The Pine Beetle. 



75 



or so beneath the terminal bud. Having reached the pith, the 

 beetle bores upwards, but the passage thus made is only occupied 

 for food or shelter, never for breeding, which is only performed 

 underneath the bark of trees in the manner just described. 



As a result of the leading shoot of a stem or branch being 

 hollowed out in the centre, it generally dies, or is broken off by 

 the wind, and the trees become much deformed. They also lose 

 a considerable quantity of their foliage, and the yield of cones 

 may also suffer to a serious extent, a matter of importance in 

 natural regeneration. It is to this action of the beetle that the 

 chief sylvicultural damage is due. Trees so affected become 

 characteristically mis-shapen, and are easily recognised, even at 

 a long distance. Underneath infested trees, especially after a 

 high wind in autumn, the ground will often be found thickly 

 strewn with the tips of shoots, each with a cavity in the centre, 

 and not infrequently containing the beetle. On young, vigorous 

 trees, especially in a sheltered situation, the shoots do not so 

 frequently break off, but the sickly appearance of the leaves, 

 and an outflow of resin from the entrance hole, readily attract 

 attention to the damage, and on cutting the shoot open the 

 beetle will often be found at work in the central gallery. 



The result of the action of the insect in destroying the ends 

 of the branches, and frequently causing them to drop off, has 

 earned for it in Germany the name of Wood Gardener or Tree- 

 pruner, a designation first suggested by Linnaeus. 



Young trees, though severely crippled and reduced to the 

 condition of mis-shapen bushes, are not often actually killed by 

 the pine beetle ; but old trees, whose shoots are more exposed 

 to the wind, and being thin, are easily broken off when injured , 

 are often completely destroyed by the persistent attack of this 

 insect. Such a result will most frequently be observed in the 

 neighbourhood of a saw mill, or of any place where pine logs 

 are stored. Often, when a small proportion of standard pines 

 are retained to grow when a wood is felled, it is found that such 

 standards become unhealthy and soon die. This result is due 

 to the fact that the felling of the wood has provided the insects 

 with abundant opportunities for propagation (stumps, stools, 

 stems, &c), and from these in the month of June the standard 

 trees are invaded by swarms of beetles. If the change that is 



