SAMPLE PLOT STUDIES 



547 



Although the number of species was large, the way in which they 

 were scattered rendered the selection of plots of uniform character 

 fairly easy. Density of stand, age, and height were the same through- 

 out, and all trees were found in extremely thrifty and healthy con- 

 dition. 



The level character of the land, and the deep, rich, well-drained clay 

 loam are also factors to be kept in mind when going over the results 

 of the first 5-year period. 



Three square plots, each one-quarter acre in area, were laid out, 

 each one being surrounded by a strip 30 feet wide, these adjacent strips 

 being accorded the same treatment as the plots. Corners were marked 

 with 5-inch cedar posts. Plot I was untouched, being left as a check. 

 Plot II was heavily thinned and Plot III lightly thinned. 



Every tree in each plot was measured in diameter at right angles, 

 the mean being used for the calculations. At the time of measurement 

 each tree was numbered, the number being painted at d.b.h. in bright 

 red paint. Parenthetically it should be added that such numbers can 

 only be seen with difficulty after 5 years, and frequent remarking is 

 necessary. Last year the trees were tagged with zinc identification 

 marks. 



The original plans were to make remeasurements of every tree every 

 five years. The first 5-year period ended last year, and the following 

 data show what had taken place. 



The points of most striking interest in the following tables are 

 that the greatest increases in both diameter growth and volume growth 

 took place where the thinning was heaviest ; that results intermediate 

 between those from the check and heavily thinned plots are found in 

 those figures secured from the lightly thinned plot. 



Table 1 



