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K. R. (Kenneth R.) Peterson.

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LI E> RARY

OF THE

UNIVERSITY
OF ILLINOIS



no



AGRICULTURE



CIRCULATING



CHECK FOR UNBOUND
CIRCULATING COPY



3M 3-58 64998



/^V^ I



BARKING -

BLACK OAK AND JACK PINE

FENCE POSTS

with Sodium Arsenite



By K. R. Peterson
C. S. Walters
W. L. Meek



BULLETIN 626



UNIVERSITY OF ILLINOIS
AGRICULTURAL EXPERIMENT STATION



CONTENTS

PAGE
DEVELOPMENT AND EARLY STATUS OF CHEMICAL BARKING 3

CHEMICAL BARKING TESTS MADE IN ILLINOIS 4

MATERIALS AND METHODS 5

RESULTS 11

Part I: Effect of Season on Peeling Time 11

Part II: Effect of Length of Exposure to Poison on Peeling Time. . . .17

DISCUSSION OF RESULTS 23

Effect of Chemical Barking on Preservative Treatment 25

Chemical Peeling for the Woodland Owner 27

SUMMARY AND CONCLUSIONS 28

LITERATURE CITED 30

ACKNOWLEDGMENTS . . . 30



Until 1952 relatively little was known about the use of chemicals as an
aid in barking trees. The tests described in this report were initiated dur-
ing the winter of 1950 and completed in the fall of 1952. Since these data
were collected, much progress has been made toward a better under-
standing of the principles of chemical barking and its application. Many
results similar to those reported herein have already appeared in print.
Although the publication of the results of the Illinois tests was unavoidably
delayed, the authors believe that the information obtained was significant,
and that it will be of value in substantiating the results of other more
recent investigations.



Urbana, Illinois March, 1958

Publications in the Bulletin series report the results of investigations made
or sponsored by the Experiment Station



SODIUM ARSENITE AS AN AID IN BARKING JACK PINE
AND BLACK OAK FENCE POSTS

By K. R. PETERSON, C. S. WALTERS, and W. L. MEEK"

THE TREATMENT OF LIVING TREES WITH CHEMICALS to facilitate the
removal of bark is a rather recent development. A number of re-
ports have been published on chemical barking research, many of them
by persons interested in peeling pulpwood (1, 3, 6, 9). b Several chem-
icals and methods have been tested. Although the results of the tests
have varied with regard to species and season and methods of treat-
ment, the technique appears promising as a means of barking trees to
be used for products other than pulpwood.

Small trees thinned from Illinois woodlands may be used as fence
posts. Most of the species, however, are not naturally durable in con-
tact with soil, requiring preservative treatment to make them so. Wood
preservatives do not penetrate bark. Therefore, it is essential that posts
be thoroughly barked or peeled before they are given preservative treat-
ment. Hand-peeling, however, is arduous and the best season for hand-
peeling is in the spring when the farm workload is heavy. If post-peeling
could be made easier or delayed by the use of chemicals until time
would be available for the work, more farmers would treat their fence
posts, thereby conserving time, money, and raw materials.

DEVELOPMENT AND EARLY STATUS
OF CHEMICAL BARKING

The use of chemicals to bark trees probably was first described in a
Canadian patent issued to A. R. White in September, 1942 (U. S.
Patent issued in July, 1943). Although 11 years earlier Cope and
Spaeth (2) described a method similar to White's, they recommended
their method for killing trees and not for barking them.

The results of formal tests of barking chemicals and techniques
began to appear in the literature about 1946 (3) when the Canadian
Forest Products Laboratory described the effectiveness of various
chemicals and seasons of treatment and cutting in barking several

K. R. PETERSON, Research Associate in Forestry ; C. S. WALTERS, Professor
of Forestry; and W. L. MEEK, formerly First Assistant in Forest Utilization
Research.

" Numbers in parentheses refer to literature citations listed at the end of this
report.



4 BULLETIN No. 626 [March,

pulpwood species. In their early tests, the Canadian researchers applied
the barking chemicals to a girdle made at breast height on the tree with
a V-shaped knife. The knife was designed to cut a shallow, narrow
groove through the bark and into the sapwood. The chemical was pre-
pared as a paste and it was held in contact with the girdle by a band of
crinkled paper pulled tightly around the tree and fastened with a tack.

The conclusions drawn from the results of the Canadian tests were
published in a series of reports, many of which appeared between 1946
and 1950 (3, 5, 6, 8). In general, soluble arsenic proved to be the best
of the chemicals tested prior to 1950 for facilitating bark removal.
Trees which were girdled but not poisoned were found to be either
similar to untreated control trees in peeling qualities or, in some in-
stances, harder to peel. June, July, and possibly the first part of August
were found to be the best months for applying chemicals under Cana-
dian conditions if the bark were to be peeled easily during the fall of
the same year. Generally, a minimum period of two months was needed
between treating and felling the Canadian trees to obtain the best
barking results.

