74 TENDING OF WOODS 



In the thicket stage each tree is struggling against its 

 neighbour for light and root space, and a regular struggle for 

 existence is set up during which the weaker trees fall behind, 

 become gradually suppressed, and finally die. The better 

 trees, being pressed upon by their neighbours, are forced 

 upwards and grow tall, straight, and clear of branches ; but if 

 the struggle is too long continued, they may be forced too 

 much and may become weak and lanky. If left to nature the 

 struggle for existence goes on all through life, the weaker trees 

 gradually dropping behind. The woodman steps in and 

 regulates the struggle by making a thinning. While doing 

 this he cuts and removes for sale the trees which are falling 

 behind, and at the same time relieves the best trees of all 

 excess of pressure, giving them just enough light and root 

 space, thus reducing without stopping the struggle for exist- 

 ence. After a thinning has been made, the remaining trees 

 soon close up and the struggle again commences, another 

 thinning being necessary in a few years' time. This continues 

 as long as the trees grow vigorously. 



The advantages of thinning are, put shortly, as follows : 



1. They enable the woodman to guide the development of 

 the wood, and to give the proper growing space to the best 

 trees which will form the final crop. 



2. In mixed woods the woodman can favour certain species, 

 cutting others out gradually, so as to get the mixture he 

 requires. 



3. By the removal of dead, dying, and unhealthy trees, 

 danger from insects, fungi, and fire is greatly reduced. 



4. The trees which are to form the final crop are gradually 

 strengthened against damage by wind. 



5. They give, under favourable conditions, early and sub- 

 stantial money returns. 



In any wood which is at all dense we can recognize four 

 classes of trees. We find certain trees with their heads right 

 out to the light and above all the surrounding trees ; they are 



