140 SCIENCE IN FORESTRY 



cost of each replanting is lost money. In fact 

 the loss caused by this insect in our woodlands 

 amounts to many thousand pounds each year. 

 Formerly it was the custom to wait for a 

 period of seven years before replanting ground 

 from which coniferous timber had been removed. 

 The accepted belief was that the ground needed 

 this period of rest; but untrained observation 

 is faulty. The real explanation is that this 

 insect was infesting the ground unobserved, and 

 was making growth impossible. The result of 

 the "rest" was that seven years' increment and 

 rent were lost, moreover bare forest land rapidly 

 degenerates by exposure, and by the growth of 

 weeds, etc., it becomes yearly more difficult and 

 expensive to plant. The total loss was thus large. 

 Now that scientific investigation has shown us 

 the life-history of the insect, it has been possible 

 to devise means, still somewhat clumsy however, 

 by which the multiplication of the insect can be 

 kept in check, and newly cleared ground can be 

 replanted with comparative safety. At present 

 investigation is proceeding and doubtless fresh 

 means will be devised. It is not unreasonable 

 to expect that the entomologist will enable us 

 completely to master these insect pests. A possible 

 solution of the problem may be the discovery 

 of parasites which would prey on the dangerous 

 insects, and even cause epidemics leading to 

 their partial destruction. The forester unaided 



