; PERMANENT SAMPLE PLOT STUDIES. 



C. F. Korstian. 



Th<> simiy of permanent sample plots originated in Ger- 

 many in ISt'lO. They were established principally for the study 

 of the development of stands and were to serve as a foundation 

 for the calculation of additional growth and for the construc- 

 tion of i'1-ov.tli :nd yield tables. 1 Accurate data was collected 

 from tlu j plots every three to five years. Work of a similar 

 nature was instituted for the United States Government in 

 1904 by H. S. Graves and G. II. Myers. This work" was in- 

 tended to cover the following points : 



1. To determine the results of different degrees of 

 thinning. 



2. To test the effect of the removal of the old trees 



on those left standing. 



3. To study the natural reproduction and the devel- 



opment of the young trees under given conditions. 



4. Description plots located in the lumber woods, to 



observe the results of different kinds of lumber- 

 ing. In these plots the trees were not measured 

 but a very detailed description of the woods was 

 made before and immediately after logging. 

 W. D. Sterrett, in an address delivered before the Society 

 of American Foresters February 14, 1907, on "The Objects 

 and Methods of Establishing Permanent Sample Plots," 3 says 

 tba.t the important lines of investigation in permanent sample 

 plot work should include the following subjects: 



1. Growth and yield of the stand. 



2. Natural reproduction. 



3. Sprout reproduction. 



4. Artificial reproduction. 



5. Effects of thinning. 



6. Effects of fires. 



7. Effects of grazing. 



8. Growth of trees left after partial clearances, as 



in lumbering. 



1 Dr. H. Martin. Die Forsteinrichtung. p. 69, 1910. 

 2 H. S. Graves, Forest Mensuration, p. 344, 1906. 

 'Proceed. Soc. Am. For., Vol II, No. 1, p. 63, 1907. 



