Bur oak
Page 1.
Introduction: discussion of classification, seral assignment and monitoring.
Page 2.
Graph.
Page 3.
Instructions: plot setup and data collection using the Excel spreadsheet.
Page 4.
References.
Caution
Bur oak.xls is an Excel workbook containing the datasheet for field data collection. Copy the Excel file to a
PDA. The .xls file will be converted to a Pocket Excel file with a .pxl extension. The file contains a
spreadsheet with formulas that provide calculations necessary for classification of a site, using the variables
defined for this ecological type.
Be careful with the spreadsheet when loaded on a PDA. Although the formulas and cells are protected on the
PC version of Excel, protection of spreadsheets/worksheets is not an option on the Pocket version of Excel. It
is possible to erase formulas and stop the classification system. Be sure to make changes only within the empty
cells, and not in any of the calculation or formula cells such as cov%, probabilities, etc.
In addition, always:
•
Keep a backup copy of the original ‘Bur oak.pxl’ file on your PDA and,
•
Save the file under a new name after finishing data collection on each site, e.g. ‘Bur oak site1.pxl’,
‘Bur oak site2.pxl’…….. to avoid overwriting previous files with data.
Monitoring Seral Stages in Bur oak-Prunus-Snowberry Ecological Type
Classification, seral assignment, and monitoring of Bur oak-Prunus-Snowberry ecological type seral stages
is according to the method of Uresk (1990). Statistical analysis of field-collected data indicates the presence
of three seral stages: late, intermediate, and early. A site is classified, and assigned to a seral stage by entering
a set of key plant measurements into the set of canonical discriminant functions developed for this ecological
type and estimating posterior probability for each seral stage (SPSS, 1995). The site monitored is assigned to
the stage with the highest posterior probability (See Bur oak.xls program for methods).
For the Bur oak-Prunus-Snowberry ecological type the key variables are the basal area of trees in square
feet per acre for Quercus macrocarpa (QUMA), and the percent canopy cover of Prunus spp. (PRUN) and
Symphoricarpos occidentalis (SYOC), using Daubenmire’s (1959) canopy cover method.
The seral stage assigned to a set of plant measurements is always associated with the greatest probability
value. If that value is 1, then succession is at the middle of the assigned seral stage. If the greatest probability
value is less than 1, then the second greatest probability value is used to determine the successional status
relative to middle of the assigned stage. For instance, if the second greatest probability is associated with an
earlier seral stage, succession is at the lower end of the assigned seral stage. On the other hand, if the second
greatest probability is associated with a later seral stage, succession is at the upper end of the assigned stage
(see example below).
When permanent macroplots are established to assess the vegetational trend of a site, re-sampling and
comparing the previously assigned seral stage to the current stage provides information about succession or
retrogression. On a finer scale, within-stage changes in vegetation successional status can be quantified by
comparing the probability values. For example, first-year field measurements collected for basal area of bur
oak and canopy cover of Prunus and snowberry on a site resulted in the following values: QUMA=82,
PRUN=32, and SYOC=20. Four years later the values obtained were: QUMA=84 PRUN=39, and SYOC=21.
Calculating the probabilities, we find:
QUMA PRUN SYOC
LATE
INT
EARLY
Stage
Year1
82
32
20
.006
.994
.000
INT
Year5
84
39
21
.211
.789
.000
INT
Difference
In both years, the site was classified and
assigned to the intermediate seral stage; the
greatest probability values (.789 in Year1 and
.994 in Year5) are associated with INT.
Placement within the intermediate seral stage is
at the upper end of the stage, as indicated by the
second greatest probability values (.211 for
Year1 and .006 for Year5) which are associated
with a later seral stage, LATE. The site shows
an upward successional change of about .21,
which is the difference between the probabilities
in Year1 and Year5.
.205
Late
Intermediate
.99
Year 1
1.0
.5
Late
1.0
.5
Intermediate
.79
1.0
Early
Year 5
1.0
.5
Late
The figure to the right illustrates this example.
These quantitative changes in the probabilities
can be used to evaluate and monitor the effects
of management alternatives.
