Forest protection was poorly developed: of insects little, of fungi no knowledge existed. Hand-picking was applied against caterpillars, also ditches into which the beetles were driven and then covered; the use of hogs in fighting insects was also known. That goats were undesirable in the woods had been observed. Some remarkable precocious physiological knowledge or rather philosophy existed: it was recognized that frost produces drought and that a remedy is to loosen the soil, aerating the roots, to drain or water as the case might require, and to prune; but also sap letting was prescribed. Against hail, dead owls were to be hung up; against ants, which were deemed injurious, ashes with vinegar were to be applied, or else an ass’s heart.
Curiosities in wood technology were rife and many contradictions among the wood sharps existed, as in our times. Only four elements, earth, water, fire, air, composed all bodies; the more fire in the composition of a wood, the more readily would it decay. Spruce, being composed of less earth and water but more fire and air, is therefore lighter than oak which, mostly composed of earth, is therefore so durable; but the latter warps and develops season splits because on account of its density it cannot take up readily and resists the penetration of moisture.
Wood impregnation, supposed to be a modern invention, was already practiced; cedrium (cedar oil) being used as well as a tar coating or immersion in seawater for one year, to secure greater durability.
4. Literature.
As regards literature, we find in Greece, besides what can be learned incidentally from the historians Herodotus and Xenophon and from the natural history of Aristotle, the first work on plant history and wood technology, if not forestry, in 18 volumes by Theophrastus (390-286 B.C.), a pupil of Aristotle and Plato.
Among the Romans, besides a number of historians, at least three writers before Christ discussed in detail agriculture and, in connection with it, tree culture; namely, Cato (234-149 B.C.) who wrote an excellent work De re rustica, in 162 chapters; Varro (116-26 B.C.), also De re rustica, in three books; and Vergilius Maro (70-19 B.C.), who in his Georgica records in six books the state of knowledge at that time. Of the many writers on these subjects who came in the Christian era there are also three to be mentioned, namely, Cajus Plinius Major (23-79 A.D.), who in his Historia naturalis, in 37 books, discusses also the technique of silviculture; Lucius Junius Moderatus Columella (about 50 A.D.), with 12 books, De re rustica, and one book De arboribus, the former being the best work of the ancients on the subject; and Palladius, writing about 350 A.D., 13 books, De re rustica, which in the original and in translations was read until past the middle ages.
Only a few references which exhibit the state of knowledge on arboricultural subjects among the Romans as shown in this literature may be cited, some of which knowledge was also developed in Greece and found application, more or less, throughout the Roman empire from India to Spain.
Nursery practice was already well known to Cato, while Varro knew, besides sowing and planting, the art of grafting and layering, and Columella discusses in addition pruning and pollarding (which latter was practiced for securing fuelwood), and the propriety of leaving the pruned trees two years to recuperate before applying the knife again.