IMPROVING PENETRATION OF COPPER IN MICRONIZED COPPER AZOLE
PRESSURETREATED MICHIGAN RED PINE

By

John Rademacher

A THESIS
Submitted to
Michigan State University
in partial fulfillment of requirements
for the degree of
MASTERS OF SCIENCE
Forestry
2011

ABSTRACT
IMPROVING PENETRATION OF COPPER IN
MICRONIZED COPPER AZOLE PRESSURE
TREATED MICHIGAN RED PINE
By
John Rademacher
Michigan red pine Pinus resinosa is a critical part of the Great Lakes region lumber
industry. The species is used for various applications such as telephone poles, dimensional
lumber, decking and various other uses. This species is native to the Great Lakes meaning lower
shipping costs and the creation of local jobs. The goal of this study overall was to improve the
penetration of MCA pressure treated red pine. Using duration, steaming and penetration
enhancers we were able to increase the penetration to allow some samples to pass the AWPA
penetration standard. We found that the average solution uptake of the treated samples was 47%
for spring samples, 106% for summer samples and 79% for fall and winter samples. Steaming
alone created better penetration than non-steamed samples but with the addition of penetration
enhancers we were able to boost the penetration to levels we had not observed with other
treatments as indicated above. Penetration enhancers alone greatly increased the penetration but
the steaming would allow for a higher moisture content, which in turn swelled the wood allowing
PE to aid greater penetration. Anatomically, red pine has issues with high resin content and pit
aspiration, which was observed but a conclusion has was not reached as to what causes the pit
aspiration or why aspiration is sporadic in red pine samples regardless of drying or treating.

DEDICATION
To my Fiancé Ashlie, my mother Virginia and my entire family for their unwavering
support, sacrifices, and confidence.

iii

ACKNOWLEDGEMENTS
I would like to thank Dr. D. Pascal Kamdem, for his patience, guidance and assistance in
my studies at Michigan State University. I am honored as to have worked with him and have
gained a vast amount of knowledge under his leadership and mentoring. I am also grateful for the
help from Dr. Stanley L. Flegler for his guidance using the scanning electron microscope. I am
also indebted to Biewer Lumber, specifically Plant Manager Andy Hehl, for his help throughout
my program and to Dr. Runsheng Yin of the Department of Forestry, MSU for his guidance and
encouragement. I am also appreciative to the help the Dr. Melinda Frame gave me in collecting
images using the Confocal Laser Scanning Microscope.

iv

TABLE OF CONTENTS
List of Tables…………………………………………………………………………..vii

List of Figures………………………………………………………………………...viii

Chapter 1: Introduction………………………………………………………………………..1

Chapter 2: Literature Review…………………………………………………………………5
2.1.1 Red pine resource………………………………………………………………….5
2.1.2 Properties of red pine……………………………………………………………...5
2.1.3 Utilization and uses of red pine……………………………………………………7
2.1.4 Preservative chemicals……………………………………………………………..8
2.1.5 Performance of treated conifers……………………………………………………9

Chapter 3: Anatomical properties of red pine………………………………………………..11
3.1 Introduction………………………………………………………………………………….11
3.1.1 Anatomical properties……………………………………………………………...11
3.2 Materials and Methods………………………………………………………………………13
3.2.1 Confocal Laser scanning microscopy (CLSM)……………………………………13
3.2.2 Scanning electron microscopy (SEM)……………………………………………..13
3.3 Results and Discussion………………………………………………………………………14
3.3.1 Microscopic features of red pine…………………………………………………..14

Chapter 4: Penetration and retention of red pine Spring wood…………………………….18
4.1 Introduction………………………………………………………………………………….18
4.2 Materials and methods……………………………………………………………………….18
4.2.1 Procurement of wood……………………………………………………………....18
4.2.2 Wood samples……………………………………………………………………...20
4.2.3 Pressure treatment………………………………………………………………….20
4.2.4 Determination of penetration………………………………………………………20
4.3 Results and discussion……………………………………………………………………….21

Chapter 5 Penetration and retention of red pine summer wood (steaming)………………..29
5.1 Introduction………………………………………………………………………………….29
5.2 Materials and methods……………………………………………………………………….30
5.2.1 Wood samples……………………………………………………………………...30
5.2.2 Steaming/ Quat additive……………………………………………………………30
5.2.3 Pressure treatment…………………………………………………………………31
5.3 Results and discussion……………………………………………………………………….32

v

Chapter 6: Penetration and retention of red pine fall and winter wood……………………36
6.1 Introduction ………………………………………………………………………………….36
6.2 Materials and methods……………………………………………………………………….36
6.2.1 Wood samples……………………………………………………………………...36
6.2.2 Penetration enhancer additives…………………………………………………….37
6.2.3 Pressure treatment………………………………………………………………….37
6.3 Results and discussion……………………………………………………………………….38

Chapter 7: Pressure treating with MCA and DDAC penetration enhancer (AWPA)……..43
7.1 Introduction ………………………………………………………………………………….43
7.2 Materials and methods……………………………………………………………………….43
7.2.1 Wood samples……………………………………………………………………...43
7.2.2 Quat additive……………………………………………………………………….44
7.2.3 Pressure treatment………………………………………………………………….44
7.3 Results and discussion……………………………………………………………………….45

Chapter 8: Conclusion………………………………………………………………………….51
Literature Cited………………………………………………………………………………...54

vi

LIST OF TABLES
Table 1. Common chemical treatment preservatives being used presently to protect conifer
species……………………………………………………………………………………………..8

vii

LIST OF FIGURES
Figure 1. Red pine geographic distribution………………………………………………………2
Figure 2. Treated red pine with blue stain present……………………………………………….7
Figure 3.Treated southern pine and red pine MCA penetration depiction………………………10
Figure 4. Symbolic depiction of the pit aspiration of softwood tracheids……………………….12
Figure 5. SEM image inside of the longitudinal tracheid of kiln dried red pine………………...15
Figure 6. CLSM image of an untreated green red pine sample with pits open and closed……..16
Figure 7. CLSM image of an untreated early wood sample with pits appearing open………….16
Figure 8. CLSM image of a treated early wood samples with pits open and closed…………….17
Figure 9. CLSM image of a treated latewood sample with pits appearing to be closed…………17
Figure 10. Graded and stamped kiln dried red pine board that was used for the study………….19
Figure 11. Treatment tank used throughout the entire experiment………………………………21
Figure 12. Spring kiln dried samples treated for 90 min. with tank refill after 45 min………….23
Figure 13. Spring kiln dried samples treated for 90 min. without tank refill……………………24
Figure 14. Spring kiln dried samples treated for 60 min. without tank refill……………………25
Figure 15. Spring kiln dried samples treated for 60 min. with tank refill after 30 min………….26
Figure 16. Spring kiln dried samples treated for 90 min. without tank refill……………………27
Figure 17. Average solution uptake for spring samples………………………………………...28
Figure 18. Average moisture content for spring samples………………………………………..28
Figure 19. Kiln dried summer wood subjected to 1 h steaming and treated with MCA and
Quat………………………………………………………………………………………………33
Figure 20. Kiln dried summer wood subjected to 1 h steaming and treated with MCA and
Quat………………………………………………………………………………………………34
Figure 21. Kiln dried summer wood subjected to 1 h steaming and treated with MCA without
additive…………………………………………………………………………………………...34
Figure 22. Average moisture content of summer samples……………………………………….35
viii

