NURSERY PRACTICE ON THE NATIONAL FORESTS. 51 



large stock. For small stock a vertical wooden moldboard is used 

 in place of the steel. This merely serves to push the trees away 

 after they are loosened, but does not cover them. 



With the digger shown in Plate XIX the principle of operation 

 is very simple. A wedge-shaped knife 7 feet long, 12 inches wide, 

 and 6 inches thick in the rear is drawn under the beds at regulated 

 depths. As the trees are loosened they are crowded out over the 

 wedge by the forward movement of the implement and are picked 

 from the soil in the rear. The digger is drawn by a horse-operated 

 capstan and steel cable and travels at the rate of 6 feet per minute. 

 The trees are removed in perfect condition. It works better with 

 transplants than with seedlings, because the latter are sometimes 

 covered with soil before they can be removed. 



All of these diggers loosen the soil to such an extent that the 

 trees must be taken up very quickly; and since their economic rate 

 of operation is considerably faster than transplanting, some extra 

 labor is required to heel in the seedlings temporarily. 



Precautions must be taken to prevent the drying out of the roots. 

 It is well known to nurserymen that conifers are quite sensitive in 

 this respect, but laborers do not generally realize its significance. 

 In semiarid regions the danger is especially great. Buckets, basins, 

 or tubs partially filled with water are sometimes kept at hand, and 

 as fast as the seedlings are dug their roots are immersed in these. 

 All the soil, and it is thought some of the fine rootlets, are washed 

 off by this practice. This has led to a different method at some of 

 the nurseries. Boxes about 3 feet long by 2 feet wide are padded 

 inside with moist burlap or with burlap over moist sphagnum moss. 

 They also contain, fastened at one end of the box, several moistened 

 burlap pads which are used to separate successive layers of trees. 

 As the seedlings are dug they are placed in the boxes in layers with 

 a moist pad between each layer and carried to the transplanting 

 area. In this manner the roots are kept constantly moist, but are 

 not washed. 



The importance of not subjecting the roots of conifers to ex- 

 posure at any time can not be emphasized too strongly. Coniferous 

 tops remain green for a long time after the roots are dead, and 

 their appearance can not be taken as a criterion of the condition 

 of the stock. An exposure of even 2 or 3 minutes, particularly 

 on a windy or very hot day, may prove fatal; and mortality in 

 transplant beds or in field planting may be due to lack of care 

 in this respect rather than to improper methods of transplanting 

 or field planting. At the Boulder Nursery experiments in exposing 

 seedlings of Douglas fir to the sun for periods varying from 3 

 minutes to 4 hours resulted in a loss in the transplant beds of 5 

 per cent when the exposure was for 3 and 6 minutes, of 8 per cent 



