In both modes of training, and with all kinds of trees, it has been found very advantageous to have the extreme branches bent downwards. By this mean; a check seems to be given to the growth of the wood of the tree, and a tendency to yield fruit is promoted. Besides, it is evident, that, in the flex ure of the extremities of wall-trees, the natural mode of growth is imitated.
Connected with this subject is the recent practice of turning the extreme branches of fruit-trees from one side of a wall to the other. The late Sir Joseph Banks having a Gainers bergamot pear-tree on a north aspect, where the fruit did not succeed, caus ed some branches be turned over to the south side, and trained downwards. There they not only pro duced fine fruit, but abundance of it. The roots of the May-duke cherry, and some others, require to be in a cool soil. On the north side of a wall, therefore, such trees thrive best ; and it has been found, that if their extreme branches be turned over the wall, and trained downwards on the south side, they are not only brought into plentiful bear ing, but yield their fruit more early hi the season.
Before leaving wall-trees, we may here notice, that, for protecting the blossom of peaches and nec tarines from the effects of hoar-frosts and cold dews nets made of coarse woollen yarn or carpet worsted have, in some parts of Scotland, been very advan tageously employed. When such nets are worked in the loom, they can be afforded at a very cheap rate. They are woven pretty close, the meshes not being larger than to admit the point of the finger. Worsted nets are better than any other, on account of the bristliness of the material and its tendency to contract. Screens covered with white paper have likewise been employed with good effect. Where such screens are made to project sufficiently from the wall, and are applied in the evenings, they will be found very effectual in preventing the radiation of heat from the earth in the cold and clear nights which often follow warm days in May and June ; and not the setting fruit only, but tender plants, such as love-apple, may thus be protected. The importance of this remark will be evident to all who have attended to the doctrines of Dr Wells and Pro fessor Leslie on the subject.
Standard fruit-trees, particularly pears, are now frequently trained in a pyramidal form, or what the French term en quenouilk. This is effected by preserving only an upright leader, and cutting in the lateral branches every year. Trees managed in this manner occupy much less room, and throw much less shade, than when allowed to spread their branches at will. If thought proper, they may like wise be planted very near together without injury; six or at most eight feet being a sufficient space be tween such trees. In general these pyramidal trees
are very productive. They are not well calculated, however, for places subject to high winds, but ra ther require a sheltered situation. In appearance they are stiffly symmetrical, and the lover of the picturesque in gardening, would greatly prefer the natural spreading of the tree.
Apple-trees are now very generally trained en buisson, or as dwarfish standards, and in this form they can be scattered along the borders of the gar den without producing inconvenience.
Particular varieties of apple are observed to suc ceed in certain soils and situations better than in others: it is the business of the cultivator to take notice of these, and to multiply them by grafting. At the garden at Dalkeith belonging to the Duke of Buccleuch, where the soil is shallow and the sub soil unfavourable, great crops of apples are yearly produced, merely in consequence of planting shal low and of frequent grafting. Mr Macdonald, the excellent gardener officiating there, annually inserts on his numerous trees not fewer than from 2000 to 3000 grafts, generally three or four sorts on each tree. The grafts are chiefly of such kinds as expe rience has taught him to prove generally successful at Dalkeith garden.
Decorticating.
When the outer bark of fruit-trees, especially of the apple kind, becomes rough and cracked, so as to admit minute insects to deposit their ova under it, it has for a long time been the practice to re move it entirely, and to cleanse the trunk and prin cipal branches with some kind of wash. This par tial decortication and cleansing, it was observed, not only produced a -healthy foliage, but had an evident effect in promoting the fruitfulness of the or in causing the conversion of leaf-buds into flower-buds. Of late years, Mr Lyon of Edin -burgh, founding wholly on his own experience, has particularly called the attention of the public to the practice of decortication ; and he has invented se veral simple instruments for facilitating the removal of the bark. He has carried the practice much farther his predecessors, who, as already no ticed, removed the bark only when it was some what diseased, and only from the trunk and larger branches. Mr Lyon recommends the stripping even of young trees, and of the new shoots of full grown trees, however healthy the bark may be. Even where the bark of a tree is healthy, a partial removal of it (as in the practice called ringing, pre sently to be noticed) may prove beneficial, in caus ing the production of fruit-buds ; but it is evident that a useful practice may be pushed too far.