Figure 23. Average solution uptake of summer samples………………………………………...35
Figure 24. Fall and winter kiln dried samples treated for 2 h with 0.5 lbs of Quat added to MCA
solution…………………………………………………………………………………………...40
Figure 25. Fall and winter kiln dried samples treated for 2 h with 0.5 lbs of Quat added to MCA
solution…………………………………………………………………………………………...40
Figure 26. Fall and winter kiln dried samples treated for 2 h with 0.0004% sodium phosphate...41
Figure 27. Fall and winter kiln dried samples treated for 2 h with 0.0008% sodium phosphate...41
Figure 28. Average kiln dried moisture contents for fall and winter samples…………………...42
Figure 29. Average kiln dried solution uptake for fall and winter samples……………………...42
Figure 30. Southern pine nominal 2x6‖ samples treated with MCA for 1, 2, and 3 h………….47
Figure 31. Southern pine nominal 2x6‖ samples treated with MCA with PE (Quat) added
increasing from 0.5%, 1% and 2%.................................................................................................47
Figure 32. Jack pine nominal 2x6‖ samples treated with MCA for 1, 2, and 3 h………………..48
Figure 33. Jack pine nominal 2x6‖ samples treated with MCA with PE (Quat) added increasing
from 0.5%, 1% and 2%..................................................................................................................48
Figure 34. Red pine nominal 2x6‖ samples treated with MCA for 1, 2, and 3 h………………..49
Figure 35. Red pine nominal 2x6‖ samples treated with MCA with PE (Quat) added increasing
from 0.5%, 1% and 2%..................................................................................................................49
Figure 36. Treated southern, Jack, and red pine nominal 2x6‖ samples uptake without PE
added……………………………………………………………………………………………..50
Figure 37. Treated southern, Jack, and red pine nominal 2x6‖ samples uptake with PE (Quat)
added……………………………………………………………………………………………..50

ix

Chapter 1
Introduction
Michigan red pine Pinus resinosa is the species that has built much of Michigan and helped
Michiganders in times of despair. In the 1930s with the great depression ongoing and much of
upper Michigan’s land having being clear-cut or abandoned the Civilian Conservation Corps
(CCC) stepped in and put people to work planting red pine plantations in what was once barren
land ( Pilon et al. 2006). This was done to restore the forests and to also create jobs when there
were few. Today much of the landscape in Michigan is still dotted with red pine plantations and
windbreaks placed by the CCC’S. In the 1980s the red pine came of age t harvest and so did
technology creating mills that could meet production quotas using moderate sized logs instead of
the old growth that the industry had come accustomed to (Pilon et al. 2006).
The trees being harvested today are roughly 55-65 year of age according to a forester for
Biewer Lumber in Mcbain Michigan. With today’s ever demanding markets for lumber, red pine
has become vital because species like southern pine and Jack pine Pinus banksiana cannot alone
supply the lumber demand the Nation needs. Red pine alone in state and national forests in
Michigan make up almost 200,000 acres, which makes this species extremely important to the
lumber industry (Pilon et al. 2006).
Since red pine is established on much of the Great Lakes region which is illustrated in
Figure 1. With the knowledge of the resource here in Michigan it is necessary to use it to its
fullest potential, by using the wood in various products. These products consist of structural
lumber in treated and non-treated form telephone poles, woodchips, and various other uses.
Treating red pine has become a product that is in the spotlight. Treating red pine can sometimes
be associated with gambling since sometimes the species treats well and other times not so well.
1

Figure 1: Red pines geographic distribution (Virginia Tech Forest Resources and Environmental
Conservation, 2009) For interpretation of the references to color in this and all other figures, the
reader is referred to the electronic version of this thesis.

2

Chemical treatment of red pine has greatly changed in the last 10 years due to
technological changes and concerns about the safety of chemicals. Today ―micronized copper‖ in
a waterborne solution is what has been established to be safer for people and the environment.
The micronized shift in chemicals came about due to the voluntary withdrawal of chromated
copper arsenate (CCA) which was the chemical of choice until 2003 (Bowyer et al 2007). Today
micronized copper azole (MCA) and micronized copper Quaternary (Quat) (MCQ) are the new
chemicals that treatment companies have begun treating various species with since CCA is no
longer viable for non-industrial use lumber (Osmose Inc.).
The micronized series of copper are better for the environment and are more aesthetically
pleasing due to the lighter color/more natural looking treated lumber. The problem that these
new micronized chemicals face it treating red pine, known for having a high resin content, and a
transition zone that from sapwood to heartwood that is very hard to treat, especially considering
that heartwood is almost impossible to treat due to aspirated pits (Wang et al. 1996). The
problem with treating red pine is that these aspirated pits are not only in the heartwood but also
the sapwood which can slow or stop the penetration of treatment solution into the wood. The
combination between high amounts of resin and aspirated pits issues for the treatment
companies, which is why this study is needed.

3

The objectives of the study are;
1. To assess the treatability of red pine treated with MCA while increasing the duration of the
treatment.
2. To evaluate the performance of steaming lumber and the use of penetration enhancers added to
MCA to aid in increasing the penetration of the treatment solution.
3. To examine the anatomical properties of red pine to view if pits are aspirated.

4

Chapter 2
Literature Review
2.1.1 Red pine resource
Red pine is a species of pine that is native to the Northeastern United State, and of high
importance to the Great Lakes region. Red pine is known by other names such as Norway pine,
Eastern red pine, and pin rouge (Anderson and Moore, 2003). The species occurs in well
drained, dry, highly acidic, sandy soils of outwash plains, and gravelly ridges (Barnes and
Wagner 1981). The tree is medium sized, and up to twenty-five meters high and seventy five
meters in diameter (Farar 1995). The wood is moderately hard and straight grained, and is used
for poles, lumber, railway ties, post and pulpwood and other uses (Anderson and Moore, 2003).
A key characteristic to red pines use in Michigan is it can grow on sandy soil, thus it was planted
as windbreaks and was planted in areas where cash crops were not, especially during the Great
Depression.
2.1.2 Properties of red pine
Red pine is a hard pine, with a density of 26 pcf (AWPA, A12-09). Being of the hard
pine family the species is planted for lumber purposes for building structures. The tree itself is
large 20-30 m, fast growing and can grow in well drained infertile soils such as sand and
outwash plains (Barnes and Wagner, Jr., 2004). The bark is a brown color with a reddish tinge to
it and is relatively thick to help fight against fire. The leaves are in clusters of 2 and are 10-17 cm
long and are relatively straight (Barnes and Wagner, Jr., 2004). The wood itself has a piney odor,
red pine being the strongest odor that is associated with the pine family (Hoadley, 1990). The
heartwood is distinct due to the dark brown/red color, while the grain is moderately uneven and
transitions from early wood to latewood are abrupt (Hoadley, 1990). Sapwood is a creamy
5

yellow color while the heartwood is a brownish red color noted earlier. Resin canals are present
in the species thus the name resinosa. The resin canals are numerous and medium sized
compared to other species and evenly distributed though out the wood (Hoadley, 1990). With
resin canals being numerous and throughout wood the pitch needs to be set when the wood is
drying in the kiln. Setting the pitch is the process of heating up the lumber to a specified
temperature to so that the resin will only flow if the temperature rises above the kiln set
temperature. If a piece of wood is kiln dried to 120°C the resin will not flow until the
temperature of the wood rises above 120°C.
Red pine is sapwood susceptible to sap stain Figure 2. The most significant stain is blue
stain. The stain not only discolors infected wood a bluish gray color, but also can reduce the
price, due to the wood being used for pulpwood instead of lumber. The fungus can either be
transported by air like many funguses or my insects such as beatles. The fungus is most active
between 70°F and 90°F but can develop between 40°F and 130°F (Bowe et al., 2005). Blue stain
attacks the wood because the fungus needs sugars and starches in the sapwood of the tree to
survive (Forest Products Laboratory, 1999). Though blue stain degrades the lumbers aesthetics
the stain is good for chemical preservation, especially red pine. This is due to the stain eating
away the resin and starches allowing the chemicals to penetrate deeper due to the lack of resin
blocking penetration (Figure 2). Though blue stain is problematic the stain can be controlled,
temperatures of 150°F are lethal to blue stain, the stain cannot grow in moistures of 20% or less
and there are fungicides that can be used along with sealing or coating the logs in a wax barrier
(Bowe et al. 2005) (Forest Products Laboratory, 1999). The best solutions though is to cut the
trees and transport the wood the mill in a timely manner to decrease the chance of the wood
being infected or the stain growing.
6

Figure 2: Treated red pine with 70-80 percent blue stain. The sample was treated with 1 percent
MCA solution with less than 20 percent heartwood, treated under pressure for 60 minutes with a
maximum pressure of 165 psi.

