SAMPLE PLOTS IX SILVlCULTUEAL RESEARCH 17 



sections. These stakes should be made permanent markers. Inter- 

 mediate lines can be established with the angle mirror, compass, or 

 transit. 



The size of plot divisions depends chiefly upon the character of 

 the data to be gathered. The larger the trees on the plot and the 

 smaller the plot, the less desirable it is to make small divisions. 

 Small divisions made in young stands can later be combined. 



Mapping and area calculations are simplified if the sides of the 

 plot divisions are in some readily usable unit such as 10 links, y 2 

 chain, 10 feet, or 25 feet. On plots the sides of which are not mul- 

 tiples of any of these lengths, in order not to have a tier of odd-sized 

 sections left along 1 or 2 sides of the plot (an arrangement in which, 

 however, there is no harm) it may be thought preferable to make 

 the sides of the sections proportional to the sides of the plot. 



DEMARCATING BOUNDARY AND CORNERS 



The plot boundary, and all plot corners, ends of line plots or 

 transects, and other stations that will be used again — such as photo- 

 graphic, litter, or soil stations — must be permanently and conspic- 

 uously marked so that they can be relocated quickly and surely. 



The boundary line may suitably be marked with blazes or paint 

 spots placed to face the interior of the plot. Such marking should 

 be done systematically. Trees on the line may be ringed or marked 

 with vertical streaks of paint placed on opposite sides of the tree 

 through which the line passes; trees outside the plot but near the 

 line may bear streaks at a slight angle with the vertical, placed to 

 face the line ; trees farther from the line, streaks at a greater angle 

 with the vertical; and trees at more than arm's length from the 

 line, horizontal streaks. 



Promiscuous marking of trees, either by painting or by blazing, 

 should be carefully avoided. If the trees on the plot are numbered 

 and properly marked, in later years there will be no question of 

 which are in and which are out, except in the case of trees that later 

 grow into the diameter class recorded. 



In Europe, plot boundaries are often indicated exactly by a shal- 

 low ditch extending along the boundary either throughout its length 

 or for a distance of from 20 to 50 feet from each corner. These 

 ditches remain clearly in evidence for many years. They should not 

 be used, however, where they will affect drainage or on slopes where 

 the}' ma} 7 cause abnormal erosion to develop. 



Painting in connection with sample-plot work should be done with 

 a good grade of zinc or lead paint, of conspicuous color, known to 

 be weather-resistant. The tannin and resin of the bark of various 

 species react differently to different paints; but so little is known 

 on the subject that no further specific recommendations can be 

 made. 12 Certain automobile and wagon enamels weather well, retain 

 their bright colors, and tend to bind the bark to which the} 7 are 

 applied. Bright yellow, bright orange, sky blue, and white are all 

 conspicuous in the woods. White is not recommended where sample- 



12 Reports on experience with different brands of paint in sample-plot marking will be 

 welcomed by the Division of Silvics, Forest Service, Washington, D.C. 



87471°— 35 2 



