HEART-ROT IN CONIFERS. 45 



sooner or later, perhaps in serious form. The peculiarity about 

 heart-rot is that in most cases we are never likely to know 

 that the disease occurs, certainly not until the first thinning 

 comes to be made. This may mean that a period of 15 to 20 

 years may elapse from the initial planting before it is found out 

 that that planting has been in reality a failure. Again, is it not 

 important that the significance of these internal diseases should 

 be realised in connection with any policy which has in view the 

 necessity of growing mature timber and storing it in a living 

 state in the forest? Unless the soil conditions are absolutely 

 suitable to the species, mature timber cannot be maintained 

 aUve in the forest without succumbing to internal decay caused 

 by fungi. 



This would, therefore, appear to be essentially a case for careful 

 investigations in order to minimise, so far as possible, the risk of 

 immense waste through absence of soil correction or a mistaken 

 choice of species. Such investigations would aim at increasing 

 our knowledge of conditions favourable and unfavourable to 

 the development of fungi causing heart-rot, and at the same 

 time of conditions favourable and unfavourable to the develop- 

 ment of the various species of timber trees. 



