Part 13

If we follow the course of any rustic lane which has not been improved, bounded by a rude fence of any kind which will form a support for the plants that come up beneath it, we see the climbing and creeping plants in their unrestrained freedom and beauty. If in the course of our walk we meet with a rude shed or any building old enough to be overgrown with mosses and incrusted with lichens, its walls are sure to be covered either with the climbing sumach or the Virginia creeper; for these plants seem designed by nature as the native embroidery of all neglected places and buildings. On many accounts, the most interesting plants are the climbers and creepers. Whether it be that we associate them with the idea of dependence on their part and of protection on the part of the tree of other object that supports them, or whether their ascent may suggest the idea of motion and progression, causing them to resemble a living creature, they never fail to interest the spectator, and to fill his mind with many poetic images.

The Virginia creeper possesses all the advantages of the English ivy, save that it is not an evergreen. But its deciduous character is not to be regarded as a defect, since if it were an evergreen it would want its annual attractions of scarlet and crimson that distinguish it in autumn. In this particular it is not surpassed by any production of the American forest, except the red maple. These colors render it very conspicuous in October, when it surrounds the trunks and branches of some of the tallest trees with its garlands of crimson, hiding them under its own splendid frondage. There is not a rustic lane where it is not seen creeping over the fences and mixing its glowing tints with other wayside plants. It is particularly luxuriant by the woodside; for though it is common in the deep forest it grows feebly and is deficient in leaves until it gains the summits of the trees. It needs the broad eye of day, and prospers only upon trees that stand outside of a wood. No other climbing plant is so generally used in New England as a drapery for houses and fences, taking the place occupied in Europe by the ivy. Many old houses are covered by it, and many an old stone-wall is completely enveloped in its foliage.

The poison ivy, or climbing sumach, is the only rival of the Virginia creeper in our woods. It is even more common in open fields, and though less luxuriant, surpasses it in the beauty of its leaf. It is a very pertinacious parasite, adhering very closely to the object that supports it, with its innumerable rootlets, but sustaining life only by communication with the soil. The growth of this plant is discouraged on account of the liability of many persons to be injuriously affected by its poisonous properties. Those who are not familiar with wild plants are generally unable to distinguish the poison ivy from the Virginia creeper. Their general appearance and habits are nearly the same, but their leaves furnish a sure mark of distinction. They are compound in each; but those of the Virginia creeper are in fives, those of the poison ivy in threes, without exception.

As we pass along the rustic lane, where it is involved in deep shadow by a dense growth of shrubbery and vines we see the woody nightshade adorning the mass with its singular halberd-shaped leaves, its dark blue flowers with a golden centre, and its pendent clusters of scarlet fruit. I know but few plants of which so little has been said that possess a greater share of beauty. There is a common prejudice against the woody nightshade, from its supposed poisonous qualities, and from our habit of identifying it with the deadly nightshade of Europe. If our plant has some poisonous qualities, they are not of a dangerous character. All parts of it may be bruised and handled with impunity, and its berries are so nauseous to the taste and smell that they are not liable to be eaten.

In the wild hedge-rows that skirt our fields and farms, made up of viburnum, elder, cornel, hazel, and wild rose-bushes, the woody nightshade, in company with the glycine, contributes greatly to the interest attached to these flowering thickets. What excites my surprise is that so few persons praise this modest little climber. How would its varied foliage, interwoven with that of more luxuriant plants, the deep but contrasted colors of its flowers and fruit, and its constant presence in the borders of all wet fallows, attract the admiration of a painter who, imbued with a love of nature equal to his love of art, should attempt to paint a New England stone-wall with its many native accompaniments!

A more conspicuous climber, and more common by the woodside than by the rustic lane, is the bitter-sweet. It is seen climbing over trees, not attaching itself by rootlets or tendrils, but twining round its supporter, like the morning-glory. It is often fifteen or twenty feet in height, covering some unfortunate tree with its own dense foliage, and finally causing it to perish by excluding light and air from it. This plant is well known to simplers, who have named it bitter-sweet, from the mingled sweet and bitter of the scarlet and orange-colored berries which they collect for medical use. I cannot learn that they contain any medicinal virtue; but it is well understood, in these days, that the possession of decided efficiency renders any medical substance unpopular. All popular remedies are physic only to the faith; hence the incomparable virtues of saffron and elder-flowers, whiteweed and everlasting!

We are prone, when thinking of plants merely as ornaments of nature, to forget that the fruit-bearing shrubs and vines have in general anything to recommend them except their fruit. It will be admitted that very many of these plants are deficient in beauty; yet I will confess that I have often admired the different species of bramble, which are so common in the rustic lane and woodside, trailing over fences and abrupt elevations, or hanging down from projecting cliffs, and exposing their clusters of red, black, and purple fruit. Our common species are not remarkable for elegance or beauty, but the country waysides would look bald and cheerless without the simple decoration afforded by these plants.

