HARVESTING THE ANNUAL SEED CROP 153 



canvas sheets are required to handle a comparatively small amount of 

 cones. The cones must be covered over on rainy days and during cloudy, 

 damp weather. To open up yellow pine cones satisfactorily they must be 

 exposed to the sun in the manner described for about a week. Douglas fir 

 and Engelmann spruce cones, having thinner cone scales, ordinarily dry out 

 and open in less time than those species with thicker cone scales. However, 

 the time required to open up cones in the sun varies greatly, depending upon 

 the weather conditions and the relative dryness of the cones at the time they 

 are spread upon the sheets for final drying. 



The sun-drying method has the great advantage of being inexpensive, 

 since the only equipment required consists of canvas sheets, the cheapest ob- 

 tainable being used for the purpose. Furthermore, the drying sheets are 

 easily transported (on pack-horses if need be) to remote places where the 

 cones have been concentrated, and the extracting process carried out there, 

 a very important consideration in our mountain forests, difficult of access. 

 The great limitation upon this method is, of course, its absolute dependence 

 upon a continuous period of fair weather, with sunny, dry days. 



By the second method of extracting seed, which uses artificial heat, tBe 

 cones are subjected to a temperature ranging from 100 to 120 degrees Fahren- 

 heit for a period sufficient to open them. The cones are spread out thinly on 

 shelves or trays of wire mesh in a closed room, but with suflicient ventilation 

 to insure the escape of tlie moisture given ofl' from the drying cones. As with 

 sun-drying, the time required to dry out the cones is variable. Yellow pine 

 cones under ordinary conditions will open up satisfactorily with a tempera- 

 ture of 100 degrees maintained for thirty-six to forty-eight hours. 



Two types of cone-drying plants may be distinguished, namely, portable 

 and stationary. A convenient form of portable plant consists of an ordinary 

 canvas tent, in which drying trays can be built and a stove set up. A perma- 

 nent drying plant may be constructed in any tight building where trays can 

 be built and a stove or furnace installed. Because of the cost, a stationary 

 plant is only advisable where large quantities of cones are available for 

 drying, or can be easily transported to the plant. The advantages of drying 

 cones by artificial heat are apparent, the process being carried on independent 

 of weather (onditions. 



Whether dried by the sun's heat or artificial heat, the cones, as they grad- 

 ually open, release the seed and a large portion of the seeds from each cone 

 fall out upon the canvas sheets or drying trays whenever the mass of coucs 

 is stirred or handled. However, a certain portion of the seeds stick in the 

 cones even after they have opened and most of the seeds have fallen out. In 

 order to extract these refractory seeds the opened cones must be given a 

 special treatment. The cones are gathered up from the sheets or trays upon 

 which they have dried, and put into a contrivance called a "churn." This 

 churn is merely a large box, about three feet square, mounted upon a frame 

 so that it can be revolved by means of a crank. One side of the churn is cov- 

 ered with wire screen or slats, which permit the passage of seed but retain 

 the cones in the churn. As a man revolves this churn, the cones are rattled 

 about vigorously and the remaining seed shaken out of them. This churning 

 process is commonly spoken of as "threshing" the cones. 



CLEANING THE SEED 



From the drying-sheets or trays the seed collector gathers up the seed 

 extracted and adds to the mass the seed he has shaken out from the churn. 

 The material which he has thus obtained is not exclusively clean tree seed by 

 any means. The individual seeds still have attached to them the little mem- 

 branaceous wings, and intermingled through the mass are broken seed wings. 



