TREBUCKET, Tribuch (Terbiech- tum), a tumbrel or cucking stool. Also a great engine Trebuchet to cast stones to batter walls.

TREL, a large vegetable, rising with one woody stem to a considerable height.

Trees may be divided into two classes, timber and fruit-trees; the first including all those trees which are used in machinery, ship-building, &c. or, in general, for purposes of utility; and the second comprehending those trees valued only, or chiefly, for their fruit. It is not necessary to form a third class to include trees used for fuel, as timber is used for this purpose where it is abundant; and where it is not abundant the branches of the timber trees, or such of them as are dwarfish, unhealthy, or too small for mechanical purposes, are used as fuel.

The anatomy and physiology of trees have already been given under the generic name PLANT and SAP.

Certain trees, it is well known, are natives of particular districts; but many of them have been transplanted from their native soil, and now flourish luxuriantly in distant countries, so that it becomes a matter of very considerable difficulty to ascertain their original foil. The following rules are given for this purpose by the Honourable Daines Barrington.

1. They must grow in large masses, and cover considerable tracts of ground, the woods not ending abruptly, by a change to other trees, except the situation and strata become totally different. 2. They must grow kindly in copses, and shoot from the flood, so as to continue for ever, if not very carefully grubbed up. 3. The seed must ripen kindly; nature never plants but where a succession in the greatest profusion will continue. Lastly, trees that give names to many places are probably indigenous.

The growth of trees is a curious and interesting subject; yet few experiments have been made to determine what the additions are which a tree receives annually in different periods of its age. The only observations which we have seen on this subject worth repeating were made by the ingenious Mr Barker, to whom the Philosophical Transactions are much indebted for papers containing an accurate register of the weather, which he has kept for many years. He has drawn up a table to point out the growth of three kinds of trees, oaks, ashes, and elms; which may be seen in the Philosophical Transactions for 1788. We shall give his conclusions.

"I find (says he) the growth of oak and ash to be nearly the same. I have some of both sorts planted at the same time, and in the same hedges, of which the oaks are the largest; but there is no certain rule as to that. The common growth of an oak or an ash is about an inch in girth in a year; some thriving ones will grow an inch and a half; the unthriving ones not so much. Great trees grow more timber in a year than small ones; for if the annual growth be an inch, a coat of one-sixth of an inch is laid on all round, and the timber added to the body every year is its length multiplied into the thickness of the coat and into the girth, and therefore the thicker the tree is, the more timber is added."

We will present our readers with a table, showing the growth of 17 kinds of trees for two years. The trees grew at Cavenham in Suffolk. <table> <tr> <th>No</th> <th>July 1785<br>F. In.</th> <th>July 1786<br>F. In.</th> <th>July 1787<br>F. In.</th> </tr> <tr> <td>1 Oak</td> <td>0 10 1/2</td> <td>0 11 1/2</td> <td>1 0 1/2</td> </tr> <tr> <td>2 Larch</td> <td>1 0 1/2</td> <td>1 3</td> <td>1 4</td> </tr> <tr> <td>3 Scotch fir</td> <td>1 3 1/2</td> <td>1 5 1/2</td> <td>1 7 1/2</td> </tr> <tr> <td>4 Spruce fir</td> <td>0 5 1/2</td> <td>0 6 1/2</td> <td>0 7 1/2</td> </tr> <tr> <td>5 Spanish chestnut</td> <td>0 7 1/2</td> <td>0 7 1/2</td> <td>0 8</td> </tr> <tr> <td>6 Elm</td> <td>2 7 1/2</td> <td>2 9</td> <td>2 11</td> </tr> <tr> <td>7 Pinafter</td> <td>2 3 1/2</td> <td>2 4 1/2</td> <td>2 7 1/2</td> </tr> <tr> <td>8 Larch</td> <td>1 5 1/2</td> <td>1 6</td> <td>1 7</td> </tr> <tr> <td>9 Weymouth pine</td> <td>0 5</td> <td>0 6</td> <td>0 7 1/2</td> </tr> <tr> <td>10 Acacia</td> <td>1 2 1/2</td> <td>1 5 1/2</td> <td>1 6 1/2</td> </tr> <tr> <td>11 Beech</td> <td>0 6 1/2</td> <td>0 6 1/2</td> <td>0 7 1/2</td> </tr> <tr> <td>12 Plane, occidental</td> <td>0 6 1/2</td> <td>0 7 1/2</td> <td>0 8 1/2</td> </tr> <tr> <td>13 Lombardy poplar</td> <td>1 8</td> <td>2 0</td> <td>2 3 1/2</td> </tr> <tr> <td>14 Black poplar</td> <td>1 2 1/2</td> <td>1 4 1/2</td> <td>1 5 1/2</td> </tr> <tr> <td>15 Willow</td> <td>2 9 1/2</td> <td>3 2</td> <td>3 3</td> </tr> <tr> <td>16 Silver fir</td> <td>0 7 1/2</td> <td>0 8 1/2</td> <td>0 9 1/2</td> </tr> <tr> <td>17 Lime</td> <td>1 8 1/2</td> <td>1 10 1/2</td> <td>2 0</td> </tr> </table>

