No ..
1'0 SUGAR PINE REGENERATioNlf
w·ere o
there were 19
observed over a
cones were
years,
means of a 20
p.
- The brush was removed
Division of Plant Disease
toothed blade
brush the
eradicate concentrated Ribes@
In bear-clover, howout of e. fe·w clumps often cleared
was necessary to cover the 1:1ree. in
it at
each other.
the brush was removed 9 the tractor was
backed across with the blade lowered to level the soil. The tractor
driver was assisted
a helper who
hidde~ ~+,,=~'~,
from the teeth of the
to
the brush
teeth
have decreased the time
of
37
, 3 feet square, 4
divided into
sampling seed supply, 16 for natural reproThe
and 16 for
for shifting any
:rooks o:r
.~~~~~~~~~~Y·· Four seed
n each plot
the
in ••
On
November 12. 1941,
in each of the 16
the soil.
The seed was a
in
the Feather River
November 1941, there \'\re:re on an average, 1..4 good
s per trap in the bear·elove:r plots and 2,.6 good
brl,l.sh plots.. On the ba.sis of this samp1et it
about 70 percent of the natural reproduction quadrats
one or more good sugar pine
•
Natura~ seedlings,.the spri~g and summer of 1~42, only 11
natural seedhngs germ1nated in 14 of the 692 natural reproduction
ra.ts of the 31 plots.. Only 5
were !\live at the end of the
first season. ~1atu.ral re:eroduotion thus was .practi,eally a failure.
In
first season one or more
in 92
seed
of
spots,
germinated. On the bash of
seeds planted,
germination was 68 percent,.
the average
of the
of the
59
21
15
e.nd height
the planted trees are
Survival
1943
Former
Inches
Bear-clover
58
38
34
High brush
47
45
41
5,..1
6.,6
Discussion
It is obvious that, in spite o~ a heavy seed crop, natural repro.
duotion was practically a ~allure. The ~ailure was probably the result
of rodent depredations. Clearing o~ the s~.11 areas very likely provided
a very good opportunity ~or rodents to find the large sugar pine seeds,.
Site preparation to take full advantage of seed crops should be accom~
panied by thorough rodent control.,
In the area cleared of high brush, seed spotting ~~s more e~~ec­
tive than planting" In the bear-clover area., however, planting was more
effective. This might be explained by the fact that the bear-clover
sprouted back so quickly that by the second season it had overtopped the
!!Jeedli.ngs. The planted stock, being several inches taller, vYas not so
completely dominated.
After 3 years very little o~ the high brush species has sprouted
back or has grown from seed in the cleared areas. It appears quite
probable that the sugar pine from the seeding and planting 'IJ'.rill become
established in these be~ore the brush can regain control.
The brush cover of bear-clover or high brush was removed. mechanically from 37 unstocked areas in cut-over stands in anticipation of a
got').d sugar pine seed crop. In the cleared areas, plots were established
to determine whether natural seedlings would result and. to compare the
effectiveness of natural reproduction, seed spotting under screens, and
planting.,
In spite of a good seed fall. natural reproduction was a failure;
probably because of rodent depredations~
After 3 years. seed spotting was less ef~ective than planting in
areas cleared in bear-clover but was more effective than planting in
areas cleared in high brush.. A fair pero.entage of the sugar pine from
seed and planting survived and grew well through the third season,
indicating possibilities of successful establishment before brush regain:s
control.,