74.Though forest trees were reared with great care round houses in the city (Hor. Ep., lib. i. v. 10. 22.), and to produce shady walks for exercise in the country, yet it does not appear clear that they were either planted in masses, or strips, expressly for useful purposes. They were planted in rows in vineyards on which to train the vine; and the sorts generally preferred were the poplar and the elm. Natural forests and copses, then, as now, supplied timber and fuel Trees which do not stole (arbores c�du�), were distinguished from such as being cut over spring up again (succis� repullulant): of the former class was the larch, which was most in use as timber. The greatest tree that had been ever seen at Rome was one brought there for rebuilding the bridge at Naumachiaria. Tiberius C�sar laid it open to public inspection, and intended it to remain as a singular monument, on account of its great size, to all posterity. It remained entire and whole, until Nero built his stately amphitheatre. It was the trunk of a larch tree, and was 120 feet in length, and 2 feet in diameter, from one end to the other. There was also a most extraordinary fir tree, that formed the mast of the vessel which, in the time of the Emperor Caligula, transported out of Egypt into Italy the obelisk which was set up in the Vatican hill within the circus there, as well as the four large stones used as supporters to it. This mast was of a height above all others; �and certain it is,� say the ancients, �that there never was known a more wonderful ship to float upon the sea than this was.� She received 120, 000 modii of lentils for the very ballast, and she took up in length the greater part of Ostia harbour; for Claudius the emperor caused it there to be sunk, together with three mighty piles or dams, founded upon it, and mounted to the height of towers, for which purpose there was brought a large quantity of earth or sand from Puteoli. The main body of this mast contained in compass four fathoms full. (Plin., Nat. Hist., lib. xvi. cap. 40.)
