38 
BULLETIN 475, U. S. DEPARTMENT OF AGEICULTUKE. 
New Mexico, northern California, Washington, Oregon, and Utah. 
In southern California only, on account of the long, dry season so 
closely following the spring planting season, planting in the fall 
after the beginning of the rains is considered best. 
SOWING. 
The time of - year when seeding should be done varies with the 
climate and, to a less degree, with the species. The important thing 
is to vary the time of sowing with climatic conditions, so that the 
seedlings will get the greatest possible supply of moisture. In gen- 
eral, tree seed should be sown immediate^ preceding or at the begin- 
ning of the characteristic period' of precipitation in the region. 
Exception to this rule may be necessar}^ on account of peculiarities 
of certain tree species or local abundance of rodents. 
FALL SOWING. 
Fall sowing is advantageous for species whose seed normally 
germinate slowly, such as white pine, the true firs, Douglas fir from 
the Pacific coast, western yellow-pine seed from Idaho or California, 
and seed which deteriorate rapidly, such as incense cedar. In regions 
where part of the precipitation comes in the form of snow and where 
after its disappearance in the spring a hot, dry period of several 
weeks or more follows, fall sowing is advisable. Fall-sown seed 
germinate earlier in the spring than others, and the plants have a 
better chance to establish themselves before the drought becomes 
severe. Danger of destruction of seed by rodents is not so great, 
because there is usually an abundance of natural foods during this 
season, but subsequent depredations by rodents during the winter 
may be very severe. In general, fall solving is preferable on areas 
which will be snow covered all winter. 
WINTER SOWING. 
Sowing on the snow in late winter and early spring has the same 
effect of inducing early germination as fall sowing. Its chief 
disadvantage is that broadcasting is the only feasible method. Fur- 
ther, seed when first sown on snow are conspicuous and likely to be 
eaten by birds, though after a day or two of sunshine they disappear. 
They also sometimes slide along the surface of the snow, and, con- 
sequentl}^, can not be distributed evenly. 
SPRING SOWING. 
Spring sowing has the advantage of not exposing seed to premature 
fall germination, to unfavorable winter weather conditions, or to de- 
struction by birds and rodents for a period longer than is necessary. 
