1. 1
Comparing Growth Rates Between Quercus falcate, Pinus taeda, and Juniperus1
virginiana2
3
*Jennifer Luther, Ryan Grubb, Carl Chmielewski4
White Hall, Union University, Jackson, TN 38305 (JL, RG, CC)5
6
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Abstract--- It is generally accepted that there is a noticeable difference in the8
diameter growth rates of softwood trees and hardwood trees. It is important to9
know the growth rate of certain tree species that are commercially valuable in10
order to know when it is the proper time to harvest. In this study, we evaluated11
the growth rates of a hardwood tree, southern red oak, and two softwood trees,12
the loblolly pine and eastern red cedar. Each of these species are extremely13
commercially valuable. One of the easiest ways to assess the growth rate of a14
tree is to take a core sample. Twenty cores were taken from loblolly pine (Pinus15
taeda), southern red oak (Quercus falcata), and eastern red cedar (Juniperus16
virginiana) at two locations in Carroll County, Tennessee. Growth rings were17
measured and counted for a period of 10 years in order to find the difference in18
the average width of the growth rings between each of the species. We looked at19
the difference between each species with the assumption that the loblolly pines20
and eastern red cedar would contain a larger growth width than that of the21
southern red oak. Our null hypothesis is there was no difference in the average22
diameter of growth rings between Quercus falcata, Pinus taeda, and Juniperus23

2. 2
virginiana. We found that eastern red cedar had a much larger growth width than24
the other two species, but there was a significant differences between the growth25
width of southern red oak and loblolly pine.26
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Introduction29
30
The three species involved in this study, loblolly pine (Pinus taeda), southern red31
oak (Quercus falcata), and eastern red cedar (Juniperus virginiana), are all very32
common species in the southeastern United States. (Sewell et al., 1999). Loblolly pine33
is one of the most commercially important species due to its wide range, rapid juvenile34
growth, and multiple uses for wood products. It has a range that extends through 1435
states from New Jersey to central Florida, and as far west as east Texas (1999). It does36
not natively grow in the Mississippi flood plain, but has been introduced due to its37
commercial value and ability to fight erosion. The loblolly is an adaptable species and38
has been found to be intolerant to moderately intolerant to shade. Most of its range is39
considered humid with warm temperatures, and having long, hot summers with mild40
winters (1999). The southern red oak is important for area wildlife who use it for shelter41
and food, and its hard, strong wood is used for general construction, furniture, and fuel.42
It is one of the more common upland southern oaks. Its range extends from Long43
Island, New York to northern Florida and west to eastern Texas. The southern red oak44
is a moderately fast growing tree of medium size. Most of the range is humid with warm45
temperatures, with hot summers and mild winters, but without any distinct dry season46

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(Belanger et al., 2004). The Eastern Red Cedar is also important species, not as much for its47
commercial value, but the wood is considered to be valuable for its beauty and durability (Sewell48
et al., 1999).49
Since these are both important species in the area, learning as much about them50
as possible is beneficial. There is already a known difference in the growth between all51
of these species, but databasing growth for different areas is important to the52
commercial industry (Houck et al., 2013). However, environmental factors can affect53
growth rates, making them highly variable. Forest crowding or how close each tree is to54
one another, soil, moisture, nutrients, insects, and disease are all factors that can affect55
a tree being able to grow to its full potential (Perry, 1978). Also, trees have been found56
to not grow at a constant rate during their life span because they tend to have a faster57
growth before reaching maturity so they will not be overtopped in the canopy (Lutz,58
2011). Our null hypothesis is that there is no difference in the average diameter of59
growth rings between Quercus falcate, Pinus taeda, and Juniperus virginiana.60
Materials and Methods61
62
Coring is the process of removing a small cylinder, or core, from the tree’s trunk.63
. When a core is taken, it is used for collecting general data about the trees past such64
as age and amount of growth per year. Core samples were collected at two properties65
in Carroll County, Tennessee. Property 1 was located at Grooms Rd, and property 2 at66
Tate School Rd. Core samples were taken from Southern Red Oak (Quercus falcata),67
Loblolly Pine (Pinus taeda), and Eastern Red Cedar (Juniperus virginiana). Trees were68
chosen at random which measured between 68 cm to 181 cm in diameter at breast69

