SAMPLE PLOTS IN SILVICULTUEAL RESEARCH 57 



usually call for the same degree of precision as that originally 

 sought; if a decision has been reached that increases or decreases 

 the demand for accuracy, the new procedure and the reasons for it 

 should be carefully described in the plot records. Over-refinement 

 is preferable to under-refinement. The notes should be kept by the 

 same system used previously. 



The man recording the measurements as they are called to him 

 should constantly check them against the data from previous meas- 

 urements. In this way current mistakes will be prevented and 

 errors in a previous measurement will be caught when it is easiest 

 to rectify them. A change made in an earlier measurement should 

 be written above the original, and the reasons for it should be noted 

 in the field. Such changes should be initialed and dated. At 

 the time of the first remeasurement a special watch should be kept 

 for trees overlooked at the time of plot establishment. Original 

 diameters can be calculated from increment cores. The original 

 heights of any missed conifers, if needed, can be estimated from 

 the height-growth data. 



At every remeasurement, all the plot corners and other permanent 

 stations should be inspected and any needed replacements or re- 

 pairs made. Any painted numbers, diameter-measurement marks, or 

 boundary lines that have become illegible, weathered, or dull should 

 be renewed. If original numbers cannot be freshened satisfactorily, 

 the numbers should be painted anew. Xails holding tags should be 

 pulled 29 so that they again protrude from the tree by from one-half 

 to three-fourths of their length. Trees that have grown into the meas- 

 urable size class since the previous measurements should be num- 

 bered (p. 27) and measured. Trees from which tags are missing 

 should be identified by means of the stem map, if any. and their 

 original numbers replaced. 



Stem maps should be revised at each remeasurement by plotting 

 the positions of any new trees and indicating any trees that have 

 died. For a plot for which a crown map has been made, if the 

 density of the crown cover has changed significantly a new crown 

 map should be prepared. Transparent overlays facilitate copying 

 usable portions of old maps in the field, and when placed over a 

 translucent table top in the office make possible rapid detection of 

 crown changes. 



The description of the plot should be brought up to date, par- 

 ticular note being made of changes evidently due to treatment. After 

 each remeasurement a report should be prepared summarizing all 

 the work done on the plot in connection with the remeasurement. 



REPORTS AND OFFICE RECORDS 30 



REPORT ON PLOT ESTABLISHMENT 



When all the field work of plot establishment has been finished, a 

 complete but concise report should be prepared, bringing together for 



29 For this work a mechanic's claw hammer with straight chisel prongs is preferable 

 to a carpenter's hammer, which has curved claws. The chisel edges of the mechanic's 

 hammer make it easier to get the claws under imbedded nails, and thus make pulling 

 a much easier and simpler task. 



30 In the appendix are given abbreviations and a numerical code for use in sample- 

 plot work (p. 73). a list of stationery, etc., needed in such work (p. 72), and specimen 

 forms for summarizing plot data (p. 66). 



