NorthPro : A Spreadsheet Program for
the Management of Uneven-aged
Northern Hardwood Stands
Jingjing Liang, Joseph Buongiorno, and Audra Kolbe
and Benedict Schulte
Department of Forest Ecology and Management
School of Natural Resources
University of Wisconsin-Madison
Abstract
NorthPro is a Microsoft Excel add-in program to simulate the growth and management of
uneven-aged northern hardwood stands of the maple-beech-birch type in Wisconsin or
Michigan. Its built-in growth models were calibrated from 623 uneven-aged plots in
Wisconsin and 1,259 plots in Michigan. Stands are described by the number of trees per
unit area in each of 12 size classes in the following species groups: shade-tolerant, midtolerant, and shade-intolerant species.
NorthPro allows managers to predict stand development by year and for many
decades from a specific initial state. Users can choose cutting regimes by specifying the
interval between harvests (cutting cycle) and a target distribution of trees remaining after
harvest. A target distribution can be a BDq distribution or any other desired distribution.
Diameter-limit cuts can also be simulated. Tabulated and graphic results show diameter
distributions, basal area, volumes, income, net present value, and indices of stand
diversity by species and size.
This manual documents the program installation and activation, provides
suggestions for working with Excel, and gives background information on NorthPro’s
growth model. It offers a comprehensive tutorial, in the form of two practical examples,
that explains how to start the program, enter simulation data, execute a simulation,
compare simulations, and plot summary statistics.
Keywords: Northern Hardwoods, Uneven-aged Management, Economics, Ecology,
NorthPro, Simulation, Software, Growth model, Diversity.
________________________________________________________________________
Contents
1. Introduction ............................................................................................................... 1
What is NorthPro? ..................................................................................................... 1
Why Simulate this Type of Stand? ......................................................................... 1
How does NorthPro work? ....................................................................................... 2
What is in this manual? ............................................................................................ 2
2. Getting Started ........................................................................................................... 3
2.1. System Requirements ......................................................................................... 3
2.2. Installing NorthPro ............................................................................................ 3
2.3. Uninstalling NorthPro ....................................................................................... 4
3. Using NorthPro ......................................................................................................... 4
3.1. NorthPro Input .................................................................................................... 4
3.2. BDq Calculator .................................................................................................... 6
3.3. Storing Data and Retrieving Stored Data ..................................................... 7
3.4. Running Simulations .......................................................................................... 8
3.5. Quitting NorthPro .............................................................................................. 9
4. Examples ..................................................................................................................... 9
4.1. Simulating the Arbogast Cutting Guide ........................................................ 9
4.2. Simulating BDq and Diameter-Limit Management Regimes ................. 19
5. Trouble Shooting NorthPro ................................................................................ 27
References .................................................................................................................... 29
Glossary ....................................................................................................................... 31
Appendix A― Species and Shade Tolerance of Trees of Maple-Beech-Birch
Forest Type in Wisconsin ........................................................................................... 33
Appendix B― The Growth Models ........................................................................... 35
Appendix C― Tree Volume equations ..................................................................... 37
Appendix D― Definition of Diversity of Tree Species and Size ............................. 39
1. Introduction
Welcome to NorthPro—a spreadsheet program to help with management decisions for
northern hardwood forests with uneven-aged systems. This paper provides background,
instruction, and additional suggestions for using the NorthPro program. The examples
contain detailed instructions for each step. If you are new to NorthPro, it will be useful to
run these examples while reading the paper.
What is NorthPro?
NorthPro (2003) is an upgraded version of the unpublished program originally written by
Kolbe. It is meant to predict the development of northern hardwood stands in Wisconsin
and Michigan. With this program, various management regimes can be considered, and
their outcomes can be quickly predicted. Two relatives of NorthPro, SouthPro and
WestPro, already exist for loblolly pine in the Southern United States (Schulte et al.
1998) and for Douglas fir in the Pacific Northwest region of the United States (Ralston et
al. 2003). We have used our experience with these programs to further simplify the data
input and the program output to maximize NorthPro’s usefulness for practitioners.
Why Simulate this Type of Stand?
Northern hardwood forests occupy almost one third of Wisconsin’s timberland area
(Schmidt 1998), and almost two fifths of Michigan’s (Leatherberry et al. 1996). Some of
these forests are managed for timber income. However, there is also much interest in
conserving biological diversity (Niese and Strong 1992). Uneven-aged management,
selecting single trees or small groups of trees at intervals of five to twenty years and
encouraging natural regeneration, helps maintain a continuous tree cover with aesthetic
1
and ecological benefits (DeBell and Franklin 1987). Effective uneven-aged management
of northern hardwoods can also be profitable (Buongiorno et al. 2000). NorthPro helps
foresters predict how a given forest stand might look in the future and what it could yield
under uneven-aged management.
How does NorthPro work?
NorthPro predictions are based on multi-species, site- and density-dependent matrix
growth models for either Wisconsin or Michigan (Kolbe et al. 1999). These growth
models update a previous model by Lin et al. (1996) with the most recent inventory data
for Wisconsin and Michigan and with the addition of site sensitivity. The models were
calibrated from the most recent North Central Forest Inventory and Analysis (NC-FIA)
Eastwide Data Base, which contained information on tree growth, mortality, and
regeneration in 623 permanent plots in Wisconsin and 1,259 plots in Michigan.
The matrix models built in NorthPro predict growth, mortality, and the rate of
ingrowth (recruitment) for shade-tolerant, mid-tolerant and shade-intolerant species
(defined in Appendix A) as functions of stand basal area, site index, and individual tree
size. The model equations are described briefly in Appendix B.
What is in this manual?
