Harvesting.—The fruit of the olive is a "drupe," a botanical term applied to fruits which are externally succulent or fleshy, with a hard-shelled seed. The shape varies according to kind : it is generally oval, sometimes round, sometimes obovate, occasionally acuminate. It varies still more in colour, according to kind, and to stage of maturity,—green, whitish, violet, yellow, red, or even black. The fruit is produced in vast profusion, so that an old olive-tree becomes very valuable to its owner.
The proper time for gathering is the eve of maturity, presuming that the cultivator aims at the production of the finest quality of oil. If delayed too long, and the fruit becomes over-ripe especially if it be allowed to fall,—there is a loss in quality, but a small gain in quantity. But while advocating the gathering of the fruit at the stage at which it will produce the best and highest-priced oil, it is necessary to point out, as one of the advantages of the crop, that should the owner be unable to gather his olives then, they are yet available even in a state which in other fruits would be regarded as rottenness—for the production of a still marketable though not so valuable commodity.
Another inducement to harvesting the olive as soon as it is fit for gathering is to be found in the fact that, by delaying too long, the productiveness of the tree for the next year is prejudicially affected. Early gathering, on the other hand, relieves the tree, and gives it time to strengthen for another crop. The olive, if left to itself, will only bear once in two years. This has been attributed in great measure to the injury received by the tree in the practice of beating down the fruit ; but there is no doubt that, in skilfully-managed plantations, the trees bear annual crops, and that the early gathering of the fruit contributes largely to this end. If the fruit is left on the tree too long, it is taking sap which ought to go to the formation of new shoots for fruiting in tho following year.
The best mode of gathering is by hand. The system elsewhere alluded to, of cultivating low growing trees, much facilitates the harvest. The gathering can be done by children, and, with the aid of light " steps," the fruit can bo reached from the top of the tree. The system of beating the fruit from the tree with light wooden rods, although very old, and still resorted to in some places, should never be by the intelligent and painstaking agriculturist. However skilfully done,
it cannot fail more or less to injure the young branches, as the blows must fall at random ; and what will suffice to bring down the fruit will also strew the ground with leaves and tender shoots. The practice has the additional disadvantage of involving the picking-over of the fruit, in order to separate leaves, sticks, and other rubbish, before pressing. Shaking the tree is also resorted to as a means of obtaining the fruit ; but, though not so injurious as beating, is not recommended. The practice obtains in Syria.
A good method of ascertaining if the fruit is fit for gathering is to apply a slight pressure with the finger and thumb ; if oil exudes, the olives are considered fit for the press. The largest fruit is the Spanish ; and the olives of Andalusia are said to surpass, both in size and quality, those of other Spanish provinces. The harvest extends over 6-8 weeks ; as the fruit matures, and is gathered, it should be laid on shelves, so as slightly to dry. Contact will do no harm, so long as it does not bring about actual heating ; excessive fermentation results in inferior quality of oil.
Yield and Value. —Decandolle states the quantity of oil produced by the olive at 50 per cent, of the gross weight ; Sieuve says that 100 lb. of olives yield 32 lb. of oil viz. :-21 from the pericarp, 4 from the kernel, and 7 from the shell ; others state it at 25 per cent., and from inferior varieties as low as 10 per cent. It is extremely difficult to give an average yield per tree. Productiveness is governed by variety, climate, soil, culture, and age. The quantity of the crop is also liable to be affected by extremes of wet or drought, lateness of season, hailstorms, gales of wind, and seasons unusually rife with destructive insects ; but after allowing for all possible drawbacks, the tree is considered to be one of the most profitable crops known to agriculture. The lowest average stated for a series of years is 1 gal. a tree ; while on other estates, the average is given at 1/-2 gal. Taking the lowest average of 1 gal. a tree, and 60 trees to the acre, the produce at 8s. a gal. would be worth 24/. an acre in the early years of bearing ; while the value of the cultivated tree increases as a matter of certainty with each additional year of age, until maturity. These figures exclude all consideration of the feeding or manurial value of the residue from the expressing process.