CLIMATE OF NORTH AMBEICA HUNTINGTON. 



407 



low temperature or long winters. Moreover, they were not selected 

 with a view to any special characteristic other than age. All the 

 available analyses of trees over 200 years of age were used, and to 

 them were added an approximately equal num])er of younger trees 

 in order to afford fair comparisons. 



From JNIr. Recknagel's figures I have computed how fast the aver- 

 age tree grows duruig the first, second, and third decade, and so on 

 to the end. This shows that the average tree grows 0.46 inch during 

 the first decade of its fife, 0.63 during the third, 0.40 in the twelfth, 

 and only 0.23 in the thirtieth. Obviously, if we are to com]) are the 



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Uncorrected Curve. ,^ ^^^^Curve corrected for ^e. 

 ■ Curve corrected for age and longevity 



Fig. 1.— Curve of growth of 50 yellow pines over 2S0 years of age. 



climate of different periods during the life of the tree, we must elim- 

 inate the differences due merely to the fact that the tree has grown 

 older. Another correction must also be apphed. A study of Mr. 

 Recknagel's figures, as well as of many others, shows clearly that if 

 a tree is to live to old age, it can not grow fast in its youth. That is, 

 if we take a large number of trees so as to obtain averages, the tree 

 which grows faster than the normal rate in its youth dies at less 

 than the average age, while one which grows abnormally slowly 

 stands a good chance of hving to an exceptional age, provided the 

 slow growth is not due to disease. These two tj^^es of correction 



