9Timber should be felled from the beginning of the Autumn up to that time when the west wind begins to blow; never in the Spring, because at that period the trees are as it were pregnant, and communicate their natural strength to the yearly leaves and fruits they shoot forth. Being empty and swelled out, they become, by their great porosity, useless and feeble, just as we see females after conception in indifferent health till the period of their bringing forth. Hence slaves about to be sold are not warranted sound if they be pregnant; for the foetus which goes on increasing in size within the body, derives nourishment from all the food which the parent consumes, and as the time of delivery approaches, the more unwell is the party by whom it is borne: as soon as the foetus is brought forth, that which was before allotted for the nourishment of another being, once more free by the separation of the foetus, returns to reinvigorate the body by the juices flowing to the large and empty vessels, and to enable it to regain its former natural strength and solidity.
2So, in the Autumn, the fruits being ripened and the leaves dry, the roots draw the moisture from the earth, and the trees are by those means recovered and restored to their pristine solidity. Up to the time above-mentioned the force of the wintry air compresses and consolidates the timber, and if it be then felled the period will be seasonable.
3In felling, the proper way is to cut through at once to the middle of the trunk of the tree, and then leave it for some time, that the juices may drain off; thus the useless liquor contained in the tree, running away through its external rings, all tendency to decay is removed, and it is preserved sound. After the tree has dried and the draining has ceased, it may be cut down and considered quite fit for use.
4That this should be the method pursued, will appear from the nature of shrubs. These, at the proper season, when pierced at the bottom, discharge from the heart through the holes made in them all the redundant and pernicious juices, and thus drying acquire strength and durability. On the contrary, when those juices do not escape, they congeal and render the tree defective and good for nothing. If, therefore, this process of draining them whilst in their growing state does not destroy their vigour, so much the more if the same rules are observed when they are about to be felled, will they last for a longer period when converted into timber for buildings.
5The qualities of trees vary exceedingly, and are very dissimilar, as those of the oak, the elm, the poplar, the cypress, the fir, and others chiefly used in buildings. The oak, for instance, is useful where the fir would be improper; and so with respect to the cypress and the elm. Nor do the others differ less widely, each, from the different nature of its elements, being differently suited to similar applications in building.
6First, the fir, containing a considerable quantity of air and fire, and very little water and earth, being constituted of such light elements, is not heavy: hence bound together by its natural hardness it does not easily bend, but keeps its shape in framing. The objection to fir is, that it contains so much heat as to generate and nourish the worm which is very destructive to it. It is moreover very inflammable, because its open pores are so quickly penetrated by fire, that it yields a great flame.
7The lower part of the fir which is close to the earth, receiving by its proximity to the roots, a large portion of moisture, is previous to felling straight and free from knots; the upper part, throwing out by the strength of the fire it contains, a great many branches through the knots, when cut off at the height of twenty feet and rough squared, is, from its hardness, called Fusterna. The lower part, when cut down, is sawed into four quarters, and after the outer rings of the tree are rejected, is well adapted to joinery works, and is called Sapinea.
8The oak, however, containing among its other elements a great portion of earth, and but a small quantity of water, air, and fire, when used under ground is of great durability, for its pores being close and compact, the wet does not penetrate it; in short its antipathy to water is so great that it twists and splits very much the work in which it is used.
9The holm oak (esculus), whose elements are in very equal proportions, is of great use in buildings; it will not however stand the damp which quickly penetrates its pores, and its air and fire being driven off, it soon rots. The green oak (cerrus), the cork tree, and the beech soon rot, because they contain equal quantities of water, fire, and earth, which are by no means capable of balancing the great quantity of air they contain. The white and black poplar, the willow, the lime tree (tilia), the withy (vitex), are of great service in particular works on account of their hardness. They contain but a small portion of earth, a moderate proportion of water, but abound with fire and air. Though not hard on account of the earth in them, they are very white, and excellently adapted for carving.
10The alder, which grows on the banks of rivers, and is to appearance an almost useless wood, possesses nevertheless most excellent qualities, inasmuch as it contains much air and fire, not a great deal of earth, and less water. Its freeness from water makes it almost eternal in marshy foundations used for piling under buildings, because, in these situations, it receives that moisture which it does not possess naturally. It bears immense weights and does not decay. Thus we see that timber which above ground soon decays, lasts an amazing time in a damp soil.
