FOREST PLANTING IN THE INTERMOUNTAIN REGION. 



tops, consequently the disease was not present among such trees. 

 This conclusion was later verified by a series of experiments. Since 

 the cause of the trouble first became known, all transplants have 

 been given a slight slope to the south, and only normal losses have 

 occurred, generally not to exceed 8 per cent. 



Other troubles such as snow molding, frost injury, and chlorosis 

 were due primarily to local peculiarities of the nursery site. Snow 

 molding has been a problem in high-altitude nurseries for a long time in 

 both Europe and America. If impossible to dispense with nurseries 

 in such situations, a method developed at the Cottonwood Nursery 

 can be used. Two logs at least 6 inches through are placed on each 

 side of the bed, across which planks are laid so that they hold up the 

 snow(^). 



Chlorosis, or "yellowing" was the most serious problem encoun- 

 tered in the successful production of nursery stock of all the coniferous 

 species raised at the Pocateilo Nursery. With chlorosis were asso- 

 ciated poor growth of roots, stems, and leaves, failure to form normal 



Fig. 1.— Douglas fir transplants (3-2), the tops of which were severely injured by a late spring frost. 



Cottonwood Nursery, Utah. 



terminal buds, and susceptibility to winter injury. Chlorosis was 

 definitely corrected at the Pocateilo Nursery by spraying with ferrous 

 sulphate at 10-day intervals (5) . A 1 per cent solution in amounts 

 sufficient to wet the tops thoroughly proved the most satisfactory 

 treatment, as stronger solutions ultimately caused chemical injury 

 to practically all of the seedlings. The soils on which the conifers 

 were decidedly chlorotic contained considerable amounts of car- 

 bonate, while the water at the Pocateilo Nursery contained much 

 calcium bicarbonate. This leads to the conclusion that the chlorosis 

 was due chiefly to a lack of dissolved iron in the water of certain 

 calcareous soils. Such a condition is probably infrequent but should 

 call for caution in locating nurseries on such soils. 



Frost damage and freezing are factors that have to be dealt with 

 everywhere. These were exceptionally difficult to cope with at the 

 Cottonwood and Beaver Creek nurseries, on account of their high 

 elevation. At lower altitudes the danger is less, but in the case of 

 Douglas fir the losses may be heavy. (Figs. 1 and 2.) Late spring 



