possessing a value which only a New-Englander knows how to prize.

The whortleberry pasture consists chiefly of upland, extending out occasionally into a level meadow, but generally of a hilly and uneven surface, covered with groves and coppice. The pasture must have been fed many years by cattle to acquire its distinguishing features. Without the grazing of these animals the ground would be evenly covered with vines and bushes. The cattle, while feeding upon the grass, consume many of the young plants which have not become woody, and in their irregular course gradually produce this grouping in a manner which is entirely inimitable by art. Hence in an old field the scattered beds of shrubbery, with greensward between them, might be compared to a map of islands, the grass being represented on the map by the water and the bushes by the land; the greensward sometimes widening into a broad expanse of verdure, and then beautifully intersected by intricate masses of shrubbery.

In the lands surrounding the older townships only do we see the whortleberry pasture in the perfection of this picturesque grouping, laid out according to the geometry of nature. In the new settlements the bushes are mixed with trees and stumps in the clearings, and have not acquired any arrangement. But if a whortleberry field has long been pastured by cattle that seldom browse upon the shrubs, the different kinds of vegetation stand in beautiful groups of a thousand various forms, like the figures on tapestry. The rocks that lift up their gray heads, sometimes with smooth flat surfaces, sometimes in lofty protuberances, covered with liverworts and patches of variegated lichens and mosses, and fringed on their edges with diminutive shrubs, form no unimportant part of this peculiar scenery. In every old pasture the different kinds of shrubs are more or less distinctly arranged into groups; some, for example, consisting chiefly of bayberry, others of roses or perhaps of brambles. But in general the plats consist of a promiscuous variety of species, in which some one predominates. One of the most common of these social plants is the sweet-fern, universally prized for its fragrance, at the very name of which we are inspired with pleasant recollections of youthful wanderings. The lambkill is especially prone to form exclusive assemblages, and the most beautiful individuals, when in flower, are generally on the outside of the group.

But there is no end of the smaller plants that spring up everywhere, some in the open space, others under the protection of a tuft of sedge-grass or a broad-leaved fern. The sweet-scented pyrola is abundant in all shady thickets, and the cymbidium and arethusa decorate the low grounds among the nodding panicles of quaking-grass and the spreading flowers of meadow-rue. The loosestrife, with its long pyramidal spikes of yellow flowers, is always conspicuously grouped in the low grounds, side by side with similar plats of low swamp-roses or crimson-spiked willow herb. But the most attractive flower in the whortleberry pasture is the red summer lily,—the cynosure of the happy children who assemble there, the queen of the meadow, and the delight of every rambler in the coppice.

The man who thinks of nature only as a field for the display of magnificent art may sneer at these rustic scenes and their native ornaments. But pride cannot make unadorned nature contemptible, nor can the grandeur of a princely estate deprive its occupants, if their culture equals their wealth, of the interest with which they behold a field covered with spontaneous vegetation, or a simple rustic farm. From the opening of spring until the fall of the leaf, the whortleberry pasture is a garden full of the fairest flowers and the most healthful fruits. And if Great Britain’s isle had been covered with whortleberries, like our New England hills, these fruits would have been celebrated in English poetry, like the fruit of the vine and the olive in the poetry of Greece and Rome.

WHORTLEBERRIES AND HUCKLEBERRIES.

We may vulgarize a word by associating it with the market. The wild pastures abound in summer with well-known fruits, some of jet and some of azure. We go out with a few friends and gather them with flowers, for present amusement. These fruits are _Whortleberries_. This is their poetical and their botanical name, the one that is associated with all the beautiful things that cluster in the same field. These fruits are also gathered for the market, and exposed for sale with cucumbers, new potatoes, and squashes. They are now _Huckleberries_. Shelley has defined poetry to be the art “that lifts the veil from the hidden beauty of the world, and makes familiar objects be as if they were not familiar.” This is done partly by a choice selection of words; and whenever a common thing is known by two names equally euphonious, we should always select that which is not in commercial use. We should say Whortleberries if we are writing an essay or a poem about them, and Huckleberries if we are going to buy a few of them in the market. The usages of the market in other matters ought to be excluded from literature. In commerce, for example, fishes are fish; in natural history fish are fishes.

THE HAZEL.

“Now let us sit beneath the grateful shade Which Hazels interlaced with elms have made.” _Virgil_, Eclogue V.

The Hazel, under which Menalcas invites his brother-shepherd to sit, is a tree of considerable size, while the American hazels are mere shrubs, seldom overtopping a rustic stone-wall. The Hazel among the Romans, like the olive among the Jews, was regarded as the emblem of peace; and this estimation of it was transmitted to the people of a later period. Hence, in popular works of fancy on the language of flowers, this is recorded as its symbolic meaning; and in ancient times a Hazel rod was supposed to have power of reconciling friends who had been separated by disagreement. These superstitions connected with the Hazel, and more particularly the one relating to the Hazel rod, named the Caduceus, assigned by the gods to Mercury as a means of restoring harmony to the human race, probably gave origin to the divining-rod, which was first made of Hazel and afterwards of the witch-elm. It is remarkable that in America this use was made of the hamamelis, a very different plant in its botanical characters, and hence called the Witch-Hazel.

There are two New England species, both delighting in the shelter of rude fences, and producing their flowers before their leaves. They are distinguished chiefly by the shape of their fruit. The common Hazel is the one most generally known. In this the shells or husks that enclose the nuts are of the same round shape, growing in a cluster, and each invested with a calyx like that of an ordinary flower. The Beaked Hazel is a smaller bush and frequents more solitary places than the other. “The calyx enclosing the nut, densely hispid and round at base, is contracted like a bottle into a long narrow neck, which is cut and toothed at the extremity.” The whole nut with its envelope resembles a bird’s head and beak. A dry sandy loam is the soil generally occupied by the Hazel. Along the old roads that pass over dry sandy plains, that border many of the river-banks in the Northern States, the Hazel, growing in frequent clumps, forms in some of these locations the most common kind of shrubbery. When we see a pitch-pine wood on one side of a road, the cultivated land on the opposite side is usually bordered with a growth of Hazels.

Both species are particularly worthy of protection and preservation. They produce a valuable nut without our care; they are ornamental to our fields and by-roads; they feed the squirrels and shelter the birds, and they add a lively interest to natural objects by their spontaneous products. The Hazel is associated with many pleasant adventures in our early days, with nut-gatherings and squirrel-hunts, and with many pleasant incidents in classical poetry. The Hazel has been a favorite theme of poets, especially those of the Middle Ages. In the songs of that period are constant allusions to the Hazel-bush, probably from its frequency in natural hedge-rows, and its valuable fruit.

THE BUTTON-BUSH.

Not much has been written of the Button-bush. We hear but little of those shrubs that do not readily admit of culture, and are not susceptible of modification by the arts of florists. The Button-bush is confined to wet, solitary places; indeed, it may be considered a true aquatic, as it grows in most cases directly out of the water. It is associated with the complaining song of the blackbird, whose nest is often placed in the forks of its branches, and it accompanies the ruder aspects of nature. It is far from being an elegant plant; and the little beauty it possesses belongs to the perfectly globular shape of its heads of flowers, which are nearly white. It is generally seen bordering the sluggish streams that flow through the level swamps, and often forms little islets of shrubbery in the middle of a sheet of water.

THE CLETHRA.