choice of one for this purpose that is a free grower, to work on such varieties as any cultivator's taste may suggest; and if neatly done by a good workman, the different varieties when in flower, on one plant, are a great curiosity.

SYLVA AMERICANA. (Concluded from p. 93.)

THE Pinus Strobus owes its selection for the construction of houses in the United States, to one quality in particular, the small expense of labour at which it can be fashioned and put together. While it is more durable and better able to bear exposure to the fierce temperature and sudden changes of the climate, than any other pine which abounds in America, it is also lighter, softer, and more free from knots. In favourable situations the diameter of the trunk varies from three to seven feet; and thus it furnishes planks for building of ample dimensions. This tree has also one important quality in common with the locust, which is denied to many other of the best timber trees. We mean the great proportion which the heart, or perfect wood, bears even in young trees to the laburnum or sap wood, being not less than eleven to one in trees of a foot in diameter. In all timber after felling, it is the sap wood which is the first to decay, and which is as unfit for any useful purpose, as the unripened products of nature generally. Hence it is an important element in the value of the white pine, that it ripens its wood at so early a period. It is true, after all, that in point of durability, when freely exposed to the elements, or when set in the ground, its timber cannot compete with many of the harder woods; but if well seasoned and kept carefully painted, it will endure for centuries, without any symptoms of decay, as is attested by many wooden houses, more especially in the large towns of New England. Where entirely covered, it seems to be incorruptible. But, were its durability less, the other qualities to which we have adverted, namely, its lightness and softness, would form a most liberal equivalent.

It is not easy to estimate, how much the rapid advancement of New England may have been owing to the abundance of this valuable tree. The importance of shelter is a point which it requires few lessons from the winter climate to set forth; and by no tree with which we are acquainted, could this want be supplied so rapidly and easily, as by the white pine. At the value which human labour has always maintained among them, the difference of expense to New England, which would have resulted from the general employment of the oak, for instance, instead of the pine, for their houses, would be enormous. In many parts of the valley of the Mississippi, this pine, as well as almost every other species of pine, is exceedingly rare. The settlers are in consequence obliged to substitute the oak, both for their houses and their furniture. Their dwellings (we speak of the new settlers,) are generally of oak filled in with earth, and are quite inferior, both in appearance and comfort, to those which we find in the newly-cleared lands of the State of the Maine.

They are scarcely less indebted to the white pine, for their commercial and naval, than for civil, architecture. It is this tree, which gives them, not indeed the frames, but the masts of vessels, for which it is admirably fitted, by the degree in which it combines the qualities of durability and lightness, as well as by the straightness of its trunk. Its place for this purpose, in the Northern and Middle States, could hardly be supplied. During their colonial existence, its value was fully appreciated by England; and, more than one hundred years ago, some statutes were passed, restricting the cutting of trees proper for masts. We have found no evidence, however, that these statutes were ever enforced; and, however useful in their design, they would interfere too much with private liberty, to render their renewal desirable, so far as respects the land of individuals.

The fame of the white pine has long since extended to Europe, principally by means of the stocks which have been imported into England, to supply in part our immense demand for masts and spars. The living tree has also been introduced into this country, but is not highly appreciated, and we have found no writer who does it full justice. The truth, is, however, that our climate is not fitted to its development. The limits within which it flourishes in America, are the 43d and 47th degrees of latitude. Now no part of Great Britain has a climate which answers to that region. The northern extremity of Scotland, which lies in about the 58th or 59th degree of latitude, is visited with winters far less rigorous than the great majority of theirs. Besides, there are few situations here which furnish the soil in which this tree chiefly delights. The most magnificent specimens of the white pine are found in the depths of forests, in a virgin soil covered with the accumulated mould of centuries, and above all on the banks of rivers, or in the beds of large cedar swamps. In pleasure grounds, it seldom rises to its greatest height, or at least requires a longer time to do so, than has yet been allowed in any instance within our knowledge. It grows, however, with considerable rapidity, and soon acquires a loftiness and bulk equal to that of most cultivated trees; and its highly polished bark and light silvery foliage, render it, from the time it springs from the soil, a desirable accession to a shrubbery.