The next section explains how to install NorthPro on your computer, followed by a
section that describes data input, saving and loading the data, running simulations, and
saving the results. Next, two examples of applications are given. We included answers to
some common questions. The manual assumes that you are familiar with the basics of
Microsoft Excel.
2
2. Getting Started
2.1. System Requirements
You must have the following hardware and software to operate NorthPro:

Computer with at least 16 megabytes of random access memory (RAM)

Windows® 95,98, 2000, Me, XP, or Windows NT™ 4

Microsoft Excel 5.0 to Excel 2002
2.2. Installing NorthPro
To install the program for the first time, follow the following steps:
1. Insert the diskette containing NorthPro.xla into your computer.
2. Select the icon named NorthPro.xla and copy it onto your hard disk. For your
convenience,
you
may
save
it
in
a
new
folder
named
NorthPro:
C:\NorthPro\NorthPro.xla.
3. Open Microsoft Excel and START A NEW WORKBOOK.
4. Under the Tools menu, select Add-ins. Once the add-ins dialogue box appears,
select Browse and choose the NorthPro.xla from its location on your hard disk:
C:\NorthPro\NorthPro.xla. Click OK.
5. Return to the Tools menu and notice that NorthPro is now the last choice in the
menu. Select NorthPro and click OK in the title box.
6. The NorthPro menu should now be in the Excel menu bar.
3
After you have installed the program, NorthPro will become a permanent option under
the Tools menu in Excel. Clicking on the name NorthPro in the Tools menu will add
NorthPro to the Excel menu, and the input data worksheet (Figure 1) will appear.
There are seven sample workbooks with the input data worksheets corresponding to the
examples given in Part 4. Copy the data from these worksheets to your input data
worksheet, and you will be able to run these simulation regimes with NorthPro.
2.3. Uninstalling NorthPro
To remove the NorthPro menu and uninstall the program, do the following:
1. Close all Excel windows.
2. Select the file NorthPro.xla and delete it from your hard disk.
3. Open Microsoft Excel and start a new workbook.
4. Under the Tools menu, select Add-ins. Deselect NorthPro to remove the title
from the add-ins list.
5. Close the Excel window.
3. Using NorthPro
3.1. NorthPro Input
In the input data worksheet (Figure 1), all cells with question marks require an entry.
NorthPro accepts only digit entries except the state entry that must be “WI” or “MI”.
NorthPro automatically converts numeric entries to one or two decimal places.
4
In Figure 1, the initial stand state refers to the number of trees per acre of the
stand in year zero, by species groups and by 2-inch diameter classes. NorthPro recognizes
three species groups: shade-tolerant, mid-tolerant, and shade-intolerant (Appendix A).
The target stand state refers to the number of trees per acre, by species group and by
diameter class that should remain after harvest. A target entry of zero instructs NorthPro
to harvest all trees in that species category and diameter class; you can prevent the
removal of any tree by entering a very high target, say 1,000. When the number of trees
in the stand exceeds the target value, the harvest is the difference between the available
trees and the target.
Figure 1 Input Data worksheet
5
Stumpage prices for pole trees are in dollars per cord; sawtimber prices are in dollars per
Mbf. All NorthPro simulations start at year zero. The cutting cycle must be non-zero. If
there is no harvest, set the year of the first harvest larger than the length of the simulation.
The re-entry cost in dollars per acre represents costs independent of volume harvested,
such as timber sale preparation and administration. NorthPro treats empty input data cells
as errors and will prompt you to fix them. You may enter zeros for price, re-entry cost,
and interest rate if you are not interested in the financial analysis.
3.2. BDq Calculator
The BDq calculator is useful if you want to define the target state or the initial state with
a BDq distribution. A BDq distribution is defined by the stand basal area, the diameter of
the smallest and largest trees, and the ratio of the number of trees in a given diameter
class to the number of trees in the next larger class.
Click on the BDq calculator icon in the input data worksheet. Use the arrow
buttons to set the basal area (square ft/acre), the q-ratio, the minimum diameter (in) and
the maximum diameter (in), then click the Calculate button. Figure 2 shows the number
of trees in each size class that would give a basal area of 90 square ft/acre with trees of
diameters from 2 to 24 in and a q-ratio of 1.7.
6
Figure 2 The BDq Calculator window
You can copy the resulting stand distribution to the input data worksheet as the initial
distribution or as the target distribution for a species group by selecting the destination
and clicking the Copy button.
3.3. Storing Data and Retrieving Stored Data
Once you have entered data in the Input Data worksheet, you can save it for later use.
You should save your work frequently to avoid losing data. It is advisable to save the
work in a particular folder to facilitate locating the file in the future.
To run several simulations, for example to examine the effects of changing some
of the parameters, you may find it efficient to work with previously saved input data. To
retrieve the data, choose File → Open command in Excel to open your saved file, or
double-click on the file icon.
7
3.4. Running Simulations
You are ready to run a simulation after you have completed the input data worksheet or
retrieved a previously saved input data worksheet. To run NorthPro, make sure that the
NorthPro menu is in the Excel menu bar. If not, click NorthPro under the Tools menu to
activate NorthPro. You can then run the simulation by choosing Run in the NorthPro
menu.
Each NorthPro simulation generates the following worksheets and charts:
1.
“TreesPerAcre” worksheet: The number of trees by species and size for each
simulated year.
2. “Basal Area” worksheet: The basal area by species and tree diameter, for each
simulated year.
3. “Products” worksheet: The physical and financial return from harvests throughout
the simulation.
4.
“Diversity” worksheet: Shannon’s species diversity indices and size diversity
indices for each year of the simulation.
5. “Diversity Chart”: A plot of Shannon’s indices of species and size diversity over
time.
