986 FORESTRY 



The experiments instituted for the investigation of the most suitable 

 time for sowing in Norrland shall be continued (Forest section) . Existing 

 experimental cultures with pine and spruce in various combinations shall 

 be revised, if need be (Forest Section). The course of growth in the roots 

 of planted trees shall be investigated with a view to the discovery of the 

 most suitable time for planting (Forest Section or Physical Section). 

 d) The problem of regeneration in special types of forest. 



The investigations previously carried on concerning the difficulties of 

 regeneration on the pine-heaths shall be continued so far as is necessary for 

 the completion of a report concerning this problem (Physical Section). 



II. — Proceedings as regards the composition of forests. 



a) Slight and extensive thinning operations. 



Existing areas for slight and extensive thinning shall be revised if 

 necessary, and new areas shall be arranged so far as time permits, chiefly in 

 pine forests and spruce forests of low productivity and in spruce forests 

 in Norrland of all grades of productivity, in the birch forests of Norrland, 

 in certain forests composed of aspen and oak, and in mixed coniferous forests 

 (Forest Section). In the last named mixed forests there shall be arranged 

 areas of young seedlands or plantations in order to throw light upon the best 

 way of raising forests of mixed composition (Forest Section), 



b) Alteration of ground flora. 



In some of the more suitable experimental areas for heavy thinning 

 the ground vegetation shall be investigated in accordance with the Raun- 

 kl\ER method, as modified by IvAGERBERG, in order to obtain fixed points 

 for estimating the effect of the most thorough thinning upon the ground 

 vegetation (Physical Section). 



III. — Diseases and injuries of foresi trees. 



a) Diseases and injuries caused by fungi. 



The occurrence and spread of the roots in the spruces whose tops were 

 broken oft" during the winter of 1910-11 shall be examined (Physical Section). 

 Moreover the roots of coniferous trees shall be taken up for closer investi- 

 gation, with special attention to the conditions in the over-aged forests in 

 Norrland (Physical Section). 



b) Injuries caused by insects. 



Investigations shall be instituted as regards injurious insects both in 

 spruce cones and pine cones and in forest plants in nurseries. The extent 

 of the increased ravages of bark beetles in certain districts shall be studied ; 

 and at the same time knowledge of the known methods of effectively deal- 

 ing with these last named insects should be spread amongst forests owners. 

 In addition to this, should other insect ravages take place, studies should 

 be instituted and advice given as to the checking of their ravages (Entomo- 

 logical Section). 