Among the trailing species of bramble, one of the most important as a natural ornament of lanes and field-borders, is the dewberry, or evergreen blackberry. It is very abundant on the edges of woods, where the trees are thin and scattered, and in pastures covered with low shrubs, where it may be recognized by its small, elegant, and shining leaves. These in protected situations remain green all winter, becoming slightly impurpled as spring advances. The dewberry covers with its close network of trailing branches the virgin turf which has been left undisturbed in the borders of lanes and wood-paths. When the soil has been repeatedly turned by the plough, this little inhabitant of the primitive sods gives place to a larger species, that trails in a similar manner upon the ground, and bears an excellent fruit.

The only native species of bramble which is admired for the beauty of its flowers, but not so common in fields and lanes as in old gardens, is the flowering raspberry. It is so called from the size of its large crimson flowers with a yellow disk, resembling a dark red single rose. The leaves of this species are not pinnate, like the leaves of other species of bramble, but palmate, resembling the leaf of the striped maple. We sometimes find it in a shady nook, concealing itself under a stone-wall, and seldom in company with other shrubs. The delicacy of its habit unfits it to contend with its more hardy congeners, and it is soon driven away from its retreat by the ingress of other species.

I have not yet spoken of the grapevine, which, if not very ornamental in gardens, where its beauty is marred by excessive pruning, cannot be surpassed in a certain kind of suggestive or relative beauty. Hence the pleasure it affords us when we see it on the borders of woods, hanging its purple clusters of fruit over some placid stream from the summit of an alder, or hiding the rudeness of a neglected building with its broad foliage. There is hardly an old road or rustic byway in the interior of the country which is not festooned by wild grapevines, and some of the most delightful arbors on old country roadsides are formed by these vines, trellised upon an ancient apple-tree or drooping birch.

When a green by-road passes over a wet meadow and crosses a brook under a natural arch formed by overhanging alders fastened together by creeping vines, the shade afforded by this arbor is greatly heightened by a twining canopy of clematis, or virgin’s bower, climbing over the trees and shrubs, always keeping on the outer surface, and supporting itself by tendrils. We often pass through copses of shrubbery completely overspread by this vine, rendered conspicuous when in fruit by multitudes of little silken and feathery tufts, which are far more beautiful than its flowers. There is not much beauty in this plant, and I attribute the interest attached to it chiefly to its poetical name and the romantic history of the European virgin’s bower.

THE CHESTNUT.

Many admirers of trees place the Chestnut before the oak because it is a taller tree with a proportional spread and denser foliage. A remarkable peculiarity in the style of its foliage is its radiated tufts, giving it a similar appearance to that which is so apparent in the horse-chestnut. But we observe an important difference between the two,—while the radiated tufts of the horse-chestnut are distinctly separated by spaces, those of the Chestnut seem to be involved in a general and more indistinct mass of foliage. A notion prevails in some parts of Europe, that this tree should not be planted near dwelling-houses, “because the flowers emit a powerful and disagreeable odor, which is offensive to most people.” I have not observed any such odor from the American Chestnut.

In general form and proportions there seems to be no specific difference between the English and the American chestnuts. On this continent it is a majestic tree, remarkable for the breadth and depth of its shade; but it is seldom cultivated by roadsides. It displays many of the superficial characters of the red oak, so that in winter we cannot readily distinguish them. The foliage bears some resemblance to that of the beech, but displays more variety. The leaves are long, lengthened to a tapering point, and of a bright and nearly pure green. Though arranged alternately, like those of the beech, on the recent branches, they are clustered in stars, containing from five to seven leaves, on the fruitful branches, that grow out from the perfected wood. When the tree is viewed from a moderate distance, the whole mass seems to consist of tufts, each containing several long pointed leaves, drooping divergently from a common centre. From this centre the aments of the male flowers come out in a similar way; and their bright silvery green, glistening upon a mass of darker foliage, always attracts attention at the time of flowering.

The Chestnut is ranked among the largest of our forest trees, sometimes in favorable situations attaining a height of nearly eighty feet. When growing isolated on a plain, its diameter is sometimes equal to its height. The Chestnut has a rather loose ramification, being in this respect inferior to the red oak, which it resembles. Its larger branches are numerous, but the spray is coarse, the terminal branches being fewer and more straggling than those of the oak. This tree is therefore not comparable in beauty with the oak when divested of its leaves. The Chestnut is a classical tree, being mentioned very frequently in the works of the Greek and Roman poets, who were familiar with it.

THE HICKORY.