6. “Species BA Chart”: A stacked area chart showing the development of stand basal
area by species group over time.
7. “Size BA Chart”: A stacked area chart showing the development of stand basal
area by timber size over time.
8
To compare various management regimes, save your output worksheets
immediately after running the simulation. Otherwise, NorthPro will replace the previous
simulation results with the new ones every time you run a new simulation.
All the data in the output worksheets are protected and you cannot change them.
To find out how results change with different input data, you can make changes on your
input data worksheet and rerun the simulation.
3.5. Quitting NorthPro
To terminate working with NorthPro, choose the command Quit under the NorthPro
menu. The NorthPro menu will then disappear, but the current worksheets will stay in the
Excel window until you close them.
4. Examples
4.1. Simulating the Arbogast Cutting Guide
One of the earliest stocking guides used in the Lake States was the Arbogast guide
(Arbogast 1957).
It was developed from field experiments applying uneven-aged
management on northern hardwood stands and sought a practical marking rule for
establishing an uneven-aged stand that would grow well.
Arbogast suggested
maintaining basal areas of 65-75 ft2 per acre for sawtimber trees (diameters greater than
11 inches), 10-20 ft2 per acre for pole trees (diameters greater than 5 inches and less than
11 inches), and 5-10 ft2 per acre for saplings (diameters greater than 1 inch and less than
5 inches). One possible interpretation of this approach is reflected by the target stand
9
distribution shown in Figure 3. Arbogast also recommended that stands be cut every 8 to
15 years.
4.1.1. Input Data
The initial stand state for this example is shown in Figure 3. It corresponds to the average
stand state observed during Wisconsin’s fifth inventory. Trees in each species group are
assembled into twelve 2-inch diameter classes ranging from 2 to 24+ inches. Each class
is denoted by its midpoint diameter. For example, the 2-inch class includes trees with
diameter at breast height (DBH) from 1 to 3 inches. The 24+ inch diameter class
includes trees 23 inches and larger in DBH. Enter these data into the “Initial State” row
of the Input Data worksheet, shade-tolerant data into cells B5 through M5, mid-tolerant
data into cells B11 through M11, and shade-intolerant data into cells B17 through M17.
In this example, you do not need to use the BDq calculator.
The target stand state is the number of trees per acre that you would like to have
in each diameter class and species group after a harvest. Arbogast’s desired number of
trees per acre has been divided by species in proportion to the number of trees per acre in
the initial state, where shade-tolerant trees compose 73% of the stand, mid-tolerant trees
compose 9%, and shade-intolerant trees compose 18%. Enter these data into cells B6
through M6, B12 through M12, and B18 through M18.
The stumpage prices in Figure 3 are based on values collected in Wisconsin
(Wisconsin Department of Natural Resources 1996-1998). Saplings (diameter classes 2
and 4 inches) often have no commercial value, while trees with commercial value are
divided into two groups: poles (diameter classes 6 through 10 inches), and sawtimber
(diameter classes 12 inches and greater). Enter the prices in cells B7 through M7, B13
10
through M13, and B19 through M19 for each species. Enter the re-entry cost into cell
B26. This value was assumed to be $30/acre for timber sale preparation and
administration. Then enter into cell B28 a real interest rate of 3 percent per year, based on
the average annual return of AAA corporate bonds from 1950 to 1997, net of inflation
(U. S. Government 1998).
Next, enter in cell B22 the year of the first harvest, assumed to be 3 years after
the beginning of the simulation. Set the cutting cycle to 10 years in B23, which fits within
the 8-15 years recommended by Arbogast. Then set the length of the simulation to 100 to
allow for 10 harvests.
Then enter a site index of 70 into cell B30, the average site index for Wisconsin’s
northern hardwoods, measured by the average total height of the dominant and
codominant trees at 50 years of age (Hansen et al. 1992). The site index of the stand
should be between 30 and 99, the range of site index values on which NorthPro was
calibrated. Finally, enter “WI” for Wisconsin in cell B32.
11
Figure 3 Input data worksheet to simulate Arbogast regime
4.1.2. Simulation Output
The simulation outcomes are displayed in tables and charts. They are located in the same
workbook as the input data worksheet.
TreesPerAcre Worksheet
This worksheet (Figure 4) shows the number of trees per acre by species and tree
diameter for each year of simulation under this Arbogast cutting guide. Scrolling to the
right reveals the trees per acre distribution for mid-tolerant and shade-intolerant species.
The underlined numbers represent the year of harvest, and the number of trees just after
the harvest.
12
Figure 4 TreesPerAcre worksheet
Basal Area Worksheet
This worksheet (Figure 5) shows, for each simulated year, the total stand basal area, the
stand basal area by species group, and the stand basal area by timber size category (pole,
small sawtimber, etc). Underlined numbers show the year of harvest, and the basal areas
just after harvest.
13
Figure 5 Basal Area worksheet
Products Worksheet
This worksheet (Figure 6) contains two parts: the upper part shows data for each harvest
in terms of basal area cut, gross income, total net present value, the pole and sawtimber
volumes cut for each species group, and the annual production in basal area and volume
cut. The volumes are computed from equations linking tree volume to tree diameter,
stand basal area, and site index (Appendix C). The lower part is a copy of the input data
for reference. The results show that in this particular case, the Arbogast cutting guide
would give low yields (4.6 cubic ft/acre/year) and negative economic returns (-48$/acre
of NPV).
14
Figure 6 Products worksheet
Diversity Worksheet
The diversity worksheet (Figure 7) shows Shannon’s indices of species group diversity
and tree size diversity for each simulated year. The underlined data show the year of
harvest and the values of the diversity indices just after harvest.
