50 forestry Quarterly. 



Principles Involved in Determining Forest Types By Raphael 



Zon, Vol. I, No. 3. 



This is one of the first purely scientific articles appearing in the Pro- 

 ceedings, and one of the best. The author shows the scientific spirit in 

 reaching after fundamental principles. He states very truly that physical 

 factors are the causes of forest types. He makes one omission in that he 

 fails to point out the importance of certain temporary types in forest 

 management. An example of such a temporary type would be Douglas fir 

 on the Pacific Coast ; in this case the forester should not "endeavor to ob- 

 tain in the shortest possible time the original forest type." Aside from this 

 slight and natural omission, the principles laid down are those generally 

 recognized by foresters to-day. 



Objects and Methods of Establishing Permanent Sample Plots. 



By W. D. Sterrett. Vol. II, No. i. 



Brief and instructive details of the objects and methods of establishing 

 permanent sample plots are given. The article is strictly preliminary ; and 

 the objects given are therefore general. Some work has been done, but no 

 results as yet obtained. This work has since been more highly developed 

 at the Coconino (now Fort Valley) Experiment Station near Flagstaff, 

 Arizona. However, the article shows the beginnings of careful experi- 

 mentation. 



A New Bxplanation of the Tolerance and Intolerance of Trees. 

 By Raphael Zon. Vol. II, No. i. 



The author begins with a thorough analysis of the factors affecting 

 transpiration. He proves that on dry soils the influence of moisture is 

 greater than that of light. Then follows account of experiments demon- 

 strating that tree roots dry the soil. This is true enough, but does not 

 bring out the comparative influence of light and moisture on tree growth, 

 and tJiis, after all, is the point, and one which it will be extremely difficult 

 to solve considering the complex inter-relation and inter-action of the 

 two factors. 



His statement that the lack of reproduction under old trees is not due 

 to lack of light but to lack of moisture is too strong; it might be that 

 with the same small amount of moisture but with light, seedlings would 

 grow. Something might be learned by experiments which would give 

 seedlings the same amount of moisture as that found in the places under 

 the trees v.here reproduction fails, but which would also give them full 

 light. It would seem that Zon's first enthusiasm for this discovery carries 

 him as far in the moisture theory as Pfeil was carried in the light theory. 

 For Zon's niaturer judgment see his and Graves' bulletin "Light in Rela- 

 tion to Tree Growth," Forest Service bulletin No. 92. 



Some Further Considerations Regarding tlie Tolerance mid 



Intolerance of Shade. By Herbert A. Smith. Vol. Ill, No. i. 



Mr. Smith speaks a word of caution against being carried too far by 

 Mr. Zon's enthusiasm for the new discoveries of the effect of moisture 

 on tolerance. 



Si'zncal Notes on Lodgepole Pine. By E. R. Hodson. Vol. 

 Ill, No. I. 



This paper gives some very interesting and important facts which were 

 hitherto unknown, and draws logical conclusions about the reproduction 