Trees sometimes attain a very great size: this must depend in a great measure on the richness of soil, but no less on the degree of heat. Indeed heat is so essential to the growth of trees, that as we go from the place within the polar circles where vegetation begins, and advance to the equator, we find the trees increase in size. Greenland, Iceland, and other places in the same latitude, yield no trees at all; and the shrubs which they produce are dwarfish; whereas, in warm climates, they often grow to an immense size. Mr Marham saw spruce and silver firs in the dock-yard in Venice above 40 yards long, and one of 39 yards was 18 inches diameter at the small end. He was informed that they came from Switzerland.

The largest tree in Europe, mentioned by travellers, is the chestnut tree on Mount Etna, already described under the article Etna, No 18. It is a certain fact that trees acquire a very great size in volcanic countries. Beside the multitude of fine groves in the neighbourhood of Albano in Italy, there are many detached oaks 20 feet in circumference, and many elms of the same size, especially in the romantic way to Eafello, called the Galleria. In travelling by the side of the lake of Bolsena, the road leads through an immense number of oaks, spread upon beautiful hills. Where the lava has been sufficiently softened, they are clean and straight, and of a considerable size; but where the lava has not been converted into a soil proper for strong vegetation, they are round-headed, and of less size; however, taken all together, they make a magnificent appearance; and the spot itself ought to be ranked among the fine parts of Italy. The fame may be observed of the small lake of Vico, encompassed with gentle risings, that are all clothed with forest-trees.

Some yews have been found in Britain 60 feet round. Palms in Jamaica attain the height of 200 feet; and some of the pines in Norfolk island are 280 feet high.

Of all the different kinds known in Europe, oak is best for building; and even when it lies exposed to air and water, there is none equal to it. Fir-timber is the next in degree of goodness for building, especially in England, where they build upon leaves. It differs from oak in this, that it requires not much seasoning, and therefore no great stock is required before-hand. Fir is used for flooring, wainscoting, and the ornamental parts of building within doors. Elm is the next in use, especially in England and France: it is very tough and pliable, and therefore easily worked: it does not readily split; and it bears driving of bolts and nails better than any other wood; for which reason it is chiefly used by wheel-wrights and coach-makers, for shafts, naves, &c. Beech is also used for many purposes: it is very tough and white when young, and of great strength; but liable to warp very much when exposed to the weather, and to be worm eaten when used within doors; its greatest use is for planks, bedsteads, chairs, and other household goods. Ash is likewise a very useful wood, but very scarce in most parts of Europe; it serves in buildings, or for any other use, when screened from the weather; handspikes and oars are chiefly made of it. Wild chestnut timber is by many esteemed to be as good as oak, and seems to have been much used in old buildings; but whether these trees are more scarce at present than formerly, or have been found not to answer so well as was imagined, it is certain that this timber is now but little used. Walnut-tree is excellent for the joiner's use, it being of a more curious brown colour than beech, and not so subject to the worms. The poplar, abele, and aspen trees, which are very little different from each other, are much used instead of fir; they look well, and are tougher and harder.

