REVIEWS 73 



the soil is for the most part bare, and what httle organic matter occurs 

 in the form of dead grass, twigs, needles, and slash decays very slowly 

 on account of a lack of moisture. Some idea of the slow rate of decay 

 may be gained from the observation that brush piles left after logging 

 usually show no appreciable decay after a period of lO years. The 

 nearest approach to the formation of humus is underneath old trees, 

 where needles and cones have accumulated for centuries. The surface 

 soil underneath this litter is usuallx- black or brown, in contrast with 

 the reddish soil typical of the volcanic formations in this region. That 

 such sites favor the establishment of seedlings is attested by the rather 

 common occurrence of groups of seedlings under standing trees or 

 around stumps. Similar observations have been made with regard to 

 burned brush piles. In the latter instance the favorable conditions may 

 be due to stimulation of nitrification by increasing the salt content of 

 the soil, as suggested by Hesselman. It seems more likely, however, 

 that the condition which favors seedlings on such spots is increased 

 moisture supply due to the elimination of competing vegetation. Al- 

 though reproduction is favored by allowing litter and slash to accumu- 

 late until they become incorporated in the soil, or by burning this mate- 

 rial, the net result of these factors in localities where reproduction is 

 generally poor has been largely negative, because the beneficial influ- 

 ences are not sufficient to prevent the death of seedlings at critical 

 times. 



This investigation is a striking illustration of co-ordination between 

 different branches of science in the solution of a forest problem. Hes- 

 selman is a forest ecologist, but the investigation is based as much upon 

 chemistry as upon forestry and botany. It is noted that for several 

 years the Swedish forest experiment station has had a chemist on its 

 staff". Incidentally it may be mentioned that the staff of this station 

 is made up of specialists who have been attached to the institution for 

 years. This organization, which is in striking contrast to that of our 

 forest experimentations, undoubtedly accounts in a large measure for 

 the high standard of scientific work for which the Swedish experiment 

 station is noted. G. A. P. 



The Rockies of Canada. By Walter D. Wilcox. Putnam's Sons, 

 New York, 1916. Third edition. Pp. 300. 



For the lover of the great out-of-doors, especially the mountains, 

 this book is a rare treat. Mr. Wilcox is an experienced mountaineer 

 and naturalist, as well as a skillful artist with the camera. The book 



