310 THINNING. 



season in which any description of wood-pruning can be performed is 

 the spring, just before the expansion of the leaves, when the sap is 

 rising with the greatest vigour. The slightest wound made in many 

 plants, either ligneous or herbaceous, at this season, especially young 

 vigorous ones where the sap-vessels are large, occasions a great loss 

 of sap, which must necessarily weaken the plant, unless speedily 

 checked by the only effectual mode in which this can be done, the 

 expansion of the leaves. For disbudding, spring is the most suitable 

 season, though it should not be done all at once, but gradually at dif- 

 ferent times up to the end of June. By this time the buds will have 

 grown into shoots, and the practice might be called disbudding. 

 Disleafing may be practised to a greater or less extent throughout 

 the whole season of growth. It is not, however, a practice to be 

 commended. The advantages of pruning just before midsummer are, 

 that the wounds may be partially healed over the same season, and 

 that the sap which would have been employed in maturing the snoots 

 cut off is thrown into those which remain. The disadvantages are, 

 that the sap which would have been elaborated by the leaves cut off, 

 and which would have added to the strength of the tree and its roots, 

 is lost. In the case of trees already sufficiently strong this is no dis- 

 advantage, but in the case of those which are too weak it is a positive 

 loss. The summer season is found better than any other for pruning 

 trees which gum, such as the cherry and the plum, provided too much 

 foliage is not thereby taken away ; and it is also considered favourable 

 for resinous trees. The autumn, on the other hand, is considered the 

 best time for trees that are apt to suffer from bleeding, such as the vine, 

 the birch, and some species of maple. The best season for pruning 

 evergreens is just before midsummer. 



Thinning. 



Thinning is an operation founded on a general knowledge of the 

 laws of vegetation and on the habits and bulk of particular plants. 

 Its object is to allow sufficient space to entire plants, or to the parts 

 of plants, to attain certain required dimensions and particular pro- 

 perties. When plants stand too close together for attaining those pur- 

 poses, whether from want of nourishment at the root, or light and air 

 at the top, they are thinned out ; and when branches, leaves, flowers, 

 and fruit are too numerous on an individual plant to be properly 

 nourished, and exposed to the sun and air, they also are thinned out. 

 As this last operation is effected by pruning, it requires no farther 

 notice in this article, which is confined to the thinning out of entire 

 plants by uprooting them. Thinning by uprooting is performed by 

 the hand alone, when the plants are small ; and when they are larger, 

 by the aid of the trowel, spade, pick, or other implements. The sub- 

 ject may be considered with reference to seedling crops in gardens, 

 and transplanted crops in plantations. Transplanted crops in gardens, 

 being generally of short duration, are placed at such distances at first 

 as mostly to render future thinning unnecessary. One general rule 