15
Figure 7 Diversity worksheet
Diversity Chart
The Diversity Chart shows the evolution of Shannon’s indices of over time. The results
show that the Arbogast guide would lead to an improvement of the stand size diversity,
but there would be a gradual decrease in species diversity.
16
Figure 8 Stand Diversity Chart
Species Basal Area Chart
This chart (Figure 9) shows the development of basal area by species throughout the
simulation period. The chart suggests that, applied in this way, the Arbogast guide would
lead to an increase of basal area in shade-tolerant trees after the first harvest, and a
decrease of basal area in that of intolerant and mid-tolerant trees. This leads to the
decrease in Shannon’s index of species diversity shown in Figure 8.
17
Figure 9 Species Basal Area Chart
Timber Size Basal Area Chart
This chart (Figure 10) shows the development of basal area by timber size throughout the
simulation. It excludes the basal area of the trees smaller than the poles, which have a
minimum diameter of 6 inches. The results suggest that under the Arbogast cutting guide
simulated here, the basal area in medium and large sawtimber would increase over time
after the first harvest, while the basal area of small sawtimber would decrease and that of
pole would stay about constant.
18
Figure 10 Size BA Chart
4.2. Simulating BDq and Diameter-Limit Management Regimes
In this example, we simulated the growth of stands with two kinds of cutting regimes:
basal-area-diameter-q-ratio (BDq) selection, and diameter-limit cut. We then compare the
results in terms of economic returns, productivity, tree diversity, and stand structure.
4.2.1. Simulation Parameters
The simulations were for 120 years with cutting cycles of 10 years. The initial stand state
was the average distribution of all the Wisconsin plots used in calibrating the growth
equations of NorthPro, with an average site index of 80 (Kolbe et al. 1999). Shade19
tolerant trees compose 73% of the stand basal area, mid-tolerant trees compose 9%, and
shade-intolerant trees compose 18%. The interest rate was set at 3 percent, in real terms
(net of inflation).
For the BDq regimes, the residual stand basal area was set at 91 ft2/ac, 74 ft2/ac or
61 ft2/ac, corresponding to a light, medium, or heavy selection (Erdmann and Oberg
1973). The q-ratio was 1.7, the average value on all the FIA maple-birch plots of
Wisconsin. Figure 11 shows the BDq to calculate the target state for shade-tolerant trees
for a light selection. Set the basal area to 66, reflecting the fact that 73% of the initial
stand is composed of shade-tolerant trees (91 ft2  .73 = 66 ft2). Set the q-ratio to 1.7, the
maximum diameter limit to 24, and the minimum diameter limit to 2. Click on the
Calculate button. The BDq calculator produces the number of trees by size class. To
copy the distribution to the Input Data worksheet, select the option box corresponding to
Shade-tolerant Target State and click on the Copy button (Figure 11). Repeat these
steps for the Mid-tolerant and Shade-intolerant Target States, using basal areas of 8 ft2
and 16 ft2, respectively.
Figure 11 BDq Distribution calculation dialog box
20
Table 1 Target state and stumpage price for BDq selection regimes
Species
Timber
Size
Shade-tolerant
Pole
Sawtimber
DBH
Class (in.)
Stumpage
Price (unit)
2
4
6
8
10
12
14
16
18
20
22
24+
0
0
12
12
12
141
146
153
152
151
149
151
$/cord
2
4
6
8
10
12
14
16
18
20
22
24+
0
0
12
13
13
128
125
128
125
125
127
127
$/cord
2
4
6
8
10
12
14
16
18
20
22
24+
0
0
14
14
14
147
149
146
145
148
145
147
$/cord
$/cord
$/cord
$/cord
$/cord
$/Mbf
$/Mbf
$/Mbf
$/Mbf
$/Mbf
$/Mbf
$/Mbf
BDq Selection (trees/ac)
Light
Medium
Heavy
138.3
81.4
47.9
28.2
16.6
9.7
5.7
3.4
2.0
1.2
0.7
0.4
113.2
66.6
39.2
23.0
13.6
8.0
4.7
2.8
1.6
1.0
0.6
0.3
94.3
55.5
32.6
19.2
11.3
6.6
3.9
2.3
1.4
0.8
0.5
0.3
16.8
9.9
5.8
3.4
2.0
1.2
0.7
0.4
0.2
0.1
0.1
0.0
14.7
8.6
5.1
3.0
1.8
1.0
0.6
0.4
0.2
0.1
0.1
0.0
23.1
13.6
8.0
4.7
2.8
1.6
1.0
0.6
0.3
0.2
0.1
0.1
33.5
19.7
11.6
6.8
4.0
2.4
1.4
0.8
0.5
0.3
0.2
0.1
27.2
16.0
9.4
5.5
3.3
1.9
1.1
0.7
0.4
0.2
0.1
0.1
27.2
16.0
9.4
5.5
3.3
1.9
1.1
0.7
0.4
0.2
0.1
0.1
Mid-tolerant
Pole
Sawtimber
$/cord
$/cord
$/cord
$/cord
$/Mbf
$/Mbf
$/Mbf
$/Mbf
$/Mbf
$/Mbf
$/Mbf
Shade-intolerant
Pole
Sawtimber
$/cord
$/cord
$/cord
$/cord
$/Mbf
$/Mbf
$/Mbf
$/Mbf
$/Mbf
$/Mbf
$/Mbf
21
Table 1 shows the desired target distribution by BDq selection regime and the stumpage
price in Wisconsin, 1996-1998.
The diameter-limits were set at 12 in. (cut all sawtimber trees), 16 in. (cut
medium and large sawtimber trees), or 22 in. (cut only large sawtimber trees).