4. 4
height. Any trees found outside of these measurements were thrown out. Trees were70
identified by GPS coordinates, and can be seen in figures 1-4. Ten trees from each71
species were selected at each site for a total of twenty sample cores per species.72
To remove the core from the selected trees, an increment borer is drilled into the73
tree and then a tray was inserted into the bore to release the core and slid it out. Bees74
wax was applied to lower friction, as to much friction would scar the wood with burn75
marks. The presence of burn marks on the cores make measuring the rings difficult.76
The cores were allowed to dry for 1-2 days to remove any moisture that could alter77
results.78
Tree rings were counted and the width of each ring measured to obtain data for a79
total of 10 years. Southern red oak was measured by finding the lighter area of the core,80
and then finding the porous vessel tissue. Loblolly pine cores where measured from a81
light strip to a dark strip, this was 1 year of growth. Eastern red cedar cores where82
measured from a darker red strip to the next darker red strip. Each ring width was83
marked with a pencil and then measured with a metric ruler. Each of these84
measurements was considered one year’s growth. An example of this method can be85
seen in Figure 7.86
Statistics, tables, and graphs were calculated using R-Studio and Excel software.87
The dependent variable for the study was the growth of each species per year, and the88
independent variable was each of the three species. An alpha level of 0.05 was used as89
a significance level. To find each species percentage of accumulated growth for the total90
10 year period, the diameter at breast height of the trunk was averaged for all samples of91
each species and the number of rings were counted per inch of each core and then92

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averaged together for each species. The formula used was: Growth % = (4/DBH x RPI))93
x 100, where DBH = diameter at breast height and RPI = rings per inch (Synder, 2001).94
On average for any tree, two to three percent is a common measurement and anything95
that measures four percent or more is excellent growth (2001).96
Results97
98
When data was put into R-studio, the mean growth width per year for each species99
was found to be 4.92 mm for loblolly pines, and 2.23 mm for southern red oaks and100
11.74 mm for eastern red cedar. The average DBH for each species was 992.03 mm for101
loblolly pine, 2042.25 mm for southern red oak, and 1054.42 mm for eastern red cedar.102
The RPI for loblolly pine was 5.95, southern red oak was 11.7, and eastern red cedar103
was 2.25. This can be seen in Figure 8. Data was analyzed to show a comparison of the104
average growth width for each species which is shown in Figure 9. A shapiro-wilks105
normality test was performed and the data was found to be normally distributed (loblolly106
pine: p = 0.38, southern red oak: p = 0.87, eastern red cedar: p = 0.095). A Bartlett Test107
was further performed and the data was found to have a homogeneity of variance (p =108
0.084). Since the data passed both of these tests and found to be parametric, an109
ANOVA test for the ring width growth was performed and since the Fcalc was extremely110
larger than Fcrit, the null hypothesis was rejected (p = <2e-16, Fcalc = 1514, Fcrit = 5.4).111
To find a comparison between each of the species a Tukey Post Hoc Test was112
performed and a significant difference was found when comparing each of the species113
(Oak-Cedar: p = 0, Pine-Cedar: p = 0, Pine-Oak: p = 0).114
Conclusion115

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116
Based on the data compiled, we found a statistical difference between the117
average width of the growth rings of each species. The growth percentage data showed118
a much higher average growth width rate in eastern red cedar than either the southern119
red oak or the loblolly pine. These differences can be seen in figures 8 and 9. This120
means we reject our null hypothesis which states there was no difference between the121
average width of the growth rings between Quercus falcata, Pinus taeda, and Juniperus122
virginiana. There is a significant difference in the width of the growth rings between123
each of the species. The fact that the eastern red cedar is especially affected by its124
environment could be one of the reasons for this tremendous difference (Grissino-125
Mayer, Undated). The eastern red cedars that were sampled could be in the optimal126
conditions for this species to reach its maximum growth potential.127
In the future, the eastern red cedar should be sampled at sites which include128
multiple soil and moisture types. Changes in the environmental conditions could prove129
to cause measurable changes in the growth of each of these species. So, another factor130
which could be researched in the future is to investigate the some of the ways the131
environment affects the growth rate of each species. Changes in the environment could132
be proven to be the reason for variations in growth rates, particularly the growth rates133
between site 1 and site 2 or even between samples at the same site. This could include134
canopy cover, rainfall, or temperature.135
Literature Cited136
137