Since 1950 a number of reports on chemical barking have been
published in this country and in Europe, only a few of which are cited
in this publication. The most comprehensive of these reports is prob-
ably the one made by Wilcox and his colleagues (11) in 1956 on the
work of the cooperative Chemical Debarking Research Project con-
ducted by the State University of New York.

CHEMICAL BARKING TESTS MADE IN ILLINOIS

In 1950 the Illinois Agricultural Experiment Station in cooperation
with the Illinois Department of Conservation, Division of Forestry,
initiated a study of the use of sodium arsenite for barking post-size
trees. The objectives of the investigation were to:

1. Find methods of reducing the cost of peeling fence posts for
preservative treatment.

2. Determine whether the method of peeling has an effect on the
treatability of posts that are to be cold-soaked in oil-soluble wood
preservatives.

3. Determine whether the peeling season could be prolonged by
killing the cambium at a time when growing conditions make peeling
easiest.

4. Develop a technique which would produce satisfactory results
under Illinois conditions.



1958] CHEMICAL BARKING OF BLACK OAK AND JACK PINE 5

MATERIALS AND METHODS

Trees. Jack pine (Finns banksiana Lamb.) and black oak (Quercus
vclutina Lam.) were chosen for treatment because a satisfactory num-
ber of trees of post-size were readily available on the Mason County
State Forest. (The original design also included hickory, but an ade-
quate supply of satisfactory trees was not available in the test area.)

Two hundred and thirty-four pines in a fifteen-year-old plantation
were pruned to a height of 7 feet and identified with numbered metal
tags. The trees ranged from 2.3 to 5.2 inches in diameter (average
diameter was 3.4 inches) at the time they were poisoned. The total
height of the pine test trees ranged from 15 to 24 feet, averaging 19.8
feet. With one or two exceptions, the trees contained only one 7-foot
post.

One hundred and eight of the 234 oak test trees were located on an
area of approximately 2 acres, and the remaining trees were on a second
area of similar size and environment. The two areas, located about 3
miles apart, were portions of larger timber stands which apparently had
been clear-cut twenty-five years earlier. Only trees which had devel-
oped from seedlings, rather than sprouts, were selected for treatment.
Most of the trees had pruned themselves to a height of at least 7 feet.

Barking chemicals. At the time the investigation was initiated,
sodium arsenite appeared to be the most promising of the barking
chemicals, and the tests were limited to this compound. Two aqueous
solutions were prepared from a technical grade, powdered form of the
chemical. One solution, designated as "weak," contained 7.5 gm. of
toxicant per 100 ml. of water. The "strong" solution contained 20.0 gm.
of sodium arsenite per 100 ml. of water.

A paste form was prepared by mixing 2 parts (by weight) sodium
arsenite, 1 part cornstarch, and 12 parts water, and heating the mixture
approximately 5 minutes.

Design of experiment. This factorial experiment related the effect
of dosage, time of treatment, and duration of treatment to the length
of time required to hand-peel posts cut from the poisoned trees. Table 1
shows the schedule of treatments for 468 trees included in the study.
Tables 2 and 3 show the poisoning and cutting and peeling schedules
for 156 3-tree lots. The test trees were randomly assigned to treatments.

The study was divided into two parts. Part I (Table 2) was de-
signed to show the most effective time of the year for applying the
different concentrations of sodium arsenite. Thus, three trees of each



BULLETIN No. 626 [March,

Table 1. Number of Trees Tested Grouped by Treatment
and by Species

Treatment Parti Part II Total



Weak solution


Black oak
36


36


72


Strong solution


36


36


72


Paste




36


36


Untreated controls


36


18 a


54


Subtotal


108


126


234


Weak solution


Jack pine
36


36


72


Strong solution


36


36


72


Paste




36


36


Untreated controls


. . 36


18"


54


Subtotal


108


126


234


Total


216


252


468











n Overlapping of schedules for Parts I and II reduced the requirements for control trees
to 18.



species were poisoned with the weak solution and a similar number
with the strong solution, each month from December, 1950, through
November, 1951. One year elapsed between poisoning the trees and the
time the posts were cut and peeled. Three untreated (control) trees of
each species also were cut each month, and the posts were peeled with
the poisoned posts.

