46 BULLETIN 275, U. S. DEPARTMENT OF AGRICULTURE. 



factor may, of course, lead to misinterpretations unless the same 

 standard is applied throughout the entire study. For this very 

 reason it seemed doubtful from the beginning whether these data 

 would be of much value. They are given here merely for the sake 

 of completeness. 



The condensed material was again tabulated. In the condensed 

 table (Table II) the relation of decay to age can easily be followed by 

 comparing columns 2 and 6. "Decay rating" is placed between 

 "Suppression" and "Wound rating" in order to bring out forcibly 

 any possible relation between these factors. 



INTERPRETATION. 



The column that interests us most is apparently the sixth, "Decay 

 rating." In glancing over this column and comparing it with the 

 neighboring ones we can read directly the connection of decay with 

 factors that may be of influence. Each separate case of decay, of 

 which one, two, or even more can occur on the same tree, may be 

 called, for simplicity's sake, in this study, a "cull case." Each cull 

 case is the result of a separate infection. The actual loss of timber 

 by fire burning out the stump does not concern us here; cull from 

 this source is included in the "volume of rot" whenever the decay 

 is directly traceable to the fire wound. Otherwise the cull from fire 

 is neglected. Cull from knots, limbs, or wind-shake is not considered. 

 Altogether there are 97 cull cases. 



The first two cull cases are negligible for practical purposes. Some 

 loss occurs in tree No. 125, 84 years old. We see that this is a very 

 badly suppressed tree, very seriously wounded, in very bad health, 

 and that it is injured by both fire and lightning. Another case occurs 

 in tree No. 124, age 87 years. Again suppression, wounding, and 

 condition of health are marked with three crosses, indicating the 

 worst possible conditions, together with two causes of wounds — fire 

 and Hghtning. In both cases fire is the more serious, lightning often 

 occurring higher up on the tree in numerous small wounds. It 

 carries advance decay to the upper part of the bole and materially 

 increases the volume-rot figure and the decay rating. The next cull 

 case is a slight one (tree No. 88, age 90 years). The tree is inter- 

 mediate, wound rating medium, health good, the decay only advance 

 rot. Continuing down the "Decay-rating" column and comparing 

 the symbols with those in the neighboring columns, we find that in 

 almost every case the rating of rot more or less expresses or is ex- 

 plained by the factors of suppression and wound rating. Apparent 

 discrepancies generally find their explanation under "Remarks" 

 (column 10). 



Suppression shows at an early age. A distinct preponderance of 

 suppression is noticeable from about the age of 84 years. The first 