2.1.3 Utilization of red pine
Red pine is a vital resource for building materials in the Great Lakes region. Not only is it used
for production purposes like lumber but the bark has occasionally been used to tan leather
(Sargent 1961). The species with the higher density is mainly used for structural purposes like
2x4‖s, 4x4‖s, and 2x6‖s but there is a host of other nominal sized lumber that this species is used
for. A few construction uses for the timer is ladders, pilings, poles and interior and exterior trim
(Barnes and Wagner, Jr. 2004). Red pine is of high importance to Michigan mainly due to the
Eastern Upper Peninsula being of the correct conditions to grow high dollar telephone poles.
Plus, the species can be used for a multitude of other application or uses such as railroad ties,
pulpwood, cabin logs, posts, and fuel (Anderson and Moore, 2003). In addition to the different
uses for the timber cost of shipping also comes into play, since the species is native shipping is
lower, there is an economic boost due to local jobs and the species can be managed by the people
who are local that use and cut the timber, unlike timber that is shipped in from other parts of the

7

United States. Red pine also has many uses in the treated form especially in decking material, but
treated lumber is also used for fencing, decorative outdoor panels, and walkways.
2.1.4 Chemical Preservative treatment
Wood preservatives have been around since the 17th century when settlers came to the new world
(Freeman et al. 2003). There has been a need for chemicals because wood is part of the basic
building blocks of the United States and many parts of the world. Before steel there was wood
and wood continues to be the most cost effective means of building structures even today. Wood
is not only renewable but can be shipped to just about anywhere in the world. With the history of
chemical treatment of wood ranging back to the 17th century there has been many chemicals and
treatments used over the years some that were good and some that were not good at all in fact
toxic, especially when manufacturing. Creosote has been one of the chemicals that have stood
the test of time. Coal-tar creosote was patented in 1836 by Moll and is still used today, where
other chemicals have come and gone (Freeman et al. 2003). The first pressure impregnation of
chemicals also used creosote, which was developed by John Bethell in 1838 and was known as
the Bethell or full cell treatment, which is the basis of chemical treatment today (Freeman et al.
2003).
Today most chemical treatment companies still use pressure to impregnate or treat wood
but the chemicals have changed. Now with the ever present carbon exchange and global
warming, chemists and chemical companies alike are looking for safer and all around better
chemicals to treat lumber. Most solutions currently are aqueous copper based solutions, the two
copper forms being used in the United States is ―soluble copper (Typically amine based) or more
recently particulate or ―micronized‖ copper based biocides‖ (Zahora 2011). Currently, there are 5

8

primary chemicals that are being used (Table 1). These chemicals are all in use currently with
chromated copper arsenate (CCA) being in limited use. The limited use of CCA is due to a
voluntary withdrawal from the residential use in December of 2003 because of health risks (EPA
2011). With the withdrawal of CCA from residential markets the other 4 chemicals have seen a
rise in use especially since a study done in 2000 by the Southern Forest Products Association
found that CCA treated 80% of residential use lumber (Freeman et al. 2003). With this
knowledge MCA, MCQ, CA, and ACQ are all competing to take CCA’s place.
Table 1:Five common treatment preservatives that are currently being used to treat and protect
conifer species.
Chemical
Preservative
MCA
MCQ
ACQ
CA
CCA

Full Name

Organics

Micronized Copper Azole
Azole
Micronized Copper Quaternary Quaternary
Alkaline Copper Quaternary
Quaternary and
Ammonia or Amine
Copper Azole
Azole
Chromated Copper Arsenic

Current Status
In use
In use
In use
In use
Limited use in USA

2.1.5 Performance of treated conifers
It is well established that all wood is different, wood is not like steel, where we know the
exact chemical make-up and how much of a certain chemical or element is in the sample or
piece. All wood has similar characteristics but all species differ. Some species have more resin
than other, which causes treatment parameters to change and some species do not treat well at
all, while others have natural decay resistance. Red pine, southern pine, and Jack pine are three
species that are from the same family (pinaceae) and genus (Pinus), but are all a little different
from each other and treat differently. The problem that plagues treatment companies is pit
aspiration which will be gone over more extensively in the Microscopy chapter, but when a pit is
9

aspirated or closed off, the wood is resistant to penetration by protective chemicals whether it is
creosote or waterborne preservatives (Bowyer et al. 2007). With this in mind, the goal for
treating conifers is to limit the closing of the cells, with changes in chemicals, treatment
parameters and kiln drying. Figure 4 portrays how two species, southern pine and red pine, react
to the same treatment differently. Southern pine usually treats very well, treating 80% or more of
the sapwood, while red pine is vary sporadic, and most times luck to reach the AWPA standard
of treating 80% or more sapwood (AWPA A3-08). The goal when treating conifers is to know
which parameters need to be adjusted for each species, and if these parameters are correct most
species with treat well.

Figure 3: Southern pine wood (left) exhibits excellent MCA penetration by the presence of the
blue indicator copper dye. Red pine wood (right) shows significantly lesser penetration by MCA.
(30 min. initial/final vacuums, 60 min. pressure duration)

10

Chapter 3
A few anatomical properties of red pine
3.1 Introduction
3.1.1 Anatomical properties
The flow of fluids threw softwoods like red pine in done through tracheids. Tracheids are
long slender cells that make up 90-95 % of the volume softwood and are 25-45 μm in diameter
and 3-4 mm in length (Bowyer et al. 2007). Imagine a tracheid looking like a soft drink straw
that is closed by pinching both ends (Bowyer et al. 2007). The walls of the tracheid are
composed of pits that allow fluids for flow laterally from longitudinal tracheid to tracheid. A pit
by definition is a gap or recess in the secondary cell wall, together with its external closing
membrane (Siau 1971). The pit is believed to be the main problem in pressure treating lumber,
due to the membrane being closed off or the pit being aspirated. An aspirated pit is a pit that has
had the torus move to one side be that is being held tightly to the aperture due to pressure a
pressure change (Siau 1971). A change in pressure on one side of the torus is all it takes to
aspirate that pit which can be caused by drying or any number of changes that the wood
undergoes once cut (Bowyer et al. 2007). Figure 4 is a depiction of how the pit aspirates and the
little change in pressure it takes to move the torus.

11

The pit is open allowing
flow around the torus, due to
the water pressure being the
same on either side of the
pit.

The torus is shifting from
positive pressure to negative
pressure. The pit is not
aspirated fully aspirated

Torus has been shifted by
the pressure difference, thus
the pit is aspirated. The
shifting of the torus was due
to the pressure differenced
on either side of the pit.

Figure 4: Depiction of the pit aspiration of softwood tracheids

Once the pit aspirates, chemicals will not be able to flow through the pit and will have to
find an open pit to continue the flow from tracheid to tracheid. It is thought that once a pit is
aspirated, it is apparently a permanent condition (Jane et al. 1970).

12

The other anatomical structure that limits chemical penetration is resin canals. Resin
canals are tubular passageways lined with living parenchyma cells, which extrude resin or pitch
into the canals, which the tree uses as a defense/healing mechanism (Hoadley 1992). The resin in
problematic first because the pitch needs to be set for the wood to be used as lumber but when
the tree is cut, the resin fills many of the canals as a defense mechanism noted earlier. With the
canals being full of resin and the pits being aspirated, treating this species becomes a difficulty
depending on the degree to which these to mechanisms are enacted, and every tree is different.
Some species have resin few resin canals and some have many, and unfortunately Pinus resinosa
has quite a few that are throughout the entire wood structure, meaning they are evenly dispersed.
3.2 Materials and Methods
3.2.1 Confocal laser scanning microscopy (CLSM)
The Zeiss 5 Pascal confocal laser scanning microscope proved fruitful in observing pits
and tracheids. We found that the best picture quality of pits was from using the reflected laser
light. The samples were cut to approximately 10mm by 10 mm by 1mm thick in the radial
direction. Neither chemicals nor water was used in sample preparation due to changing the
sample and perhaps aspirating more pits. Images were collected with using a 50x EC EpiPlan
(NA0.7) objective, and reflected laser light was recorded from the surface of the wood samples
using the 488nm Argon laser for illumination and a 475-525nm band pass filter for isolation of
the laser line (Frame 2011). Confocal images were recorded at 1 micron increments through the
Z-thickness and Maximum Intensity Projection was used to generate the through-focus
projection for each image (Frame 2011).
3.2.2 Scanning electron microscopy (SEM)
13

