670 PRACTICE OF AGRICULTURE. Pa at HI. 



leaves and fruit in the summer season, and to admit the rays of the sun, so as to give the 

 fruit colour and flavour. 



4114. In pruning the apple tree and all other standard trees, Knight observes, (he points 

 of die externa] branches should be every where rendered thin and pervious to the light, 

 so that the internal puts of the tree may not be wholly shaded by the external parts ■. the 

 light should penetrate deeply into the trie on every side; but not any where through it. 

 When the pruner has judiciously executed his work, every pari of the tree, internal as 

 well as external, will be productive of fruit ; and the internal pari, in unfavourable Beasons, 

 will rather receive protection than injury from the external. A tree thus pruned will not 

 only produce much more fruit, but will also be able to support a much heavier load of it, 

 without danger of being broken : forany given weight will depress the branch, not simply 

 in proportion to it-- quantity, but in the compound proportion of its quantity and of its 

 horizontal distance from the point of suspension, by a mode of action similar to that of the 

 weight on the beam of the steel-yard ; and hence a hundred and fifty pounds, suspended 

 at one foot in distance from the trunk, will depress the branch which supports it no more 

 th in ten pounds, at fifteen feet in distance, would do. Every tree will, therefore, support 

 a larger weight of fruit without danger of being broken, in proportion as the parts of such 

 weight arc made to approach nearer to its centre. 



■11 l',. Where a tree is stunted, <»• the head ill-shaped, from being originally badly primed 

 or barren, from having overborne itself, or from constitutional weakness, the most expedi- 

 tious remedy is to head down the plant to within three, four, or five eyes (or inches, if an 

 old tree), of the top of the stem, in order to furnish it with a new head. The n coverj > »f 

 a languishing tree, if not too old, will be further promoted by taking it up at the same 

 time, and pruning the roots; for as, on the one hand, the depriving too luxuriant a tree 

 of part even of its sound healthy roots will moderate its vigour ; so, on the other, to relieve a 

 stunted or sickly tree of cankered or decayed roots, to prune the extremities of sound 

 roots, and especially to shorten the dangling tap-roots of a plant affected by a bad sub- 

 soil, are, in connection with heading down, or very short pruning, the renovation of the 

 soil, and draining, the most availing remedies that can be tried. 



4116. A tree often becomes stunted from an accumulation of mass, which, affects the 

 functions of the bark, and renders the tree unfruitful. This evil is to be removed by 

 scraping the stems and branches of an old tree; and on a young tree a hard brush will 

 effect the purpose. Wherever the bark is decayed or cracked, Abercrombie and Forsyth 

 direct its removal. Lyon, of Edinburgh, has lately carried this practice to so great a 

 length as even to recommend the removal of part of the bark of young trees. Practical 

 men, in general, however, confine the operation to cracked bark, which nature seems to 

 attempt throwing off; and the effect in rendering the tree more fruitful and luxuriant is 

 acknowledged by Neill in his Account of Scottish Gardening and Orchards, and by different 

 writers in The London and Caledonian Horticultural Transactions. 



4117. The other diseases to which orchard trees are subject are chiefly the canker, gum, 

 mildew, and blight, which, as we have already observed, are rather to be prevented by 

 such culture as will induce a healthy state, than to be remedied by topical applications. 

 Too much lime, Sir II. Davy thinks, may bring on the canker, and if so, the replacing a 

 part of such soil with alluvial or vegetable earth would be of service. The gum, it is 

 said, may be constitutional, arising from offensive matter in the soil ; or local, arising from 

 external injury. In the former case, improve the soil ; in the latter, apply the knife. The 

 mildew, it is observed by T. A. Knight and Abercrombie, " may be easily subdued at its 

 appearance, by scattering flour of sulphur upon the infected parts." As this disease is now 

 generally considered the growth of parasitical fungi, the above remedy is likely to succeed. 

 For caterpitJars and other insects in spring, Forsyth recommends burning rotten vvocd, 

 weeds, potato-hulm, wet straw, &c, on the windward side of the trees when they are in 

 blossom. He also recommends washing the stems and branches of all orchard trees with 

 a mixture of "fresh cow-dung with urine and soap-suds, as a whitewasher would wash 

 the ceiling or walls of a room." The promised advantages are, destruction of insects 

 and " line bark ;" more especially, he adds, " when you see it necessary to take all the 

 outer bark off." 



4118. With the Herefordshire orchardists pruning is not in genera/ use ; the most ap- 

 proved method is that of rendering thin and pervious to the light the points of the external 

 blanches, so that the internal branches of the tree may not be wholly shaded by the external 

 parts. Large branched should rarely or never be amputated. The instrument generally 

 used for the purpose of pruning is a strong flat chisel, fixed to a handle six feet or more 

 in length, having a sharp edge on one of its sides and a hook on the other. (A'nighl's 

 Treatise on the Apple and Pear. ) 



4119. The culture of the soil among orchard trees is always attended with advantage; 

 though it can so seldom be properly conducted in farm orchards, that in most cases it is 

 better to lay them down with grass seeds for pasture. To plough between the trees and 

 take corn crops, even if manure is regularly given, cannot be any great advantage, unless 