The goodness of timber not only depends on the soil and situation in which it stands, but likewise on the season wherein it is felled. In this people disagree very much; some are for having it felled as soon as its fruit is ripe, others in the spring, and many in the autumn. But as the sap and moisture of timber is certainly the cause that it perishes much sooner than it otherwise would do, it seems evident, that timber should be felled when there is the least sap in it, viz. from the time that the leaves begin to fall till the trees begin to bud. This work usually commences about the end of April in England, because the bark then rises most freely; for where a quantity of timber is to be felled, the statute requires it to be done then, for the advantage of tanning. The ancients chiefly regarded the age of the moon in felling their timber; their rule was to fell it in the wane, or four days after the new moon, or sometimes in the last quarter. Pliny advises it to be in the very instant of the change: which happening to be in the last day of the winter solstice, the timber, says he, will be incorruptible.

Timber should likewise be cut when of a proper age; for when it is either too young or too old, it will not be so durable as when cut at a proper age. It is said that oak should not be cut under 60 years old, nor above 200. Timber, however, should be cut in its prime, when almost fully grown, and before it begins to decay; and this will be sooner or later according to the dryness and moistness of the soil where the timber grows, as also according to the bigness of the trees; for there are no fixed rules in felling of timber, experience and judgment must direct here as in most other cases.

Great attention is necessary in the seasoning of tim- Some advise the planks of timber to be laid for a few days in some pool or running stream, in order to extract the sap, and afterwards to dry them in the sun or air. By this means, it is said, they will be prevented from either chopping, calting, or cleaving; but against shrinking there is no remedy. Some again arc for burying them in the earth, others in a heat; and some for scorching and scalding them in fire, especially piles, posts, &c. which are to stand in water or earth. The Venetians first found out the method of scalding by fire; which is done after this manner: They put the piece to be seasoned into a strong and violent flame; in this they continually turn it round by means of an engine, and take it out when it is everywhere covered with a black coaly crust; the internal part of the wood is thereby so hardened, that neither earth nor water can damage it for a long time afterwards.

Dr Plott says, it is found by long experience, that the trunk or body of the trees, when barked in the spring, and left standing naked all the summer exposed to the sun and wind, are so dried and hardened, that the fappy part in a manner becomes as firm and durable as the heart itself. This is confirmed by M. Buffon, who, in 1738, presented to the Royal Academy of Sciences at Paris a memoir entitled, "An easy method of increasing the solidity, strength, and duration of timber;" for which purpose he observes, "nothing more is necessary than to strip the tree entirely of its bark during the season of the rising of the sap, and to leave it to dry completely before it be cut down."

By many experiments, particularly described in that essay, it appears, that the tree should not be felled till the third year after it has been stripped of the bark; that it is then perfectly dry, and the sap become almost as strong as the rest of the timber, and stronger than the heart of any other oak tree which has not been so stripped; and the whole of the timber stronger, heavier, and harder; from which he thinks it fair to conclude, that it is also more durable. "It would no longer (he adds) be necessary, if this method were practised, to cut off the sap; the whole of the tree might be used as timber; one of 40 years growth would serve all the purposes for which one of 60 years is now required; and this practice would have the double advantage of increasing the quantity, as well as the strength and solidity, of the timber."

The navy board, in answer to the inquiries of the commissioners of the land revenue, in May 1789, informed them, that they had then standing some trees stripped of their bark two years before, in order to try the experiment of building one half of a floop of war with that timber, and the other half with timber felled and stripped in the common way. This very judicious mode of making the experiment, if it be properly executed, will undoubtedly go far to ascertain the effects of this practice. We are sorry that we are not able to inform our readers what was the result of the experiment.