The next of their principal forest trees, which we shall notice is the White Oak. The general appearance of oaks is more familiar to us, than that of any other class of forest trees, except the elm tree. The oak is far less lofty than the pine, and has no pretensions to the elegance of the elm; but as an emblem of robust vigour, it stands, both here and in the New World, at the head of all the sons of the forest. In short, a full grown oak can be considered as occupying the same place among fine trees, which the Hercules does among fine statues, and may be described in the terms applied to that magnificent work of art by the poet, as "strength embodied." Such has been its character in all ages. It is also supposed to be a tree of slower growth and longer life than any other, though its superiority in this last respect over the chestnut, is far from incontestable. The useful qualities of its wood have also been appreciated from time immemorial, in every country in the temperate zone. For these reasons probably, the oak has been regarded with a degree of veneration, from the earliest ages of mankind. The first funereal monument on record was an oak tree. But in no country has it been more valued, more honoured or cherished, than in that of our own, for it has long been recommended to us by many historical and poetical associations, and the achievements of our gallant navy, as well as the vast benefits, which we have derived from our commerce. Of all the species of this genus, which grow in the latitude of New England, the most valued is the white oak, (Quercus Alba.) This is easily distinguished from every other tree of the same kind by the whiteness of its bark, and by the persisting, or holding on, of a few of the dried leaves, in the winter season. Its leaves are also without prickles or bristles at the end of their lobes, a quality in which it agrees with no large oak except the swamp white oak, (Quercus prinus discolor.) It bears a greater analogy than any other oaks, to the celebrated European white oak, or Quercus pedunculata.

Which of the two trees furnishes the finer timber, is a question which has been investigated with great care. It is stated by high authority, that the wood of the American white oak is lighter, more elastic, and more flexible, than that of the English, but that it is on the whole weaker and less durable; and this opinion is sanctioned by a large number of writers.

The timber generally selected for ship-building in America is what is called the pasture oak. This is greatly preferred to that which grows in crowded forests, where the trees, from their vicinity to each other, are robbed of much of the nutriment which they derive from the soil, as well as of the genial influence of the sun and air. Hence the building of a single large vessel requires the timber of many acres, and as the white

oak is constantly felled in great quantities, both for home consumption and for exportation, the period cannot be distant when serious difficulty will be experienced there in procuring a supply of this valuable wood.

In this connexion, it may be proper to make one or two remarks on the felling of trees. It is generally agreed, that the durability of timber depends materially on the season when this operation is performed; but what that season is, is a question on which directly opposite opinions are held by the ablest writers. The principal cause of the decay of wood of all descriptions, is thought to be the sap, which remains after felling; and hence the desired object is, to procure timber as free as possible from this ingredient. To this end, it has been recommended to fell the tree in the winter season, as it is then deemed to contain the smallest quantity of sap; and such we believe is the general practice. This doctrine, however, has been opposed with great ability, by some writers, who state, and with truth, that trees are not devoid of sap in winter, but that it exists in abundance, though greatly thickened by the cold. They maintain, therefore, that it is much more difficult to expel than in summer, when in a more liquid form, and that the proper time for felling the tree is, not when it contains the least sap, but when the sap which it does contain, may most easily escape or be expelled. This opinion certainly seems to be the better one, though the winter season is so much more convenient on many accounts than any other for the procuring of timber, that the old practice will probably maintain its ground.

Besides the white oak, there are four other species in New England, which grow to a large size. Of these the most valuable are the Swamp White, and the Black Oak. The swamp white oak is not abundant, and grows only in moist soils. It has been less used than the white oak, partly on account of its rarity; but its timber is heavier, and it is thought that it may be found, on accurate examination, to be superior. The black oak is valued not for its timber, which is of an inferior quality, but for its bark, for it is this which furnishes the quercitron, so much used for imparting a beautiful yellow dye to wool, paper, &c.

Next to the pines and oaks, there seems to be no tree in America, of more extensive celebrity than the Sugar Maple. The extraordinay neatness of its appearance, and the beauty of its foliage, which in summer is of the liveliest green, and in autumn assumes the richest and most glowing red, are sufficient to recommend it as a beautiful ornament, in gardens and avenues. The bark is remarkably smooth, and the tree is infested, we believe, by no insect, nor subject to any maladies. The branches are disposed with much regularity, though without stiffness, and so arranged, that their usual outline is an elegant oval. It is to this tree we are chiefly indebted for the beautiful curled and bird's-eye maple, employed in cabinet work, which rivals, if it be not admitted to surpass in brilliancy and richness, the finest woods of tropical climates. But the sugar maple derives its chief reputation, as well as its name, from the qualities of its sap. A large portion of the sugar used in the western districts of New York, is derived from the maple. Michaux remarked, nearly thirty years since, that at least ten millions of pounds of this sugar were then annually made in the United States. This quantity is far less than might be procured from the same source, in case of necessity. According to Dr. Rush, the northern part of New York and Pennsylvania alone, contained at the same period, thirty millions of sugar maple trees; and, if we suppose each tree to yield on an average from two to four pounds of sugar annually, the product would go far towards supplying the whole consumption of the country.

