XL'RSERY PRACTICE FOR PRAIRIE -PLAINS PLANTING 



111 



of deciduous field-planting stock, and that caliper and total weight 

 of the seedlings were much more important. 16 



Because caliper of stem is considered the best and most practical 

 basis of grading deciduous nursery stock, the nurseryman should 

 instruct and train his field graders as to the caliper specifications for 

 each species. In case only one plant able grade (includes premium 

 and marginal sizes) is considered for field planting, the proeess is 



100 



80 



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q3 60 



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^ 40 



s 



CO 



20 





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RUSS 



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AN MULBE 



A 



RRY' J 



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1/16 



2/16 



3/16 



4/16 



5/16 



6/16 



CALIPER OF STEM (inches) 



Figure 41. — First-year field survival in a drought year of various caliper classes 

 of stock within the same height class. The walnut and catalpa are in the 

 8- to 12-inch class, the mulberry in the 18- to 24-inch. 



very simple, and the men can easily learn to estimate caliper, especially 

 in the smaller size classes, to the nearest sixteenth or thirty-seeond of 

 an inch. 



Some nurserymen have used height of top as a basis for grading 

 nursery stock. While this is a fairly good basis.it is not as foolproof 

 as caliper of stem. This is indicated by the curves in figure 41 . which 

 show that survival percent in a given height class varies considerably 

 over a range of calipers. 



In summary, it might be said that stocky, sturdy seedlings of good 

 caliper are much preferred to tall, spindling stock of poor caliper. 



At what point on the stem seedlings should be calipered is a moot 

 question. At 1 or 2 inches above the ground line or root collar, it i< 



'« It is conceivable that heavy watering or fertilizing of the stock in dense stand? might produce seedlings 

 of adequate caliper, but having a very poor root system and stein-root ratios as high as :^:1 or 4:1. Such 

 stock would probably have poor field survival. However, if the nursery practices recommended in this 

 publication are followed as regards stand density and proper use of water, it is almost impossible to get 

 seedlings that are seriously defective because of poor balance. 



