PERMANENT SAAIPLE PLOTS. 



By Theodore S. Woolsey, Jr. 



As early as 1906 the need for a systematic study of cut-over 

 areas on the National Forests was keenly felt. It was impossible 

 to predict to any degree of accuracy the net increment of the trees 

 left after cutting, the height and diameter growth of individual 

 trees, the death rate of some of the older trees nor was it possible 

 to foretell the actual effect on reproduction and on the remaining 

 stand of the different methods of marking, brush disposal, or graz- 

 ing. Preliminary instructions were drawn up by the writer in co- 

 operation with Mr. G. A. Pearson in 1909. These early instruc- 

 tions have since been amplified and amended chiefly through the 

 efforts of Mr. Pearson and Mr. H. D. Burrall. While the exact 

 methods cannot perhaps be applied directly to other parts of the 

 United States, chiefly on account of the larger number of trees per 

 acre, yet the instructions undoubtedly contain many points that 

 will be of interest professionally. As issued on December i, 191 1 

 they are as follows : 



The general object of these "intensive" reproduction plots is to secure 

 accurate data along the following lines as a foundation for a system of 

 management : 



1. Actual increment in feet board measure or cubic feet. 



2. Height and diameter growth of individual trees. 



3. Death rate in different age classes. 



4. Effect of the different degrees of cutting, methods of brush disposal, 

 ground cover, soil, exposure, grazing, fires, insects, etc., upon seeding 

 reproduction or the growth of individual trees. 



5. Accurate photographic record to supplement paragraph 4. 



LOCATION AND AREA. 



Areas should be selected on which a timber sale has occurred not more 

 than five years before the establishment of the plots. Where a sale area 

 exhibits only slighly varying degrees of forest density, type, exposure and 

 slope, reproduction plots covering five per cent, of the total area will 

 usually suffice. In broken country or where the stand or types are 

 irregular ten per cent, is often necessary. It is desirable that large plots 

 of from 10 to 15 acres be established where one general density, exposure, 

 type or slope would be included, otherwise areas of from 5 to 10 acres 

 should be selected which embody a single feature. No plot of over 15 

 acres or under 5 acres should be established; the major dimension should 

 not be more than 13 chains and the minor not less than 5. 



Plots should be established and designated so that major plots can 



