There are great differences also in trees in respect to age. The almond and the pear[2525] are the most fruitful when old, which is the case also with the glandiferous trees and a certain species of fig. Others, again, are most prolific when young, though the fruit is later in coming to maturity, a thing particularly to be observed in the vine; for in those that are old the wine is of better quality, while the produce of the younger trees is given in greater abundance. The apple-tree becomes old very early, and the fruit which it produces when old is of inferior quality, being of smaller size and very liable to be attacked by maggots: indeed, these insects will breed in the tree itself. The fig is the only one of all the fruit-trees that is submitted to any process with the view of expediting the ripening of the fruit,[2526] a marvellous thing, indeed, that a greater value should be set upon produce that comes out of its proper season! All trees which bear their fruit before the proper time become prematurely[2527] old; indeed, some of them wither and die all of a sudden, being utterly exhausted by the too favourable influence of the weather, a thing that happens to the vine more particularly. (28.) On the other hand, the mulberry becomes aged[2528] but very slowly, and is never exhausted by its crops. Those trees, too, the wood of which is variegated, arrive at old age but slowly,—the palm, the maple, and the poplar, for instance. (29.) Trees grow old more rapidly when the earth is ploughed and loosened about the[2529] roots; forest trees at a later period. Speaking in general terms, we may say that care employed in the culture of trees seems to promote their fertility, while increased fertility accelerates old age. Hence it is that the carefully tended trees are the first to blossom, and the first to bud; in a word, are the most precocious in every respect: but all natural productions which are in any way weakened are more susceptible of atmospheric influences. CHAP. 52.—TREES WHICH BEAR VARIOUS PRODUCTS. CRATÆGUM. Many trees bear more than one production, a fact which we have already mentioned[2530] when speaking of the glandiferous trees. In the number of these there is the laurel, which bears its own peculiar kind of grape, and more particularly the barren laurel,[2531] which bears nothing else; for which reason it is looked upon by some persons as the male tree. The filbert, too, bears catkins, which are hard and compact, but of no use[2532] whatever. (30.) But it is the box-tree that supplies us with the greatest number of products, not only its seed, but a berry also, known by the name of cratægum;[2533] while on the north side it produces mistletoe, and on the south hyphear; two products of which I shall shortly have to speak more[2534] at length. Sometimes, indeed, this tree has all four of these products growing upon it at the same moment. CHAP. 53.—DIFFERENCES IN TREES IN RESPECT OF THE TRUNKS AND BRANCHES.