FOREST PATHOLOGY IN FOREST REGULATION. 41 



cubic feet, making constant reference to the total volume of the 

 tree necessary, the volume of the rot was expressed in percentage of 

 the total volume. Advance rot — that part of the wood already under 

 the influence of the mycelium — is included. It must be kept in mind 

 that all figures given under this heading (column 5) are therefore 

 likely to be high. To be on the conservative side, all measures of 

 decay were taken very carefully, and in all cases where there was 

 any possible doubt the uncertain part was measured as decay. But 

 since the same procedure was followed consistently the results are 

 directly comparable. 



Table I gives us our working material in figures. Column 1 shows 

 the individual number of each tree from the field notes and is given 

 only for convenience of reference, the trees being arranged in the 

 order of their ages (column 2). Column 3 shows the actual or total 

 volume in cubic feet of each tree, considered as a perfect cone. 

 Column 4 gives the volume in cubic feet for the average tree of the 

 same age. Column 5 shows the volume of rot (including advance 

 rot) in cubic feet expressed as a percentage of the total volume of 

 the tree. Column 6 shows the character of the wounds. 



CONDENSATION OF DATA. 



It proved difficult to interpret intelligently this mass of figures. 

 If there existed any relation between decay and possible influencing 

 factors, it certainly did not appear very clearly from this table. 

 It became necessary to simplify and condense the material. 



Instead of expressing dominance or suppression by the relation 

 of the actual to the normal volume in figures, the system of crosses 

 described above for the field notes was used. Three classes were 

 adopted — dominant, intermediate, and suppressed. Those volumes 

 which came closest to the average were considered intermediate 

 and entered in the table with one cross, which expresses the affirma- 

 tive; a dash signifies negation. In the intermediate class therefore 

 there can be not more than one cross. The deviation from this 

 average shows in the two other classes, and as here all degrees are 

 possible, the degree of suppression or of dominance is shown with one, 

 two, or three crosses. Thus, three crosses under "Dominance" 

 niiitii that the (rce is as far beyond the average as is possible in that 

 locality. On the oilier hand, one cross under " Suppression " means 

 thai fli'' tree is decidedly suppressed, two crosses that it is badly 

 pressed, and three crosses indicate the highest degree of sup- 

 pression. This classification is admittedly arbitrary; it seemed to 

 answer the purpose, however, and has so many advantages, with its 

 possible grades and its graphical clearness, that it may be retained 

 until some better method is devised. (Table II, columns li, 4, and 5.) 



