Healing time for pruned Douglas-fir

    Front Cover
        Front Cover 1
        Front Cover 2
    Introduction
        Page 1
    Sources of materials examined
        Page 2
    Results
        Page 3
        Page 4
        Page 5
    Tables and figures
        Page 6
        Page 7
        Page 8
        Page 9
        Page 10
        Page 11
        Page 12
        Page 13
        Page 14
        Page 15
        Page 16
        Page 17
        Page 18

No. i1907
UNITED STATES DEPARTMENT OF AGRICULTURE
FOREST SERVICE
FOREST PRODUCTS LABORATORY
Madison 5, Wisconsin
In Cooperation with the University of Wisconsin

HEALING TIME IR PIUNIFO
DOUOLA-I-II
September 1951




Digitized by the Internet Archive
in 2013
http://archive.org/details/heaprOOfore




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obtEL-nedI i,, 'u T1 .r -t'. r w~4 +'I n~ 'i .-,V r
tree,, r wri Ol h~Cymt- anX~ o.t2 td Yl o v n, ;*.BUl
and 1 ia rL i f~q no an t m, rr- i' iau rcn~ -; n; n22 r2u
c.vi dr. n:. wa,3 und in In r :cu L,, thau. rl2* 2. ui22k wc.)( ,
to inf et-on Iy dk, ,ay finaril
Th(. treesL. had n nruncd. Or a-, .o'r .v' ul*-2 3
and wore0 1,2 :-u 0,o ,,- t--- d 2' 2 2.C1 '2.C.6ilc ~ t;r-
~ro2 :11A~ 'Ain--, of :ar I done7 In o n wJ...oc d. C~h
w cst r,, an Iq nrnn atd Lir ix~l2 i- d cy i+cr,2' clc,, '-r C2
i~n~r.h 'l~on of F ct lai.1 y La.a~u of; ianvt i1.: s ant
r 0.2.:.The work aL: v,-)r.n .1 a(; t 7"'I c t- L~.1
for w2,~a ;.th reward to 22.2. Jo X rx 2 ')1 20, t was
722 ~n 2 ~s;as d,,.tcrm ncd 'L o a'LL2 unnal~a a' o 2 .I 2 -
1.t N adic on it m.+ri o %,-t theK lUnavrl- ti

