REPORTS OF THE SWEDISH FORESTRY RESEARCH INSTITUTE. 97 



12. Reports of the Swedish Forestry Research 



Institute. Nos. 13 14, 1916 1917. 



By J. M. Murray. 



These Reports fill two large volumes extending to 1301 pages 

 of Swedish text, with summaries in German, English, and French, 

 occupying 172 pages. The subjects dealt with are all of con- 

 siderable interest. Although some deal with matters which are 

 of most value in Sweden, still, even from these we, in Scotland 

 particularly, can gather much information of use in dealing with 

 our own special problems. Then, in connection with each 

 subject there is given a fairly comprehensive list of literature. 



The first report, by Nils Sylven, gives particulars of the 

 North-Swedish pine, Pinus silvestris lapponica, Fr. This variety 

 of Pinus silvestris (Mayr gives it specific rank as P. lapponica) 

 resembles very much the variety engaditiensis (Heer) of the Alps. 

 Some authorities have even classed these varieties together. 

 Sylve'n would appear to indicate that the agreement of the 

 characters is not complete. He instances, among other things, 

 the difference in colour of the ripe cones, e?igadinensis being 

 more greenish-yellow and lapponica more straw or brownish- 

 yellow. He also cites Engler's researches. 



Gunnar Schotte gives the results of observations of snow 

 damage in the woods of Southern and Mid Sweden. In this 

 we find much material of interest, especially since he shows 

 what classes of woods and trees are most affected, and how the 

 method of management influences the amount of snow-break. 

 As means of preventing serious damage the author, while 

 advocating selection of races with short and small crowns, 

 and those with drooping branches, use of seeds grown in 

 the locality to be forested, and mixed woods, falls back on 

 probably the surest of methods — early and strong thinning. 



Hendrik Hesselman has done a large amount of work on 

 nitrate-formation in natural soils. This work was carried out 

 by three methods — testing the nitrifying power of a sample 

 of the soil in a suitable solution of ammonium sulphate ; 

 the nitrification estimated in a soil sample preserved in an 

 Erlenmeyer flask, and the nitrate content of plants. An 

 elaborate account of the conditions in different types of wood 

 is also given. The question of available nitrogen in soils is 



VOL. XXXIV. TART I. G 



