Competition and individual size This lab will observe the effects of competition on pine trees. All of the pine trees in each of the study areas were planted at the same time, and therefore are the same age. They are also known as "improved" trees. This means that they have been genetically selected from a few parent trees over two or more generations. Thus, these trees are similar in their genetic make-up. There are three main factors that determine the rate of growth in trees: water, nutrients, and sunlight. All of the trees are on the same deep sandy soil. It is droughty and nutrient poor. Pines can grow under both of these conditions, so we will assume that competition for sunlight is the main factor responsible for the differences in the size of the trees. However, note that it is likely that competition for all three resources contributes to the size difference in the trees to some extent. Experiment 1. Measure the circumference of 50 sand pine (Pinus clausa) trees along the road or other open area. Measure the circumference of 50 pine trees in the middle of the stand. Take the measurement at breast height (4½ feet or 1.4 m from the soil surface). Plot your results using histograms. Test the difference between your means with a t-test – see handout 5b. Discuss your results. What type of competition is this? Experiment 2. Measure 100 longleaf pine (Pinuspalustris) trees at random. Fifty will be from the area of high competition from hardwoods and 50 from the area where hardwood competition has been reduced by the use of fire. Determine the height (m) using a Merritt Hypsometer and the circumference at breast height (cm) with a tape. To use the Merritt Hypsometer, stand 66 feet from the tree that you wish to measure, plumb the hypsometer stick 25” from your eye. Line up the stick with the base of the tree (rather than stump height in this case), read the height on the scale, then multiply by 16 to get the height in feet. Report your data in SI (metric units - meters) see link below for metric converter. Note if the tree is in the open (O), or if hardwood trees shade it (S). Graph this information in the form of a scatter graph (see Fig. 1 below for example). Place height on the vertical axis and circumference on the horizontal axis, using different symbols or colors to represent the different populations (hardwood open, hardwood shaded, burnt area open, burnt area shaded). In addition, use histograms to graph the plants by height alone, and by circumference alone, again using different shading or colors to represent the different populations (hardwood open, hardwood shaded, burnt area open, burnt area shaded).  Discuss your results. Also use F and t-tests to see if the differences are statistically significant. Does competition effect growth height or circumference the most, or is it equal? What type of competition is this? Figure 1. Example of a scatter graph. Write up: Supplement your write up with i.

1. Competition and individual size
This lab will observe the effects of competition on pine trees.
All of the pine trees in each of the study areas were planted at
the same time, and therefore are the same age. They are also
known as "improved" trees. This means that they have been
genetically selected from a few parent trees over two or more
generations. Thus, these trees are similar in their genetic make-
up.
There are three main factors that determine the rate of growth in
trees: water, nutrients, and sunlight. All of the trees are on the
same deep sandy soil. It is droughty and nutrient poor. Pines
can grow under both of these conditions, so we will assume that
competition for sunlight is the main factor responsible for the
differences in the size of the trees. However, note that it is
likely that competition for all three resources contributes to the
size difference in the trees to some extent.
Experiment 1. Measure the circumference of 50 sand pine
(Pinus clausa) trees along the road or other open area. Measure
the circumference of 50 pine trees in the middle of the stand.
Take the measurement at breast height (4½ feet or 1.4 m from
the soil surface). Plot your results using histograms. Test the
difference between your means with a t-test – see handout 5b.
Discuss your results. What type of competition is this?
Experiment 2. Measure 100 longleaf pine (Pinuspalustris) trees
at random. Fifty will be from the area of high competition from
hardwoods and 50 from the area where hardwood competition
has been reduced by the use of fire. Determine the height (m)
using a Merritt Hypsometer and the circumference at breast
height (cm) with a tape. To use the Merritt Hypsometer, stand
66 feet from the tree that you wish to measure, plumb the
hypsometer stick 25” from your eye. Line up the stick with the

2. base of the tree (rather than stump height in this case), read the
height on the scale, then multiply by 16 to get the height in feet.
Report your data in SI (metric units - meters) see link below for
metric converter. Note if the tree is in the open (O), or if
hardwood trees shade it (S). Graph this information in the form
of a scatter graph (see Fig. 1 below for example). Place height
on the vertical axis and circumference on the horizontal axis,
using different symbols or colors to represent the different
populations (hardwood open, hardwood shaded, burnt area open,
burnt area shaded). In addition, use histograms to graph the
plants by height alone, and by circumference alone, again using
different shading or colors to represent the different populations
(hardwood open, hardwood shaded, burnt area open, burnt area
shaded). Discuss your results. Also use F and t-tests to see if
the differences are statistically significant. Does competition
effect growth height or circumference the most, or is it equal?
What type of competition is this?
Figure 1. Example of a scatter graph.
Write up: Supplement your write up with information on sand
pine and longleaf pine communities in the southeastern United
States and on competition between pines and hardwoods. What
type of management tool is used to reduce competition from
hardwoods on pines?
Acknowledgments:
I would like to thank Dr. Alvin Diamond for his advice,
suggestions and for providing me with his version of this lab.
References:
Smith, R. L. and T. M. Smith. 2001. Ecology and Field
Biology (6th Ed.), Benjamin Cummings. Relevant sections of
Chapter 12 and Chapter 14.

