Green ash
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
Green ash.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 ‘Green ash.pxl’ file on your PDA and,
•
Save the file under a new name after finishing data collection on each site, e.g. ‘Green ash site1.pxl’,
‘Green ash site2.pxl’…….. to avoid overwriting previous files with data.
Monitoring Seral Stages in Green ash-Prunus Ecological Type
Classification, seral assignment, and monitoring of green ash-prunus ecological type seral stages is
according to the method of Uresk (1990). Statistical analysis of field-collected data indicates the presence of
four seral stages: early, early intermediate (EINT), late intermediate (LINT) and late. 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 Green ash.xls
program for methods).
For the green ash-prunus ecological type the key variables are the basal area of trees in square feet per acre
for Fraxinus pennsylvanica (FRPE) and the percent canopy cover of Prunus virginiana and P. americana
combined (PRSP), 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 Green
Ash and canopy cover of Prunus on a site resulted in the following values: FRPE=59 and PRSP=42. Four
years later the values obtained were: FRPE=54 and PRSP=43. Calculating the probabilities, we find:
FRPE PRSP
LATE LINT
EINT
EARLY
Stage
Year1
59
42
.390
.509
.100
.001
LINT
Year5
54
43
.082
.849
.068
.001
LINT
Difference
In both years, the site was classified and
assigned to the late intermediate seral
stage; the greatest probability values
(.509 in Year1 and .849 in Year5) are
associated with LINT.
Placement
within the late intermediate seral stage
is at the lower end of the stage, as
indicated by the second greatest
probability values (.390 for Year1 and
.082 for Year5) which are associated
with a later seral stage (LATE). The
site shows a downward successional
change of about .34, which is the
difference between the probabilities in
Year1 and Year5.
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.
.340
Late
Early Intermediate
Late Intermediate
.51
Early
Year 1
1.0
.5
Late
1.0
.5
1.0
Early Intermediate
Late Intermediate
.85
1.0
.5
Early
Year 5
1.0
.5
Late
1.0
.5
1.0
Early Intermediate
Late Intermediate
.34
1.0
.5
Early
Change
1.0
.5
1.0
.5
1.0
.5
1.0
Page 1 of 4
Monitoring Seral Stages in Green ash-Prunus Ecological Type
80
Basal Area >1''
Prunus cover
60
40
2
Basal area (ft /acre), Canopy cover (%)
Green ash-Prunus
Ecological Type by Seral Stage
20
0
Late
L.Intermediate
E.Intermediate
Early
Mean Values
Green ash BA (ft2/a)
*Prunus cover (%)
84
31
31
50
41
7
13
6
Mean values of plant variables through four stages of succession in a green ash-prunus ecological
type. Smoothed lines connect the means for each key plant variable at each stage. Graph provides a
guide for an approximate mixture of species variables at each seral stage.
*Chokecherry (Prunus virginiana) and American plum (P. americana)
Page 2 of 4
Monitoring Seral Stages in Green ash-Prunus Ecological Type
DATA COLLECTION,
SUMMARIZATION
30m
40m
10m
40m
30m
40m
30m
20m
20m
30m
AND
TYPE LIMITS
PLOT LIMITS
TRANSECT
CALCULATIONS
Green Ash
Enter Ash DBH
DBH BA
10.5
87
1.0
1
8.8
61
11.3
100
1.1
1
2
3
1.0
1
9.3
68
8.1
52
10.0
79
1.3
1
1.2
1
2.0
3
9.2
66
7.6
45
7.8
48
7.6
45
8.4
55
11.3
100
8.2
53
10.3
83
7.5
44
7.1
40
9.3
68
3.1
8
1.0
1
9.2
66
7.2
41
1.1
1
1.2
1
8.9
62
9.1
65
1.4
2
1.7
2
1.1
1
6.9
37
3.3
9
3.4
9
2.6
5
4.4
15
5.1
20
4.9
19
7.0
38
3.0
7
2.8
6
3.1
8
2.0
3
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
Enter Daubenmire classes 1 through 6
Xsect Frm
PRSP
1
1
2
1
2
2
1
3
2
1
4
4
1
5
3
1
6
5
1
7
3
1
8
2
1
9
6
1
10
4
1
11
4
1
12
2
1
13
4
1
14
0
1
15
2
1
16
6
1
17
2
1
18
4
1
19
3
1
20
2
1
21
4
1
22
3
1
23
0
1
24
3
1
25
2
1
26
2
1
27
6
1
28
2
1
29
3
1
30
5
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%
Basal Area
2
2
0
3
4
4
2
3
3
5
4
6
6
3
2
2
6
2
2
5
1
2
1
3
4
6
6
3
3
4
43
54
Seral Stage Classification Probability
LATE LINT
EINT
EARLY
0.082 0.849 0.068 0.001
Assigned Stage
LINT
1. Following one of the layouts in the figure above, based
on area covered by vegetation type, establish an 800m2
plot and two 30 m permanent transects, a minimum of
20m apart, within the Green ash-prunus type.
Recommendations are to establish two plots per section
within the ecological type.
2. Using the ‘Green ash.xls’ spreadsheet (see figure at
right) installed on your PDA:
Record the DBH in inches of
each Fraxinus
pennsylvanica (FRPE) tree > 1” diameter within the
800m plot.
Record canopy cover of Prunus spp.* (PRSP) within a
20cm x 50cm quadrat at one-meter intervals along each
transect (30 readings/transect) using Daubenmire (1959)
classes 1 through 6.
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 spp. for
the site. It also provides classification probabilities by seral
stage and the seral stage assignment.
*Prunus spp. = Prunus virginiana and P. americana.
Calculations
Basal area per tree (in inches) = DBH2 / 4 x 3.14.
BA (ft2 / acre) = Sum basal of all Green Ash trees on plot, divide
by 144 to convert basal in inches to basal in feet. Multiply BA (ft)
by 5.06 to convert BA per 800m2 to BA per acre.
Cover (%) = Sum Daubenmire midpoint values for Prunus spp.
and divide by 60.
Page 3 of 4
Monitoring Seral Stages in Green ash-Prunus 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