CXXVIII THE ROYAL SOCIETY OF CANADA 



Many ecological investigations of a similar interesting nature will 

 be carried out by such parties. 



It may be noted also that the larch sawfiy (Nematus erichsonii) 

 which caused such great destruction of the tamarack in eastern Canada 

 has been found in the last two years working in the forests of Manitoba. 



Forest Reproduction. 



While the forest may be reproduced by growing trees in the forest 

 nursery and planting them out in the forest the method which will 

 most generally be adopted in Canada owing to the great extent of our 

 forest lands is to allow nature to do the work by distributing naturally 

 its seed supply. The investigation of the ssupply of seed and the con- 

 ditions that affect reproduction are therefore most interesting and con- 

 siderable attention has been given to them. A special bulletin entitled 

 Forest Conditions on the Rocky Mountains, by Mr. T. W. Dwight, 

 Assistant Director of Forestry, dealing with this question was issued 

 during the past year. 



As is well known, the supply of seed varies very much from year to 

 year and it is only at intervals of three or four years that most of the 

 coniferous trees at least have very large crops of seed. Consequently 

 the period of rotation of the good seed years has to be investigated so 

 that provision can be made for carrying on operations so as to give the 

 best opportunity for the scattering of the seed supply. For instance, 

 the year 1911 produced a very plentiful crop of seed of the spruce trees, 

 while last year the crop was quite scanty and probably will be for an- 

 other year or two. 



The investigations in this matter must also include a study of the 

 condition of the soil is best suited for the germination of the seeds so 

 that timber operations may be carried on with the object of leaving 

 the ground in the best condition for reproduction. The seed will as a 

 rule germinate much better if it comes in contact with the mineral 

 soil and it may be necessary to assist this by opening up the forest in 

 a proper way and by disposing of the debris of lumbering operations 

 so as to leave the soil open to the seed. This also involves carrying 

 out the lumbering operations in sueh a way as to leave trees which 

 will furnish a supply of seed and distribute it properly. One of the 

 difficulties in selecting seed trees to be left is that trees grown in the 

 forest are not strongly rooted and if left isolated are easily thrown by 

 the wind. The trees to be left must also be so distributed that the seed 

 may be carried by the prevailing winds over the area which it is desired 

 to have reforested. In most cases the group system would be the one 

 most likely to be adopted in Canada although on higher ridges and 

 mountains slopes it might be necessary to adopt the strip system. 