2 Ha;.nI. Knots J.n S, > r22 wth I .12 '] r2.

IA t. H '.1 7

2's Lub~




:ource s of IMater-ial Examined

Ku-el 'rc1:
In th-- fall :Df 195" a stand- Jmprrovement project of thinninC and 1 -LninG 33-
yar ~ ~ ~ ~ ol ,lsfr ;oige ado s Jthe qualJ7ty III wac LjcCun in the
KugEcl arc : ara on the-: Olym 4c iTational Forest near the I niC _er Eancer Station.
This sta-, was of natural se,.-nd-,rrc.h believed Lo have dcvclo!_ ed after a
fiLre a~~iaey50 years ago. Permanent sa~eplot's were established by
th.re Pacific _ior.hwec"! S-tatlon in thet. iinned stands whi c-11, though predominantly
eve-as0,contained tr-ees from 30 -to 50 -cars old. Com ,tition had develo-Ded
c he til-,, el, thinnin,, and ha" resulted in s-me decrease in diameter growth.
ilie ~ w ext 2-ded. only abc ,at one-third .f -."he distance do-, "he stems.
Thr rrthe dead limbs e_-tended virt,_-a_117 to the CrouLnd. T'_e pru~ninE
o ,cratic7,. r'~~ only dead branches and did._; not- e_::tend inothe live crown.
TLrlzn r -'o hg of reach wras done with an ax, and abov .D thl s, to 20 feet
from -712 Croundl, wit- a saw.
Frori ec1d 1_ of thesee pruned trees, one Lolt to i.n-Lude one wbrf. branches
was talkcn at an- average of 5 _fet a ove -ro und --t reprcsen ax isng From
each of cof -th, same trees, a olt-s was taken a--' an average he-ight of 12 foet
to r -r ,n aw p)r-u-nngz.
_W Lr d R- v cr
In thc 1,!nt Lr of 1 440- a t io zt- d of 18-foct prun~nC. ,n srmal i~cle Douglas-
fl r on tho la.ind Ti i %-r District- oi' fth. Glfiord -nh~ t.< --l 1,'crest was under-
tu.ken the Z~ Iac-_ fic 17, rthlwcst ~ai~.Theo -1ru-nn work wao done by CCCI labor.
T 141s 1. water stand was puare Doug1P.s-flr about Jyears old which had -,.)Gen es-tab-
1 h( ~na-tural reseedin- soon after a burnLa. '1itc-qualit1-1 measurements
J- thc, v*_ nit%, indicated a ,oor site HII.
T_--es d, si mnatod as crou trees for jannin avcra :(,d about 15 fo_ to the li '
C-'ri ;w h n -rumcd. r le cro- ns of scomc o' h lcss ca. Jiocd dclninuant. b, -
r-ar. a~t-ouj. 1( f, t abt_ ve, yrod ib nural libshcddi-ng 1-ad occ'urrod. Limb
d~fsi -c ration was n,,tcd ft3 b, n [Lgji1-)e exsc-,-t on the loicr 41 fecot of the Loic,
wh Gr 4--.;s 4 .dn- 'ac nearlyieun'Pt wh Ilc tho brancl( -i._ wcrc in poroccss of
a rluin~r -)f the lewer 1imbo -Wcs (Ion(. h a Acoo club, while for
h -f ols 01 saw-- w -r,:? usck k. The Hebo -)run-ng clu .' Is ussentially a heavy
,,r -d i~o~eshod (-, thc- end a ri c c o-f 1/14-inchl th -ck sLee 1. The limobs
ar(- r.A1 ly onu or more blow- a. or ne--ar t-11ei r 1)a se.
om 1 o the tree- cn W ind v-Cr ar-a a 'Loll to i-clude onu whorl
( ~~a:a an avc ra 7c of' 4 fc- 'I L',ovC -roun,)d wa,- t -kc:, t 'D rc-r,-sent pr-uning
-I '-I T' 'ui. Frorm a h -) t- h+ r c-.-, a _olt w,-s --akcn at an average
12I'A Ct f, v--ound -to rc!- rc-c-t saw lvin
Je 2 o7
1' ohn; H( -:re. 1)o ?run*,_, Cila-. Journal i or stry- 'vol 3~ b.
JUJy




Thc bolts wc~(, iand1 f7 -1 r-, i 'd 1--: ~ 2. '~ ii:2 .' 2 t
ncr17 vcrt 7cal, ratdji -ir~2 4 r~ k. I; I-L CI %S~ r'
knot r'i tt w i qu i-, d ~. ;. ~ '~'' 7227 W. *;7~
~-. ~4 7~2~ :rt, l' U, -rt"~ni ~cLi. c*,,q atr,'7.ar.'n
ui t:- I. 7,2 1VI. 7 '~1U 'd nut :r>;a Df c) nt rcw*
.'r .:r, nd. U iU i 2.2.I .2' ~2 T C ilL ro 7s -(cio- sho wVd r,7
;2t c 7 n n '' th. i 1 2 2> 2 j 20'7 C 0. 1

S r +, '

t:~~ 'trUA.
I.( 4,2.7 VI.
.IA

kn n t i : f< r -d 'c 1- c.' 1-- 1( cl, ,al; d =,1- whcn ci ar 1 wc'
-, r du'o tl ~- di stab c-nd. r. WOd .'.11'.ra2N'1~.2 22irn; '7.
01thc 719
wh-x rci c-ar wooid wa 1),-in .;- >,21. I 127i
To L11t'tmorc 7 r t'I1d~'rc~..c,{
" olm <"1 1 17.1u to 'i a c -'.12 2.-2 'i 12~ ~
WcodU r tIn.-,u a l :'C7(u l. '
W~.7k ~',r huna 'th(- t7 h I n IK 27 t27 .'*r
(21,aly a" n I ,D-t;a' ';a" r..- 7

rC' 2 r";d u. L :1-'r
a:2 .!2rc 1: ot7
Ln2: r.'7 "n- '7
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iv1T W r72' -n d tw't7.' .7 L 4 .I'' 1,1 1- ) a '. A :run
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r n' t'"" rA 1'.'.L! '1.7 1 V 2 L 2. 2 27' 1,i a

