666 JOURNAL OF FORESTRY 



the measurements are given. Mattson arrives at the following conclu- 

 sions: (1) The determination of the form class by means of the 

 diameter quotient is quite positive. (2) The actual form class is inde- 

 pendent of the d. b. h., and if the average form class for the stand is 

 determined, sufficiently accurate results w^ill be obtained. (3) The 

 average form class of a stand increases v^ith age. (4) Variations in 

 the determination of the form period of trees on three sample plots by 

 three persons w^orking at different times w^ere less than 2^ per cent, 

 indicating that the use of this method in pine stands is very practicable. 

 (5) The use of the form period method is limited to the determination 

 of the average form class, and is not applicable to individual trees. 



B. L. G. 



Skogsvardsforeningens Tidskrift, February, 1917, pp. 201-36. 



The Forest Division of the Swedish Forest 

 Experiment Experiment Station during the year 191G occu- 



Station of pied itself with studies in silviculture, silvics, 



Stveden mensuration, and applied entomology. The ger- 



minating properties of Pinus sylvestris lapponica 

 seed were intensively studied on ten sample plots, and studies to deter- 

 mine the best time of the year for the planting of seed in Norrland 

 progressed with the conclusion of observations on three sample plots. 

 jVIore areas are taken under observation; studies of the effect of thin- 

 nings on six sample plots were continued, and thirty-three new sample 

 plots were established; 8,031 stem analyses of felled sample trees were 

 made during the year; silvicultural control of wood borers occupied 

 much attention ; progress was made in researches on the nitrification 

 of humus, and new and accurate methods for the determination of 

 the percentage of humus in forest soils, as well as the limonite (iron) 

 content, were devised by members of the investigative staff'. The 

 fungus diseases of northern pine were also studied. The entomolo- 

 gical division conducted a rather extended study of wood borers and 

 measuring worms and a promising attempt was made to propagate 

 parasites of the nun moth. The Division for Reforestation Experi- 

 n_ients in Norrland established 51 new permanent sample plots, and 

 summarized the results of observations on previously est^blisihed 

 sample plots. B. L. G. 



Skogsvardsforeningens Tidskrift, February, 1917. 