Early
1.0
.5
Intermediate
.21
1.0
Early
Change
1.0
.5
1.0
.5
1.0
Page 1 of 4
Monitoring Seral Stages in Bur oak-Prunus-Snowberry Ecological Type
Bur oak-Prunus spp- Snowberry
Ecological Type by Seral Stages
140
100
Basal Area (ft2 /acre)
80
100
60
80
40
60
Canopy Cover (%)
Basal Area
Prunus spp
Snowberry
120
20
40
20
0
LATE
INT
EARLY
Mean Values
Basal Area (ft2 /a)
*Prunus spp (%)
Snowberry (%)
131
40
9
57
6
11
27
11
35
Mean values of plant species through three seral stages of succession in a Bur oak-Prunus sppSnowberry ecological type. Smoothed lines connect the means for each key plant variable at each
stage. Graph provides a guide for an approximate mixture of variables at each seral stage.
*American plum (Prunus americana) and chokecherry (Prunus virginiana)
Page 2 of 4
Monitoring Seral Stages in Bur oak-Prunus-Snowberry Ecological Type
DATA COLLECTION,
30m
SUMMARIZATION
OR
40m
10m
20m
40m
40m
20m
30m
30m
AND
30m
CALCULATIONS
VEG TYPE LIMITS
2
2
2
4
5
1
4
2
4
3
3
1
Recommendations are to monitor two sites per section
(640 acres) within the ecological type. Sites should be at
least ¼ mile apart.
Enter Daubenmire classes 1 through 6
DBH BA
7.0
7.3
7.4
8.9
8.8
17.3
8.6
13.6
2.5
5.0
14.3
4.5
4.7
12.2
8.6
23.6
2.5
5.0
14.3
4.5
8.6
3.6
22.5
5.0
14.3
4.5
Basal Area
Xsect Frm
38
42
43
62
61
235
58
145
5
20
161
16
17
117
58
437
5
20
161
16
58
10
397
20
161
16
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
84
PRUN SYOC
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
Mean cov %
4
2
2
6
6
1
1
3
5
5
4
3
1
4
2
3
2
2
1
3
2
1
3
2
2
5
6
3
4
2
1
3
3
1
3
1
4
5
3
5
4
4
4
2
2
3
3
6
6
6
5
6
6
2
3
3
1
2
1
3
3
5
39
Seral Stage Posterior Probability
LATE
INT EARLY
0.21
0.79
0.00
Assigned Stage
INTERMEDIATE
3
2
2
2
4
2
1
5
2
4
1
4
3
1
1
1
2
4
21
TRANSECT
1. Within the Bur oak-Prunus-Snowberry type, establish a
permanent plot with an area of 800m2. Ideal plot
dimensions are 20m x 40m; however, on some sites it may
be necessary to use two 10m x 40m plots. Along the plot
boundaries, establish two 30m transects, a minimum of
20m apart. (See figure above)
Bur Oak
Enter DBH only
PLOT LIMITS
2. Using the ‘Bur oak.xls’ spreadsheet (see figure at left)
installed on your PDA:
Record the DBH in inches of each Quercus macrocarpa
(QUMA) tree 1” or greater in diameter within the 800m2
plot.
Record canopy cover of Prunus spp. (*PRUN) and
Symphoricarpos occidentalis (SYOC) within a 20cm x
50cm quadrat at one-meter intervals along each transect
(30 readings/transect) using Daubenmire (1959) class
codes 1 through 6. *American plum (Prunus americana) and
chokecherry (Prunus virginiana).
Class Code
1
2
3
4
5
6
Cover Class
>0 - 5%
5 - 25%
25 - 50%
50 - 75%
75 - 95%
95 – 100%
Mid Point
2.5%
15%
37.5%
62.5%
85%
97.5%
The spreadsheet calculates basal area for each tree and for the
site, and mean percent canopy cover for Prunus and
snowberry for the site. It also provides classification
probabilities by seral stage and the seral stage assignment.
‘Bur oak.xls’ Calculations
Basal area per tree (in inches) = DBH2 / 4 x 3.14.
BA (ft2 / acre) = Sum basal of all trees on plot, divided by 144 to
convert basal in inches to basal in feet. BA (ft) x 5.06 converts BA
per 800m2 to BA per acre.
Cover (%) = Sum of Daubenmire cover class midpoint values for
each species divided by 60.
Page 3 of 4
Monitoring Seral Stages in Bur oak-Prunus-Snowberry Ecological Type
REFERENCES
Daubenmire, R. 1959. A canopy-coverage method of vegetational analysis. Northwest Science.
33(1):43-64.
SPSS 12.0 for Windows. 1989-2003. SPSS Inc. 444 N Michigan, Ave, Chicago, IL 60611.
Uresk, D. W. 1990. Using multivariate techniques to quantitatively estimate ecological stages in a
mixed grass prairie. J. Range Mgt. 43(4):282-285.
Page 4 of 4