4.2.2. Running Simulations
To run a series of simulations, load the input data for the first management regime, run
the simulation, save your outcome and proceed to load and run the second management
regime. Figures 12 and 13 show the Input Data worksheet for the light BDq selection
regime and the 12 inches diameter-limit cutting regime, respectively. The two
spreadsheets differ only by the number of trees in the target states.
Upon running a simulation, NorthPro will generate the four tables and the three
charts described in the first example. Because NorthPro replaces all the previous tables
and charts upon running a new simulation, you should save the workbook for each
simulation. You can then compare the data on net present value, basal area, number of
trees, diversity of species and size, and volume production for different regimes. To that
end, comparative charts and tables can be built with Excel from the NorthPro output
worksheets.
22
Figure 12 Input data worksheet for light BDq selection
23
Figure 13 Input data worksheet for 12 inches diameter-limit regime
4.2.3. Simulation Results
Figure 14 shows as an example the NPV and total volume of the different cutting regimes
over 120 years, with 10-year cutting cycles. We built this figure with Excel from the
results in the products worksheets of the six simulations done with NorthPro. Figure 14
shows that the 12 in. diameter limit cuts yielded the highest NPV and annual production
in all cases. The 22 in. diameter limit cuts had the lowest NPV and volume.
For all six cutting regimes, after 120 years, the stand basal area reached a homeostasis,
where growth over a cutting cycle replaced the harvest almost exactly. For example,
Figure 15 shows how basal area developed with the light BDq selection. The figure was
24
generated by NorthPro (Species BA Chart). The heavy BDq selection regime led to the
highest species diversity after 120 years and the light selection led to the highest size
diversity. Generally, BDq selections generated higher species and size diversity than the
diameter-limits cuts (Figure 16).
Vol ( ft3/ac/year)
25
NPV ($/ac)
800
NPV
Vol
700
600
20
500
15
400
10
300
200
5
100
0
0
Light
selection
Medium
selection
Heavy
selection
12 in diam
cut
16 in diam
cut
22 in diam
cut
Figure 14 The NPV and Volume Yield of Different Cutting Regimes on Wisconsin
Site 80, over 120 years
25
Figure 15 Development of Stand Basal Area by Species of Light Selection on
Wisconsin Site 80
3
Size diversity
0.7
Species diversity
0.6
2.5
Size
0.4
1.5
0.3
1
Species
0.5
2
0.2
0.5
0.1
0
0
Light
Medium
Heavy 12 in diam 16 in diam 22 in diam
selection selection selection
cut
cut
cut
Figure 16 Effect of Management Regime on Tree Diversity after 120 years on
Wisconsin Site 80
26
5. Trouble Shooting NorthPro
Why can’t I open NorthPro?
Make sure you have the right version of NorthPro (2003). It should be 368KB in size and
the file type should be Microsoft Excel Add-In.
I may have installed an earlier version of NorthPro, what should I do?
You have to remove the previous version of NorthPro before running NorthPro (2003).
Please follow the steps below:
1. Delete all NorthPro files from the hard disk.
2. Open a new Excel worksheet, go to Add-ins in the Tools menu, click to deselect
NorthPro, then click OK.
3. Repeat the steps to install the current version of NorthPro.
NorthPro does not insert a new input data worksheet, what can I do?
Before inserting a new input data worksheet, NorthPro checks if there is a worksheet
named “Input Data” already in use. If there is one, NorthPro will not generate a new input
data worksheet. To get a new input data worksheet, close all Excel windows and reopen
NorthPro.
I have finished entering all the input data and tried to run the simulation, but nothing
happened. Is there anything wrong?
Probably not. You may have been editing a cell when you tried to run the simulation.
Click on a blank cell before you run the simulation again. If the problem persists, reinstall
NorthPro.
27
Why is there no BDq calculator in the example worksheets?
The example workbooks contain only the input data. After you have installed NorthPro,
the BDq calculator icon will appear in the new input data worksheet. At that point, you
can copy data from the example workbooks into the input data worksheet.
Why is the BDq calculator not working?
NorthPro must be installed before using the BDq calculator. If you want to use the BDq
calculator on a previously saved input data worksheet, NorthPro must be in the Excel
menu bar.
Why can’t I copy all the contents from the example worksheet to the input data
worksheet?
All the cells of the input data worksheet are protected from being edited except those that
need entries. Copy only the data from the example worksheet and paste them to the
corresponding locations in the input data worksheet.
For further assistance, or to send us your comments, please visit our web site:
http://*******************
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References
Arbogast, C., Jr. 1957. Marking guides for northern hardwoods under the selection system.
USDA For. Serv. North Cent. For. Exp. Stn. Pap. 56.
Baker, F.S., 1950. Principles of silviculture. McGraw-Hill, New York. 414 pp.
Buongiorno, J., A. Kolbe, and M. Vasievich, 2000. Economic and Ecological Effects of
Diameter-Limit and BDq Management Regimes: Simulation Results for Northern
Hardwoods. Silva Fennica 34(3): 223-233.
DeBell, D.S., and J.F. Franklin. 1987. Old-growth Douglas-Fir and Western Hemlock: A 36-year
record of growth and mortality. Western Journal of Applied Forestry 2:111-114.
Erdmann, G.G., and R.R. Oberg, 1973. Fifteen-year results from six cutting methods in secondgrowth northern hardwoods. Research Paper NC-100. USDA Forest Service, North Central
Forest Experiment Station, St. Paul, MN. 12 pp.
Godman, R.M. and C.H. Tubbs, 1973. Establishing even-age northern hardwood regeneration by
the shelterwood method: a preliminary guide. Res. Pap. NC-99. USDA Forest Service,
North Central Forest Experiment Station, St. Paul, MN. 9 pp.
