THK INFLUENCE OF THINNING 23 



rot on adjoining areas ii6, or 96.6 per cent, of the trees showed typical 

 rot in the stump section, and out of 75 grand firs similarly treated ']2, 

 or 96 per cent, showed typical rot at the stump. In most cases several 

 borings were made in the same tree in order to secure a boring which 

 expressed an average condition of the annual rings, and also included 

 the pith, or center, of the heartwood whenever this was not too badly 

 rotted. The tree was recorded as being infected whenever the core of 

 the boring gave evidence to the presence of rot. The measurements on 

 the cores taken from the tree were made immediately, so as to lose 

 nothing by the shrinkage of the wood and to guard against future pos- 

 sible loss. The cores were given the same number as the tree from 

 which they were taken, an indelible pencil being found very useful in 

 this numbering. A device for receiving the core of the boring as it 

 emerged from the tree was made from one-inch stems of the common 

 elderberry fashioned into a trough. By this method the cores were 

 extracted without loss or further breakage and allowed of much greater 

 accuracy in making the measurements and counting the rings. 



The total height of the tree as well as the lengths of the original and 

 secondary crowns were accurately computed by the use of a Klaussner 

 hypsometer. The crown widths were secured by measuring the length 

 of an average lower branch of each crown and multiplying by two. 

 The viability of the sporophores was determined principally by the 

 presence or absence of the fresh, white hymenial layer, and in doubtful 

 cases the fruiting bodies were removed from the tree and carefully 

 examined. Sporophores which were alive the preceding year and as 

 yet gave no evidence of imminent sporulation showed a zone of fresh 

 brown tissue of last year's growth on the outer edge. These were 

 classed as live. The age of the sporophores as determined by the 

 annual zones was an important part of the data. In many cases the 

 trunk of the tree was chopped into where it was thought necessary to 

 examine the wood tissues directly adjacent to the sporophores. Since 

 several borings were made in most cases at different points on the cir- 

 cumference at diameter breast height, and since the increment in domi- 

 nant or isolated trees is chiefly in the lower portion of the trunk,^ it is 

 believed that the readings taken from the cores will prove to be true 

 indications of the variations in annual increment during the 20-year 

 period. The large number of trees entering into the data will serve 

 also to lessen the possible error due to the unequal distribution of incre- 

 ment. Trees of all ages and sizes were grouped together in compiling 

 the data used for the curves. A general average of the growth of all 



^Loc. cit. (i). 



