AGRICULTURE ROOM -LNCI. 4.
Comparative Growth
of
SUPP}flS ED SECOND-GrSO"TH DOUGLAS FI
Before and \fter
RELEASE B LOGGING
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F 24 (
by
Denver P. McCofflb CONTENTS
Page Objec t - i
Instrumente ------i
Method cf Procedure ------i
Results ------
Eicus1cn nd flecornenct1ons ------4 ppendix
of Area ------
Field Data 7
Pictures ------13
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S s 3000 Orchard St. Corvcilis, Oregon 'pril 30, ic:9
Mr. W F. MeCulloch of Forestry Oregon State Co11ee
Dear Mr. MeCulloch:
I have trie honor to transmit herewith for your pprova1
a report on the Copar1son of Growth of Second-growth Douglas
Fir Before and After Release by Logging with Specific reference
to the Recovery of Sup:ressed Trees.
Pccurate methods were used throughout the project to ob-
tain the desired data, but due to the Inherent characteristics sor Doutls fir to grow in svcn-ged stands, it was extreely difficult to find a desirable area.
Practically all Douglas fir is clear-cut, and whenever
any trees are left, slash fires retard the growth so nuch that
a true record of natural groth is 'lifficult to obtain. A
difference in growth did not occur until about two years after
logging and then the growth would be either negative or pos-
itive depending upon the site factors, fire, climate, mechan-
leal injuries, physiographic .nd biotic factors.
Sincerely yours, s i
Object:
The object of this report is to determine the growth of
second-growth Douglas fir, Pseudot ug. taxifoita, before and
after release by logging «itb specific r-iference to the recov-
ery of suppressed trees
Instruments:
Ti instrurnens used were an increment borer, graduated
scale in l/2O, aad diameter tape.
Method of Procedure:
Before any nesurements had been taken it was thought
that any area hich had been logged would be satisfactory,
but most areas are cler-cut, and at least five or six years
are required for groiing in order that the growth my be ac-
curately measured with a scale calibrated In 2üths of an inch.
fter considerable inquiry from locl woodsmen and na-
tives of the surrounding farm$ and niils near !hilomath, Cre-
gon, an area was found near the highíay in the S1/ of ec.3O,
T.11 S., and R.6 . This property, which belongs to Fish &
Hodge, Real Istate Brokers, Albany, Oregon, was logged in 19Tl,
sixten years ago.
The suppressed trees were determined by their crowns
and trunks. In the main, a suppressed tree has a misshapen,
flattened, short, nd narrow crovm; the trunk is considerably
smaller than dominant or co-domin:nt trees of the same age.
The treos ere measured for diameter at breast height outslie 2 s
the bark. Increment bor1ns were taken on the average radius
at or about two reet froi tne ground In the event thìt this
timber should be used for structural purposes, by making the
borings low ori the stump, the strength and quality of the fin-
ished product will not be degraded. fter removing the core,
by counting back sixteen annual growth rings, and tneasuring
the growtii witn a scale, th nount of' growth since logging
can be determined. By counting back an additional sixteen
years, sixL?en annual growth rings, t1e amount of gro: tu was
deternined for tkie period before logging.
Results:
It is to be expected tnt he degree to which gro th is
accelerated by cutting will depend upon the proportion of the
stand removed, providsd age, site, composition, and other fac-
tors renain coiiparable. It has ben thought that ali ages
seldom fail to rspod; however, ai Uie trees measured, which
were in a 110-ye a r-old, even-zged stand, 16 of thea showed a
decrease in growth after logging; one tree showed equal growth;
93 trees showed an increase in gro th after logging.
