NURSERY PRACTICE FOR PRAIRIE-PLAIXS PLANTING 



107 



be graded in a number of size classes, this procedure is the mosl 

 feasible and economical. The Forest Service, however, has adopted 

 a single usable grade, with consequent simplification of the commercial 

 practice, making possible a field-grading technique which not only so 

 reduces exposure time of seedlings as to preclude injury but also 

 considerably reduces the cost of the operation. 



Deciduous seedlings can be exposed to the air longer than conifers 

 without being injured, and 

 Alba H. Briggs of the 

 Prairie States Forestry 

 Project has found that most 

 nursery seedlings exposed 

 for 2 to 3 hours on the 

 surface of a plowed field 

 showed no drop-off in sur- 

 vival in field plantations. 

 Wilding cottonwood and 

 mulberry, however, were 

 adversely affected by more 

 than an hour's exposure. 

 Present technique in Fed- 

 eral nurseries in the plains 

 is such that seedlings are 

 not exposed more than 5 to 

 15 minutes. 



The general technique 

 developed for field grading 

 is outlined in the series of 

 steps given below, one man 

 performing one only of the 

 steps involved. Although 

 operation 2 is necessary 

 only for a few species, it 

 must in these cases be per- 

 formed on the individual 

 seedlings before they are 

 bunched or bundled, if the 

 laterals are to be removed 

 effectively. 



The five or six operations 

 follow one another in logical Figure 38.— The first operation in field grad- 

 sequence and, therefore, the i n g- Pulling undercut nursery seedlings. 



system lends itself readily 



to efficient crew organization. Occasionally, when conditions permit, 

 steps 1 and 3 can be performed to advantage by one man. When 

 step 2 is omitted, a unit crew of nine men can work three rows at a 

 time very efficiently, operations 1 and 3 being performed by three 

 men each, one on each row, and operations 4, 5, and i\ being handled 

 by one man each working all three rows. An average out put o( 3,000 

 usable seedlings per man per day can reasonably be expected of a large 

 crew of 30 to 40 men if they are properly organized and supervised. 



1. After being undercut, all the seedlings regardless of size are 

 pulled, soil and leaves shaken free, and trees laid down crosswise on 

 the row behind the puller as he progresses up the row (fig. 38). 



S^aM 



