SAMPLE PLOTS IN SILVICULTURAL RESEARCH 21 



The subplots on each plot should be numbered in a single series. 



Several schemes are used for numbering plot sections. By one. 

 the rows of sections are numbered across the plot from left to right, 

 and the tiers of sections are lettered accordingly. Each unit is then 

 distinguished by a letter and a number, as B-3. By another scheme 

 the units are numbered consecutively back and forth across the plot 

 like the sections in a township. The coordinate scheme has many 

 more advantages than has the consecutive-numbering plan. 



If plot data are to be put on punch cards, locality names should 

 be coded and an entirely numerical scheme should be used to desig- 

 nate subplots and plot sections. 



LOCATION SURVEY 



Each sample plot or group of sample plots should be referenced 

 to some permanent and readily definable object or point. The sur- 

 vey traverse should begin at the point selected as a tie and, whenever 

 possible, should end at the " initial " corner of the plot or plot 

 series. Objects such as Land Office survey corners, bench marks, 

 railroad switches, bridges, and road or trail intersections make 

 excellent reference points for plots not within experimental forests. 

 Objects that can readily be moved, such as fence posts, logging- 

 railroad spurs, or posts set along highways, are much less desirable. 



As an aid in relocating plots, distinctive markers calling atten- 

 tion to the plots should be established along the nearest road or trail. 

 Small tin or cloth signs bearing appropriate wording and tacked 

 on trees near the road or trail are often very helpful in showing the 

 way to the plots and as a means of relocating the traverse line. A 

 number of research agencies are now using special tin signs about 

 6 inches square for this purpose. These signs are especially helpful 

 if they give the plot designation and the distance to the plot. Some 

 agencies use signs along roads and trails not only to show where 

 the plots are located but to inform the public as to the purpose of 

 the plots and the conditions illustrated by them. 



Photographs are helpful in showing the location of a plot or 

 series of plots, as on a side hill or in relation to some outstanding 

 topographic feature. This value is illustrated by the aerial photo- 

 graph of the Deception Creek Experimental Forest, Coeur d'Alene 

 National Forest, Idaho, that appears as plate 1, B. A series of 

 photographs centering along the line of the plot-location survey 

 not infrequently aids in relocating lines and finding plots without 

 instruments, especially if trees along the line bear distinctive mark- 

 ing, either painting or blazing. 



A ,c motor log " from, the post office or some other unmistakable 

 point in the nearest town to the place where the cars of visitors to the 

 plots are to be parked is very useful. Distances should be read from 

 a speedometer and recorded to the nearest one-tenth mile. The log- 

 should be complete enough to be followed easily by a person un- 

 familiar with the locality. 



A location survey for temporary plots may not be necessary, but 

 is helpful if the plots are reexamined. It need not be so accurate 

 as that for permanent plots. 



