646 PRACTICE OF AGRICULTURE. Paut III. 



Resid. vol. ii.) In the same manner, the absence of culture, or the removing of the 

 vegetable to a colder climate and a worse soil, tends to contract or consolidate the pai-ts 

 of the plant. (Planter's Guide.) 



3970. The effect of culture on ivoody plants is similar to that on culinary vegetables and 

 cultivated grasses ; but the law operates of course less rapidly, owing to the less rapid 

 growth of trees, from the lowest bush to the oak of the forest. In all of these, the cul- 

 ture of the soil tends to accelerate vegetation, and, by consequence, to expand the fibre 

 of the wood. It necessarily renders it softer, less solid, and more liable to suffer by the 

 action of the elements. 



3971. The effect of culture on the ligneous plants in common use in planting and gar- 

 dening is readily exemplified. Every forester is aware how much easier it is to cut over 

 thorns or furze trained in hedges, than such as grow naturally wild, and are exempt 

 from culture. Gardeners experience the same thing in pruning or cutting ovilt fruit 

 trees, or shrubs ; and the difference in the texture of the raspberry, in its wild and in its 

 cultivated state, is as remarkable ; for, although the stem, in the latter case, is nearly 

 double the thickness to which it attains in the former, it is much more easily cut. On 

 comparing the common crab, the father of our orchards, with the cultivated apple, the 

 greater softness of the wood of the latter will be found not less striking to every arbori- 

 culturist. The common oak in Italy and Spain, where it grows faster than in Britain, 

 is ascertained to be of shorter duration in those countries. In the same way, the oak in 

 the highland mountains of Scotland or Wales is of a much harder and closer grain, 

 and therefore more durable, than what is found in England ; though on such mountains 

 it seldom rises to the fifth part or less of the English tree. Every carpenter in Scotland 

 knows the extraordinary difference between the durability of Highland oak, and oak 

 usually imported from England, for the spokes of wheels. Every extensive timber dealer 

 is aware of the superior hardness of oak raised in Cumberland and Yorkshire, over that 

 of Monmouthshire and Herefordshire ; and such a dealer, in selecting trees in the same 

 woods in any district, will always give the preference to oak of slow growth, and found 

 on cold and clayey soils, and to ash on rocky cliflPs, which he knows to be the soils 

 and climates natural to both. If he take a cubic foot of park-oak, and another of forest- 

 oak, and weigh the one against the other, (or if he do the like with ash and elm of the 

 same descriptions,) the latter will uniformly turn out the heavier of the two. The Scotch 

 pine does not stand longer than forty or fifty years on the rich and fertile land in both 

 England and Scotland, where it is oflen planted, and where it rushes up with extraordi- 

 nary rapidity. In the northern districts of Scotland, on the other hand, the difference 

 between park pine and Highland pine is universally known and admitted, and the supe- 

 riority of the latter is proved by its existence in buildings of great antiquity, where it is 

 still found in a sound state ; a difference which can be ascribed to no other cause than 

 the mountainous situations (that is, the natural state) in which the former timber is pro- 

 duced, and where, the trees being of slower growth, the wood is consequently of a harder 

 texture. A friend of Sir Henry Steuart's felled some larch trees, which had grown nearly 

 fifty years in a deep rich loam, close to some cottages and cabbage gardens. The wood 

 was soft and porous, and of no duration ; it was even found to burn as tolerable fire- 

 wood, which larch of superior quality is never known to do. (Tr. on Coim. lies., and 

 Planter's Guide.) 



3972. The general effect of pruning is to increase the quantity of timber produce. 

 The particular manner in which it does this is by directing the greater part of the sap, 

 which generally spreads itself in side-branches, into the principal stem. This must 

 consequently enlarge that stem in a more than ordinary degree, by increasing the annual 

 circles of the wood. Now, if the tree be in a worse soil and climate than those which 

 are natural to it, this will be of some advantage, as the extra increase of timber will still 

 be of a quality not inferior to what would take place in its natural state ; or, in other 

 words, it will correspond with that degree of quality and quantity of timber, which the 

 nature and species of the tree admit of being produced. If the tree be in its natural 

 state, the annual increase of timber, occasioned by pruning, must necessarily injure its 

 quality, in a degree corresponding with the increased quantity. If the tree be in a better 

 climate and soil than that which is natural to it, and, at the same time, the annual increase 

 of wood be promoted by pruning, it is evident that such wood must be of a very different 

 quality from that produced in its natural state (that is, very inferior). Whatever, there- 

 fore, tends to increase the wood in a greater degree than what is natural to the species, 

 when in its natural state, must injure the quality of the timber. Pruning tends to increase 

 this in a considerable degree, and, therefore, it must be a pernicious practice, in as far as 

 it is used in these cases. Pruning is not here considered in regard to eradicating dis- 

 eases, preventing injuries, or increasing the natural character and tendency of trees : for 

 those purposes it is of great advantage. Mr. Knight has shown, in a very striking 

 manner, that timber is produced, or rather, that the alburnum or sapwood is rendered 

 ligneous, by the motion of the tree, during the descent of the true (or proper) sap. It 



