84 CIECULAK 3 3 3, U.S. DEPARTMENT OF AGRICULTURE 



and aspect; Altitude (total and relative) ; Soil and rock; Soil cover (under- 

 brush, advance reproduction, litter, humus) ; History (origin, date of tires, 

 date of cuttings, present condition) ; Tie-survey notes and sketch map. 



73. The form of tally sheet may vary with the species and type studied, al- 

 though the Forest Service form 547 is capable of wide application. It should, 

 however, not omit any of the following items : Date ; locality ; survey notes ; 

 name of party chief; plot number; ages of sample trees; average age; area; 

 species; site class (entered in office) ; diameter, tallied by crown class; height 

 measurements of sample trees; plot description (see last paragraph). Wher- 

 ever possible, provision should be made for complete computation on the original 

 sheet of basal area, volume, etc., as filing is much simplified thereby. 



74. Since site determination of the plots in the field and by inspection has 

 been found difficult, inaccurate, and of little value, but since there is need of 

 some current means of determining whether the plots found are satisfactorily 

 distributed through the various site classes, a tentative series of height-age 

 curves should be prepared on the basis of the first 15 or 20 plots on which 

 measurements are taken, and subsequent plots allocated tentatively to site 

 classes thereby. 



75. A two-man party is adequate for the collection of these data. Of these 

 men only one need be experienced. Where more than one party are working 

 on a single study, it is of the greatest importance to coordinate their methods. 

 It is desirable to start with a single party of two experienced men, later to 

 split this party in two by giving each an assistant, and so on. If this is im- 

 practicable, at least the man in charge of the project should train each crew 

 when it is starting work, so that he may impress his conception of normality, 

 etc., upon each. It is also essential that one man have direct charge and 

 responsibility of both field and office work. 



76. If volume tables are not already available, data should be collected for 

 their preparation. The plan of felling and measuring 1 or 2 average dominants 

 on each plot has been found inadequate because the range of diameters and 

 heights will not be properly covered. See preceding section on volume-table 

 preparation. 



OFFICE WORK 



77. For each plot a curve of height over d.b.h. should be prepared for each 

 important species. 



78. For each plot the basal area should be computed to three significant 

 figures and totaled by species and crown class. 



79. For each plot the number of trees should be totaled by species and 

 crown class. 



80. For each plot the volume should be calculated and totaled by species 

 and crown class. Volume should be interpolated to the nearest foot of height. 

 This may be done with sufficient accuracy by putting the volume table in 

 graphic form or in the form of an alinement chart. 



81. The fundamental volume figure is that in cubic feet including the 

 entire wood of the stem. Subordinate figures should be obtained in board 

 measure by means of the International (%-inch) log rule. The local rule 

 should also be used in cases where the material involved is now merchantable, 

 preference being given to the Scribner. 



82. For each plot the average d.b.h. is calculated by dividing the sum of 

 the basal areas by the number of trees. 



83. For each plot the average height is read from the height-diameter 

 curve corresponding to this average d.b.h. 



84. For each plot the actual total age is determined by adding the seedling 

 allowance to the average of the determined ages. 



85. For determining the site index a series of curves showing the relation 

 between the average height of the dominant trees and their ages should 

 be prepared. The basis should be the average height of dominants (or of 

 dominants and codominants) at 50 or 100 years, depending on the probable 

 rotation age. The curves should be at 10-foot intervals at the selected age. 

 The height of individual trees, if used at all, should be merely a guide to the 

 location of the curves. The curves should, of course, be applicable to the 

 principal species being studied. 



86. The site index of each plot should be read to the nearest foot. By 

 site index is meant the average height of dominants which the plot has attained 

 or will attain at the age chosen for classification. 



