Eepr-inted from JOull.NA:t.
OF
FORESTRY, "\7oL. 55, No. 3, March 1957 Purchased by the Forest Service for Official Use William G. Morris, R.. R.. Silen
and H. lrgens-Moller1
Consistency of Bud Bursting in Douglas-Fir
their progeny can be planted to ad­
POSSIBILITY OF STRONG genetic con­
trol over time of bud bursting in
vantage in areas where late spring
Douglas-fir has been suggested by
recorded observations extending
over a period of 22 years. If more
tions in the early 1930's showed
that tardiness in beginning annual
detailed studies now under way
bear out these observations, the
knowledge will have important ap­
plication in selecting seed for
planting forest lands in the Doug­
las-fir region of the Pacific North­
frosts are likely to occur. Observa­
growth apparently does not lessen
a tree's chance of making the same
height growth as one having an
early start.
Study Areas and Early Observations In 1915, plantations were estab­
lished at Wind River, Washington,
at an elevation of 1,100 feet, and
near Mt. Hood, Oregon, at eleva­
tions of 2,800 and 4,600 feet (Fig.
1). Seed for these plantations came
from 120 parent trees at 13 differ-
west.
Records taken since 1933 on
three plantations in Oregon and
;
Washington indicate that relative
order of vegetative bud bursting
is constant between progenies from
widely
separated seed
sources
growing in the same plantation.
This relationship apparently holds
true regardless of altitude of plan­
tation, date when growing season
•
began, or stand age. Repeated ob­
servations of individual wild trees
have further shown that naturally
seeded trees growing side by side
burst their buds at different dates
but in about the same order year
after year.
Growth of a Douglas-fir tree both
in height and in branch elongation
is resumed each spring from the
dormant buds formed the previous
growing season. If freezing tem­
peratures occur when the buds are
in the tender, freshly opened stage,
they are usually damaged and no
growth occurs that year. Late bud
bursting protects a tree against
"
'
this damage.
Time of bud bursting in relation
to spring frosts is therefore impor­
tant to tree growth. If late-bud­
bursting trees transmit this charac­
teristic to succeediilg gener tions,
1Morris and Silen are research forest­
ers, Pacific Northwest Forest and Range
Expt. Sta., Forest Service, U. S. Dept.
Agrie., Portland, Ore. Irgens-Moller is
a graduate student, Oregon State College,
Corvallis, Ore.
"'
'"
121•
.,
nr
LEGEND
Principal range of Pacific coast form of Douglas fir in Oregon and Washington 0
Plantations x
Seed sources FIG. 1.-Locations and elevations 'bf seed sources and test plantations on which
Douglas-:fir bud bursting was observed.
208
MA.Bea 1957
209
ent localities west of the Cascade
Range, from Darrington in north­
drainage resulted in warm spring
days and cold sprnig nights. (5)
ern Washington to Benton near
Corvallis, Oregon, 250 miles south.
Seed source elevations ranged from
100 to 3,850 feet. Plantation lay­
out was identical in that progenies
from each parent tree were planted
in the same relative position at the
Time of bud bursting (early or
late) had no apparent relation to
three locations.
This was <lone to
eliminate personal bias in the selec­
tion of planting site.
These plantations, with an eleva­
tional range of 3,500 feet, have fur­
•
nished unusual material for com­
parison. From observations in 1933
and 1934, Munger and Morris2
found that: (1) Bud bursting on
the two ·Mt. Hood plantations aver­
age 2 to 4 weeks later than at Wind
River. (2) In some years, buds
burst as much as a month earlier
than in others. (3) Ranking of the
13 seed sources according to date
of bursting was nearly the same for
having warm spring days and
nights, such as occur in wide val­
leys.
Those
with
intermediate
bursting buds came from higher
ing buds came from localities in
narrow valleys where cold air
"Munger, Thornton T., and William G.
Morris. Growth 0£ Douglas·fir trees of
known seed source. U. S. Dept. Agric.
Tech. Bul. 537, 40 pp., illus. 1936.
Seed Source Ranking
Progenies from the 13 seed
sources have been rated at various
times since 1933 for stage of bud
bursting. These ratings are believed
valid for purposes of comparison
even though they have differed
somewhat in technique and inten­
sity of sampling, and though it has
not always been possible to make
observations at the same stage of
growth.
In 1933, 1934, and 1936, 10 to
15 offspring from each of 4 to 21
parents were classified in one of the
following groups: (1) All buds
tight. (2) Buds ·bursting on most
but not all branches; new needles
on greater part of tree not spread
out in normal brush-like arrange­
ment. (3) New needles spread out
the early- as for the late-bursting
years.
