THE PERIODICITY AND DISTRIBUTION OF RADIAL 



GROWTH IN TREES AND THEIR RELATION TO 



THE DEVELOPMENT OF "ANNUAL" RINGS. 



J. G. Grossenbachee, 



INTRODUCTION. 



The study of the so-called "annual" rings in trees has re- 

 ceived the attention of numerous investigators during past years 

 and still claims the interest of many. Research along that line, 

 however, is not as active as formerly apparently owing to the 

 general prevalence of the idea that the causes of ring formation 

 are beyond our ability to fathom at present ; although it is gen- 

 erally conceded that an environment resulting in discontinuous 

 radial growth is somehow responsible for their occurrence. 



In studying crown-rot of fruit trees 1 I found that radial 

 growth and especially its distribution on trees during late sum- 

 mer seemed to have a relation to the occurrence of the disease. 

 A number of more or less incidental remarks had been noted in 

 the 1 literature concerning irregularities in the time of commence- 

 ment and closing of cambial activity, but the irregularities oc- 

 curring in fruit trees during late summer and fall were found 

 so marked that the literature was more carefully examined. The 

 number of significant papers on the subject proved so large and 

 the conclusions drawn so varied and contradictory that it seemed 

 desirable to discuss radial growth and the factors thought to 

 determine its distribution in a separate paper before writing up 



1 Crown-rot, Arsenical poisoning and winter-injury. N. Y. State Agrl. 

 Expt. Sta. Tech. Bui. 12:367-411. 1909. 



Crown-rot of fruit trees: field studies. N. Y. State Agrl. Expt. Sta. 

 Tech. Bui. 23: 1-59. 1912. 



1— S. A. 