Hahn, J.T. 1984. Tree volume and biomass equations for the Lake States. Research Paper NC250. USDA Forest Service, North Central Forest Experiment Station, St. Paul, MN. 10p.
Hansen, M.H., T. Frieswyk, J.F. Glover, and J.F. Kelly, 1992. The Eastwide forest inventory
data base: users manual. Gen. Tech. Rep. NC-151. USDA For. Ser. North Central Forest
Experiment Station, St. Paul, MN. 48 pp.
Kolbe, A.E., J. Buongiorno. and M. Vasievich, 1999. Geographic extension of an uneven-aged,
multi-species matrix growth model for northern hardwood forests. Ecological Modeling 121:
235-253.
Leatherberry,E.C. et al, 1996. Michigan forest statistics, 1993. Resource Bulletin NC-183. USDA
Forest Service. Northeastern Forest Experiment Station, Upper Darby, PA. 15p.
Lin, C.R., J. Buongiorno, and M. Vasievich, 1996. A multi-species, density-dependent matrix
growth model to predict tree diversity and income in northern hardwood stands. Ecological
Modelling, 91: 193-211.
Microsoft Corporation. Microsoft Excel User’s Guide. Version 5.0. 660 pp.
Niese J.N., and T.F. Strong, 1992. Economic and tree diversity trade-offs in managed northern
hardwoods. Can. J. For. Res. 22, 1807-1813.
Pielou, E.C., 1977. Mathematical Ecology. Toronto: John Wiley & Sons, 385 pp.
Preston, R.J., 1977. North American Trees. Ames: The Iowa State University Press. 399 pp.
29
Ralston, R., et al. 2003. WestPro: a computer program for simulating uneven-aged Douglas fir
stand growth and yield in the Pacific Northwest. General Technical Report PNW-GTR-574.
USDA Forest Service, Pacific Northwest Station, Portland, OR. 25 p.
Schmidt, T.L., 1998. Wisconsin forest statistics, 1996. Resource Bulletin NC-183. North
Central Forest Experiment Station, St. Paul, MN. 150p.
Schulte, B., J. Buongiorno, C.R. Lin, and K. Skog. 1998. SouthPro: A Computer Program for
Managing Uneven-Aged Loblolly Pine Stands. Forest Products Laboratory: USDA Forest
Service. FPL-GTR-112. 47 p.
Smith, D.M. 1986. The practice of silviculture. New York: John Wiley & Sons, 8th ed.
U. S. Government, 1998. Economic report of the President. U.S. Government Printing Office.
Washington, D. C. 402P.
Wisconsin Deparment of Natural Resources, 1996-1998. Forest products price rates. Madison,
WI. NR 46.30.
30
Glossary
BA Chart ― A NorthPro-generated chart showing, for a selected range of years, the per acre
basal area of shade-tolerants, mid-tolerants, shade-intolerants, and the whole stand.
BDq distribution ― A tree distribution, by diameter class, defined by a stand basal area (B), a
maximum and minimum tree diameter (D), and a q-ratio (q), the ratio of the number of trees
in a given diameter class to the number of trees in the next larger class.
Cutting Cycle ― The number of years between successive harvests A. For two-cut silvicultural
systems, this is also equal to the number of years between successive harvests B.
Diameter class ― One of twelve 2-inch diameter at breast height categories used by NorthPro to
classify trees by size. Diameter classes range from 2 to 24+ inches, with each class denoted
by its midpoint diameter. Diameter class 2 is for trees with diameters from 1 to less that 3
inches. The 24+ inch class is for all trees 23 inches in diameter and larger.
Diversity Chart ― A NorthPro-generated chart showing changes in the Shannon index of
species and/or size diversity over a selected range of years.
Initial stand state ― The number of live trees per acre, by species and size, at the start of a
simulation.
Input Data worksheet ― A worksheet to enter the data for running a NorthPro simulation.
Microsoft Excel add-in ― A command, function, or software program that runs within
Microsoft Excel and adds special capabilities. NorthPro is an add-in.
Midtolerants ― See species groups.
Net present value (NPV)― The net revenue discounted to the present.
Pre-harvest stand state ― The number of live trees per acre, by species and size, immediately
before a harvest.
Products worksheet ― A NorthPro output worksheet that shows, for each harvest, the basal area
cut, the volume of pole and sawtimbers removed by species group, the gross income
generated, and the net present value of the harvest, as well as the total net present value of the
stand and its mean annual production in terms of basal area cut and volumes harvested, on a
per acre basis.
Pole-size trees ― Trees suitable for the production of poletimber, but too small to produce saw
logs. In NorthPro, these include trees from 5 to less than 11 inches.
Re-entry costs ― Costs per acre associated with each harvest that are not reflected in the
stumpage prices. These may include, for example, the added expense of marking the stand
for single-tree selection or controlling hardwood competition.
Sawtimber ― Trees suitable for the production of saw logs.
recognize three classes of sawtimber trees:
NorthPro’s marking guides
31
(1) Small sawtimbers ― Trees with diameters of 11 to less than 15 inches.
(2) Medium sawtimbers ― Trees with diameters of 15 to less than 21 inches.
(3) Large sawtimbers ― Trees with diameters of 21 inches or larger.
Setup File worksheet ― A worksheet to store NorthPro setup files. It is typically hidden.
Setup Files ― Collections of related input data that are stored together on a Setup File
worksheet. Setup Files may contain data for initial stand states, target stand states, cutting
cycle parameters, stumpage prices, or fixed costs, and may be used in varying combinations
as input for NorthPro simulations.
Shade-intolerants ― See species groups.
Shade-tolerants ― See species groups.
Site index ― The average height of a stand’s dominant and codominant trees at age 50 years.
