FOREST TREE SEED AND SEED COLLECTING 155 



19. Drying Cones in Improvised Rooms. Cones are often 

 collected with the expectation of opening them by solar heat. 

 Adverse weather conditions sometimes delay the work until winter 

 and it becomes necessary to resort to artificial heat. A room 

 or cabin is temporarily equipped' with a stove, and a number 

 of adjustable and portable trays, arranged one above another at 

 intervals of from 9 to 12 inches, are covered with cones. The 

 bottoms of the trays should be of wire with the mesh sufficiently 

 close to prevent the winged seed from dropping through. At best 

 this is a rough and ready method, and great care must be taken 

 that the heat and ventilation are under control. Several reliable 

 thermometers should be hung in various parts of the room and 

 read hourly. The presence of a window opposite the door will 

 facilitate ventilation. Ventilators at the four upper corners of 

 the room should be provided, if possible, to facilitate the distribu- 

 tion and regulation of the heat. This simple method of seed ex- 

 traction is often used in the United States. Pettis in a single 

 season removed the seed from 4000 bushels of white pine cones 

 by this method at a cost of approximately 25 cents per bushel. 

 The temperature should not be raised above 130 F. even with 

 the most resistant species. For less resistant species such as the 

 western yellow pine and white pine a temperature of 120 F. 

 should be considered the maximum. 



20. Drying Cones in Small Kilns. The drying chamber of 

 most small kilns is constructed of masonry or other non-con- 

 ducting material into which the heat is introduced through hot 

 air pipes. The wire-bottomed trays holding the cones are placed 

 in the drying chamber one above the other through doors in the 

 side of the chamber. The seed that drops from the cones during 

 the progress of drying rattles down from tray to tray and collects 

 in the bottom of the chamber, from where it is removed from time 

 to time. Careful watch of the progress of drying is kept, and the 

 trays are removed as soon as the cones open. When sufficiently 

 dry they lose their flexible character and become stiff and brittle. 

 The temperature and humidity can be controlled at will by shut- 

 ting or opening the valves which regulate the entrance of heat 

 and by opening or closing the ventilators. 



21. Utilizing Kilns Constructed for Other Purposes. Where 

 large kilns constructed for the curing of hops or kilns used for 

 drying timber are available they can often be advantageously 