The maple sugar can be made of a quality equal to the best imported. We have seen it formed into very good loaf sugar. It is, however, in a brown state that it is generally used; and, except in the districts where it is produced, it is less agreeable to the palate of consumers generally, than the product of the cane. To manufacture it, requires a great expense not only

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of labour, but of fuel; and hence it probably cannot be sold, at a distance, for a price which will enable it to compete with the imported article. The sap of the tree, or maple juice, as it is called, is greedily coveted by wild and domestic animals, who break through enclosures for the sake of obtaining it, and is generally an agreeable and wholesome beverage. We have been informed, however, of one instance, in which it proved to be of a highly intoxicating quality. This circumstance occurred about thirty years since. All the sap procured from the maple trees of an extensive district, was found to have undergone a vinous fermentation; and children who drank it freely were in some cases rendered delirious, for two or three days. We have heard of no other instance of this phenomenon, nor have we learned that any probable explanation has been given of its cause.

The last of the American forest trees which we shall notice, is one of which we need say but little. We mean the American Elm. In a strictly economical point of view, this tree is of little value, as neither its wood nor its bark is employed to any extent in the useful arts. It is subject to the disadvantage of being more attacked by the cankerworm, than any other forest trees, and is one of the first to shed its foliage in autumn. It is a tree also, which proves rather a troublesome inmate in small gardens and enclosures, as it spreads its roots far and wide, and frequently protrudes them above the surface of the ground, so that it completely monopolizes a large extent of soil. But where a proper space can be allotted to it, there is no tree which rivals it in grace and majesty. Michaux pronounces it to be decidedly the most magnificent vegetable production of the temperate zone.

Many of the most important classes or genera of forest trees are common to both continents, such as the oak, ash, elm, &c. Those trees of the old world and the new, which bear the same name, generally resemble each other to a great degree; but in almost every instance, the resemblance stops short of complete exactness. Thus we find that the elms, willows, and larches of Europe and America, though manifestly belonging to the same class of vegetable productions, differ from each other materially either in their size, their beauty, or the value of their timber. This seems merely an application of the general law of nature, which leads her to avoid, in all her productions, any thing like mathematical resemblance; a rule, of which we have a familiar proof, in the fact that no two leaves can be found on any tree, which do not manifestly differ in shape or size.

ON FOREST AND TIMBER TREES.

We know from experience that in our climate the pear, the cherry, the plum, and the quince, while young, and but of a single summer's growth, are tender trees, and require protection, during the first winter, on a naked and defenceless soil. We know that these trees, during the first winter, are liable to be thrown out by frost and destroyed, unless we afford them protection; but in the second winter, if they grow well, we have rarely witnessed any injury from winter.

I am inclined to believe that the climate of the valley of the great Hudson river is exposed to a degree of extreme cold during winter, which is unknown in the same latitudes on high hills remote from that river, or on the lands near the sea. The same remarks may apply to the valley of the Connecticut, from the position of this river, throughout its whole extent, from Canada to the sea.

I have good evidence that the climate of the whole valley of the North river is, in all low situations, another and much more severe and destructive climate, during winter, than ours at Boston-the extreme cold of Canada being brought down and concentrated by the prevailing winds, which usually blow either north or south, and seldom across the stream; and the frosts of summer are more common and destructive in these valleys, as the dews exhaled by day descend and rest on these

injury, or to replant them exactly as they were, then, in order to diminish the loss of water and oxygen, the plants ought to be shaded from the light, or, if that cannot be done, they ought to have a suitable proportion of their leaves or branches cut off. De Candolle says, this practice was wont to be so universal upon the Continent, that the gardener's maxim was, "If you plant your own father, you must cut off his head." Sir Henry Stewart has proved the bad science of such universal barbarity.

It is important not to plant the roots too deep, so as to be out of the reach of air, or too shallow to expose them to drought. If the holes are made sufficiently large and deep, so as to have the roots surrounded, when the plant is in its place, by well pulverized surface mould, a tree should not be planted more than an inch deeper than it stood in the nursery. The object in transplanting cabbage, brocoli, &c. is, by checking their growth to throw them earlier into flower or head. Trees are frequently transplanted in their young state, by nurserymen, purposely to abridge their long roots, and to increase their root fibres. They are therefore in the best condition for final planting, after they have been one year transplanted, and done well, in the nursery. They are then removed with nearly their entire roots.

SCIENTIFIC PRINCIPLES OF STRIKING.

By certain experiments, not by any means praiseworthy, yet, beyond all question, it has been proved that, if the head of a snail or earth-worm be cut off, the body will not only live for a considerable time, but a new head will be reproduced, with a mouth capable of taking food. By similar experiments it has been found that the legs of spiders and the feet of frogs, when cut off, are reproduced.

Upon a similar principle, when the roots of certain plants, which are to them what the head is to animals, are cut off, new roots may, under peculiar circumstances, be reproduced. The chief condition required for the reproduction of such roots, is the preservation of their life, till the roots have time to form, and various expedients are resorted to with this view, as well as for the quick production of their roots.

