Every individual being, whether of an animal or vegetable nature, has its average period of existence, during which it passes through all its stages, falls into decay, and, arrived at its limit, disappears from the face of the earth. As many years as a seedling Pear-tree requires to arrive at its full growth, so many years it takes to decay and die off. The age depends on the particular race, its degree of acclimation, the conditions, more or less favorable, under which the tree has been planted, and the care with which it has been subsequently managed.

Of all fruit-trees, the Pear, when sprung from a good race, attains the greatest age. This age varies from one hundred or one hundred and fifty up to three hundred years, or more. It is easy to ascertain its age by examining, when the tree has been sawed over by the ground, the annual layers, which show the progress of its growth, its stoppage, and decline. These layers, very large near the centre, become smaller and smaller towards the circumference, where they are almost imperceptible. It is in accidental situations that trees attaining the greatest age are found; but the soil must be rich, deep, and free from stagnant water. From these observations, the truth of which may be corroborated by every careful observer, it will be understood how necessary it is, in our cold and variable climates, when it is intended that the trees should attain a great age, only to plant stocks raised from seeds of hardy and vigorous sorts. In raising from seed, there are always some seedlings which have no similarity to their parents. For this reason, it is necessary to make a careful selection in the second year of their growth.

All the seedlings having a smooth bark, of an olive-green color, spotted with gray, and a stem that naturally grows straight and upright, may be considered to possess the characteristics indicative of firmness of growth and long duration.

The seedlings from the Wild Pear of the woods have been patronized; some authors have recommended the Sucree Verte Pear, which succeeds better in a strong soil than those of the Poire d'Amande and Napoleon. In several experiments made within the last ten years, we have obtained fine stocks from these three varieties, but have found that the most substantial have been derived from the Sucree Verte. Nevertheless, we have observed that vigorous varieties from recent regenerations gave a better result. The stocks which were selected and planted, were budded in the summer of the fourth year of their growth, not at six inches above the ground, but at three feet or more, for the following reason: Trees worked too near the ground are liable to sun-stroke, as formerly stated, whilst those budded at the height of three feet are not. Those young trees raised for orchard culture, do not undergo any cut or wound which cannot heal the same season. Their shoots are shortened back at the proper period, in order to form a fine pyramid, either with a half stem or tall stem; and, when older, the trees are subjected to a moderate thinning of the branches. Thus treated, they afford the prospect of good crops for many years.

It will be understood, that the nearer we conform in practice to the rules of a rational system of cultivation, the farther we put off the period of weakness and decay, and the more we deviate from such system the sooner does that period arrive. Crops too heavy for the richness of the soil, too severe pruning, and inconsiderate lopping or thinning of the branches, and inattention to the destruction of insects, are so many causes which hasten the period of individual decay in the Pear-tree. The time, however, will come when attention to all these points is useless, when the tree loses its vigor, and only produces poor and flavorless fruit, containing no seeds. The terminal shoots are short, slender, their bark cracks, and they no longer perfect their wood, losing their leaves, and becoming dried up.

When a tree presents these characteristics of old age, it ought to be destroyed, for it uselessly occupies room, has an unsightly appearance, and can only deposit diseased excretions by; its roots, which it ought not to be allowed to do. No other tree ought to be planted in the same place till many years have elapsed, unless, indeed, the soil occupied by the decayed tree be removed. - Gardener*' Chronicle.