NURSERY PRACTICE FOR PRAIRIE-PLAINS PLANTING 



109 



should be used. For species having a heavy root system, such as 

 walnut, coffeetreej and soapberry, two tics, one below the point of 

 heaviest root caliper and one near the top of the bundle, are helpful 

 to prevent loosening. Two ties should be used as little as possible, 

 however, since they cause very compact bundles, which do not keep 

 as well in overwinter storage as bundles tied above the roots only; 

 in the heel-in beds it is harder to get soil in contact with the center of 

 tight bundles. 



6. The seedlings are heeled in temporarily until transported to the 

 place of storage. Because the seedlings are seldom if ever watered 

 in the temporary heel-in beds, the soil should be firmly tramped 

 around the roots and the entire bed should be mounded over with 

 soil, leaving only a few inches of top exposed. 



Some nurserymen will find it convenient to pick out the marginal 

 grades also and heel these in separately from the premium grades. 

 In case of stock shortage, the trees in the marginal grade may be 

 shipped and planted in the more favorable sites where moisture con- 

 ditions are better. Sometimes the marginal grades are transplanted 

 in the nursery to get them up to larger size the second year. 



Practical Value of Caliper in Grading Deciduous Seedlings 



A relatively low top-root ratio has long been regarded as a very 

 important criterion in selecting conifer planting stock. Top-root 

 ratio, as used by nurserymen, indicates the "balance" of a seedling, 

 the relation of the weight of the entire top including foliage to the 

 weight of the root severed at the ground line, on either a green or an 

 oven-dry basis. It should not be confused with stem-root ratio, the 

 weight of stem without leaves divided by weight of roots, or with 

 leaf-root ratio, the weight of the leaves divided by weight of roots. 



To provide a comparison of these criteria of balance as employed 

 on deciduous stock, table 23 presents top-root, leaf-root, and stem- 

 root ratios for four species grown in a North Dakota nursery. It 

 will be seen that there is a fair correlation between the criteria, and 

 that for these species the values fall in ascending order by all six 

 methods. The table would further indicate that as a practical field 

 method, ratios expressed on a fresh-weight basis are satisfactory, 

 since they correspond quite closely with the oven-dry values. 



Table 23. — Comparison of several criteria of balance in fiardwood nursery stock 



Age class and species 



I u|,-rn„i ratio 



■ ratio • 



Stem-ru 



Fresh 



weight 



3-0 bur oak 0.74 



3-0 chokecherry 1.72 



3-0greenash 2.40 



3-0 Russian-olive I 4. 55 



Oven- 

 dry 

 weight 



0.71 

 1.57 

 2.23 

 4. 32 



Fresh 

 weight 



Oven- 

 dry 

 weight 



Fresb 

 weight 



0.53 

 1.22 

 1.68 



2 47 



0.49 

 1.05 

 L. (8 



-• is 



0.21 



.50 



Oven- 

 dry 

 weight 



22 



8 



Weight of stem + leaves 

 Weight of roots 



- W. :. 

 Weight of roots 



J tVeight of stem (without Leaves) 



Weight of r 