0f the 110 trees rnesured, there was 9.l decrease in
dimeter growth as compared to 13.lt increase in diameter
growth during tne period after logging. There w're 199.6?! of
growta before logging as compared to 328.8" of growth after
logging during the same period of time. s ç s rv. Trees ' No. o1n I No. iow1ng i ITo. howing t flBH easurei t Increase In t Decrease In , no U'hauge t o.h. Growth t Growth t In Growth t
T T t I
liC 93 16 1 1 ' I t t I
I t t
Table 1. DistrIbution of Growth
- t --- -- y I Total Dia , Average Dia Total Dia Pverage Dia Percent of Increase Growth , Growth t Growth Growth lo .yrs. yrs. 16 yrs. , In Growth 16 yr. t , ' After After Before t Before t After -Logging , Login , Logging , Logging Logging -î---- t t t
l996" t l.81 t 328.8" t ;LO" t 6O ! t t I
t i t I __t s-. , I t Table :. Comparison in Groth Before nd ifter Logging
(16 yrs. before loggthg)
,
ç . T
X; (16 yrs. after loggIng)
tive Growth Before and M'ter Logging s 4 s Discussion and Rcomwendatipn:
It as flOtEd that the trees, regardless of diameter,
which were the most suppressed pparent1y showed the largest
marease lfl increment provIded that fire 1d not burned the
trees enough to retard their growth. In all cases the trees
that showed a decrease In growth after logging had been more
affected by fire than the surrounding trees.
No ctifference li, growth could be determined unt;i1 at
least two years after logging, at which time increased growth
started gradually or abruptly as the years passed. For this
reason, i is recommended tmLmt a stwiy of this nature, which Oo7 // A,-ç/ vy could be crrid on in Section ¿5 of the,rboretum, be post- 5 poned until the year 1940. The area from which this data was taken probably 'Nul be altered, nd it is very inconvenient
for a student to work if one has only a few hours a day to be
applied.
It is also suggested th:t increment borings should be
nade during a dry day so that they will not bcome saturated.
If the cres get ;et, it is practic1ly impossible to 'stermine
the growth to ithin tiirec or four years, when trie increment
measures not more than 1/64 of an incn per year, as it easily
can in suppressed trees. By holding the core up toward the
sun-light th annual gro ;tti rings c:n be seen distinctly and
measured accurately s n
A P P E N P 1 X
Map of Area
Field Dat
Pictures
* * * s ;;_.
i'ti'.
- - _lI._ i Z&I
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ap of the !rea and Surrounding Country s N
cx p 43
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OD j e
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I-4
o 'j N-O)N r-4 r-4 r-4 '-4 r4 4 H r4 r4 -4 r-4 r4 r-4 r- t-4 i-4 r-4 r-4 *'-4 r-4 r- -4 r-4 r4 r4 i-f r-4 r-4 r-4 r- i-4 r-4 r-4 H r4 r-4 r-4 r-4 ,4
Ç j
c r-
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O O E:' s
Gro th in 1/20" Groth in 1/2O Tree No rBH o.b. 16 yrs. Before 16 yrs. After in. Logging Logging
41 15 1: 4:: 19 1? 19 43 17 15 28 44 16 19 34 45 9 11 10 4$ 16 18 25 47 9 20 12 48 13 15 4 L,; 11 16 50 18 1i 28 51 1$ 11 15 52 14 O 33 53 17 19 30
4 1 I ' _P 3_ r-r i J , 56 14 11 18 5? 21 34 41 c:o Ç) qt ,_Q 59 20 42 33 60 20 25 24 s 73 15 13 52 '71 20 39 ¿2 72 14 24 19 73 16 15 23 74 16 16 12 75 1L. 1.3 1 7d 16 4 12 77 15 18 28 78 18 11 20 79 11 9 16 80 13 20 81 16 18 33 8 17 8 8: 15 r) "5 84 17 10 85 1 16 30 86 15 ia 32 8? 16 16 37 88 15 28 41 89 13 10 22 93 15 17 91 15 24 45 93 16 7 20 93 18 16 32 s 94 16 8 43 o cl
'-s -' ( _a Q0(Qcoo I C) lo
H lt
-,;2 HIHHHHH ?ao1ccNHupc t 1'
1 I o Lr114 : lo (D HH HHH H-CTI-' O) s-'. l:i b
o I
I c Ç p.3 lbt4c 4* G, -'.ø p-I. s
Center of' re e.sured
s
Relative Size of Suppressed Trees Stun
s Burnt Stump and Tree 11 n
Second Growth tnd PrtL1iy Opened r
D
Typical Crowns of Suppressed Trees 1?
s r
Burnd 7estern End of Area !Aasured n r '1
Unburned Es torn End of Area Measured
n