70 



EXPElllMEXT STATION. 



[Jan. 



The age of the tree, obtained by counting the annual rings, 

 was found to be one hundred and thirty-one years, and the 

 height, which was estimated after the tree was felled, was be- 

 tween 11 T) and 125 feet. The south and east radii showed the 

 greatest development. This is not surprising, since the light 

 conditions are 10 or 15 per cent, more favorable in the morn- 

 ing than in the afternoon, and there naturally occurs more 

 photosynthetic activity and therefore more growth on the south- 

 east side of the tree than on any other side. Careful measure- 

 ments were made of the annual rings in decades by Sumner C. 

 Brooks, and the results of these measurements, showing the 

 grand period of growth, are shown in Fig. 1. By studying the 



10 ZO 30 40 50 60 70 80 90 100 110 120 130 YR 5 



Fig. 1. — Showing grand period of growth of elm tree, Uhnus Americana, L. The figures 

 on the ordinates represent centimeters, and those in the abscissse, years. 



curve it will be seen that the maximum period of growth oc- 

 curred between the tenth and thirtieth years, following which 

 there is a gradual decline in the decade growth, as might be 

 expected. Even between the one hundred and twentieth and 

 one hundred and thirtieth year the growth in thickness of the 

 trunk indicated considerable vigor and was about two-thirds 

 that which occurred between the first and tenth year. 



There were a few small, dead branches on the tree, and a 



