458 Forestry Quarterly. 



promising, without realizing that by the addition of one sentence, 

 they have destroyed the hope of ever arriving at a mathematical, 

 practically useful, statement of light requirements, namely : In 

 interpreting the results of the light readings, account must be 

 taken also of other factors of tree growth, such as moisture con- 

 tent of the soil, age and vigor of the specimen, quality of the soil 

 and relative humidity." 



While, then, physical measurements should by all means be con- 

 tinued and may be expected to make us clearer as to the role 

 which light plays in the economy of the tree and the forest, for 

 practical purposes it would appear that the development of physio- 

 logical methods, such as Medevev's, will bring us much sooner 

 to a rational check on our personal judgment, which after all can 

 never be dispensed with in silviculture and, indeed,, in all opera- 

 tions which have to do with nature's creative forces. 



To the very valuable literature reference we may only add Dr. 

 McDougall's work which has been overlooked, and Dr. Engler's 

 contribution briefed in this issue. B. E. F. 



Chaparral Studies in the Dzvarf Forest or Blfiii-ivood of 

 Southern California. By Fred G. Plummer. Bulletin 85. U. 

 S. Forest Service. Washington, D. C. 191 1. Pp. 48. 



The area within the United States covered by the true chaparral 

 amounts to about 5^^ million acres. It protects about three-fourths 

 of the upper water-sheds of the streams along the coast in Califor- 

 nia for a distance, along the axes of the Sierras, of 450 miles. The 

 forests are on the high elevations. Below is the chaparral. Still 

 farther down is the sagebrush country, the growth becoming thin- 

 ner and thinner toward the bare, arid or semi-arid, sandy belt 

 bordering the ocean. Along the coast the average rainfall is 

 thirteen inches, insufficient to support a for'est, and only in a few 

 places is it enough for a scattering woodland of oaks. The point 

 where the rainfall, increasing with the altitude, is sufficient to 

 support a forest averages about 2,000 feet. The topography is 

 exceedingly diversified and it is said that between the ocean and 

 the mountain summits, five distinct climates may be defined. 



The author lists 16 species which dominate the chaparral and 

 55 species holding a secondary place. Besides these 46 species are 

 listed as important. Greasewood or chamisal {Adenostoma 



