108 JOURNAL OF FORESTRY 



indicator of the capacity of land for crop production in the Great Plains 

 area, no equally comprehensive treatise has as yet appeared in this 

 country showing the use of native plants as indicators of the capability 

 of land for forest crop production. Cajander, however, has recently 

 treated the native vegetation of central and eastern Europe in a com- 

 prehensive manner as indicators of site quality in the demarkation of 

 forest types. 



Korstian's article serves a very useful purpose, however, in calling 

 the attention of American foresters to the indicator significance of the 

 lesser forest vegetation in determining site quality. It briefly cites the 

 more important American literature, correlating the distribution of 

 native vegetation with site and the utilization of such a correlation in 

 the classification of the agricultural potentialities of the land and also 

 the recent literature on the use of native vegetation as indicators of 

 forest sites. These studies were made in connection with the measure- 

 ment of permanent sample plots on the Datil National Forest in New 

 Mexico. Summaries were made of the vegetation on 53 list quadrats, 

 and tabulations were made of the per cent of quadrats on which the 

 different species occurred. The results so far secured have led the 

 author to initiate studies, which are now under way, to determine the 

 feasibility of using native plants as indicators of suitable forest-planting 

 sites. He believes that careful studies on the indicator significance of 

 native vegetation will be of great value in explaining the presence or 

 absence of tree growth on certain areas, in the selecting of species and 

 sites in reforestation, and in establishing a working basis for the classi- 

 fication of the potential productivity of forest lands. 



J. W. T. 



Forests of Porto Rico — Past, Present, and Future — and their Physi- 

 cal and Economic Environments. By Louis S. Murphy. Department 

 of Agriculture, Bulletin No. 354 ; contribution from the Forest Service. 

 Pp. 98. Figs. 7. Plates XIT. Washington, D. C, 1916. 



In co-operation with the Government of Porto Rico Board of Com- 

 missioners of Agriculture, Louis S. Murphy, of the United States For- 

 est Service, publishes a comprehensive bulletin on the forests of Porto 

 Rico. This bulletin is unique in that it discusses the past, present, and 

 future conditions of the forests. From it we learn that Porto Rico is 

 about four times as large as Long Island ; that in density of population 

 it ranks fourth among the political subdivisions of American territory, 

 and only Rhode Island, Massachusetts, and New Jersey exceed it in 