The JSM-6400 SEM was used because of the clarity of the images that can be obtained
and the magnification abilities of the microscope. The samples were 4mm by 4mm by 3mm, and
were coated using a carbon coater. Samples were all prepared using a razor, for clean and precise
cuts. The SEM produces quality images by using electrons. Specifically an electron beam that is
projected over the sample where an interaction occurs producing secondary electrons that escape
the surface, which are collected by the Everhart-Thornley detector and converted to image by the
cathode-ray tube (Flegler et al. 1993). The problem we encountered was that the samples were
charging, even when gold coating and carbon coating were used. We found the carbon coating to
work the best but the images were not satisfactory due to the inability for proper sample
preparation due to chemicals altering the resin and the pits. We were able to obtain a couple
quality images, Figure 5 being the best before the electron beam distorted the sample. More work
would be beneficial for another project, but we found the CLSM, to be the best for the time and
money allotted for this project.
3.3 Results and Discussion
3.3.1 Microscopic features of red pine
The SEM in the beginning of this study looked to be the way to observe the anatomical
structure of red pine. The problems we soon encountered were we were not able to chemically
prepare the samples as the standard calls for and we also receive high amounts of charging on the
samples. Figure 4 is the depiction of the inside of a longitudinal tracheid cell kiln dried red pine
at 3600 magnification, which looks unobstructed but further analysis is needed. Further analysis
is needed for two reasons. First the sample preparation resulted in poor quality images due to the
tearing of the cells and the cut being of the transverse surface instead of the radial surface. Future

14

studies may want to cut according to the radial and the tangential views to aid in finding if the
pits are aspirated or open according to the methods that were used by (Dute et al. 2010).
The CLSM was very helpful in looking at the pits; the key will be in future studies to
allow a study that focuses only on the structure of red pine. We found that some pits were open
and others were closed. It did not seem to matter if the samples were of treated or untreated early
wood (Figures 7-8) we saw both aspirated and non-aspirated pits. The latewood did show more
aspirated pits but more work needs to be done to have conclusive results (Figure 9). What we say
is that green wood that is wood that has not been kiln dried seemed to have the most open, nonapirated pits. We also found it easier to find pits on these samples, whether that be because of our
limited sample number and time using the microscope, we are not sure. The one aspect of this
study that we are sure of is that more work needs to be done in the future on the CLSM to view
the pit structure in all samples of treated, untreated, and kiln dried lumber. We were able to see
that some samples pits were non-aspirated which is why in some samples we observed greater
penetration, but more work needs to be done especially a study documenting the before and after
of kiln drying wood.

Pits
Pith

Figure 5: Inside the longitudinal Tracheid of kiln dried red pine. The magnification was 3600x
taken using 6400 SEM. On the left side of the wall one can see the pits of the sample.

15

Non-aspirated
pits

Aspirated pits

Figure 6: Untreated green sample of red pine sapwood; roughly half pits are open, and half are
not. Closed pits appear to be filled ―White color‖. Picture was taken using reflected light. Scale
bar: 20 μm

Non-aspirated pits

Figure 7: Untreated early wood ―sapwood‖ All pits appears to be open. Picture was taken using
reflected light. Scale bar: 20 μm

16

Non-aspirated pits

Aspirated pits

Figure 8: Treated early wood ―sapwood‖. Some of the pits appear open while others appear
closed. Picture was taken using reflected light. Scale bar: 20 μm

Aspirated pits

Figure 9: Treated latewood ―sapwood‖ sample of kiln dried red pine. Pits appear to
be all closed in the picture. Picture was taken using reflected light. Scale bar: 20 μ

17

Chapter 4
Pressure treatment of spring wood
4.1 Introduction
During different seasons the moisture, growing conditions, and temperature change in
trees. These changes during the season affect the growth cycles in the wood which is why there
are ring from the stresses during the summer months to the prime growing environment the
spring brings. In knowing the differences in the seasons we wanted looked at the four different
seasons. Spring season was used to begin, this experiment. The spring samples were all gathered
from Biewer Lumbers sawmill in Mcbain, MI, which is where all the wood from this study was
procured. Spring wood, which in the study was from the end of April, was observed to be full of
water due to the higher precipitation that comes with Michigan springs.
4.2 Materials and Methods
4.2.1Procurement of Lumber
All lumber for the study was procured from Biewer Lumber sawmill, in McBain, Michigan
(Biewer Lumber 2009-2011). The red pine ranged in age from 50 to 55 years old and was from
the North eastern area of Lower Michigan. Logs were cut and on the landing from 1 to 5 days
maximum, before being shipped to the McBain sawmill. Generally the logs were in the log yard
less than a week depending on when the manager could allow the study logs to be cut in the
sawmill. After the log was cut to lumber the wood went into the drying kiln to be dried and then
graded (Figure 10). Kiln drying methods and specific temperatures were not noted due to
confidentiality agreements with the study and we did not want the parameters changed since this
was a study about how to improve pressurize chemical treatment of red pine. Jack pine used in
18

the study was also procured the same way as red pine. The lumber was picked up for the study
within one week of the lumber coming out of the kiln and planed. The lumber was transported
from McBain to the Natural Resources Building in East Lansing, Michigan, within 3 hours of the
samples being loaded on the truck. The samples were then cut to 17.25‖ and placed in one of two
chest freezers in the lab to control the moisture content. The exception was the summer wood for
the study, these samples moisture content was very low in the 9-12 % MC so the decision was
made that keeping the samples at room temperature 70 degrees Fahrenheit, since the temperature
at the time of procurement was around 70 degrees Fahrenheit the wood was already at an
equilibrium moisture content (EMC).
However the southern pine in the study was procured in the study from Biewer Lumber
but it was cut and shipped in from sawmills in the Southern United State, due to the native area
of southern pine being not native to the Great Lakes region. To know the specifics of where the
lumber came from was not available since we were not working with these mills and southern
pine is known to treat well, which is why it was a control in certain treatments.

Figure 10: Graded and stamped kiln dried red pine that was used in this study, all lumber was
graded and kiln dried by Biewer Lumber, Mcbain Michigan.

19

4.2.2 Wood samples
The red pine samples were gathered from Biewer Lumbers sawmill in Mcbain, MI. The
lumber was from the upper northeast area of Lower Michigan, as was all samples for this study.
The lumber was trucked in to Michigan State within one week from the moment the lumber
came out of the kilns and cut to nominal 2‖x4‖x8’ and 10’ (5.1 x 10.2 cm x 2.4 and 3.1 M)
lengths. The Lumber was then kiln dried according to Biewer Lumbers standards, but not noted
due to confidentiality. The lumber was then unpacked, loaded in a pickup truck and driven the
2.5 h to Michigan State University, East Lansing, MI. Boards were marked and cut to 17.5‖
(44.4cm) lengths and stored in Freezers to preserve the moisture content, until a later date for
treatment.
4.2.3 Pre- treatment Moisture content
Samples were cut to 16‖ (40.6 cm) and the remaining 1‖ (2.54cm) samples were oven dried
according to ASTM standard D4442-07 (ASTM 2009). Samples were then allowed to reach
room temperature over 12 hours, while being stored in a conditioning room at 70-80°F (21-27°C)
and 50-60% humidity. Samples were not end sealed in this case to view maximum penetration,
from all surfaces.
4.2.4 Pressure treatment
Samples were all treated in the treatment tank that was 12‖ diameter that was 16.5‖ long
(Figure11) using 1% Cu MCA solution. The tank is filled with solution via initial vacuum
ranging from 20-25‖Hg, when vacuum is diminished solution is then pumped into cylinder via,
pressurized liquid transfer pump. A valve located at the top of the cylinder indicates when
solution has filled the tank along with weighing the solution before and after tank filling. Tank is
20

then pressurized for 1-2 h depending on the schedule, and in a couple cases the tank was refilled
after 30 or 45 min.‖, half the treatment duration‖ to view if adding solution helped penetration.
The Maximum continuous pressure reached was 180 psi and the minimum pressure was 160 psi.
Following positive pressurization period the samples were subjected to a final vacuum (20-25‖
Hg) to withdraw free solution in wood and follow industrial practices, that are used to reduce
weight for shipping costs. Following treatment samples were weighed, and allowed to dry for 24
h before samples were cut in half longitudinally, and sprayed with heartwood/sapwood indicator
―reddish color‖ and copper indicator ―bluish color‖ (AWPA M2-07)(AWPA A3-08).

Figure 11: Treatment tank used for all treatments for the entire experiment. Tank is 12‖ x16‖
and can handle pressures above 200 psi.

