22 CIRCULAR 3 3 3, U.S. DEPARTMENT OF AGRICULTURE 



PLOT MAPS 



At least two general maps are needed. The first should be a 

 sketch map showing the general location of the plot or series of plots 

 and the tie-in traverse. It should show the plot in relation to nearby 

 roads, camp sites, streams, etc.. and should be accompanied by clear 

 and definite instructions for reaching the plot from a nearby town 

 or from some other specific and generally known point. A high- 

 way and road log map showing the way from the nearest town is 

 often helpful. For plots on an experimental forest, in some cases it 

 will be unnecssary to prepare a special map of this character be- 

 cause all plots will be located on a map of the area. 



The second map should show the position and. by appropriate 

 symbol, the designation of all corners and permanent stakes, the 

 position and character of each subplot, and the bearing and distance 

 of each boundary line. Great care should be taken to make station 

 designations on the map correspond exactly with those on the plot. 

 The scale of the map and the area of the plot or plots should in- 

 variably be shown. In some cases it is well to indicate the position 

 of each tree. 



General plot maps are more convenient for use if north is toward 

 the top of the page and all letters and figures read from one direc- 

 tion, preferably, the left. The maps should be of letter size (8 by 

 10y 2 inches) or. if that is impractical, of double letter size or of Atlas 

 size (18 by 21 inches). 



For many plots, one or several additional maps will be needed. 

 Some will give such details as the location of subplots, camera points, 

 skid trails, slash piles, old logs, windfalls, and rock outcrops. In 

 some ecological studies it is desirable to plot the location of patches 

 of spreading plants such as honeysuckle, squaw carpet, chaparral 

 species, and bunch grasses. The purpose of the study largely de- 

 termines what details should be shown, and how far it is necessary 

 to show changes in plot appearance between one measurement and 

 another. 



Symbols used in sample-plot mapping are shown in the appendix 

 (p. 76). 



On detailed plot maps it is not essential to have the north side 

 of the plot at the top of the map : convenience in field work should 

 govern. Thus in many instances in which the plot is located on a 

 slope, for greatest convenience in sketching, the mapper should face 

 downhill. "This makes, the lower plot boundary parallel the top of 

 the page. 



On all maps north should be indicated by an arrow, and the plot 

 corner numbers should be given. The combination lessens the likeli- 

 hood of confusion and error in either field or office work. 



In mapping as in all other plot work, a high degree of accuracy 

 is essential. 



All maps should be dated and initialed. 



INDIVIDUAL TREE CONTROL 



NUMBERING TREES AND MARKING THE MEASUREMENT POINT 



A control of individual tree measurements on a plot may be 

 needed as a means of preventing duplicate measurements. In per- 