3. Links:
Metric converter: http://www.convert-me.com/en/
Sand pine:
http://www.na.fs.fed.us/spfo/pubs/silvics_manual/Volume_1/pin
us/clausa.htm
Longleaf pine:
http://www.na.fs.fed.us/spfo/pubs/silvics_manual/Volume_1/pin
us/palustris.htm
http://www.archives.state.al.us/emblems/st_tree.html
Data sheet for pine lab
Species of pine: Longleaf pine (Pinuspalustris)
Date: 09/17/13
Experimental group (circle one):
Burnt area
Hardwood area
#
Height
(ft logs)
Height
(ft)
Height
(m)
Circumference
(cm)
O or S
#

4. Height
(ft logs)
Height
(ft)
Height
(m)
Circumference
(cm)
O or S
1
1.8
28.8
45
S
26
1.8
49
O
2
2.0
52
O
27
3.1
82

5. O
3
1.75
51
O
28
1.6
49
O
4
2.3
66
O
29
2.3
67
O
5
2.0
80
O
30
2.2
72

6. O
6
2.5
71
O
31
2.3
64
O
7
2.8
58
O
32
2.7
86
O
8
2.5
65
O
33
3.0
80

7. O
9
2.4
65
O
34
3.1
88
O
10
3.0
66
O
35
2.5
67
S
11
2.6
62
O
36
2.8
90

8. O
12
2.3
81
O
37
3.2
78
O
13
2.5
78
O
38
3.0
80
O
14
2.6
71
O
39
2.0
71

9. O
15
2.8
66
O
40
3.0
92
O
16
2.5
69
O
41
2.3
75
O
17
2.8
80
O
42
2.3
89

10. O
18
2.9
79
S
43
2.5
79
O
19
3.1
70
O
44
2.0
78
O
20
2.8
79
O
45
2.3
64

11. O
21
2.0
70
O
46
2.7
80
O
22
1.75
65
O
47
2.0
74
O
23
3.1
65
S
48
2.1
98

12. O
24
2.0
55
O
49
2.4
79
O
25
1.8
52
O
50
2.5
73
O
Height in the Height (ft) column is height in foot-logs column x
16
Data sheet for pine lab for RM&ED FA2016
Species of pine: Longleaf pine (Pinuspalustris)
Date: 09/17/13
Experimental group (circle one):
Burnt area

13. Hardwood area
#
Height
(ft logs)
Height
(ft)
Height
(m)
Circumference
(cm)
O or S
#
Height
(ft logs)
Height
(ft)
Height
(m)
Circumference
(cm)
O or S
1
1.7
27.2
42
S

14. 26
-
-
1.0
11
S
2
1.6
50
S
27
2.7
68
S
3
1.5
48
O
28
2.3
74
S
4
2.3
50
O

15. 29
1.75
48
S
5
1.7
61
O
30
2.6
65
O
6
2.0
49
S
31
2.6
58
S
7
2.5
40
O

16. 32
2.0
58
O
8
1.8
62
O
33
2.0
59
O
9
1.9
58
O
34
1.75
70
O
10
2.7
42
S

17. 35
2.75
68
O
11
2.5
42
S
36
1.7
80
O
12
1.9
46
O
37
1.8
52
O
13
1.9
57
S

18. 38
2.3
69
O
14
2.2
60
O
39
2.5
77
O
15
2.8
46
S
40
2.5
76
O
16
2.5
43
S

19. 41
2.2
56
O
17
2.8
58
O
42
1.9
76
O
18
2.3
65
O
43
1.8
61
S
19
2.5
64
O

20. 44
2.4
58
S
20
2.5
63
S
45
1.9
40
S
21
2.2
57
O
46
2.0
68
O
22
2.0
33
S

21. 47
2.2
75
O
23
2.0
54
O
48
2.0
41
S
24
2.6
48
S
49
2.0
64
O
25
1.8
52
O

22. 50
1.5
43
S
Height in the Height (ft) column is height in foot-logs column x
16
Data sheet for pine lab for BIO/EBS 6691
Species of pine: Sand pine (Pinus clausa)
Date: 09/17/13
Road side/Open area
Inside stand
#
Circumference
at BH (cm)
#
Circumference
at BH (cm)
#
Circumference
at BH (cm)
#
Circumference
at BH (cm)

23. 1
127
26
98
1
89
26
46
2
115
27
120
2
76
27
116
3
111
28
111
3
90
28
113
4
125
29
112
4
77
29
120
5
72
30
97

24. 5
99
30
111
6
136
31
90
6
86
31
79
7
116
32
102
7
116
32
107
8
114
33
123
8
95
33
100
9
109
34
130
9
97
34
117

25. 10
84
35
97
10
77
35
100
11
79
36
85
11
116
36
118
12
106
37
117
12
75
37
89
13
126
38
106
13
112
38
103
14
102
39
104

26. 14
83
39
70
15
124
40
78
15
106
40
87
16
71
41
90
16
54
41
76
17
79
42
128
17
92
42
78
18
102
43
114
18
99
43
87

27. 19
126
44
121
19
113
44
84
20
114
45
88
20
61
45
102
21
113
46
97
21
90
46
66
22
121
47
130
22
69
47
79
23
81
48
90

28. 23
70
48
110
24
102
49
85
24
63
49
93
25
111
50
108
25
69
50
54
Pine Competition – statistical tables
From:
Zar, J. H. (1974) Biostatistical Analysis. Prentice Hall,
Englewod Cliffs, N. J.