Size diversity ― The diversity of tree diameter classes as measured by the Shannon index. With
twelve diameter classes, size diversity reaches its maximum value of 2.48 when the basal area
or number of trees is distributed evenly among the diameter classes.
Species diversity ― The diversity of species groups as measured by the Shannon index. With
three species classes, species diversity reaches its maximum value of 1.10 when the basal
area or number of trees is distributed evenly among the species groups.
Species groups ― The three categories used by NorthPro to classify trees by species (Baker
1950).
Shade-tolerants ― Trees having the capacity to survive under deep shade.
Mid-tolerants ― Trees whose shade-tolerance is not well defined and that fall
between the categories of shade-tolerant or shade-intolerant.
Shade-intolerants ― Trees lacking the ability to survive under deep shade.
Stumpage prices ― Prices paid to a landowner for standing timber.
Target stand state ― The desired number of live trees per acre in each species group and
diameter class after a harvest.
Total net present value ― The sum of all discounted revenues minus the sum of all discounted
costs.
Workbook― The workbook is the normal document or file type in Microsoft Excel. A
workbook is the electronic equivalent of a three-ring binder. Inside workbooks you’ll find
sheets, such as worksheets and chart sheets.
Worksheet ― Most of the work you do in Excel will be on a worksheet. A worksheet is a grid of
rows and columns. Each cell is the intersection of a row and a column and has a unique
address, or reference.
32
Appendix A― Species and Shade Tolerance of Trees of Maple-BeechBirch Forest Type in Wisconsin
FIA code Common name
Shade-tolerant species
318
Sugar maple
316
Red maple
951
American basswood
972
American elm
12
Balsam fir
261
Eastern hemlock
701
Iron wood
241
Northern white-cedar
391
American hornbeam
94
White spruce
531
American beech
975
Slippery elm
319
Mountain maple
95
Black spruce
313
Boxelder
317
Silver maple
Scientific name
Proportion (%)
Acer saccharum
Acer rubrum
Tilia americana
Ulmus americana
Abies balsamea
Tsuga canadensis
Ostrya virginiana
Thuja occidentalis
Carpinus caroliniana
Picea glauca
Fagus grandifolia
Ulmus rubra
Acer spicatum
Picea mariana
Acer negundo
Acer saccharinum
23.24
13.29
8.66
4.77
3.88
3.39
2.41
1.08
0.81
0.43
0.42
0.40
0.11
0.09
0.04
0.02
Mid-tolerant species
371
Yellow birch
541
White ash
129
White pine
802
White oak
762
Black cherry
977
Rock elm
823
Bur oak
125
Red pine
763
Chokecherry
804
Swamp white oak
462
Hackberry
373
River birch
68
Eastern redcedar
Betula alleghaniensis
Fraxinus americana
Pinus strobus
Quercus alba
Prunus serotina
Ulmus thomasii
Quercus macrocarpa
Pinus resinosa
Prunus virginiana
Quercus bicolor
Celtis occidentalis
Betula nigra
Juniperus virginiana
4.14
2.28
1.95
1.32
1.27
0.38
0.35
0.26
0.14
0.04
0.03
0.02
0.00
Shade-intolerant species
746
Quaking aspen
375
Paper birch
833
Northern red oak
743
Bigtooth aspen
543
Black ash
544
Green ash
402
Bitternut hickory
837
Black oak
809
Northern pin oak
601
Butternut
Populus tremuloides
Betula papyrifera
Quercus rubra
Populus grandidentata
Fraxinus nigra
Fraxinus pennsylvanica
Carya cordiformis
Quercus velutina
Quercus ellipsoidalis
Juglans cinerea
7.98
4.53
4.46
1.99
1.94
0.88
0.66
0.58
0.48
0.29
33
105
71
741
407
500
602
742
761
766
660
552
901
Jack pine
Tamarack
Balsam poplar
Shagbark hickory
Hawthorn
Black walnut
Eastern cottonwood
Pin cherry
Wild plum
Apple sp.
Honeylocust
Black locust
Pinus banksiana
Larix laricina
Populus balsamifera
Carya ovata
Crataegus sp.
Juglans nigra
Populus deltoides
Prunus pensylvanica
Prunus americana
Malus sp.
Gleditsia triacanthus
Robinia pseudoacacia
0.27
0.15
0.15
0.11
0.11
0.08
0.05
0.04
0.02
0.01
0.01
0.01
34
Appendix B― The Growth Models
NorthPro contains two site- and density-dependent, multi-species matrix growth models
for Wisconsin and one for Michigan (Kolbe et al. 1999). The models were calibrated
from the North Central Forest Inventory and Analysis (NC-FIA) Eastwide Data Base
(Hansen et al. 1992). The database contains information on individual trees in 623
permanent plots from Wisconsin’s fifth inventory and 1,259 plots from Michigan’s fifth
inventory, representative of the maple-birch forest type. All plots were measured twice at
intervals of 6 to 18 years, averaging 13 years between measurements. In the model,
regeneration, tree growth, and mortality are affected by stand state and by the interaction
between trees of different species and sizes.
The accuracy of the model was tested on post-sample plots. Predictions were
found to be accurate in the short run, and consistent with prior knowledge in the steady
state (Kolbe et al. 1999). For a given site index, Michigan plots consistently showed
slightly higher growth rates than those in Wisconsin. Therefore, each state has its own
model. The model parameters, obtained by multiple regression based on individual tree
and plot data, are shown in Table B1.
Upgrowth, the yearly proportion of trees moving from one diameter class to the
next, was found to depend on stand basal area, tree diameter, and site quality for all three
species groups.