11This is most evident at Ravenna, a city, the foundations of whose buildings, both public and private, are all built upon piles. The elm tree and the ash contain much water and but little air and fire, with a moderate portion of earth. They are therefore pliant, and being so full of water, and from want of stiffness, soon bend under a superincumbent weight. When, however, from proper keeping after being felled, or from being well dried while standing to discharge their natural moisture, they become much harder, and in framings are, from their pliability, capable of forming sound work.
12The maple tree, which contains but little fire and earth, and a considerable portion of air and water, is not easily broken, and is, moreover, easily wrought. The Greeks, therefore, who made yokes for oxen (called by them ζυγὰ) of this timber, call the tree ζυγεία. The cypress and pine are also singular in their nature; for though they contain equal portions of the other elements, yet, from their large proportion of water, they are apt to bend in use; they last, however, a long time, free from decay; the reason whereof is, that they contain a bitter juice, whose acrid properties prevent the rot, and are not less efficacious in destroying the worm. Buildings, in which these sorts of timber are used, last an amazing number of years.
13The cedar and juniper trees possess the same qualities as the two last named; but as the cypress and pine yield a resin, so the cedar tree yields an oil called cedrium, with which, whatsoever is rubbed, as books, for instance, will be preserved from the worm as well as the rot. The leaves of this tree resemble those of the cypress, and its fibres are very straight. The statue of the goddess, as also the ceiled roof in the temple of Diana at Ephesus, are made of it; and it is used in many other celebrated temples, on account of its great durability. These trees grow chiefly in the island of Crete, in Africa, and in some parts of Syria.
14The larch, which is only known in the districts on the banks of the Po and the shores of the Adriatic, on account of the extreme bitterness of its juices, is not subject to rot and attack of the worm, neither will it take fire or burn of itself, but can only be consumed with other wood, as stone is burnt for lime in a furnace; nor even then does it emit flame nor yield charcoal, but, after a long time, gradually consumes away, from the circumstance of its containing very little fire and air. It is, on the contrary, full of water and earth; and being free from pores, by which the fire could penetrate, it repels its power, so that it is not quickly hurt thereby. Its weight is so great, that it will not float in water, when transported to any place, and is either conveyed in vessels, or floated on fir rafts.
15This property of the wood was discovered under the following circumstances. Julius Cæsar, being with his army near the Alps, ordered the towns to supply him with provisions. Among them was a fortress called Larignum, whose inhabitants, trusting to their fortifications, refused to obey the mandate. Cæsar ordered his forces to the spot immediately. In front of the gate of this fortress stood a tower built of this species of timber, of considerable height, and constructed after the manner of a funeral pile, with beams alternately crossing each other at their extremities, so that the besieged might, from its top, annoy the besiegers with darts and stones. It appearing that the persons on the tower had no other arms than darts, which, from their weight, could not be hurled any great distance from the walls, orders were given to convey bundles of fire-wood and torches to the tower, which were quickly executed by the soldiers.
16As soon as the flames, reaching almost to the heavens, began to encompass the tower, every one expected to see its demolition. But as soon as the fire was extinct, the tower appeared still unhurt; and Cæsar, wondering at the cause of it, ordered it to be blockaded out of arrow’s flight, and thus carried the town, which was delivered up to him by its trembling inhabitants. They were then asked where they obtained this sort of wood, which would not burn. They shewed him the trees, which are in great abundance in those parts. Thus, as the fortress was called Larignum, so the wood, whereof the tower was built, is called larigna (larch). It is brought down the Po to Ravenna, for the use of the municipalities of Fano, Pesaro, Ancona, and the other cities in that district. If there were a possibility of transporting it to Rome, it would be very useful in the buildings there; if not generally, at least it would be excellent for the plates under the eaves of those houses in Rome which are insulated, as they would be thus secured from catching fire, since they would neither ignite nor consume, nor burn into charcoal.
17The leaves of these trees are similar to those of the pine-tree; the fibres of them straight, and not harder to work in joinery than the pine-tree. The wood contains a liquid resin, of the colour of Attic honey, which is a good remedy in cases of phthisis. I have now treated of the different sorts of timber, and of their natural properties, as well as of the proportion of the elements in each. It only remains to enquire, why that species of fir, which is known in Rome by the name of Supernas, is not so good as that which is called Infernas, whose durability in buildings is so great. I shall therefore explain how their good and bad qualities arise from the situations in which they grow, that they may be clearly understood.