16 EXTRACTING AND CLEANING FOREST TREE SEED. 



or frame with a wire-screen bottom, in which the cones are shaken 

 or worked over. The framework is usually of G-inch boards, varying 

 from 3 by 6 feet to 5 by 7 feet in size. One-half inch mesh woven 

 wire is used for the bottom. The tray may be stationary, supported 

 on legs; or equipped with handles at both ends, so that it can be 

 shaken by two men; or equipped with handles at one end and sus- 

 pended by ropes from a tree at the other, so that it can be shaken by 

 one man. Either of the last two devices is more satisfactory than the 

 first, since much more thorough shaking of the cones is possible. 

 A canvas sheet should be spread beneath the shaker to catch the seeds 

 as they fall through the screen bottom. A similar shaker, but of 

 different size and shape, consists of a box 30 by 18 by 18 inches, with- 

 out a top and with wire screen bottom. This, too, is hung from the 

 limb of a tree and is shaken in the same way. It contains about a 

 bushel of cones and has a capacity of 50 bushels a day. Wooden, 

 blocks are often put in tray shakers to increase the jarring effect. 



BOX SHAKERS. 



All of these devices, while crude, can be used to advantage when 

 other methods are not practicable. Better results can be obtained by 

 the use of revolving cone shakers. These may be either box-like or 

 cylindrical in shape and are often known as " churns " or " drums." 

 The box shaker has been more generally used. It may be con- 

 structed readily from a dry-goods box of proper size. It should be 

 large enough to hold from 2 to 4 bushels of cones when half full. 

 Four feet long by three feet square in cross section is a common size, 

 although both larger and smaller boxes are used with good results. 

 One or more sides of the box should be composed entirely of wire 

 screen. A frame is needed for support, and the extracted seeds fall 

 through to a canvas placed beneath. With most species a |-inch 

 mesh is most satisfactory for the screen. With lodgepole pine a 

 ^-inch mesh lets the seed through as readily and keeps out more 

 rubbish. 



Half of one side of the box should be made into a hinged door 

 through which the cones can be placed in or dumped out of the 

 shaker. Lengthwise through the center of the box should be run an 

 axis of 2 by 4 inch or 3 by 3 inch lumber, or 2-inch iron pipe : pro- 

 jecting through the box and supported at both ends like a windlass. 

 By attaching a crank to this axle the whole box can be revolved. 

 The efficiency of the shaker may be increased by placing small cleats 

 inside the box or by adding small wooden blocks to the cones to 

 increase the jarring effect. The additional devices are unnecessary 

 and undesirable, however, with species such as western yellow pine, 

 which give up their seeds readily, since it breaks up the cone scales 

 and makes cleaning of the seed more difficult. 



