398 BOTANICAL GAZETTE [November 



Hartig then obtained results comparable to the present ones; 

 that is, at about the middle of June he observed that growth was 

 most advanced near the middle of the tree and decreased in both 

 directions from that point. And yet he persists in his assertion 

 that growth ceases in trees in open stand first in the youngest 

 branches. Such being the case, the only possible solution of the 

 data given above is that there must have been a marked accelera- 

 tion of growth in the apical portions after June 21 and a corre- 

 sponding decrease in the parts below. Whether the same applies 

 in the pitch pine further investigation must decide. There was an 

 increase in radial growth in the apical shoot and at the same time 

 a decrease below between June 3 and 15, but that growth ceased 

 first above cannot be deduced from the present observations. 



As regards the theory advanced by Friedrich concerning two 

 periods of maximum growth in trees, little can be said. The 

 second period if present in Pinus rigida must be the minor one, 

 inasmuch as the ring was on an average more than half completed 

 on June 15. 



Width of the ring 



Measurements were made from sections of tree III to determine 

 the width of the ring at different heights. According to Hartig, 

 in trees in open stand the amount of wood formed increases from 

 apex to base. This may arise from one of two alternatives; either 

 the annual ring may decrease in size owing to the increasing diame- 

 ter, or the reverse may be true. The latter, he says, is but rarely 

 the case and sometimes oacurs in trees which are exceptionally well 

 nourished, that is, those possessing a large vigorous crown. From 

 these observations it is to be expected that in Pinus rigida the ring 

 would increase perceptibly in width toward the base, inasmuch as 

 the crown is as a rule not exceptionally well developed. Such was 

 the case. At cuttings i and 4, the completed ring on February 21, 

 1910, was about the same width. At cutting 8 it was but 0.85 the 

 size of that above, while cutting 12 showed a still further decrease 

 to o . 70. It follows that in Pinus rigida, if there is such a decrease 

 in the size of the ring from apex downward in young vigorous 

 growing trees, the same applies with even greater force in older 

 trees with longer axis and poorly developed crown. 



