REVIEWS 693 



One of the most significant conclusions (No. 6, p. 5) is that 

 "Growth . . . depends upon environmental conditions, and no 

 part of the observations suggested a seasonable rythmic action." The 

 correlation between growth and soil moisture seems unmistakable. At 

 Carmel, California, where it is warm enough for growth the year 

 round, the Monterey pine showed growth when the rains came, and 

 ceased when the soil became dry. Western yellow pine did the same 

 during the summer, showing two periods of growth. The correlation 

 was shown in a particularly striking way by the response in growth of 

 Monterey pine and of California live oak to the addition of water. 

 Growth showed on the dendrograph within 24 hours in the former 

 tree, and within only 2 hours in the latter. 



The period of enlargement of the trunk is comparatively brief, even 

 when the warm season is long. After enlargement ceases there is 

 generally a certain amount of shrinkage, leaving the net gain less 

 than would have been supposed at the termination of growth. 



Some species begin growth in diameter when the buds open, as in 

 Douglas fir, others not until the new leaves are partly or in some cases 

 completely developed. An interesting contrast in this respect is 

 1 eported by Korstian ^ in a dendrographic study of box elder and 

 blue spruce. 



Barrington Moore. 



' Korstian, C. F. "Diameter Growth in Box Elder and Blue Spruce."' Hot. 

 Gaz. Vol. 71, No. (), pp. 4.'54-461, 1921. 