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the healing, period is the important factor. These trees probably were no-,.-
pruned severely enough to cause a setback of any kind from loss of green
branches. Furthermore the Kugel Creek stand was thinned when pruned, a
factor reflected only in the period of growTth subsequent to pruning.
The average rates of growth, expressed as rings per inch, for the knots healed
over in each year following pruning are given in table 2. These values show
that there is a relation between healing time and growth rate. The greater
the number of rings to the inch, the slower was the healing. The relationship
is more ap,--parent in the Kugel Creek ma-terial, especially w hen the unhealed
knots are considered.
That there arc still other underlying causes for differences in healing rates
between the two areas is brought out by the saw-.pruned material from Kugel
Creek. It was 6 years before any of these kn~ots were overgrowna by clear wood
although the growth rate for these first-healed knots was close to that for
the first-healed knots in all the other columns of table 2.
This leads to a consideration of stub length left after pruning. Table 3 shows
the effect of this variable. Under similar conditions of p~r-,u-ing the knots
with longer stubs took longer to heal. Both ax- and saw-- rtuned material from
Kugel Creek had longer stubs and took longer to heal before clear wood was
produced than did the material from Wind River (fig. 1).
While working conditions and skill of the non in pruning may have some influ-
ence on the length of stub left, i't appears that the bark thickness accounted
for the longer stubs at Kugel Creek. Tile operator of a pruning tool, especi-
ally a sa T is restricted by the bark in his attempt to get close to wood of
the bole of -the tree and leave a short stub. At comparable heights at the
time of felling it was found that bark thickness, while variable, average from
0.1 to 0.2 inch -thicker at Kugel Creek than at 'vind River.
Stub length is undoubtedly affected by the typ~e of tool used in pruning. No
comparison of tools is made here, however, because different tools were used
at the different heights in each stand and the stands were growing under quite
different conditions and were of different age classes.
The effect of knot diameter is given in table 4, which shows no apparent
relationship between time to heal and knot size. On the average;, the healed
knots were as large, or larger, than the unhealed knots in most cases. Further-
morc' the knots which healed over in 3 or 4 years were usually just as large as
those which healed later or not at all. Only from saw-pruned dead branches at
Wind River arc the unhealed knots of appreciably greater diameter than the
healed.
The greater influence of other factors than knot diameter is further shown in
figures 2: ',5 and 4. Both knots in figure 2, from different trees, were the
result of dead branches pruned 13 years previous to examination. Because of
thu more rapid diameter-growth rate of tree A, clear wood was produced after
10 years as comnpared to tree B, which had no clear wood after 15 years. The
knot in tree D was 0.2 inch in diameter and that in tree A', was 1.2 inches.
Also, it should be noted that both the bark thickn~ess and length of the stub
wore greater in tree A than in t'1ree B. The thick bark probably accounted for
the longer stub in A, 0.9 inch, as compared to the 0.4-inch stub in B.
Ropet. !1(-. 1%,'-4-




No dccay was found to ha,:c entoricd thi. trunk wood from ar,-! 2 tF ,rIumA
branches. A little rot was noted in the outer 1,art of s-::, -) I thcrra~i(
stubs, but its progress aT,-par(,ntly was; stcp~ ud wh(3l tht- u W(Xru h i vL iu
A Minute o--cning, visibL2 with a handI luns, had d 2.,loi%2d betw(-cn wo()ed of tihe,
branch andi t .at -f th(- trunk beyond thc. rinb! a', Wic,- thc cran(,h di (1. I u
every (-asc this jj,, riin- had lb cn flillcd wit.1 a th al;Q:~t around tho,
branc',. Tkual ,d-ovcr stuLxs aisD had -a layc r .f iitt'h acr-s-,; th cut or s.:
ends,
This si -udy ,--vcs results of prunin tr(-, 3". -ry. or x mcre Ina Cndr-
tion of the dato- indicatol- somcwha- creatcr muat~s:ight be ; aincd by
prunin- when the tr,-:es wc -possibly no morc than half as old as the trees
studied. ThI advantuf- s include:
(1) -A' s.-allor knotty core.
I2 'c rtr bran :h' stub 3 due t(Io thinncr lbar' ..
(5)) lKnto of the (Incaccd portions of branches 1,m:nint- bcfoCrc
th'ey die.
()Quic!.:_ r healinf- over vmundo bc O.-u o-; th". reasonL; 1-vun '-- 2 n
()LesS work in pruninz s inck 'Uranc-,(s will bc :-mllcr at tImo of cuttin,-.
Furtlher cxrmnsare ncodcd --n ;-oun ,r tr sto smbstanti&Lu t,: points,