(4) Trees with earliest
bursting buds came from localities
elevations, with cold spring days
and nights. Trees with latest burst­
annual height growth.
again used at Wind River for sam­
ples of three to six trees from each
seed source. Due to the lateness of
sampling on the lower Mt. Hood
plantation, however, terminal shoot
elongation in inches was estimated
for ten branches in the upper
crown. Ten trees from each seed
source were used as a sample. On
the upper Mt. Hood plantation rel­
ative .bud development was deter­
mined through the same scheme of
sampling as on the lower planta­
tion. Buds were classified as (1)
tight, (2) slightly swelling,
swelling but not burst, or
(3)
(4)
burst. The same system of weight­
ing was applied to data from the
1955 observations as those in the
1930's, except on the lower lift,
Hood plantation, where ''inches of
average shoot elongation'' were
compared to obtain ranking.
Bud Bursting Consistency
Despite the influence of normal
sampling error and differences in
on entire tree; new shoots noticea­
bly elongated. In order to rank the
seed sources as to earliness of bud
bursting, the percent of progenies
falling within each classification
were assigned weights of 1, 2, and
rating methodology, the rankings
are remarkably consistent (Table
1). The early-bursting group­
3, respectively. The three weighted
percentages were then added for
Hazel, Forston, and Benton-are
always found near the bottom.
each group of seed-source prog­
enies, and the sources listed by
ranking.
Records by Morris for several
trees in the Portland area further
support the view that earliness of
In 1955, these classifications were
bud bursting of individual trees
Carson, Portland, and Lakeview­
rank in the upper part of all the
lists. The late-bursting group­
TABLE !.-THIRTEEN SEED SOURCES OF DOUGLAS-FIR RANKED ACCORDING TO S TAGE OF BUD BURSTING OF PROGENIES ON GIVEN
DATES IN THREE PLANTATIONS
(June
Rank'
1
2
3
4
5
6
7
8
9
10
11
12
13
1933
30)
(June
9)
Lower2
Mt.Hood
(2,800 feet)
Wind River
(1,100 feet)
Portland
Carson
Lakeview
Gates
Santiam
Race Track
Palmer
Wind River
Granite Falls
Benton
Darrington
Fortson
Hazel
(June
29)
Upper8
Mt.Hood
(4,600 feet)
(Portland
and Carson
burst
earliest.)
_
(Granite Falls,
Darrington,
Benton, Fortson
andHazel burst
latest.)
1934
1936
(May 21)
(May 3)
Wind River
(1,100 feet)
Wind River
(1,100 feet)
Carson
Portland
Lakeview
Gates
Santiam
Race Track
Palmer
Wind River
Granite Falls
-Darrington
Benton
Fortson
Hazel
Portland
Carson
Lakeview
Gates
Santiam
Race Track
Palmer
Wind River
Granite Falls
Benton
Darrington
Fortson
Hazel
(June
23)
1955
(July
7)
(July 7)
Wind River
(1,100 feet)
Lower'
Mt.Hood
(2,800 feet)
Upper
Mt.Hood
(4,600 feet)
Carson
Portland
Granite Falls
Lakeview
Race Track
Gates
Palmer
Darrington
Santiam
Wind River
Benton
Hazel
Fortson
Carson
Portland
Race Track
Wind River
Gates
Santiam
Lakeview
Pahfier
Darrington
Hazel
Granite Falls
Benton
Fortson
Lakeview
Portland
Carson
Palmer
Santiam
Darrington
Race Track
Gates
Wind River
Granite Falls
Hazel
Benton
Fortson
11 is most advanced; 13, least.
s:Examined when bursting was too far advanced to permit ranking other than by two broad groups.
8E:xamined when bursting was not sufficiently advanced to permit ranking other than by two broad gr-oups.
'Exa.mined when bursting was too far advanced to accurately recognize differences between the earlier bursting seed sources.
210
remains co11Sistent through the
years. For 14 years, two trees less
than 200 feet apart have, on the
average, burst tl;teir buds 7.8 days
apart. This is statistically signif­
icant at the 1 percent level, with
standard error of ± 1.07. Tree 1
invariably burst its buds before
Tree 2 (Table 2). The narrow
range in interval between bud
bursting dates, regardless of ex­
tremes in climatic variation during
this time, is remarkable. Pheno­
logical records irom nine other
trees, observed over periods of from
JOURNAL OF FORESTRY
TABLE 2.-SELECTED BuD-BURSTING DATES OP' Two DOUGLAS-FI& TREES OBSERVED
NEAR PORTLAND, OREGON/ DURING
Item
Greatest interval
Least interval
Earliest season
Latest season
Year
1952
1943
1947
1955
THE
PERIOD.
1942-55
Bud-bursting date
Tree
Tree 1
April
May
April
May
29
4
14
18
May
May
April
May
2
11
6
24
27
Iriterval
(days)
12
2
10
9
lg50 feet elevation.
3 to 15 years, show the same con­
sistency.
All the above-cited observatio11S
suggest a strong genetic control
over time of bud bursting in Doug­
las-fir. Proof must of course come
from more detailed studies. How­
ever, the observations do strength­
en the longheld view that Douglas­
fir planting stock should be matched
closely in growth period to the area
to be planted.