After the planks of timber have been well seasoned and fixed in their places, care is to be taken to defend or preserve them; to which the smearing them with linseed oil, tar, or the like oleaginous matter, contributes much. The ancients, particularly Hesiod and Virgil, advise the smoke-drying of all instruments made of wood, by hanging them up in the chimneys where wood fires are used. The Dutch preserve their gates, portcullices, drawbridges, sluices, &c. by coating them over with a mixture of pitch and tar, whereon they fix small pieces of cockle and other shells, beaten almost to powder, and mixed with sea-fand, which incrusts and arms them wonderfully against all assaults of wind and weather. When timber is felled before the sap is perfectly at rest, it is very subject to worms; but to prevent and cure this, Mr Evelyn recommends the following remedy as the most approved: Put common sulphur into a cucurbit, with as much aquafortis as will cover it three fingers deep; distil it to dryness, which is performed by two or three rectifications. Lay the sulphur that remains at bottom, being of a blackish or fand-red colour, on a marble, or put it in a glas, and it will dissolve into an oil; with this oil anoint the timber which is infected with worms. This, he says, will not only prevent worms, but preserve all kinds of woods, and many other things, as ropes, nets, and masts, from putrefaction, either in water, air, or snow.

An experiment to determine the comparative durability of different kinds of timber, when exposed to the weather, was made by a nobleman in Norfolk; of which an account is given by Sir Thomas Beevor. This nobleman, in the year 1774, ordered three posts, forming two sides of a quadrangle, to be fixed in the earth on a rising ground in his park. Into these posts were mortised planks, an inch and a half thick, cut out of trees from 30 to 45 years growth. These, after standing 10 years, were examined, and found in the following state and condition:

The cedar was perfectly sound; larch, the heart found, but the sap quite decayed; spruce fir, found; silver fir, in decay; Scotch fir, much decayed; pinaster, quite rotten; chestnut, perfectly sound; abele, found; beech, sound; walnut, in decay; fycamore, much decayed; birch, quite rotten. Sir Thomas Beevor justly remarks, that the trees ought to have been of the same age; and Mr Arthur Young adds, they ought to have been cut out of the same plantation.

The immense quantity of timber consumed of late years in ship-building and other purposes has diminished in a very great degree the quantity produced in this country. On this account, many gentlemen who wish well to their country, alarmed with the fear of a scarcity, have strongly recommended it to government to pay some attention to the cultivation and preservation of timber.

We find, on the best authority, that of Mr Irving inspector general of imports and exports, that the shipping of England in 1760 amounted to 61,17 in number, the tonnage being 433,922; and the shipping in Scotland amounted to 976 in number, the tonnage being 42,818. In 1788 the whole shipping of Britain and Ireland and their colonies amounted to 13,800 being 1,359,752 tons burden, and employing 107,925 men. The tonnage of the royal navy in the same year was 413,667. We are informed also, on what we consider as the best authority (the report of the commissioners of the land revenue), that the quantity of oak timber, Report. of English growth, delivered into the dockyards from 1760 to 1788 was no less than 768,676 loads, and that the quantity used in the merchants yards in the same time was 516,630 loads; in all 1,285,306 loads. The foreign oak used in the same period was only 137,766 loads. loads. So that, after deducting the quantity remaining in the dock-yards in 1760 and 1788, and the foreign oak, there will remain about 1,542,284 loads of English oak, consumed in 28 years, which is at an average 37,653 loads per annum, besides from 8,300 to 10,000 loads expended annually by the East India Company within the same period (a).

The price of wood has risen in proportion to the demand and to its diminution. At the conquest, woods were valued, not by the quantity of timber which they contained, but the number of swine which the acorns could support. In 1608, oak in the forests was sold at 10s. per load, and fir-wood for 2s. per load. In 1663 or 1665, in navy contracts from 2l. to 2l. 1s. 6d. per load was given. In 1756 it rose to 4l. 5s. per load, and 3s. in addition, because no tops are received. Plank four inch sold in 1769 for 7l. a load, three inch 6l.; which prices were the same in 1792.