4.3 Results and Discussion
The spring treatments consisted of treating red pine samples with MCA in a 1% Cu
concentration (Cu/Az = 96:4). The goal of this cycle of treatments was to view if changes in
treatment cycles improved the penetration. That is we changed the duration of the cycles and
21

refilled the tank half way through the treatment process. This means that we refilled the tank at
30 min. for a 60 min. duration and 45 min. for 90 min. duration (Figures 12 and 15). The
remaining samples were then treated without refilling the tank halfway through the treatment
(Figures 13, 14, and 16). The reason behind experimenting with refilling the tank was that
perhaps after the first half of the treatment some samples were not submerged in solution. This
however was not the case by looking at figures 12 ―refilled‖ and 13 ―non-refilled‖, since both
treatments did not treat well and both still have sporadic penetration through what cells were
open, in fact by observations the non-refill samples of board I treated better. In addition, the
remaining treatments Figures 14-16, did not show any observable improvement in penetration,
whether the treatment had a tank refill or did not have a tank refill.
The only observable detail was that when penetration was observed to increase, also did
the uptake as in Figures 13 and 17. When looking at the graph of Figure 17 and the pictures of
the samples one can view that uptake does correspond to increase in penetration in most
observable cases. However, in the spring treatments we did not view a difference with the
moisture contents affecting the penetration, though almost all samples were around the 15%
moisture content.
What we can gather from this information is that there may be an increase in penetration
with increasing the duration, but nothing that stands out as an achievement. We know that
refilling the makes little to no change in penetration. The main difference that seems to affect
penetration is the wood samples themselves. This could be due to different drying conditions, as
in different locations in the pack being dried, receiving different drying temperature. The reason
behind this is that when drying lumber, one has to account for wood being a superb insulator, so
samples or boards on the inside of a lumber package may not be receiving the same temperatures
22

as the lumber on the outside of the pack. A future study would need to be done with a
temperature probe to observe and record the differences in moisture and temperature associated
with the location of the lumber in the pack or in the kiln. The problem was that with this study all
the kiln drying methods and temperatures are trade secrets for each company, and thus we were
not able to examine drying techniques and temperatures.

Figure 12: Spring kiln dried samples treated for 90 min. with tank refill at 45 min. Initial and
final vacuum 30 min.

23

Figure 13: Spring kiln dried samples treated for 90 min. without tank refill. Initial and final
vacuum 30 min.

24

Figure 14: Spring kiln dried samples treated for 60 min. without tank refill. Initial and final
vacuum 30 min.

25

Figure 15: Spring kiln dried samples treated for 60 min. with tank refill at 30 min. Initial and
final vacuum 30 min.

26

Figure 16: Spring kiln dried samples treated for 90 min. without tank refill. Initial and final
vacuum 30 min.

27

Percent

Spring samples average solution
uptake
70.0
60.0
50.0
40.0
30.0
20.0
10.0
0.0

% UPTAKE

SPKD SPKD SPKD SPKD SPKD SPKD SPKD SPKD SPKD
A1-5 D1-5 I1-5 F1-5 N1-5 O1-5 C1-5 B1-5 K1-5
Spring kiln dried samples

Figure 17: This graph indicates the average percent solution uptake for each set of samples, a set
of samples as in A1-A5 is samples all from one board.

Average moisture content for spring
samples
20.0

Percent

15.0
10.0
5.0

Moisture content %

0.0

Spring samples

Figure 18: This graph indicates the average moisture content for each set of samples, a set of
samples as in A1-A5 is samples all from one board.

28

Chapter 5
Penetration and retention of red pine summer wood (steaming)
5.1 Introduction
Moisture plays an important role in the treatment of lumber. Moisture content is ―the
quantity of moisture in wood expressed as a percentage of the oven dry weight‖ (Siau 1971).
From the moment the tree is cut moisture is being lost to the surrounding environment. The first
that is lost is free water; this is free water which is stored in the lumen. The other form of
moisture that is present in wood is bound water; this is water that is in the cell wall. Bound water
is‖ limited to approximately 30 percent of oven dry weight of the wood‖ (Siau 1971). For the
lumber companies these two sources of water in wood can present problems, because the wood
needs to be dried for shipping and structural purposed, but if the wood is dried to fast or slow,
the wood can be difficult to chemically treat and the lumber can become unstable, warping. The
problem is that to chemically treat lumber the wood must have a moisture content below the fiber
saturation point (FSP) so that chemicals can enter the cells. What this means is that the lumen is
empty so water can be absorbed, but the cell walls are saturated at FSP ( Bowyer et al. 2007).
Most Micronized solutions are water borne as previously noted; meaning if the lumber is below
FSP the wood is more easily treated due to the ability to absorb water. The goal when treating
lumber is to have a moisture content in the area of 15-20% moisture, this way the wood is not
completely dry but not saturated, allowing the optimal condition for chemical uptake.
The equilibrium moisture content (EMC) is the bound water moisture content, meaning
that the moisture content is at equilibrium with the surrounding environment (Siau 1971). The
EMC means that the moisture content of wood is always changing, meaning, if wood is stored
dry indoors versus wet outdoors, and the wood outdoors will have the higher EMC. When
29

treating lumber it is extremely important to keep track of temperature, storage of lumber, and
humidity, because the EMC is always changing and if the EMC becomes too low it becomes
increasingly more difficult to treat as is wood with very high moisture higher than the FSP. The
formula used to calculate moisture content is very important and is something everyone working
in the wood industry must know.
Percent Moisture Content = [(weight with water- oven dry weight)/oven dry weight] x 100
5.2 Materials and Methods
5.2.1 Wood samples
In September of 2009 we received our summer wood for treatment, the problem that was
not known at the time, was that the lumbers moisture content was too low, below 12% which we
would learn is too low for quality pressure treatments . This was solved when procuring other
lumber by talking directly with foresters to know when the lumber will be available, to ensure
the highest moisture content possible. As before the samples were procured from Biewer
Lumbers sawmill in McBain MI and cut to the exact specifications as spring wood with the
exception of the samples not being frozen. The lumber was then stored at 70°F on racks, for
treatment at a later date since moisture would change little due to outdoor temperatures being
equivalent to indoor temperatures.
5.2.2 Pre-treatment steaming and end sealing
After not meeting the AWPA penetration standard in many of the springwood samples
with higher moisture contents and not having the ability to obtain new samples since summer
season was over we decided to try and raise the moisture content. The moisture content was

30

raised by steaming the wood samples, using an autoclave. The samples were steamed at 180°F to
200°F for one hour, in the autoclave, and then allowed to cool to touch. This was done because
at these temperatures the polymerized resins will begin to flow once again and allow water to
penetrate the lumen and cells raising the moisture content and hopefully opening up cells to
allow for improved penetration. Once samples were cooled, the samples were end sealed with a
marine grade epoxy and placed in the conditioning room at 70-80°F (21-27°C) and 50-60%
humidity for 24 hours to set the epoxy and the samples were then treated. Samples were end
sealed to observe if steaming was increasing penetration through the tangential and radial
surfaces and to mimic the treatment of longer lumber in industrial applications.
5.2.3 Pressure treatment
The copper concentration of MCA for the summer samples was around 0.80%, which
was lowered due to industrial standards also lowering, since this study is intended to help the
industry we changed our concentrations when they did, since our solution came from industry
treatment plants. A performance enhancer (PE) was also added to aid in penetration, which was
Quaternary or Quat. The Quat was added to aid in breaking down the resins that had polymerized
while during the industrial high temperature kiln drying. The concentration was .5lbs to 55lbs
(0.9%). The 16‖ samples were placed into the 12‖x 16.5‖ treatment tank filled with solution
using the same process as spring samples and treated for a total of 3h. A 30 min initial vacuum
for tank filling, (20-25 in Hg) followed by 120 min positive pressure(180 psi) and a 30 min
final Vacuum for recycling solution was used once again (20-25 in Hg). Following treatment
samples were weighed, and allowed to dry for 24 h before samples were cut in half
longitudinally, and sprayed with Heartwood/sapwood indicator ―reddish color‖ and copper
indicator ―bluish color‖ (AWPA M2-07)(AWPA A3-08).
31