Striking by Layers.-The common mode of striking by layers is to select a branch, to slit, tongue, or cut it half through, in a direction sloping upwards, or to take off a ring of bark, or pierce it in several directions with a brad-awl, or twist a wire round it, to bring the part operated upon in the earth, leaving the point above ground, and to fix it in its place by a crotched stick. The descending pulp, otherwise called elaborated sap, or cambrun, is stopped short by the cut, in its passage toward the root, rood buds are formed by it, which soon send out roots into the moist earth, and when these are deemed strong enough to feed the plant, the branch is cut off a little below, and the tree in miniature is ready for planting out. The soil should not be too damp, lest the cut part canker.

SCIENTIFIC PRINCIPLES OF GRAFTING.

When the finger is cut with a knife, the blood-vessels soon contract their cut extremities into an opening so narrow, that the thicker and red part of the blood cannot pass, and the bleeding therefore ceases. But even then there oozes out the thin watery part of the blood, consisting chiefly of matter, the same or similar to the white of an egg, which, being thus separated from the rest of the blood, thickens by the heat of the body, as the white of the egg does by boiling. If the lips of the finger cut accordingly be kep: close together by sticking plaster, they will become united by means of this natural glue or serum in little more than a day. Upon the same principle I once succeeded, as others have done, in managing to unite the whole upper joint of a finger which a boy had chopped off by machinery; and experiments have been successful in causing the spur of a cock to unite and grow upon his comb.

It is upon similar principles that the science of grafting is founded; for if a young branch, like the boy's finger, be

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taken off by a clean cut, and the cut extremities immediately joined, the descending pulp will thicken like the watery part of blood, and while it remains soft the sap from the cut end of the sap-vessels will force its way through to their continuation above in the cut slit, which, if the process be successfully managed, will grow as well, or nearly, as if it had never been cut.

If, again, instead of applying the same cut scion to the part it was cut from, a scion from another tree be applied, as if I had applied to the boy's finger the tip of another boy's finger, chopped off by the same accident, there seems no good reason to doubt that a similar healthy joining might, by care, be effected. In the case of animals, indeed, such joinings are rare, because rarely tried, but in garden plants they are exceedingly common, for the purpose of continuing esteemed varieties of valuable fruits and flowers, accidentally produced by cultivation, as well as for forwarding the fruiting of young trees, since seedlings require years to arrive at a bearing state. On examining the joining of a graft about a fortnight after it has been made, I have found, as in a healing finger-cut, a number of small roundish grains, in the form of a thin layer, produced from the thickening of the pulp, and destined to form the hard substance termed the callus, which in general projects a little externally, and the scar differs in appearance from the other parts of the bark. It is, however, only in the space between the pulp-wood and the bark that the uniting substance is formed, and therefore it is evident that the slip to be grafted must have this part applied to the same part of the stock, and, if these differ in thickness, at least to one side.

One of the most obvious principles of this process is, that the sorts to be grafted should be alike, or nearly alike, because, in that case, the arrangement of the sap and pulp-vessels being similar, their cut ends will more readily apply mouth to mouth, and less obstruction or interruption of the circulating juices will take place.

To this principle there is an exception, arising from the peculiar design which the graft is intended to fulfil. Where the design to increase fruit bearing, the stock may be of firmer texture than the cutting, as when a peach cutting is grafted on a plum stock, which, having narrow vessels, a part of the descending pulp is stopped short, and serves to strengthen the branch. If it be intended to increase the branches and leaves, on the other hand, a plum cutting grafted on a peach stock might probably do so, by allowing the ascent of more

sap.

Binding of the Graft.-When the joining has been made, by cutting and properly fitting the bark of the slip to the back of the stock, at least on one side thereof, it must be bound so as to prevent this junction from being deranged. This is usually done with a ball of three parts of clay, well worked, with one part of fresh horse droppings, and a little finely chopped straw, the whole about an inch thick, and two inches or more in length, being tied with a ribbon of bass.

The principle upon which this is done, is to prevent the oxygen of the atmosphere from getting to the fluid pulp at the joining, where it would unite with the carbon, and form carbonic acid gas, and thereby rob the pulp of its solidity. The exclusion of light is necessary on the same account, for, as in the case of the finger-cut, the oxygen would unite with the carbon, and would prevent the thickening of matter from the blood. On the same account, moisture, by supplying oxygen, would be injurious; and dryness might act both as exhausting the pulp, and by causing the edges of the back to shrivel and gape, which would facilitate the entrance of the air and its oxygen.

PRUNING.

We have been the constant advocates for summer instead of winter pruning-of pruning after the leaves have expanded, and the limbs have nearly or quite completed their vernal growth, in preference to pruning when trees are leafless and the growth dormant. We have done so because we considered