So great an expenditure of valuable timber within so short a period, gives reason to fear that the forests of this country will soon be entirely dismantled, unless something is done to raise fresh supplies: The building of a 70 gun ship, it is said, would take 40 acres of timber. This calculation is indeed so excessive, that it is scarcely credible. This, however, is no exaggeration. According to the prevailing opinion of experienced surveyors, it will require a good soil and good management to produce 40 trees on an acre, which, in a hundred years, may, at an average, be computed at two loads each. Reckoning, therefore, two loads at 8l. 16s. one acre will be worth 35l. and consequently 40 acres will only be worth 1,420l. Now a 70 gun ship is generally supposed to cost 70,000l.; and as ships do not last a great many years, the navy continually requires new ships, so that the forests must be stripped in a century or two, unless young trees are planted to supply their place.

Many plans have been proposed for recruiting the forests. Premiums have been held forth to individuals; and it has been proposed that the crown-lands should be set apart for the special purpose of raising timber. With respect to individuals, as they must generally be disposed to sow or plant their lands with those vegetables which will best reward their labours, it is not to be expected that they will set apart their fields for planting trees unless they have a greater return from them than other crops. But bad must that land be which will not yield much more than 35l. produce in 100 years. But though it be evident that good land will produce crops much more lucrative to the proprietor than timber, yet still there are lands or pieces of land which might be applied with very great advantage to the production of wood. Uneven ground, or the sides of fields where corn cannot be cultivated, might very properly be set apart for this purpose; barren lands, or such as cannot be cultivated without great labour and expence, might also be planted. Hedge-rows and clumps of trees, and little woods scattered up and down, would shelter and defend the fields from destructive winds, would beautify the face of the country, render the climate warmer, improve barren lands, and furnish wood for the arts and manufactures.

But to cultivate forest timber has also been thought of such national importance, that it has been deemed worthy of the attention of government. It has been proposed to appropriate such part of the crown-lands as are fit for the purpose solely of producing timber for the navy. This appears a very proper scheme in speculation; but it has been objected, that for government to attempt the farming of forests would be really to establish groups of officers to pocket salaries for doing what, it is well known, will never be done at all. But to this objection we reply, that such an agreement might be made with the inspectors of forests, as to make it their own interest to cultivate trees with as much care as possible. Their salary might be fixed very low, and raised in proportion to the number of trees which they could furnish of such a size in a certain number of years. After all, we must acknowledge that we must depend greatly on Russia, Sweden, Norway, and America, for supplying us with timber; and while these countries take our manufactures in exchange, we have no reason to complain. Still, however, we ought surely not to neglect the cultivation of what is of so much importance to our existence as a nation, for it may often be impossible in time of war to obtain timber from foreign countries.

In the beginning of this article we mentioned the general division of trees into timber or forest-trees and fruit trees. We have already said all that our limits will permit respecting the former; we will now, therefore, say something of the latter. Our observations shall be confined to the methods of preserving fruit trees in blossom from the effects of frost, and from other diseases to which they are liable.

The Chevalier de Dicenberg of Prague, we are told, has discovered a method of effectually preserving trees in blossom from the fatal effects of those frosts which some times in the spring destroy the most promising hopes of a plentiful crop of fruit. His method is extremely simple. He surrounds the trunk of the tree in blossom with a wisp of straw or hemp. The end of this he sinks, by means of a stone tied to it, in a vessel of spring water, at a little distance from the tree. One vessel will conveniently serve two trees: or the cord may be lengthened so as to surround several, before its end is plunged into the water. It is necessary that the vessel be placed in an open situation, and by no means shaded by the branches of the neighbouring trees, that the frost may produce all its effect on the water, by means of the cord communicating with it.—This precaution is particularly necessary for those trees the flowers of which appear nearly at the same time as the leaves; which trees are peculiarly exposed to the ravages of the frost. The proofs of its efficacy, which he had an opportunity of observing in the