Table l.--Distribution of healed and unh.aled !nots in pruned Douplas-fir
Zrouped according to area s~led, method of pruning and con-
dition of branches at time of pruning
Arean : Years required for healing :Knots :Total
prunin : : not :knots
method, and:-------------------------------------------------- healed:
condition : 1 : 2 : 3 : 4 : 5 : 6 : 7 : 8 : 9 :10 :11 :12 :13:
of branches: : : : : : : : : : : : : :
- - - - - - -:- ---- --- -, -, - -, -
: : :: :: :-: : :: :
Number of knots
Wi nd River : : : : : : : : : : : : : :
Sa-w: : : : : : : : : : : ::
Dead : 0 : 0 : : 0 : 1 : : : 4 : 4 :...:...:...:..: 4 : 18
Live : O : 0 : 2 : 2 : 4 :15 : 9 : 6 : 0 :...:...:.,,:..: 10 : 48
Both : 0 : : 3 : 2 : 5 :1 :10 :10 : 4 :...:...:...:.: 14 : 66
::: :: : ::: :: ::: :
Hcbo Club: : : : : : : : : : : : :
Dead : 0 : 0 : 1 : 4 :11 : : 7 : 6 : 5 :...:...:...:..: 8 : 49
Live : 0 : 0 : 1 : 2 : 1 : 2 : 1 : : 2 :...:...:...:..: 2 : 14
Both : 0 : 0 : 2 : 6:12 : 9 : 8 : 9 : 7 :...:...:...:.: 10 : 63
Kugel Creek: : : : : : : : : : : : : :
Saw : : : : : : : : : : : : : : :
Dead : 0 : 0 : 0 : 0 : I : 5 : 3 :13 : 4 : 9 : 2 : 2: 15 : 52
:: :: :: :: :: ::: :
Ax
Dead : 0 : 0 : 1 : 1 : 2 : 5 : 7 : 6 : 6 : : 7 : 3 : 3: 2 : 82
:et. :::: ::::::::: :
lict. No. ftlt9()7




Tablc 2.-Diameotcr growth rate after pruning~ f Douglas-fir,_ for hv al(d and
unh,.alt-d knots kroujl-cd a( cord1in t rcaM9j~ ,. of @
running, and condition of' br~ncli(, at timt ; of .-run~n,-
Healing Growth rato
tim c. --- - - - - - - - - - - - - - - -
At Wind Rivc.r At Kug(,1 (,rc-k
%aw -rue : Hcbo-club pruned "Jaw-rn ~xiud
Dcbad Livc. Both Dcad :Live Both D~c~ad 1)(- ad

Ycars ---n -Rin -s :Rings

- nll.

i nch

i), ur
Sinch

:IAingo :Ring~s :E-,.r.--s : Fin,-,s -,;r :~u 1)-,r

:incKi :inch :inch

S10 11
S14 :12
S15 :...
* Ce .e .* 0 0

8 : 10
10 : 10
10 : 11
10 10
13 14
15 11
13 14

7:
LO
9:
12
20
12

C.. *Ce.*C*c eec.o, * cc. C.eecc.*
8 : ...~..,.....: 7

10
10
11
11
12
11

6
10
14
13
1~0
31

inch

2
3
4
5
6
7
8
12
15

rich

1 : # . 0 0 : . 0 0 : 0 : 0 0 . . : 0 0 0 & 0 : 0 0 0 0 : 0 0 0 . 41 . & : 0 0 0 * .

Rept. No. P11-907




_T__ _~~ ____ __

Table 3.--Length of stub left in pruning Douglas-fir branches grouped by
area sampledmethod of pruning, condition of branch when
pruned, and time required to heal
Eealing : Stub length
time ------------------------------------------------------------------
: At Wind River : At Kugel Creek
:--P----------------C------------ -------------------
: Saw-pruned : Hebo-club pruned : Saw-pruned : Ax-pruned
:-------------------- -----------------D :t: Do-d :-Dea
: Dead Live : Both : Dead : Live : Both : Dead Dead
........ : -: -- : -- : : ......

