14 



BULLETIN 12<)4, U. S. DEPARTMENT OF AGRICULTURE. 



Another factor of some importance is the percentage of good 

 plant able stock which may be graded out as it is dug from the nursery 

 beds. A special study of grading practice was made and arbitrary 

 grades were established for the various age classes of western yellow 

 pine. Table 8 shows the percentage of each grade for each age class 

 studied. 



2-C 



Fig. 3.— Development of western yellow-pine stock of different age classes grown in the Cottonwood 

 Nursery, Wasatch National Forest, Utah 



Table 8. — Results of the grading of different age classes of western yellow pine 



nursery stock. 



Age class. 



Grade. 



Firsts. 



Seconds. 



Culls. 



2-0 



Per cent. 

 32.5 

 1.1 

 46.6 

 70.7 

 52.5 

 20.4 

 27.2 

 39.6 

 56.0 

 23.2 



Per cent. 

 48.7 

 9.4 



Per cent. 

 18.8 



3-0_. 



89.5 



1-2. . 



53.4 



2-1(1917) 





29.3 



2-1 (1918) i 





47.5 



3-1 ._ 





79.6 



1-1-1. 





72.8 



2-1-1 





60.4 



2-1-1 (2-1 firsts) 2.... 





44.0 



2-1-1 (2-1 seconds) * 





76.8 









1 Thislot of stock was considerably below the average for 2-1 stock on account of having been injured in the 

 transplant bed. 



2 Some of the 2-1 western yellow pine stock, graded into firsts and seconds and re-transplanted, gave these 

 results when graded the following spring as 2-i-l stock. 



In the grading of seedling stock the firsts were stock which was 

 considered suitable for field planting, while the seconds were con- 

 sidered suitable for transplanting but unsuitable for field planting. 

 The culls were stock unsuitable for use either for field planting or 

 for transplanting and were discarded. In grading this stock it was 

 assumed that trees selected for field planting should have the proper 

 balance between root and top. The necessary grading of 2-0 seed- 

 lings as illustrated in Table 8 adds from SI to SI. 50 a thousand to the 

 cost of the 2-0 planting stock on account of the cost of the stock dis- 

 carded, which makes it but little cheaper than 2-1 stock for field 

 planting. The extremely low percentage of 3-0 stock suitable for 

 field planting is due to the unbalanced top and root development, 

 the very long coarse tap root, the almost complete absence of fibrous 

 secondary laterals developed within 12 inches of the root collar, and 