5.3 Results and Discussion
The moisture content of the samples after receiving the one hour steam cycle rose to
roughly 20% (Figure 22). Raising the moisture content noticeably improved penetration
compared to the samples previous moisture content in the range below 12 percent moisture. The
explanation behind why the samples penetration improved could be for a few reasons, as in
moving the resin, swelling the wood, and bringing the wood samples back to a higher EMC. The
steam also made the resin that was plasticized it into a polymer that is not completely solid
allowing the high pressure associated with treatment to move the solution where it was once
blocked before.
The most likely explanation is that the steam creates swelling in the wood. The swelling
of the samples means that all the checks, cracks, and defects in the wood would open larger that
when the sample had a lower moisture content. The swelling would allow the solution to
penetrate through the cracks and areas of the wood that were once smaller.
To aid the steaming Quat was used and also aided in improving penetration. Quat is used
in soaps, in this case we were supplied with 47% Quat, but in soap applications the concentration
is much lower, sometimes around 1%. The goal was to view if the Quat would break down the
resins as soap does, to allow solution to penetrate deeper. After looking at samples like Figures
19 and 20, it is easy to see that the steaming and Quat are aiding in penetration, but more work
needs to be done to view the maximum amount of Quat and temperature/ duration of steam
creates the best penetration without degrading the wood.
However with steaming alone as Figure 21 indicated greatly improved penetration of
MCA solution into samples. The question that we were left with was that was steaming alone
32

solely increasing the penetration or was the PE that we added increasing the penetration, or both.
After viewing the uptake graph (Figure 23) we for the most part viewed higher average amounts
of solution uptake in samples that were treated with PE and steam, but the observations made on
Figure 21 indicate that the penetration is on par with PE and steam treated samples viewed in
Figure 19. So with this in mind we aimed at observing if treating samples solely with PE’s would
in fact mimic what we saw in steamed samples with PE added or would the results differ.

Figure 19: Kiln dried summer wood, which was subjected to 1 h of steaming and treated with
MCA and Quat PE.

33

Figure 20: Kiln dried summer wood, which was subjected to 1 h of steaming and treated with
MCA and Quat PE.

Figure 21: Kiln dried summer wood, which was subjected to 1 h of steaming, treated with MCA
without Quat PE added.

34

Percent

Average moisture content for
summer samples
30.0
25.0
20.0
15.0
10.0
5.0
0.0

Moisture content %

Summer samples

Figure 22: Average moisture content of summer samples that were steamed for 1 h in autoclave.

Percent

Summer samples solution uptake
180.00
160.00
140.00
120.00
100.00
80.00
60.00
40.00
20.00
0.00

% Uptake

SUKD 1- SUKD 6- SUKD
5
9
1A-5A

SUKD
6A-9A

SUKD
1B-5B

SUKD
6B-9B

Summer kiln dried samples

Figure 23: Average amount of solution uptake in steamed summer samples.

35

Chapter 6
Pressure treatment of fall and winter wood with penetration enhancers added
6.1 Introduction
The goal of the fall and winter treatments was to experiment solely with penetration
enhancing chemicals such as Quat and sodium phosphate. This was done due to not being able to
experiment with drying standards and because an additive would be easy to implement into
industrial practices if proved beneficial. Michigan winters can be very tough on all living
organisms including trees, but with cold temperatures comes freezing, which helps preserve the
moisture content when a tree is cut into logs, but increases drying times and sometimes
temperatures. The winter can also be a trying time for chemical treatment companies because
wood needs to be unfrozen to properly chemically treat. With the knowledge that fall and winter
wood is usually the hardest to treat, due to lack of blue stain and higher drying temperatures, we
wanted to continue using the Quat that aided in improving summer wood samples penetration.
We also wanted to experiment with amine salts, due to the high cost of Quat to view if this PE
would improve penetration, as Quat did in the summer samples.
6.2 Materials and Methods
6.2.1 Wood samples
Samples were gathered from Biewer Lumbers sawmill in Mcbain, MI. Winter and fall
samples were picked up at the same time, in mid-December 2010. The fall samples were from
late November 2010 and thus had been cut for 2 weeks, but due to the cold temperatures the
wood was at near freezing conditions resulting in little moisture loss for the fall wood. Lumber
was again procured according to the same methods as spring wood and frozen when cut to 17.5‖
lengths. The samples were then cut 24h prior to treatment to 16‖ lengths for treatment and end
36

sealed, which is why samples were cut 24h before due to epoxy setting time. Also at the time of
cutting the samples a sample was taken and oven dried for moisture, as we did with previous
treatments.
6.2.2 Penetration enhancer additives
In the past treatments we looked at changing treatment parameters, but in some cases
companies cannot change their parameters due to cost, which is why we aimed at penetration
enhancers. After viewing the results from Quat and steaming the samples we wanted to see what
Quat could do without steam. We also added sodium phosphates to our PE experiment as a more
inexpensive option, if the salts did work. As stated earlier, Quat is an additive to soap, Quat is
not breaks the resin down, it is a lubricant, due to the viscosity. The idea behind adding Quat is
that it not only breaks down resins to allow deeper penetration but it also binds the resin acids
that in many cases inhibits the copper from penetrating deeper. This is the reasoning behind the
salts, is that the salts would perhaps aid in the binding or bonding with the resin acids that tend to
filter out the copper. We believed that if we can add a chemical that will readily bond with the
resin acids that the copper may be able to penetrate deeper than when there is no PE added.
6.2.3 Pressure treatment
The duration did not change from the summer treatments; we decided to keep with 2 h
duration, due to the results from summer treatments. The same 12‖ diameter tank pictured in
Figure 11 was used. The pressure for all the treatments was in the area of 180 psi and the initial
and final vacuum was in the area of 25‖Hg. The biggest change was adding only PE for these
treatments, since our MCA concentration of copper was still around 0.80% (0.799% actual). The
Quat for all the fall and winter treatments was a concentration of 0.9% and the two different
37

concentrations of sodium phosphates were 0.0004 and 0.0008 percent concentrations. The PE
was added before each treatment and thoroughly mixed using an electric mixer. Following
treatment samples were weighed, and allowed to dry for 24 h before samples were cut in half
longitudinally, and sprayed with heartwood/sapwood indicator ―reddish color‖ and copper
indicator ―bluish color‖ (AWPA M2-07)(AWPA A3-08).

6.3 Results and Discussion
To say the least we saw improvements over our original spring treatments. The Quat
additive greatly improved observable penetration. We observed results similar to that of the
summer treatments with steam added. Figure 24 and 25 indicate the quality of penetration that
we could never achieve with only using MCA without additives or changes to drying. We still
have a little ways to go to achieve perfect penetration, penetration better than 80 percent in
sapwood. As far at the sodium phosphates, figure 27 indicates that we did see some
improvements in penetration over some spring samples but more research needs to be done.
Figures 26 and 27 indicate that by doubling the concentration we also saw better penetration. In
looking at the increasing in penetration with concentration, perhaps if the concentration is
increased penetration would also increase. The problem that we had was that time, funds, and the
amount of the salt we had was limited due to this being a small trial. By looking at the moisture
contents, (Figure 28) we see that the average moisture contents was around 15%, so we knew
that we were in the moisture content that is optimal for treating, the problem was that the uptake
(Figure 29) did not match the moisture content as what we saw in past treatments. This could be
due to a number of reasons, heartwood, being the main cause. Heartwood being in the center of

38

the tree is made up of thick walled cells, but is more prone to aspirated pits, which is why
heartwood can be almost impossible to achieve any penetration at times. We do know that the
sodium phosphates for the most part were not as successful at increasing penetration and uptake.
We did view and increase in uptake with the increasing amount of salts added from 0.0004 to
0.0008 percent, which is positive.
However, we did not a large noticeable difference between the summer and winter and
fall samples being for the most part above 80%. This means that the steam 1h steam and the
concentration of PE could be increased to view an increase in penetration, or that PE alone may
be that main factor in increasing penetration, which is why we decided to do a small study for the
AWPA discussed in the next chapter. What we did achieve was an increase in penetration adding
the PE, what we have not achieved in a ―Home Run‖, that is there still needs to be work done
with steaming and PE concentrations.

39

Figure 24: Fall and winter kiln dried samples treated for 2 h with 0.5lbs Quat PE added to MCA
solution.

Figure 25: Fall and winter kiln dried samples treated for 2 h with 0.5lbs Quat PE added to MCA
solution.

40

Figure 26: Fall and winter kiln dried samples treated for 2 h with 0.0004% Sodium phosphate
PE added to MCA solution.

