FOREST PATHOLOGY IN FOREST REGULATION. 23 



so many varying conditions with regard to soil, climate, admixture of 

 the species, and representation that here again typical areas must be 

 chosen for independent studies. The more diversified the types 

 studied and the greater the number of trees per type and in the aggre- 

 gate, the more reliable will be the results. 



The choice of the particular area to be studied is, of course, impor- 

 tant. The unit of study should be representative, typical for the 

 larger unit. In general it will not be difficult, with some care, to make 

 the proper choice. 



The result of the writer's studies, still unpublished, on the critical 

 age of incense cedar served to work out the methods which should be 

 applied in a modified form to the at present more important investi- 

 gations on white fir. European precedent could not be used; Martin, . 

 Moller, and Hemmann worked on managed forests. New methods to 

 suit our conditions had to be evolved. 



The only satisfactory result could be expected from careful dis- 

 section and analysis of as large a number as possible of trees of dif- 

 ferent ages. Unlike other investigative work, studies of this kind 

 can not well be carried out on timber-sales areas where the actual 

 felling and bucking of the trees is done by the purchaser. The 

 purchaser is none too willing to cut trees containing rot unless he is 

 compelled to do so; much less does he care to buck such trees, which, 

 after all, are the ones from which we must expect most valuable 

 instruction. He is not obliged to cut trees below a certain diameter 

 limit, which, of course, can not be left out. All this is particularly 

 true for the so-called inferior species, the handling of which often 

 comes so near being a loss to the purchaser that any additional cost 

 would work a distinct hardship. For the same reason it is impos- 

 sible to have the trees on timber-sales areas bucked in odd log lengths, 

 as dictated by the irregular and varying extent of the decay. As 

 will be seen, a few of the notes used for this study are incomplete, 

 because they had to be taken in connection with timber sales. 



It becomes necessary, therefore, to carry on investigations of this 

 kind on representative areas chosen for the purpose and to have the 

 systematic cutting and dissecting of the trees done by crews, involv- 

 ing much work and a large expenditure. This way of handling the 

 problem has proved to be the only feasible one; and, as long as 

 immediate results may be expected, which if properly applied must 

 lead to very considerable savings as well as to progress in silvicul- 

 tural management and forest regulation, the expense and work seem 

 to be justified. 



FIELD METHODS. 



Before the actual felling begins, notes are taken first on the larger 

 forest unit of which the area to be studied forms a part, such as eleva- 

 tion, climate, water table, soil in general, history (lightning and 



