6 BULLETIN 1264, U. S. DEPARTMENT OF AGRICULTURE. 



The open-trench method of transplanting was used very success- 

 fully. (PL II, fig. 2.) The object of transplanting is the production 

 of planting stock which is most likely to survive in field planting, 

 especially on adverse sites. Its principal effect is to retard height 

 growth and to stimulate the development of the finer lateral feeding 

 rootlets. (Figs. 3, 4, 5, and 6.) Such transplant stock is much more 

 suitable for planting on adverse sites than seedling stock. Since con- 

 ditions are relatively unfavorable on many of the planting sites in the 

 intermountain region, it is evident that transplant stock must be 

 used on the majority of such sites. 



Where heavy snows lie long, as at the Cottonwood Nursery, 

 winter mulching proves more of a detriment than a benefit. Mulch- 

 ing was given a thorough trial during the earlv years with hay, straw, 

 and leaves; but the results were very unsatisfactory, because the loss 

 from snow molding in winter and early spring was thereby greatly 

 increased. 



PROTECTION FROM DISEASES AND INJURIES. 



As already noted, the three old nurseries of this region were dis- 

 advantageously located in some respects. Some of the difficulties 

 and injuries that had to be contended with were the direct results of 

 the locations and would not assume very much importance in a better 

 natural site. Other difficulties due to the dry air and intense sun- 

 light are inherent in the climate and will always have to be guarded 

 against. On the other hand, these factors minimize certain dangers 

 that elsewhere are of great importance. For example, all of the 

 coniferous species grown at the nurseries in this region are subject to 

 damping-off, which, however, has never been of sufficient severity 

 to warrant the use of the acid treatment that is being generally used 

 in other regions (6). The nursery practice in this region has indicated 

 that in this semiarid climate damping-off can be minimized by sowing 

 seed of good quality about June 10, when an abundance of sunlight 

 and daily light watering assure prompt and vigorous germination. 

 During the period in which the seedlings are susceptible to this dis- 

 ease, just enough water is applied to keep them from suffering from 

 drought. When excessive rainfall occurs during the critical period 

 it is necessary to remove the shade frames to let in as much sun and 

 air as possible. 



Stem girdle, on the other hand, is a nursery injury which the 

 climatic characteristics tend to accentuate rather than to relieve. 

 Prior to 1918 this disease was one of the chief causes of loss to spruce 

 transplant stock. The side of the trench against which the trees 

 were transplanted was supposed to be perpendicular; but, as a 

 matter of fact, it always had a slight slope, depending on the direction 

 in which the trench was opened. Since all rows run east and west, 

 the slope of the transplanted trees of necessity had to be either to 

 the north or south. During 1916 and 1917 a large number of both 

 Engelmann spruce and Norway spruce (Picea excel&a) were trans- 

 planted, about half leaning to the north and the other half to the 

 south. It was later found that on all beds where the trees leaned 

 to the north the loss was approximately 25 per cent greater than 

 among those leaning to the south. This abnormal loss on trees 

 leaning to the north was found to be due to stem girdle caused by 

 excessive heating of the surrounding surface soil (4) • Trees leaning 

 toward the south shaded the soil surrounding the base by their own 