Figure 27: Fall and winter kiln dried samples treated for 2 h with 0.0008% Sodium phosphate
PE added to MCA solution.

41

Average moisture content for fall and
winter samples
Percent

20.0
15.0
10.0
5.0
0.0

Moisture content %

Fall and winter samples

Figure 28: Average kiln dried fall and winter samples moisture contents.

Percent

Fall and winter samples solution
uptake
140.00
120.00
100.00
80.00
60.00
40.00
20.00
0.00

% Uptake

FAKD WIKD FAKD WIKD FAKD WIKD FAKD WIKD
9A-E 14A-E 5A-E 12A-E 1A-E 15A-E 2A-E 13A-E
Fall and winter kiln dried samples

Figure 29: Average fall and winter kiln dried samples solution uptake.

42

Chapter 7
Pressure treating with MCA and DDAC penetration enhancer (AWPA)
7.1 Introduction
The basis behind this mini study was to present that data for an AWPA poster
competition. The overall reason though was to view if increasing the concentration of Quat (PE),
in MCA would yield deeper penetration into out treated samples. We know that adding a PE
helps with penetration but would more PE increase the penetration, this was the question we
were out to prove, at least in a small experiment. The goal was to view 3 species southern pine,
red pine and Jack pine, which are all species that are used in the lumber industry, especially the
great lakes region. We knew that southern pine treated very well, usually better than 80 sapwood
penetration, and we knew that Jack pine is extremely hard to treat due to the heartwood content
the species is known for. That being said, red pine was our middle of the road species, treatable
but can be troublesome at times.
7.2 Materials and methods
7.2.1 Wood samples
Wood samples were once again gathered from Biewer Lumbers sawmill in Mcbain,
Michigan. The samples this time around were nominal 2‖x6‖x8’ boards due to short notice on
the study and samples being readily available in 2x6. Once samples were brought to Michigan
State, East Lansing Michigan, the wood was cut into 17.5‖ lengths and frozen, due to treatment
chemicals no being available. Once chemicals were available samples were thawed, and cut to
16‖ lengths and end sealed once again to mimic treating larger boards. Boards were cut and

43

numbered according to board as other treatments and in this case species were mixed for
treatment because the goal was to view how increasing concentrations affected penetration in
each species.
7.2.2 Quat additive
We used the same 47% concentrations of Quaternary as before, to add to our MCA
solutions in increasing strengths. The MCA solution had a 0.80% copper concentrations and
Copper to azole ratio of 96:4. We treated our MCA only boards for 1,2, and 3 hours to have a
basis as to how MCA treated wood does, using only MCA and increasing the duration as we did
in the spring samples. Then we used the remaining samples from each board for our PE
experiment. The concentrations were 5%, 1%, and 2% PE added to MCA.
7.2.3 Pressure treatment
The treatment procedure mimicked all the other treatments that we did. We used the same
green12‖ diameter treatment tank as the other treatments and filled that tank completely full. The
biggest difference was that for non PE MCA treatments we increased our pressure treatment
duration from 1h to 2h to 3h, for one to view the best treatment duration, and also to view how
increasing duration, affects penetration. For the MCA with PE we kept the duration set at 2h,
because from observations and past treatments 2h seemed to be equal or a little less than the 3h
treatment, but the 3h treatment penetration increase was negligible in our view. The pressures
were in the range of 25 in Hg for the initial and final vacuum, while the positive pressure was in
the range of 180 psi. Following treatment samples were weighed, and allowed to dry for 24 h
before samples were cut in half longitudinally, and sprayed with heartwood/sapwood indicator
―reddish color‖ and copper indicator ―bluish color‖ (AWPA M2-07)(AWPA A3-08).
44

7.3 Results and discussion
Even before this study from treating experience both industrially and experimentally we
knew that southern pine would treat the best, in all cases, since there is less resin in southern pine
than red pine, and southern pine has a record of treating well. With this in mind we treated
southern pine with MCA and as Figure 30 illustrates we easily penetrated most if not all the
sapwood in all three durations 1,2,and 3 h. Knowing this we knew that the PE would keep with
this standard of quality penetration, which Figure 31 indicates better than satisfactory
penetration. We did see a change however in uptake from MCA to MCA with PE, in fact we
viewed an increase in uptake in samples treated with PE (Figures 36 and 37). Which can be good
or back, it is good that we are allowing more penetration of chemicals but bad due to increasing
weight when MCA treated southern pine is already treating very well.
Next we treated Jack pine; the problem from the start is that Jack pine is notorious for
high amounts of heartwood, which in the treatment world we know as almost being impervious
to solution penetration. The problem was that the lumber we were given for the study had high
amount of heartwood and even when sorting the lumber to better match the southern pine and red
pine we were unable to find samples of only heartwood(Figures 32 and 33). What we did find
was that we penetrated the sapwood and thus the wood samples would pass the AWPA standard
for penetrating 80% or more sapwood (Figures 32 and 33) (AWPA A3-08). The low numbers in
the uptake of MCA with PE treatment was due to the high amount of sapwood (Figure 37). Plus,
by looking at Figure 36 it is easy to view how heartwood affected penetration, in looking at how
the samples boards differ in heartwood in Figure 32.

45

Since this study was all about red pine, we saved the most positive or influential
improvements adding PE gained last. We not only viewed increases in penetration with
increasing the amount of PE added we also viewed a higher and constant uptake from sample to
samples in MCA with PE (Figure 36 and 37). This is due to the PE allowing improved
penetration in all samples and also the samples having little to no heartwood. The most
interesting data or observation was the with increasing the amount of PE from 0.5% to 2%, we
also viewed an increase in penetration in both boards from left to right in Figure 35, MCA with
PE added. This shows that indeed the Quaternary is aiding in penetration and breaking down the
resins. The question for further studies will be how much PE should be added before we view
decreases in perhaps structure or what is the maximum effective amount of PE that should be
used to treat the sapwood of red pine or other species. We know that MCA alone does not always
treat red pine well as Figure 34 indicates, and we also know that duration does help, in allowing
the solution to penetrate deeper. The problem with treating red pine with MCA alone is that there
is sporadic penetration meaning, it cannot be for the most part predicted, which results in
problems for some chemical treatment companies and creates problems for quality control. MCA
is a great treatment chemical that treats many species extremely well and is much friendlier for
the environment; as far as red pine goes MCQ will perhaps be the micronized chemical for the
future treatment of red pine, but time, treatment methods and additives will dictate this.

46

Figure 30: Southern pine samples treated with MCA. The top two samples of each column are of
the same board as is the bottom two samples. Treatment duration is increasing from one hour to
three hours from the left column to the right column.

Figure 31: Southern pine samples treated with MCA with PE added. The top two samples of
each column are of the same board as is the bottom two samples. Treatment duration was set at 2
h with PE concentrations increasing from 0.5 %, 1 %, and 2 % from the left column to the right.
47

Figure 32: Jack pine samples treated with MCA. The top two samples of each column are of the
same board as is the bottom two samples. Treatment duration is increasing from one hour to
three hours from the left column to the right column.

Figure 33: Jack pine samples treated with MCA with PE added. The top two samples of each
column are of the same board as is the bottom two samples. Treatment duration was set at 2h
with PE concentrations increasing from 0.5 %, 1 %, and 2 % from the left column to the right.
48

Figure 34: Red pine samples treated with MCA. The top two samples of each column are of the
same board as is the bottom two samples. Treatment duration is increasing from one hour to
three hours from the left column to the right column.

