50 JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



reported upon are : first, that late thinning does not appreciably 

 affect the total volume of the crop ; second, that the stimulus to 

 growth given by it is chiefly confined to the larger and more 

 vigorous trees ; third, that the quality of the timber, and conse- 

 quently the financial value of the crop, is improved ; and fourth, 

 that the increase in volume due to it is not maintained for a 

 long period, but culminates in four or five years, according to 

 soil and situation. The better the soil and situation the longer 

 are the effects of thinning noticeable, and vice versa. With regard 

 to the first of these conclusions, it may be explained that the 

 removal of trees in thinning of course decreases the volume of 

 the standing crop at the time, but that the increased growth later 

 on makes up to some extent for this deficiency, so far as it affects 

 the increase in volume which would take place between the 

 time of late thinning and the cutting of the crop. The advan- 

 tage of thinning is, therefore, represented by the interest on the 

 realised thinnings, plus the increase in value due to greater bulk 

 and quality at the final cutting. These are, of course, general 

 statements, and will not be verified in every case. It must also 

 be remembered that the resulting benefits are greatly dependent 

 upon the condition of the soil and crop previous to thinning. 

 Where a rich store of humus is present, and the crop vigorous 

 and healthy enough to make use of it, an increase of air and 

 light cannot fail to stimulate the functional activity of the leaves, 

 resulting in the better nourishment of the cambium and a 

 broader wood-ring. 



As a general rule, the necessity for thinning at any stage 

 depends upon the soil and situation. When the latter are good, 

 the trees quickly settle the question of predominance, and are 

 also able to endure a greater amount of shade without succumb- 

 ing. On the other hand, poverty of soil and unfavourable 

 situation only support a relatively slow growth, and the aid of 

 the forester is required in order to decide which are to remain 

 for the final crop and which to go. 



Such are the main points which require attention in growing 

 a crop of unmixed timber-trees which is desired to yield the 

 greatest bulk per acre, combined with the best quality. The 

 principles involved are applicable to all species and to all 

 climates, and although there are other systems of growing 

 woods which are recognised by scientific foresters, yet the one I 



