FOREST TREE SEED AND SEED COLLECTING 151 



Photograph by U. S. Forest Service 



FIG. 27. Storage building for pine and spruce cones. Medicine 

 Bow National Forest. 



14. DRYING CONES BY ARTIFICIAL HEAT 



The essential requirements in drying cones by artificial heat 

 are that they be quickly opened and that the seed does not 

 depreciate in germinative energy or germinative capacity. These 

 are best attained : 



a. By having the cones properly cured before drying. 

 ' b. By subjecting them to a uniform temperature and only 

 sufficiently long to effect their opening. 



c. By keeping the air as dry as possible in the heated chamber. 



15. Curing the Cones Before Kiln Drying. When first col- 

 lected, cones usually contain large quantities of water. If placed 

 in the kiln they are likely to dry on the surface and become stiff 

 and hard while the center remains green. When this condition 

 occurs no amount of later drying will cause them to open satisfac- 

 torily. This is particularly true of the large succulent cones of 

 white pine and similar species. In small establishments the cones 

 are cured or prepared for kiln-drying by spreading them out a few 

 layers in depth on. wire-bottomed or lath trays arranged tier above 

 tier in the curing room. As the cones are received, they are 

 transferred from the sacks to the trays. By means of large win- 