Part II (Table 3) was designed to show the minimum amount of
exposure time required between poisoning and felling to obtain the best
peeling results. One hundred and twenty-six trees of each species were
poisoned May 15, 195 l, a a time that was judged to be favorable for
"sap-peeling" (barking posts during the spring when it is made easier
by physiological and anatomical changes in the tree). Nine treated trees
and three untreated controls of each species were cut, and the posts
were peeled each month following treatment. Thus, exposure times
ranged from one to twelve months in length. As Parts I and II over-
lapped for six months (December, 1951 through May, 1952), one set
of control trees served both parts for that period.

Application of barking chemical. All trees except the untreatec
controls were girdled at breast height with a girdling saw (Fig. 1

" Previous experience showed that the peak of the sap-peeling season in Illinois
occurs about ten days after the hardwood leaves attain full size. This "rule of
thumb" and periodic tests on nontest trees were used to set the poisoning date.



1958] CHEMICAL BARKING OF BLACK OAK AND JACK PINE

Table 2. Schedule of Treatments for 3-Tree Lots: Part I



Date of
treatment


Black oak


Jack pine




Treatment




Treatment


Untreated
controls


Year Month


Weak Strong
solution solution


Untreated
controls Weak
solution


Strong
solution


1950 Dec


1


Trees girdled and poisoned

13
14
15
16
17
18
19
20
21
22
23
24

Butt posts cut and peeled a

13 49
14 50
15 51
16 52
17 53
18 54
19 55
20 56
21 57
22 58
23 59
24 60


25
26
27
28
29
30
31
32
33
34
35
36

25
26
27
28
29
30
31
32
33
34
35
36


37
38
39
40
41
42
43
44
45
46
47
48

37
38
39
40
41
42
43
44
45
46
47
48


61
62
63
64
65
66
67
68
69
70
71
72


1951 Jan


2


Feb.


3


Mar


4


Apr


5


May


6


June


7


July. .


8


Aug.


9


Sept


. . 10


Oct. . .


11


Nov


. . . 12


Dec


1


1952 Jan.


2


Feb.


3


Mar


4


Apr. . .


5


May


6


June


7


July. .


8


Auer.


9


Sept..


. . . 10


Oct


... 11


Nov


... 12







* The three trees in each lot produced from 3 to 7 7-foot posts. For example, only 1 post
was cut from each of the 3 pines in Lot 37; 6 posts were cut from 3 oaks in Lot 13.

designed to cut a groove (kerf) 14 inch wide. The girdles were cut
through the bark and into the sapwood to a depth of 1/4 inch.

The sodium-arsenite solutions were applied to the girdles with a
pump-type oil can. No measurement was made of the volume of solu-
tion applied to each tree, but the dosage was "liberal" (Fig. 2). About
620 ml. of solution were required to treat 72 oaks, an average of 8.6 ml.
per tree. About 480 ml. of solution were applied to a similar number of
pines, an average of 6.7 ml. per tree.

Two men, one girdling and one applying the solution to the girdle,
treated 72 jack pine trees at an average rate of 3.4 man-minutes per
tree.

The paste was applied with a hand-operated caulking gun (the type
commonly used for home maintenance) equipped with a i/2-inch nozzle.



BULLETIN No. 626



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1958]



CHEMICAL BARKING OF BLACK OAK AND JACK PINE




This girdling saw, shown partially disassembled, was built of two pruning-
saw blades spaced about 1/4 inch apart with flat washers. Two stove
bolts and wing nuts held blades in position. Although the saw was used
to girdle all trees treated with sodium-arsenite solutions, it was rated as
an unsatisfactory tool for this purpose. Bark clogged the space between
the blades, and the girdle was believed to be too narrow for best results.
Wider spacing of the blades might have overcome the objectionable
features. Other features of the tool, such as its lightness and cutting
speed, were quite satisfactory. (Fig. 1)



A pump-type oil can was
used to apply the sodium-
arsenite solutions to girdled
trees. The first portion of
the solution applied was
readily absorbed; treatment
was stopped when the tree
no longer promptly ab-
sorbed the solution and the
liquid began to flow down
the trunk. A small paint
brush probably would be
a less tiring and quicker
method of applying the so-
lution than the oil can.

(Fig. 2)




10



BULLETIN No. 626



[March,



The gun held about 430 gm. of paste and one loading treated about 20
pines, an average of 21 gm. of paste per tree or 6.5 gm. of paste per
inch of tree diameter. The authors concluded that the paste-gun method
of poisoning would not be practical for a commercial operation, par-
ticularly where girdles wider than 1/2 inch were used.

Collection and analysis of peeling data. An axe, a bark spud made
from a section of automobile springleaf, and a carpenter's draw knife
were used interchangeably to peel the posts. The choice of tool de-
pended on which one was best suited for the post being peeled. The
posts were supported in a "buck" during the peeling operation (Fig. 3).
Posts cut during freezing weather were stored overnight in a warm
room and peeled there the following day.

