78 MISC. PUBLICATION 43 4, U. S. DEPARTMENT OF AGRICULTURE 



Table 21. — Effect of stand density on caliper of seedlings as shown by number of 



"ings in each caliper class 



Species and number of seedlings in 

 10 lineal feet of row ' 



Caliper class 



Aver- 

 age cali- 



1/16 

 inch 



2/16 

 inch 



3/16 

 inch 



4/16 

 inch 



5/16 

 inch 



6/16 

 inch 



7/16 

 inch 



per of 

 all seed- 

 lings 



Honevlocust: 



20 



Num- 

 ber 

 2 

 5 

 14 

 27 

 19 

 44 

 47 





 



1 







9 



38 



104 



Num- 

 ber 

 4 



12 

 10 

 21 

 29 

 41 

 25 



3 

 6 



6 

 16 

 27 

 72 



87 



Num- 

 ber 

 3 



10 

 17 

 15 

 22 

 12 

 34 



3 



14 

 23 

 25 

 22 

 41 



Nim- 

 ber 

 6 



Num- 

 ber 

 3 



Num- 

 ber 

 2 

 

 

 

 

 

 1 



4 

 6 

 2 

 

 

 

 



Num- 

 ber 

 

 



o 







o 





 







1 





 

 

 

 



Inch 

 0.22 



43 - - 



14 ! 2 



? ! 



K) 



. 18 



50 



. 15 



71 - 



. 13 



80 



.14 



98.-- 



1 



7 



3 







1 



5 



. 11 



115 . _ 



. 13 



Green ash: 



18 



.26 



30 



7 ! 3 



16 i 6 

 15 5 

 18 I 2 

 13 2 

 6 



.25 



45 



.22 



59 



.20 



81 



.17 



147 - 



.13 



239 



.11 











i 6-inch-wide bands with rows 40 inches apart. 



Observations made from 1935 to 1938 in 20 different deciduous 

 nurseries in the plains region indicate that densities ranging from 5 to 

 10 seedlings per lineal foot of row, after the early season losses, produce 

 the greatest number of premium-grade seedlings. It is best as a rule 

 to grow the fast-growing species of 1-year stock in slightly denser 

 stands than the slow-growing species. Also, species to be grown 2 

 years in the nursery in the Northern States can be grown in denser 

 stands than species requiring only 1 year. The ideal sowing rate 

 will result in the desired stand density with allowance for the inevitable 

 losses which occur before the stand is established. 



Sowing rates to produce a given density will be governed by the 

 viability of the seed and the ratio that exists between viability and 

 ultimate final stand. Although the viability of the seed can be deter- 

 mined by germination tests, the ratio between viable seed sown per 

 lineal foot of row and the ultimate stand varies greatly. Numerous 

 factors determine this ratio, such as soil texture and fertility, weather 

 conditions (especially during the germination period) , intensity of the 

 nursery care, growth habits of the species, amount of loss from disease, 

 insects, and rodents, and, lastly and perhaps most important, the size 

 of the seed. Large-seeded species such as plum, apricot, honeylocust, 

 and many others, which produce a sturdy vigorous growth immedi- 

 ately upon germination, can normally be expected to show lower 

 mortality during and immediately following germination than small- 

 seeded species such as elm and mulberry. Seedlings from small- 

 seeded species are normally very delicate during early life and heavy 

 losses can occur quickly from soil crusting, heat, wind burn, drought, 

 and other causes. Figure 22 illustrates the comparative size of various 

 species during early life. 



For all species a certain percentage of loss is unavoidable and some 

 oversowing must be done to allow for subsequent loss. Alba H. 

 Briggs of the Prairie States Forestry Project, Lincoln, Nebr., in a 

 study conducted at a Nebraska nursery during the summer of 1937, 

 found that, at the end of the season, honeylocust, coffeetree, and wal- 

 nut retained over 90 percent of their original stand, plum 89 percent, 

 hackberry and Chinese elm 87 percent, Kussian-olive 65 percent, choke- 

 cherry 60 percent, American elm 38 percent, and mulberry 20 percent. 