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Belanger, R. P., Krinard, R. M. 2004. Southern Red Oak. Silvics of Forest Trees of the138
United States USDA Ag Handbook. 654:2.139
Grissino-Mayer, H. D. The Science of Tree rings. The University of Tennessee.140
Available at: http://web.utk.edu/~grissino/index.htm.141
Houck, J. E., Eagle, B. N. 2007. Hardwood or Softwood? Hearth & Home. 12:49-50.142
Lutz, J. 2011. How Trees Grow. Forest Research Notes. 8:1-4.143
Perry, T. O., 1978. Trees and Their Typical Ages and Growth Rates. Metro. Tree Impr.144
1:1-12.145
Sewell, M. M., Sherman, B. K., and Neale, D. B. 1999. Consensus Map for Loblolly Pine146
(Pinus taeda L.). I. Construction and Integration of Individual Linkage Maps From147
Two Outbred Three-Generation Pedigrees. Genetics. 151:321-330.148
Snyder, Michael. 2001. How Do I Measure the Growth of My Trees? Wood Whys?149
Northern Woodllands.org150
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Fig. 1. Randomly selected loblolly pine from site 1. GPS coordinates for each sample162
are: loblolly 1 at 36⁰ 03’ 29.39” N -88⁰ 32’ 58.11” W, loblolly 2 at 36⁰ 03’ 30.60” N -88⁰163
32’ 61.17” W, loblolly 3 at 36⁰ 03’ 31.61” N -88⁰ 32’ 58.46” W, loblolly 4 at 36⁰ 03’ 34.95”164
N -88⁰ 32’ 60.01” W, loblolly 5 at 36⁰ 03’ 37.20” N -88⁰ 32’ 55.78” W, loblolly 6 at 36⁰ 03’165
32.54” N -88⁰ 32’ 69.18” W, loblolly 7 at 36⁰ 03’ 31.92” N -88⁰ 32’ 77.44” W, loblolly 8 at166
36⁰ 03’ 31.70” N -88⁰ 32’ 40.30” W, loblolly 9 at 36⁰ 03’ 32.80” N -88⁰ 32’ 76.80” W,167
loblolly 10 at 36⁰ 03’ 32.74” N -88⁰ 32’ 76.26” W.168
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Fig. 2. Randomly selected loblolly pine from site 2. GPS coordinates for each sample177
are: loblolly 1 at 35⁰ 96’ 81.98” N -88⁰ 44’ 72.50” W, loblolly 2 at 35⁰ 96’ 83.21” N -88⁰178
44’ 71.46” W, loblolly 3 at 35⁰ 96’ 82.76” N -88⁰ 44’ 74.11” W, loblolly 4 at 35⁰ 96’ 82.45”179
N -88⁰ 44’ 73.67” W, loblolly 5 at 35⁰ 96’ 83.70” N -88⁰ 44’ 60.12” W, loblolly 6 at 35⁰ 96’180
84.66” N -88⁰ 44’ 59.99” W, loblolly 7 at 35⁰ 96’ 84.39” N -88⁰ 44’ 59.21” W, loblolly 8 at181
35⁰ 96’ 84.57” N -88⁰ 44’ 60.42” W, loblolly 9 at 35⁰ 96’ 84.51” N -88⁰ 44’ 60.52” W,182
loblolly 10 at 35⁰ 96’ 82.75” N -88⁰ 44’ 60.60” W.183
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Fig 3. Randomly selected southern red oak from site 1. GPS coordinates for each191
sample are: oak 1 at 36⁰ 03’ 30.43” N -88⁰ 32’ 61.24” W, oak 2 at 36⁰ 03’ 31.36” N -88⁰192
32’ 63.67” W, oak 3 at 36⁰ 03’ 32.57” N -88⁰ 32’ 61.50” W, oak 4 at 36⁰ 03’ 34.72” N -88⁰193
32’ 62.54” W, oak 5 at 36⁰ 03’ 34.95” N -88⁰ 32’ 60.06” W, oak 6 at 36⁰ 03’ 32.35” N -88⁰194
32’ 69.91” W, oak 7 at 36⁰ 03’ 32.43” N -88⁰ 32’ 69.40” W, oak 8 at 36⁰ 03’ 30.63” N -88⁰195
32’ 71.97” W, oak 9 at 36⁰ 03’ 29.01” N -88⁰ 32’ 77.29” W, oak 10 at 36⁰ 03’ 32.18” N -196