Peeling times were measured with a stop watch and recorded on
data forms together with a narrative description of results.






Test posts were held in a "buck" during the peeling operation. The 1
of the peeling buck were set in the soil to a depth of about 2 feet tc
give the equipment stability. The operator is using a carpenter's drav
knife to peel the post. (Fig.



1958] CHEMICAL BARKING OF BLACK OAK AND JACK PINE 11

The measurement data were punched on cards, and the organiza-
tion and computation of the data were made by business machines.

Only one post was cut from each pine tree, but from one to three
posts were cut from each oak tree. Since missing values complicated the
analyses, the analyses of variance (Tables 5, 7, 9, 11) apply only to data
for the butt posts.

The diameters in inches and the peeling times in seconds for the
butt posts were analyzed statistically. Differences in diameters were not
a significant source of variation. However, the differences among peel-
ing times were found to be significant, and an analysis of variance was
made for each group of species data to determine the effects of treat-
ment, month, and the interaction of treatment and month.

A hypothesis that peeling times fitted a cyclical pattern over the four
seasons of the year was tested using first and second harmonics. The
test showed no significance and the hypothesis was rejected.

RESULTS

Part I: Effect of Season on Peeling Time

Pine. The month of treatment and average peeling times for jack
pine posts which were cut and peeled one year after the trees were
poisoned are shown in Table 4 and Figure 4.

An analysis of variance (Table 5) for the peeling data showed that
treatment, month, and their interaction were highly significant sources
of variation. This means that the variation of peeling time from month
to month was characteristic of the treatment applied, as shown in
Figure 4. Since the two sources of variation were interdependent in
their effects on peeling time, the average independent effects of the two
variables on peeling time become relatively unimportant.

Treating with the strong sodium-arsenite solution in August gave
the lowest peeling time for posts cut from jack pines that were poisoned
each month and felled one year later (Lots 25 to 72, Table 2). The
poisoned posts were peeled at a rate averaging 97 seconds per post, and
the untreated posts were peeled at the height of the sap-peeling season
at a rate averaging 62 percent slower (157 seconds per post).

The control trees peeled most rapidly from April through August.
During this time poisoning was detrimental, or at best neutral, except
for the strong solution applied in August. The sap-peeling season for
jack pine appeared to be somewhat longer than that for oak.



12



BULLETIN No. 626



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CHEMICAL BARKING OF BLACK OAK AND JACK PINE



13




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14



BULLETIN No. 626



[March,



Table 5. Analysis of Variance for Jack Pine Post-Peeling Data: Part I

Peeling times obtained from 7-foot butt posts cut from healthy trees and from
trees poisoned monthly. Treated trees exposed to poison one year before posts
were cut and barked.



Source of variation


Degrees of
freedom


Sum of
squares


Mean
square


Variance
ratio (F) a


Treatment


2


268,605


134302


16.02***


Month


11


991,032


90093


10.75***


Treatment by month


22


984,722


44760


5.34***


Error


72


603,541


8382




Total


107


2,847,900

















a *** _ s ig n ifi can t a t .001 level.

Oak. The effects of treatment at various months of the year on the
length of time required to peel black oak posts cut one year following
treatment are shown in Table 6 and Figures 5 and 6. Table 7 shows an
analysis of variance for the oak-peeling data.

Treatment and month, but not the interaction of these two variables,
were highly significant sources of variation (Table 7). Therefore,
standard errors and standard deviations for average peeling times for
each month and treatment are shown in Table 6.

The lowest average peeling time per post for all treatments com-
bined was recorded for June, 234 seconds (Table 6 and Fig. 6A). The
lowest of the average peeling times for the three methods of treatment
was for the strong sodium-arsenite solution (Table 6 and Fig. 6B),
313 seconds, although the time was only slightly lower than that for
the weak solution (332 seconds). The average peeling times for both



Table 7. Analysis of Variance for Black Oak Post-Peeling Data: Part I

Peeling times obtained from 7-foot butt posts cut from healthy trees and from
trees poisoned monthly. Treated trees exposed to poison one year before posts
were cut and barked.



Source of variation


Degrees of
freedom


Sum of
squares


Mean
square


Variance
ratio (F) a


Treatment


2


297,746


148873


20.32***


Month .


11


408,108


37100


4.85***


Treatment by month


. . . 22


191,120


8687


1 18 NS


Error


72


527,334


7324




Total


107


1,424,308

















** = significant at .001 level.
NS = not significant.



CHEMICAL BARKING OF BLACK OAK AND JACK PINE



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Online LibraryK. R. (Kenneth R.) PetersonBarking black oak and jack pine fence posts with sodium arsenite → online text (page 1 of 2)