(a) A writer in the Bath Transactions says, that the aggregate of oaks felled in England and Wales for 30 years past has amounted to 320,000 loads a-year; and affirms that he has documents in his possession founded on indisputable facts. The difference between this account, and that which we have given in the text from the report of the commissioners, we leave to be reconciled by those who have proper opportunities. We give the facts merely on the authority of others. spring of 1787, were remarkably striking. Seven apricot cipaliers in his garden began to blossom in the month of March. Fearing that they would suffer from the late frosts, he surrounded them with cards as above directed. In effect, pretty sharp frosts took place fix or eight nights: the apricot-trees in the neighbouring gardens were all frozen, and none of them produced any fruit, whilst each of the chevalier's produced fruit in abundance, which came to the greatest perfection.

The following is the method proposed by Mr William Forsyth for curing injuries and defects in trees; for which a reward was given to him by his majesty, on condition that he should make it public. It is equally applicable to forest as to fruit trees (B).

Take one bushel of fresh cow-dung; half a bushel of lime rubbish of old buildings (that from the ceilings of rooms is preferable); half a bushel of wood ashes; and a sixteenth part of a bushel of pit or river sand. The three last articles are to be sifted fine before they are mixed; then work them well together with a spade, and afterwards with a wooden beater, until the stuff is very smooth, like fine plaster used for the ceilings of rooms. The composition being thus made, care must be taken to prepare the tree properly for its application, by cutting away all the dead, decayed, and injured parts, till you come to the fresh found wood, leaving the surface of the wood very smooth, and rounding off the edges of the bark with a draw-knife, or other instrument, perfectly smooth, which must be particularly attended to. Then lay on the plaster about one-eighth of an inch thick all over the part where the wood or bark has been so cut away, finishing off the edges as thin as possible. Then take a quantity of dry powder of wood ashes, mixed with a sixth part of the same quantity of the ashes of burnt bones; put it into a tin box, with holes in the top, and shake the powder on the surface of the plaster, till the whole is covered over with it, letting it remain for half an hour to absorb the moisture: then apply more powder, rubbing it on gently with the hand, and repeating the application of the powder, till the whole plaster becomes a dry smooth surface.

All trees cut down near the ground should have the surface made quite smooth, rounding it off in a small degree, as before mentioned; and the dry powder directed to be used afterwards should have an equal quantity of powder of alabaster mixed with it, in order the better to resist the dripping of trees and heavy rains. If any of the composition be left for a future occasion, it should be kept in a tub or other vessel, and urine of any kind poured on it, so as to cover the surface; otherwise the atmosphere will greatly hurt the efficacy of the application. Where lime rubbish of old buildings cannot be easily got, take powdered chalk, or common lime, after having been flaked a month at least. As the growth of the tree will gradually affect the plaster, by raising up its edges next the bark, care should be taken, where that happens, to rub it over with the finger when occasion may require (which is best done when moistened by rain), that the plaster may be kept whole, to prevent the air and wet from penetrating into the wound.

By this process, some old worn-out pear trees, that bore only a few small, hard fruit, of a kernelly texture, were made to produce pears of the best quality and finest flavour the second summer after the operation; and in four or five years they bore such plenteous crops, as a young healthy tree would not have produced in four times that period.

By this process, too, some large ancient elms, in a most decayed state, having all their upper parts broken, and a small portion only of the bark remaining, shot out shoots from their tops, above thirty feet in height, in fix or seven years from the first application of the composition.

Thus may valuable trees be renovated; and forest trees, which are useful or ornamental from their particular situation, be preserved in a flourishing state. But what is far more interesting, a perfect cure has been made, and found timber produced, in oak trees, which had received very considerable damage from blows, bruises, cutting of deep letters, the rubbing off the bark by the ends of rollers, or wheels of carts, or from the breaking of branches by storms.