144 Practical Forestry 



and plantations must have noticed that trees having an 

 abundance of room and light on all sides make compara- 

 tively short and thick trunks that are well furnished with 

 branches ; whereas such as are grown up in a circumscribed 

 space and amongst others are tall and straight, with clean, 

 well-formed stems destitute of branches for the greater 

 part of their height. All species, or nearly all, are governed 

 by the same laws, that is to say, those that have the least 

 room laterally within certain prescribed limits, which will 

 be described hereafter, produce the tallest, cleanest and 

 straightest trunks, and vice versa. 



The influence of light has not, in this country at least, 

 been sufficiently taken into account in the rearing of timber, 

 but it has everything to do in directing the growth of trees, 

 and should be reckoned as a most important factor by the 

 forester. Thus, if it be allowed in excess, as when the trees 

 stand far apart, the growth of lateral shoots and large 

 branches will be greatly induced, the result being short and 

 thick boles, that are rough and knotty, and ill-adapted for 

 constructive purposes. On the other hand, by keeping 

 the trees thick on the ground, light is, to a greater or less 

 extent, excluded, and the trees grow tall, straight and 

 branchless for the greater part of their height, and are of 

 the greatest economic value. But here another and very 

 important question crops up. To what extent in a wood, 

 managed solely for the value of the timber it produces, 

 will it be profitable to thin ? In dealing with this, two 

 distinct bearings should be kept in mind the first, that 

 too small a quantity of branches and consequently of 

 leaves, must, to a greater or less extent, check the growth 

 of the trees, and so diminish the production of timber ; 

 and, second, that by having too large a quantity, the value 

 of the timber is greatly reduced in consequence, and the 

 number of trees to the acre much diminished as well. 



There is, therefore, a medium between these two, by 

 adopting which, the greatest quantity of the most valuable 

 timber will be produced ; although, at the same time, it is 

 astonishing, when looked at from a physiological point of 

 view, what a small quantity of foliage is required to keep a 



