EXTRACTING AND CLEANING FOREST TREE SEED. 9 
the sheet successively and throwing the cones toward the center. 
One corner of the canvas is then thrown over, nearly covering the 
cones; next, the corners to the left and right of the first are folded 
over; and finally the remaining corner, opposite the first, is drawn 
over all and tucked under the farther edge of the pile. The four 
thicknesses of canvas help to retain the heat absorbed by the cones 
during the day and furnish good protection from rain. As an addi- 
tional precaution the canvas folds may be weighted with rocks and 
an extra sheet thrown over the pile. A sheet more than 14 feet 
square is not easily handled by one man. 
When cones are dried on platforms or in trays protection must be 
afforded by covering with sheets of canvas, which should be large 
enough to overhang the racks and protect the seed in the lower tray. 
With cones spread directly upon the ground, the use of cover sheets 
requires less time and labor in respreading the cones, but makes many 
more sheets necessary. 
Covering cones at night protects them from nocturnal rodents, as 
well as from dampness. It is usually necessary, however, where 
rodents are abundant, to protect the drying areas by poisoned grain. 
Birds may often be frightened off by cloth streamers on small stakes, 
or wires, around the sheets. When racks are used for drying, squir- 
rels may be kept out by tacking sheets of tin sloping downward on 
each leg of the frame. Care must also be exercised to prevent seeds 
which have fallen from dried cones from being blown away by high 
winds. This is best done by catching the seeds in a canvas-bottomed 
tray with 4-inch sides. 
Space required—The space required for spreading cones varies so 
much with different species, and even with the same species in dif- 
ferent localities, that it is hard to give specific definite figures. The 
following table indicates the average number of square feet of drying 
surface per bushel for each of the four species most commonly col- 
lected, as well as the capacity of a 12 by 14 foot canvas sheet. This 
applies to green cones spread thinly. As they dry their volume will 
expand at least 50 per cent, bringing the cones into closer contact and 
making more frequent raking necessary. 
Bushels per 
: Square feet ie 
Species. © 12 by 14 feet 
Sih | per bushel. ane eek 
ie 
cniense geditver guticd oo oes ee is 5 ree Ta) re hese iee. LK | 12to16| 14.0 to 10.5 
LS OE Fae SS ee ee ee ee es Sore 2 Oe SS oe | 16 to 20 10.5 to 8.4 
LAP E ES TESS OnE 6 oh tee otic eee ovat ee gg ot oe nC a Oe ce a Se ies 22 to 28 7.6 to 6.0 
9.3to 7.6 
Lodgepole pine (seldom dried out cf doors).................-.-.-.2.-------.- 18 to 22 | 
For yellow pine and Douglas fir, the two chief species handled. 16 
square feet per bushel will usually be needed, making it possible to 
spread 10.5 bushels on each 12 by 14 foot drying sheet. To allow 
58241 °—Cir. 208—12—__2 