The Hickory, including several species, is very generally distributed over this continent, but is found in no other part of the world. It is distinguished from the walnut by its foliage and general habit of growth, by the smaller number of leaflets on the leaf-stem, and by their darker color and firmer texture. The aments of the Hickory are in threes, and the outer shell of the fruit opens at four angles when it is ripe; the aments of the walnut are single, and the outer shell of the nut is undivided. The two trees differ also in their general appearance. The Hickory rises to a greater proportional height, with less length and spread of the branches, the lower ones being higher from the root of the tree and smaller than those of the walnut. Many of the trees are flattened at the top, and take a cylindrical form, when they approach to any regularity; but their outlines are more frequently irregular, displaying frequent gaps, and presenting several distinct masses of foliage.

The Hickory, therefore, when full-grown, has seldom much elegance, and little of the beauty of grace and symmetry. Its picturesque qualities are its sturdy habit, its great height, its dense and dark green foliage, its approach to a cylindrical shape, and its general eccentricity of growth. I have never seen a Hickory with long spreading branches like those of the butternut, nor with neat and prim foliage like that of the ash. The different species are so common in all the southern parts of New England as to form a notable arboreal feature of our landscape. In Massachusetts we see them following the lines of the old stone-walls, having come up from nuts planted by squirrels on the strip of land around the borders of the fields. We are indebted to this fortunate circumstance for thousands of beautiful and valuable trees, which, but for this narrow border of neglected land, would not have been allowed to “cumber the ground.” The trees that originated in these borders had ample room to expand, assume their normal shape, and acquire their full dimensions; and as we see them running upwards with but little width, we may consider this to be their natural style of growth.

Hickories are abundant on fertile slopes, near brooksides, and on rocky hills that abound in clay and yellow loam. They do not prosper on light, sandy soils, and are not found in bogs. They are even a better indication of a fertile soil than the oak. The shellbark alone drops its leaves before they are tinted in the autumn. The most remarkable species in New England are the shellbark, the fignut, the white hickory, and the bitternut. These four have nearly the same outward characters. They are, indeed, so much alike that the shellbark alone is readily distinguished by the exfoliation of the outer rind of its bark as soon as it has come to fruit-bearing. The bark of the other three species is channelled or furrowed, like that of the ash. The fruit of the fignut is fig-shaped; and as the epithet ficiformis was very early applied to this species, it is evident that the vulgar name of pignut is a corruption of the true name, which ought to be restored.

Had the old painters been acquainted with the Hickory, they would have admired it beyond most other trees. The peculiarities of its shape are remarkable. The breaks in its foliage cause that variety and irregularity of outline which are generally regarded as picturesque qualities. I see, while I am writing, directly before my window, a tall Hickory, standing on an elevation that makes the sky its only background. It is tall and narrow in its shape, and its head is divided into five distinct masses of foliage, separated by a considerable opening. Two of these masses are on the right, and three on the left, the highest making a flattened top, projecting over the right side, and hanging down in a large flowing mass. Yet this tree is perfectly normal in its proportions, for I can discover no marks of mutilation in any part of it.

The spray of the Hickory, like other trees with pinnate leaves that bear a large seed, is coarse; but its alternate branching gives it variety, and takes away some of that heaviness so disagreeable in the spray of the ash. All its branches are liable to be twisted, because they cannot be broken by the wind, and these contortions often extend throughout the ramification of the tree. It puts them forth from a central shaft, that usually extends to the summit of the tree, and, being small, they are often bent down very considerably by the weight of their fruit. The geographical bounds of the Hickory are the southern parts of New Hampshire on the north, Tennessee and North Carolina on the south, and the shores of Lake Erie on the west. The wood of the Hickory is exceedingly hard, heavy, and tough, and is in America the symbol of courage and firmness.

RELATIONS OF TREES TO TEMPERATURE.

Not long since, in one of my rambles in Essex County, Massachusetts, which is one of the most open and cultivated sections of the country, I entered a little valley near the sea, comprising about fifty acres of well-cultivated land, surrounded by a sort of amphitheatre of hills, which were covered with a dense forest of pines and firs. It was occupied by an intelligent farmer, whose careful observation had taken note of many things which are overlooked by the generality of his class. He remarked that his seed-time and harvest were several days earlier than on the farms in the open country, and that he had crocuses and tulips in his garden, on the south side of the surrounding wood, so early as to astonish his neighbors in the outer world. In regard to the relative temperature of the woods and of the open plain in summer, he remarked that it varied according to the time of day or night. The woods were cooler than the open country, in clear, calm weather, from about nine o’clock in the morning until near noonday; after this time the heat in them increased more rapidly than in the open country, and at the time of dew-fall it was greater in the woods, and continued so during the early part of the night. If the sky were cloudy, not much difference could be perceived at any hour in the temperature of the two situations. In cold and windy weather the woods afforded a comfortable shelter, and this shelter made them apparently warmer, even when the thermometer would indicate no difference.

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.