Years : Inch : Inch : Inch : Inch : Inch : Inch :

Inch

: Inch

: 0.2 :
.6 :
.4
4 "
: .7 :
:......:
:......:

0.i
.2
.2:
.4
.4:
.5:
r
eetog
oeee +
o
oe

. e 0 0 : * *10 0 .

eeeee~e re a o gbo e Oo e oeeoa 0
0 0eeeee0 0 o*oeee oeoooereeeee oo0 ee

: 0.4 :
: .2 :
.4
.4
o

0.1
.2
.3
.4
.4
.5
.3
4
o,. oe e
o 1 0e 4
41e oe 04

0.0 : 0.2 :......o .....:

0.6
.6
.5
.4
.7
.9
.8
.9
.9
.8
.9

.2
.2
.2
.3
.3
.3
+ ~,

.2 :.0
3 *'04
o3:
.3
.3
.4
41
r te
419o

0.7
.6
.6:
,C;
.7
7:

.6 : 6 : .6 : ,

: .9

.5 : .7 :

Unhealed:

Rcpt. No. R1El07




Ta-~bleI~.- t diwmct(:r naralll to -ith of' tr :>jrr nli-'r
:Tht3~ruj a~~ .cL.rca ui rZ, j r_,i
condit ion of t runch -, nrun~c aind t imc r, r ,i to iiu

Knot diamctcr
At W-Lnd ldiver 1 c>~A r(,,k
Saw-pruncd 1-Ttjb-club pruncd ,a-prlni. Ax-jruni-,d
-, Live : Both Doad : Livc : Boti L~d

Years In-l- 1-- Inch Inch

2
6
7
10
11
12
135

1
'C
.6
C-
9)
9*9.9*.
99* Se.
9.9999
999999.
9

C-
'-
I.
.0
.6
p.
.8
**999
.9....
.99...
'-7
9,

0."
.7
'-7

o.4{
S.
.5

* Inch
* *9S.49.
* *9*99*
* C,
* .8
* .7:
* .6:
* 999999-
* ., 99*.*
* *99999
* 9#** 9*
* (
* 9-i.

i.e~
9*999*.
999999
0.6
.4
9)
.5
9
* I
9*999 9.
9******
99*999.
* *.99

999999999999 **.* 999*9*999
9*****9*9*9** *999999999999
* 1.1
.7
* .5
-1
.6
.7 .6
* 7
91 9~
* .7
'I 9~)
* 96
C-
.2 .5

leapt. :.RL 7

Healin-:
t ime




,
O
Figure I.-Theos cumulative carves show the percentage of prnmed branches that had been
overgrown by clear wood at the end of each year after the pruning date. This
point in healing was being reached sooner in the Wind River than on the Kugel
Creek trees, apparently because longer stubs were left on the Kugel Creek trees
rather than because of the pruning method or the condition of the branches
when pruned,

ZM 85291 F




LI/VE PRUNVEO

4
-I
- -
-~, t
I

WIND R1 VER
-- I1

iv -~

12 /3

YEARS AFTER PRUNN

L EGEAID:
SAW PROVED
-HE80 CL U8 PROVNED
---X PROVED

Q)
)
LQ4

50

30[-

20 -

0L
0




C
Figure 2 --Both of th -se knots were .10ad when prun -ith a sae 15 year& before the tree was
f elLei In A ,-omparative ly rapid dianter gr-,w?;t. cov ,,red thct 0 C )-ir h liorg st,,'b
with clear wood 'n the eleventh year af'er prun-ing I.- B, a k7,,ot of smaller
diameter having a shorter stub (0.4 inh), but from- a tree with slower growth
rate, had not been overgrown nor would it have been overgrown for several
additional years, The thicker bark on A may ar:-oiunt for the longer stub,

Zm 85292 F







Figure 3o--Pruned branch showing covering of cut surface by growth of the
last year. Shorter branch stubs or pruning while the branch
was alive presumably would have saved several years in
accomplishing this result..
ZA 85102 F

ipoNo. R!907




45 02 F




Fiire 4-,-Fom~ iar, c,,f woor~ud l~ arore b- am;: b cay be jc.iayei )y
'iori s of pitch a; bark
zm, 84563 F




zti S4 S 63r

12 1 1 1 31 1 14 1 1 1,51 1 1




UNIVERSITY OF FLORIDA
ii11 1 1 1 11 III III N 1i i l 1 1I I l l ll
3 1262 08927 3444