REFORESTATION ON THE NATIONAL FORESTS. 7 



corners and either tied in bundles or one side thrown over the cones. 

 When this is done, the cones retain to some extent the heat absorbed 

 during the hours of sunlight, they are not wet by night dews, and they 

 are somewhat protected against nocturnal rodents. 



On the Bitterroot National Forest, western yellow-pine cones have 

 been very successfully dried and opened in bins of the type shown 

 in Plate II, fig. 2. These are 16 feet wide by 14 feet deep and are 

 covered, in sections of three, by a single tin roof. There are 8 

 floors spaced 18 inches apart in each bin. The bottom floor is 

 built to retain any seed which may fall from the cones, and is of 

 solid matched boards. The other floors are of loose 6-inch boards, 

 which can be removed successively from the lowest to the highest. 

 This allows all the cones to fall to the bottom floor, from which 

 they are easily removed during the course of the extracting opera- 

 tions. The side walls consist of successive pairs of 6-inch boards, 

 each pair being separated from the next by a 6-inch open space. 

 The lower edge of each pair is flush with one set of floor boards. 

 The bins are, accordingly, a series of boxes inclosed on the sides for 

 only two-thirds of their height. Each bin is divided into four com- 

 partments 4 feet wide and 14 feet deep, and the total capacity of the 

 four compartments is 640 bushels of unopened Idaho western yellow- 

 pine cones. The bin is designed to secure as much free circulation 

 of air over and around the cones as possible and to protect them 

 from rain or snow. Canvas sheets are used to protect the walls 

 during driving storms. Western yellow-pine cones open well in the 

 bins without artificial heat in from four to six weeks, the time re- 

 quired depending upon the weather. 



Drying with Artificial Heat. 



The cones of lodgepole pine must always be opened by means 

 of artificial heat. It is necessary to open those of other species by 

 this method only when weather conditions are unfavorable for 

 drying by natural heat. Artificial drying is a quicker method than 

 the other and is not dependent on the weather; but it is more diffi- 

 cult and more expensive, and ordinarily does not yield as good seed. 



DRYING PLANTS. 



Permanent type. — Some of the artificial drying is done at large, 

 fully equipped, permanent plants, to which conss are shipped from 

 a large area (PL III, fig. 1). At these plants the cones are put on 

 cars, which are run into kilns resembling in construction those in 

 use at hardwood distillation plants (PL III, fig. 2). Here seed 

 extraction is reduced to a science and is done at a low cost, provided 