88⁰ 32’ 74.39” W.197
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Fig. 4. Randomly selected southern red oak from site 2. GPS coordinates for each206
sample are: oak 1 at 35⁰ 96’ 77.17” N -88⁰ 44’ 67.21” W, oak 2 at 35⁰ 96’ 79.84” N -88⁰207
44’ 68.71” W, oak 3 at 35⁰ 96’ 00.32” N -88⁰ 44’ 70.70” W, oak 4 at 35⁰ 96’ 79.95” N -88⁰208
44’ 72.86” W, oak 5 at 35⁰ 96’ 79.49” N -88⁰ 44’ 74.59” W, oak 6 at 35⁰ 96’ 80.57” N -88⁰209
44’ 74.52” W, oak 7 at 35⁰ 96’ 84.44” N -88⁰ 44’ 83.11” W, oak 8 at 35⁰ 96’ 84.04” N -88⁰210
44’ 82.21” W, oak 9 at 35⁰ 96’ 86.60” N -88⁰ 44’ 85.29” W, oak 10 at 35⁰ 96’ 88.03” N -211
88⁰ 44’ 86.17” W.212
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Fig. 5. Randomly selected eastern red cedar from site 1. GPS coordinates for each221
sample are: cedar 1 at 36⁰ 03’ 31.45” N -88⁰ 32’ 71.10” W, cedar 2 at 36⁰ 03’ 30.31” N -222
88⁰ 32’ 73.93” W, cedar 3 at 36⁰ 03’ 29.07” N -88⁰ 32’ 76.99” W, cedar 4 at 36⁰ 03’223
31.07” N -88⁰ 32’ 78.78” W, cedar 5 at 36⁰ 03’ 31.30” N -88⁰ 32’ 78.37” W, cedar 6 at224
36⁰ 03’ 30.88” N -88⁰ 32’ 62.27” W, cedar 7 at 36⁰ 03’ 32.73” N -88⁰ 32’ 63.95” W, cedar225
8 at 36⁰ 03’ 35.20” N -88⁰ 32’ 68.35” W, cedar 9 at 36⁰ 03’ 40.58” N -88⁰ 32’ 55.32” W,226
cedar 10 at 36⁰ 03’ 35.93” N -88⁰ 32’ 53.17” W.227
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Fig. 6. Randomly selected eastern red cedar from site 2. GPS coordinates for each236
sample are: cedar 1 at 35⁰ 96’ 84.54” N -88⁰ 44’ 64.42” W, cedar 2 at 35⁰ 96’ 81.52” N -237
88⁰ 44’ 63.52” W, cedar 3 at 35⁰ 96’ 82.98” N -88⁰ 44’ 66.68” W, cedar 4 at 35⁰ 96’238
77.83” N -88⁰ 44’ 66.27” W, cedar 5 at 35⁰ 96’ 75.07” N -88⁰ 44’ 65.45” W, cedar 6 at239
35⁰ 96’ 78.68” N -88⁰ 44’ 47.42” W, cedar 7 at 35⁰ 96’ 83.82” N -88⁰ 44’ 71.09” W, cedar240
8 at 35⁰ 96’ 83.17” N -88⁰ 44’ 74.07” W, cedar 9 at 35⁰ 96’ 83.58” N -88⁰ 44’ 69.12” W,241
cedar 10 at 35⁰ 96’ 81.66” N -88⁰ 44’ 60.07” W.242
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Fig. 7. Example of reading tree core to find ring width. Image found at245
http://academic.emporia.edu/aberjame/ice/lec10/lec10.htm.246
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Fig 8. Total growth percent of each species seen graphically. The growth percent for253
each species is loblolly pine = 1.72%, southern red oak = 0.65%, and eastern red cedar254
= 4.33%.255
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Loblolly Pine Southern Red Oak Eastern Red Cedar
Growth%

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Fig 9. Comparison of average growth width between species for each of the 10266
years.267
0
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4
6
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2005 2006 2007 2008 2009 2010 2011 2012 2013 2014
Averageringwidth(mm)
Loblolly Pine Southern Red Oak Eastern Red Cedar