250 
Journal of Agricultural Research 
Vol. XXX, No 3 
per cent, 4 or one-third greater growth 
for the season was attained by the 
spring lot when fall planted; and (4) 
82 per cent, or four-fifths as great 
growth was made by the spring-sown 
lot when spring planted. 
Judging from the experiences of 
1918-19, then, 2-0 western yellow 
The question naturally arises: Why 
are fall-sown seedlings of this species 
less able to withstand the rigors of the 
planting site when fall planted, and 
yet fully the equal of spring-sown 
seedlings when spring planted? This 
leads to a consideration of the dif¬ 
ferences between plants from spring 
DATES OF EXAMINATIONS 
Fig. 2— First-year survival on the planting site. Fall and spring plantings of western yellow pine 2-0 
stock derived from fall and spring sowings (each curve is based on 600 plants) 
Table VI .—Records of the second growing season of 2-0 western yellow pine 
! 
Survival percentages 0 
Growth data 
Season planted 
Season sown 
Thrifty 
Un¬ 
thrifty 
i 
! 
Total 
living 1 
1 
Total 
Average 
stem- 
height 
growth 
in 1919 
Number 
of 
measure¬ 
ments b 
Fall_ 
! 
Spring_ _ 
13.1 
3. 2 
i 
16.3 
83. 7 
Inches 
0. 82 
32 
Fall_ 
Fall___ 
7.7 
3. 7 
11.4 ! 
88. 6 
. 61 
32 
Spring_ 
Spring_ 
18.1 
4. 2 
22.3 ! 
77. 7 
. 50 
94 
Spring_ 
Fall_ 
18.2 
4.5 
22.7 1 
77.3 
.61 
94 
a Figures based on examination of 600 plants in each lot. 
b The largest common number of thrifty individuals used in determining averages. 
pine seedlings from spring sowing 
survive and grow better than those 
from fall sowing when planted in the 
fall. When planted in the spring, 
there is practically no difference in 
survival as a result of season of sowing, 
but during the second field season the 
fall-sown plants lead in growth. 
and fall sowings. Time of sowing 
seems to be only an indirect factor, 
one which is influential only in its 
effect on time of germination, which 
in turn affects plant development and 
hence ability to survive and grow in 
the field. The inferior plants resulting 
from late germination were described 
4 The basis for this figure is too small to insure accurate averages 
