German Seed-Extracting Establishment. 33 



Gayer's "Forest Utilization," 1909, the chapter upon the equip- 

 ment of seed-extracting houses contains some dangerous obser- 

 vations. For example, "to extract seed at 140° F. (60° C)." The 

 chapter has in general remained almost literally the same since 

 1878 and still earlier (4th and 5th editions) ; it proves how little 

 kiln-drying science has progressed since then in the knowledge 

 of foresters. The average Scotch pine seed germination is often 

 given them as only 65 per cent. 



My conclusion is, therefore, that cones should be slowly dried 

 at first in the preliminary drying-room and exposed to continu- 

 ally increasing degrees of heat up to the highest temperature of 

 113° to 122° F. (45° to 50° C), and this process shortened as 

 much as possible by the removal of the resulting moist air. For 

 this purpose the following arrangement of the drying-kiln should 

 serve : 



In the preliminary drying-room the cones are spread out flat 

 upon wood drying-trays about 51 inches (1.3 m) long and 30 

 inches (75 cm) wide. The floors and sides of these consist of 

 wooden slats nailed near each other with a space between ; I 

 recommend soft wood slats between which little cones possibly 

 do not stick so fast as between oak sticks. The drying-trays are 

 about four inches (10 cm) deep, but should be covered only with 

 one copious layer of cones so that when the cones increase in 

 size upon opening, there is still sufficient room. These drying- 

 trays are then shoved into a carrying rack, above one another 

 about 10 to 15 high, so that they stand over one another with 

 two to four inches (5 to 10 cm) space between, and so that the 

 workman can fill the highest tray from the ground. 



The whole rack is mounted on a low truck moving upon rails, 

 and after opening a sliding door is pushed into the drying-kiln 

 in which a current of dry air circulates around every tray. The 

 drying-kiln is a room about five feet (i^ m) wide, 6| feet (2 m) 

 high and 26 to 30 feet (8 to 9 m) long with tight walls which 

 takes 10 such trucks (with tray racks) coupled to one another on 

 the broad side. 



Hot air is let into this drying-kiln through a series of separate 

 openings on both sides. The hot air apertures are arranged on 

 both sides in a series above one another from the bottom, to the 

 top and especially in the vicinity of the exit-door of this drying- 

 kiln, while air holes are located near the entrance-door, through 



8 