Figure 35: Red pine samples treated with MCA with PE added. The top two samples of each
column are of the same board as is the bottom two samples. Treatment duration was set at 2 h
with PE concentrations increasing from 0.5 %, 1 %, and 2 % from the left column to the right.
49

MCA Absorption non PE
Treatments 1-3
140.0
RP Board 1

100.0

RP Board 2

80.0

JP Board 1

60.0

JP Board 2

40.0

SP Board 1

20.0

Percent

120.0

SP Board 2

0.0
1

2

3

Treatments (Hours)

Figure 36: Absorption of pine species treated with MCA without PE. Board 1 indicates the top
two samples in a column while board 2 indicated the bottom two samples in the above figures.
RP = Red pine JP = Jack pine SP = Southern pine

Percent

MCA Uptake with PE
Treatments 1-3
160.00
140.00
120.00
100.00
80.00
60.00
40.00
20.00
0.00

RP Board 1
RP Board 2
JP Board 1
JP Board 2
SP Board 1
SP Board 2

1

2

3

Treatments (PE)

Figure 37: Absorption of pine species treated with MCA with PE added, with two hour treatment
time. Board 1 indicates the top two samples in a column while board 2 indicated the bottom two
samples in the above figures. RP = Red pine JP = Jack pine SP = Southern pine

50

Chapter 8
Conclusion
Using CLSM and SEM microscopes we were able to view both open and closed pits. The
images that we gathered did not show enough evidence on our part to know if what may be
causing pit aspiration or why some pits appear aspirated while a row next to the aspirated pits
appear to be non-aspirated. We learned that the CLSM is highly valuable in viewing samples that
cannot be altered, but future SEM studies using other techniques may also be fruitful.
The spring treatments taught us that increasing the duration and refilling the tank half
way through the pressure treatment may have yielded small increases in penetration but not the
answer that we were looking for and not the solution to the industries problem. We found from
all the treatments combined that 2h was the optimal treatment time. This time gave the solution
proper time to penetrate and even an hour about 2h yielded little to no change in penetration.
After treatment of all 4 seasons using various methods and chemicals, we did not observe
definitive differences. This could be due to industry drying standards and it could also be due to
the smaller scale of this study. We do know that blue stain greatly influences the ease of
chemical treatment during the summer months, which is why some treatment companies may say
that summer wood tends to treat easier. Secondly, the wood during the winter is frozen in certain
parts of the Great Lakes Region, which in some instances causes the temperature and duration of
kiln drying lumber to increase, thus placing causing higher differences in pressure/moisture in
wood causing perhaps more aspirated pits. We believe the biggest opponent to increasing or
decreasing penetration may be in the drying process, whether that be duration, temperature, or
the final moisture of the wood upon exciting the kiln.

51

Chemical solutions may be the easiest way to influence changes in penetration. Our
constant chemical throughout this experiment was MCA. MCA treats many species well mainly
southern pine, where most in no all treated southern pine passed the AWPA standard for
sapwood penetration, but the problem is that every species is not the same even if they are in the
same genus or family (AWPA, A3-08). MCA did treat some samples of red pine well but the
treatments were not predictable, the entire basis of this study was to find a predictable treatment
for red pine, on that the industry could use with confidence. Penetration enhancers gave us a
partial answer to what the industry and what we were looking for. We found that PE increased
our uptake and penetration, especially with increasing the amounts of PE added from 0.5% to
2.0%. The problem was that still in some samples PE did not give us the predictable and quality
treatment that we wanted.
PE and steam was the best combination for treating red pine with MCA or MCQ that we
found. The high temperature steam ―around 200 °F‖ allowed the wood to swell which opened the
wood and cells to allow the solution to penetrate. Steam and MCQ was our best combination for
improving penetration because the steam moved and cracked the plasticized resin, while the
Quaternary broke down the now penetrated resins allowing deeper penetration in most if not all
treated samples. The combination of steam and MCQ gave us the combination that we had been
looking for. It also was a partial solution that the industry was looking for since they also tried
the MCQ after our increases observed in lab.
Steam however may be the magic wand if you will that the industry is looking for
because any sample or piece of wood can be steamed and treated with any chemical a company
desires. We observed that steam improved penetration with both MCA and MCQ, but steam
could also be helpful in treating other species and could be used with other chemicals. Steam
52

also may allow sawmills to still use high temperature fast drying methods but allow treatment
companies the ability now to penetrate woods such as red pine or Jack pine that were considered
more difficult to treat.
Above all this research has opened up new methods to treat red pine. Companies have
already adopted some of our treatment methods and ideas. The main goal of this research was to
improve the penetration of red pine which we did. Though we improved the penetration, there is
still room for improvements and further testing needs to be done. What this study has done is
open the doors on treating red pine, we know that there are options now and it is a matter of time
and funding to find the correct combinations to have red pine treatment perfection.

53

LITERATURE CITED

54

Literature Cited

Anderson, M.K. and L.M. Moore. 2003. United Stated Department of Agriculture, plan guide:
Red pine Pinus resinosa. USDA NRCS National Plant Data Center. Available at.
http://plants.usda.gov
ASTM Book of Standards. 2009. Standard Test Methods for Direct Moisture Content
Measurement of Wood and Wood-Base Materials, West Conshohocken, PA
Available at: http://www.astm.org/search/standards-search.html?query=d444207&searchType=standards-full
AWPA Book of Standards. 2009. American Wood Protection Association. Birmingham,
Alabama. Available at: www.awpa.com/standards/updates.asp
Barnes, B.V. and W.H. Warren, Jr. 1981 Michigan trees. The University of Michigan Press. Ann
Arbor, Michigan.
Barnes, B.V. and W.H. Warren, Jr. 2004. Michigan Trees: A guide to the trees of the Great
Lakes Region. Revised and updated. The University of Michigan Press. Ann Arbor,
Michigan. P. 92.
Bowe, S., S. Hubbard, T. Mace, J. Koning, and J. Cummings Carlson. 2005. Blue Stain: is it
coloring your bottom line red? DNR Publication and University of Wisconsin extension.
Wisconsin.
Bowyer, J.L., R. Shmulsky, and J.G. Haygreen. 2007. Forest Products and wood science. Fifth
edition. Blackwell Publishing. Ames, Iowa.
Dirr, M.A. 1990. Manual of woody landscape plants: their identification, ornamental,
characteristics, culture, propagation, and uses. fourth edition. Stipes Publishing Co.,
Champaigne, Illinois.
Dute, R., D. Rabaey, J. Allison, & S. Jansen. 2010. Torus-bearing pit membranes in species of
Osmanthus. International Association of Wood Anatomists Journal 31:217-226.
Farrar, J.L. 1995. Trees of the northern United States and Canada. Iowa State University Press,
Ames, Iowa.

55

Frame. M. 2011. Center for advanced microscopy (CLSM).Michigan State University. East
Lansing, Michigan.
Freeman, M.H., T.F. Shupe, R.P. Vlosky, and H.M. Barnes. 2003. Past, present, and the future of
the wood preservation industry. Forest Products Journal. Vol. 53, No. 10. pp. 8-15.
Flegler, S.L., J.W. Heckman, and K.L. Klomparens. 1993.Scanning And Transmission Electron
Microscopy An Introduction. Oxford University Press., Inc., New York, New York.
Forest Products Laboratory. 1999. Wood handbook—Wood as an engineering material. Gen.
Tech. Rep. FPL–GTR–113. Madison, WI: U.S. Department of Agriculture, Forest
Service, Forest Products Laboratory. 463 p.
Hoadley, B.R. 1990. Identifying wood: Accurate results with simple tools. First edition. The
Tauton Press, Inc. Newtown, Connecticut.
Hoadley, B.R. 1992. Understanding wood: a craftsman’s guide to wood technology. Eighth
printing. The Taunton Press, Inc. Newtown, Connecticut.
Jane, F., W, K. Wilson, and D.J.B. White. 1970. The structure of wood. Adam and Charles Black
Publishers Ltd. London, England.
Osmose, Inc. 1016 Everee Inn Road, Griffin, Georgia 30224
Pilon, J., J. Bielecki, R. Doepker, F. Krist, and L. Pedersen. 2006. Guidelines for Michigan Red
pine management based on ecosystem management principles for state forestland in
Michigan. Michigan Department of Natural Resources statewide council.
Sargent, C.S. 1961. Manual of the trees of North America. Vol. 1. Docer Publications, Inc., New
York, New York.
Siau, J.F. 1971. Flow in wood. First edition. Syracuse University Press. Syracuse, New York.
Virginia Tech. 2009. Pinus resinosa Fact Sheet. Department of Forest Resources and
Environmental Conservation. Available at:
http://www.cnr.vt.edu/DENDRO/DENDROLOGY/syllabus/factsheet.cfm?ID=110
Wang, J. Z. and R. DeGroot. 1996. Treatability and Durability of Heartwood. Available at:
www.reeis.usda.gov/web/crisprojectpages/219807.html (verified November 3, 2009)
Zahora, A. 2011. Further studies of the distribution of copper in treated wood using an XRF
microscope technique. Viance R&D Technology Center. Charlotte, North Carolina.

56