FOREST TREE SEED AND SEED COLLECTING 149 



spruce, Douglas fir, white fir, and many other species may be 

 adequately dried by solar heat. 



13. DRYING CONES BY SOLAR HEAT 



In drying cones by solar heat they are sometimes placed in thin 

 layers on wire screens arranged one above the other and freely 

 exposed to the sun. A canvas is spread beneath to catch the seed 

 as it falls. The screens should be of suitable size to be easily 

 moved under shelter at night or during inclement weather. When 

 collecting seed in large quantities it is usually more economical to 



Photograph by U. S. Forest Service 



FIG. 26. Drying yellow pine cones by solar heat near Golden, Colorado. 



spread the cones evenly on large pieces of canvas (Fig. 26), or 

 upon a carefully smoothed level bit of ground that is hard and 

 compact, where they are exposed to the direct rays of the sun. If 

 facilities afford, it is advantageous to cover them at night and 

 during wet weather. The thicker the layer of cones on the canvas 

 or on the ground, the longer and more irregular the drying. They 

 should be spread thin so that the sun can strike each cone. If 



