SOME ASPECTS OF SILVICAI, RKSlvAKCIl 277 



(2) The causes of the high mortaHty of these seedlings, which pre- 

 vents adequate representation of the higher diameter-classes. This will 

 include a study of damage caused by insects, for which the co-operation 

 of the Dominion Entomological Branch has been secured. It is hoped 

 also that arrangements can be made for a similar study of forest fungi, 

 particularly the one responsible for the heart-rot of balsam. 



(3) Rate of growth of the reproduction present to determine how 

 long after cutting one may reasonably expect another crop. 



(4) The cumulative effects of repeated fires on reproduction. Re- 

 sults thus far secured appear to indicate that under some conditions a 

 single burn of light or moderate intensity may be favorable to the re- 

 production of at least some coniferous species. Beyond any question, 

 however, repeated fires are increasingly destructive. 



(5) This raises the question as how far it is desirable to go in utiliz- 

 ing fire as a useful servant under adequate control. This, of course, 

 ties up with the whole problem of slash disposal, the previous consid- 

 eration of which in the East has been largely based upon questions of 

 fire protection. We need now to consider much more carefully the 

 silvical aspects, or the question of the effects of controlled burning 

 operations on natural regeneration, as well as a measure of sanitation, 

 in connection with the ravages of insects and fungi. Portable fire- 

 fighting pumps have now been devised which give good promise of 

 solving at least part of the difficulties in controlling slash-burning oper- 

 ations. This point opens up the question of how far it is desirable to 

 go in advocating clean-cutting with slash-burning, as contrasted with 

 the selection system, and what restrictions are necessary by regions and 

 types. Here comes in also the question of the extent to which conifer- 

 ous reproduction may be due to seeds stored in the soil. Studies of 

 natural regeneration on old burns of known age, as well as on old cut- 

 tings, will be highly suggestive in connection with a number of these 

 problems. It is proposed also to conduct slash-burning operations 

 under control in selected localities and observe the establishment of 

 natural regeneration through a period of years. 



(6) The lack of utilization of the hardwoods in the mixed forests 

 of the northeast is still the greatest obstacle to good forestry practice. 

 Here are involved the problems of transportation and markets. While 

 these are outside the scope of silvical research, they will amply justify 

 all the attention that can be given them. The use of tractors for log- 

 hauling may help solve the first, and the apparent possibility of using 

 up to" 10 per cent of birch as a filler, with spruce and balsam, in the 



