ESTABLISHING FORESTS BY PLANTING 381 



the crew is too large, the hole diggers furthest away from the 

 flanking man are likely to get badly out of alignment from the 

 accumulated errors of the others. 



It is often necessary to establish lines of flags across the plant- 

 ing area in working with large inexperienced crews in order to 

 keep the rows reasonably straight and at the desired distance 

 apart. A line of flags may be used to guide the direction of they 

 flanking man or a line may be set for each man in the crew. It 

 is necessary to set the flags sufficiently close in the lines to enable" 

 the planters to keep a straight course across the field by sighting 

 along the lines. When a line of flags is set for each planter they 

 should be of different colors in order to eliminate confusion in 

 following the lines. The flags are set by the foreman of the 

 planting crew. Care must be taken in setting the flags that they 

 be in straight lines across the planting area and that the lines be 

 correctly spaced. The distance between the plants in the line 

 is determined by the eye or by means of a measuring stick carried 

 by the planter. 



26. The Number of Plants per Acre 



The approximate number of plants required per acre in irregu- 

 lar spacing is found by dividing 43,560, the number of square 

 feet in an acre, by the area in square feet allotted to each plant. 



The number of plants required per acre in regular spacing is as 

 follows : 



Square planting, 



No. of plants required = 7^ -. ^-TT r- 



(Planting distance) 2 



Rectangular planting, 

 No. of plants required = 



Spacing in line X spacing between lines 

 Triangular planting, 



No. of plants required = ^ > - ^ , T ^ i X 1.155. 



(side of equilateral triangle) 2 



Superposed squares, 



No. of plants required = . , 43 ^ 60 - 



% (side of square) 2 



When the planting is in squares at 6-foot intervals, each plant 

 occupies 36 square feet; therefore, the number of plants required 