The equation for mortality, the yearly proportion of trees in a diameter class that
die, varied between the species groups. Where stand basal area was significant, the
parameter coefficients indicated that a high stand density would increase the mortality
35
rate. Mortality was highest for the largest and smallest trees. Trees on a good site are less
likely to die.
The yearly ingrowth, the number of trees entering the smallest diameter class, was
a negative function of stand basal area, for all species.
Table B1 Equations of growth models for the Maple-Beech-Birch forest type (Kolbe et al
1999)
UpGrowth rate (proportion/year)
Shade-tolerant species
Wisconsin
Michigan
Mid-tolerant species
Wisconsin
Michigan
Shade-intolerant species
Wisconsin
Michigan
U = 0.0164 – 0.0001BA + 0.0055D – 0.0002D2
U = 0.0126 – 0.0002BA + 0.0058D – 0.0003D2 + 0.00002S*D
U = 0.0134 – 0.0002BA + 0.0051D – 0.0002D2 + 0.00002S*D
U = 0.0159 – 0.0002BA + 0.0064D – 0.0003D2 + 0.00001S*D
U = 0.0069 – 0.0001BA + 0.0059D – 0.0002D2
U = 0.0090 – 0.0001BA + 0.0052D – 0.0003D2 +0.00003S*D
Mortality rate (proportion/year)
Shade-tolerant species
Wisconsin
Michigan
Mid-tolerant species
Wisconsin
Michigan
Shade-intolerant species
Wisconsin
Michigan
M = 0.0336
– 0.0018D + 0.0001D2 – 0.00002S*D
M = 0.0336 + 0.00004BA – 0.0036D + 0.0001D2 – 0.00001S*D
M = 0.0417
– 0.0033D + 0.0001D2
M = 0.0358 + 0.00010BA – 0.0051D + 0.0002D2
M = 0.0418
M = 0.0516
– 0.0009D
– 0.0048D + 0.0001D2
Ingrowth (trees/acre/year)
Shade-tolerant species
Wisconsin
Michigan
Mid-tolerant species
Wisconsin
Michigan
Shade-intolerant species
Wisconsin
Michigan
I = 18.187 – 0.097BA
I = 13.899 – 0.050BA
I = 4.603 – 0.035BA
I = 4.903 – 0.048BA + 0.01N
I = 7.622 – 0.059BA
I = 9.024 – 0.085BA
2
BA=basal area (ft /ac), D=diameter at breast height (in.), S=site index,
N=number of trees/acre of that species
36
Appendix C― Tree Volume equations
In Northpro, the volume for poletimber trees (dbh between 5 and 11 inches) and
sawtimber trees (dbh greater than 11 inches) is calculated with Hahn’s (1984) equations.
The volume of saplings (dbh less than 5 inches) is set to zero. Tree volume depends on
tree diameter and merchantable tree height, H, calculated as follows:

Shade-tolerant species:
H  4.5  5.34  (1  exp( 0.23D))1.15  S 0.54  T 0.83  B 0.06

Mid-tolerant species:
H  4.5  7.19  (1  exp( 0.28D))1.44  S 0.39  T 0.83  B 0.11

Shade-intolerant species:
H  4.5  6.43  (1  exp( 0.24D))1.34  S 0.47  T 0.73  B 0.08
where: D = diameter at breast height (DBH), S = site index, T = (1.00001-d/D), d = top
DBH outside bark (4 inches for cubic foot volume, 9 inches for board foot volume), B =
stand basal area
For shade-tolerant species, the indicator species was sugar maple. For midtolerant trees it was yellow birch, and for the shade-intolerant trees it was quaking aspen.
Next, gross tree volume is computed with the following formulas (Hahn 1984):
 Shade-tolerant species:
V = 1.375 + 0.002*D2H
 Mid-tolerant species:
V = 0.002*D2H
 Shade-intolerant species:
V = 2.706 + 0.002*D2H
For poletimber, the cubic foot volume is converted to cords (1 cord = 128 ft3). For
sawtimber, the cubic foot volume is converted to thousand-board feet-Scribner log rule
(MBF) with the conversion factors in Table C1 (Schmidt 1998).
37
Table C1 Scribner rule conversion factors
DBH
Scribner rule conversion factor
(inches)
Softwoods
Hardwoods
9.0-10.9
0.783
―
11.0-12.9
0.829
0.832
13.0-14.9
0.858
0.861
15.0-16.9
0.878
0.883
17.0-18.9
0.895
0.900
19.0-20.9
0.908
0.913
21.0-22.9
0.917
0.924
23.0-24.9
0.924
0.933
25.0-26.9
0.930
0.940
27.0-28.9
0.932
0.945
29.0+
0.936
0.954
38
Appendix D― Definition of Diversity of Tree Species and Size
NorthPro uses Shannon’s index to measure the stand diversity in terms of tree species
(how well trees are distributed across species class: shade-tolerant, mid-tolerant, and
shade-intolerant) and size classes. NorthPro measures the presence of trees in a class by
their basal area, which gives more weight to larger trees.
The tree species diversity is defined in NorthPro as:
m
H species  
i 1
y 
yi
log i 
y
 y
where yi is the basal area of trees of species i per acre. In NorthPro, m=3 (shade-tolerant,
mid-tolerant, shade-intolerant). The tree species diversity reaches a maximum value of
ln(m)=1.10, when basal area is equally distributed in all three species groups, and a
minimum value of 0 when all trees are in the same species group.
Similarly, tree size diversity is:
n
H size  
j 1
 yj
log
y
 y
yj



where, again, yj is the basal area of trees in diameter class j per acre. In NorthPro, n=12
diameter classes. The tree size diversity reaches a maximum ln(12)=2.48 when basal area
is equally distributed in all diameter classes, and a minimum of 0 when all trees are in the
same diameter class.
39