FOREST TREE SEED AND SEED COLLECTING 163 



In this type of plant, the drying is not uniform because of 

 the unequal temperature within the kiln. Long experience has 

 thoroughly demonstrated that a uniform temperature is impossible 

 when the cones are distributed in trays placed one above the 

 other. As a result, the cones on some of the trays and around 

 the margins dry much more rapidly than others. When they are 

 removed, it is almost always necessary to sort out the unopened 

 cones by hand labor and return them to the kiln. At the Wyeth 

 plant an effort is made to maintain a temperature of 120 F. in 

 the hot end of the kiln and from 90 to 100 F. in the other. Kum- 

 mel states that this temperature should not be exceeded. 



The operation of this plant has shown the great importance of 

 ample storage and curing space. Thoroughly ripened cones and 

 those adequately cured will open in the kiln in from 2 to 4 hours. 

 On the other hand, cones heated in transit or received in wet 

 condition, often required 10 hours or even longer in the kiln. 

 Those received in sacks in wet condition and permitted to remain 

 in the sacks for some weeks could not be opened later either by high 

 temperature or prolonged heating. 



30. THE NEWER TYPE OF PLANT FOR SEED EXTRACTION 



The Foxpark plant erected in District 2 for the extraction of 

 lodgepole pine seed is an example of the newer type. The drying 

 cylinder in this plant is 30 feet long and 4 feet in diameter with 

 partial divisions extending from the perimeter toward the axis 

 which keep the cones from collecting in a mass at the bottom as 

 the cylinder revolves. The cones enter at the upper end of the 

 cylinder which is slightly raised above the other and gradually 

 dry in their progress toward the exit at the lower end. It is 

 impossible to separate the open cones from those which have not 

 yielded their seed and the entire process is held back by the more 

 resistant ones. Although manual labor is reduced to a minimum 

 and the necessary heat is produced by the burning of the opened 



