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, mid- tolerant, 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). Shade-
19 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 DBH Stumpage BDq Selection (trees/ac) Size Class (in.) Price (unit) Light Medium Heavy Shade-tolerant 2 0 $/cord 138.3 113.2 94.3 4 0 $/cord 81.4 66.6 55.5 Pole 6 12 $/cord 47.9 39.2 32.6 8 12 $/cord 28.2 23.0 19.2 10 12 $/cord 16.6 13.6 11.3 Sawtimber 12 141 $/Mbf 9.7 8.0 6.6 14 146 $/Mbf 5.7 4.7 3.9 16 153 $/Mbf 3.4 2.8 2.3 18 152 $/Mbf 2.0 1.6 1.4 20 151 $/Mbf 1.2 1.0 0.8 22 149 $/Mbf 0.7 0.6 0.5 24+ 151 $/Mbf 0.4 0.3 0.3 Mid-tolerant 2 0 $/cord 16.8 14.7 23.1 4 0 $/cord 9.9 8.6 13.6 Pole 6 12 $/cord 5.8 5.1 8.0 8 13 $/cord 3.4 3.0 4.7 10 13 $/cord 2.0 1.8 2.8 Sawtimber 12 128 $/Mbf 1.2 1.0 1.6 14 125 $/Mbf 0.7 0.6 1.0 16 128 $/Mbf 0.4 0.4 0.6 18 125 $/Mbf 0.2 0.2 0.3 20 125 $/Mbf 0.1 0.1 0.2 22 127 $/Mbf 0.1 0.1 0.1 24+ 127 $/Mbf 0.0 0.0 0.1 Shade-intolerant 2 0 $/cord 33.5 27.2 27.2 4 0 $/cord 19.7 16.0 16.0 Pole 6 14 $/cord 11.6 9.4 9.4 8 14 $/cord 6.8 5.5 5.5 10 14 $/cord 4.0 3.3 3.3 Sawtimber 12 147 $/Mbf 2.4 1.9 1.9 14 149 $/Mbf 1.4 1.1 1.1 16 146 $/Mbf 0.8 0.7 0.7 18 145 $/Mbf 0.5 0.4 0.4 20 148 $/Mbf 0.3 0.2 0.2 22 145 $/Mbf 0.2 0.1 0.1 24+ 147 $/Mbf 0.1 0.1 0.1
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).
NPV ($/ac) Vol ( ft3/ac/year) 800 25
700 NPV Vol 20 600
500 15 400
300 10
200 5 100
0 0 Light Medium Heavy 12 in diam 16 in diam 22 in diam selection selection selection cut cut 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 2.5 0.6
0.5 2 s
0.4 e i e c z
i 1.5 e S 0.3 p S 1 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://*******************
28 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 second- growth 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 NC- 250. 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. NorthPro’s marking guides recognize three classes of sawtimber trees:
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-Beech- Birch Forest Type in Wisconsin FIA code Common name Scientific name Proportion (%) Shade-tolerant species 318 Sugar maple Acer saccharum 23.24 316 Red maple Acer rubrum 13.29 951 American basswood Tilia americana 8.66 972 American elm Ulmus americana 4.77 12 Balsam fir Abies balsamea 3.88 261 Eastern hemlock Tsuga canadensis 3.39 701 Iron wood Ostrya virginiana 2.41 241 Northern white-cedar Thuja occidentalis 1.08 391 American hornbeam Carpinus caroliniana 0.81 94 White spruce Picea glauca 0.43 531 American beech Fagus grandifolia 0.42 975 Slippery elm Ulmus rubra 0.40 319 Mountain maple Acer spicatum 0.11 95 Black spruce Picea mariana 0.09 313 Boxelder Acer negundo 0.04 317 Silver maple Acer saccharinum 0.02 Mid-tolerant species 371 Yellow birch Betula alleghaniensis 4.14 541 White ash Fraxinus americana 2.28 129 White pine Pinus strobus 1.95 802 White oak Quercus alba 1.32 762 Black cherry Prunus serotina 1.27 977 Rock elm Ulmus thomasii 0.38 823 Bur oak Quercus macrocarpa 0.35 125 Red pine Pinus resinosa 0.26 763 Chokecherry Prunus virginiana 0.14 804 Swamp white oak Quercus bicolor 0.04 462 Hackberry Celtis occidentalis 0.03 373 River birch Betula nigra 0.02 68 Eastern redcedar Juniperus virginiana 0.00 Shade-intolerant species 746 Quaking aspen Populus tremuloides 7.98 375 Paper birch Betula papyrifera 4.53 833 Northern red oak Quercus rubra 4.46 743 Bigtooth aspen Populus grandidentata 1.99 543 Black ash Fraxinus nigra 1.94 544 Green ash Fraxinus 0.88 pennsylvanica 402 Bitternut hickory Carya cordiformis 0.66 837 Black oak Quercus velutina 0.58 809 Northern pin oak Quercus ellipsoidalis 0.48
33 601 Butternut Juglans cinerea 0.29 105 Jack pine Pinus banksiana 0.27 71 Tamarack Larix laricina 0.15 741 Balsam poplar Populus balsamifera 0.15 407 Shagbark hickory Carya ovata 0.11 500 Hawthorn Crataegus sp. 0.11 602 Black walnut Juglans nigra 0.08 742 Eastern cottonwood Populus deltoides 0.05 761 Pin cherry Prunus pensylvanica 0.04 766 Wild plum Prunus americana 0.02 660 Apple sp. Malus sp. 0.01 552 Honeylocust Gleditsia triacanthus 0.01 901 Black locust Robinia pseudoacacia 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 U = 0.0164 – 0.0001BA + 0.0055D – 0.0002D2 Michigan U = 0.0126 – 0.0002BA + 0.0058D – 0.0003D2 + 0.00002S*D Mid-tolerant species Wisconsin U = 0.0134 – 0.0002BA + 0.0051D – 0.0002D2 + 0.00002S*D Michigan U = 0.0159 – 0.0002BA + 0.0064D – 0.0003D2 + 0.00001S*D Shade-intolerant species Wisconsin U = 0.0069 – 0.0001BA + 0.0059D – 0.0002D2 Michigan U = 0.0090 – 0.0001BA + 0.0052D – 0.0003D2 +0.00003S*D
Mortality rate (proportion/year) Shade-tolerant species Wisconsin M = 0.0336 – 0.0018D + 0.0001D2 – 0.00002S*D Michigan M = 0.0336 + 0.00004BA – 0.0036D + 0.0001D2 – 0.00001S*D Mid-tolerant species Wisconsin M = 0.0417 – 0.0033D + 0.0001D2 Michigan M = 0.0358 + 0.00010BA – 0.0051D + 0.0002D2 Shade-intolerant species Wisconsin M = 0.0418 – 0.0009D Michigan M = 0.0516 – 0.0048D + 0.0001D2
Ingrowth (trees/acre/year) Shade-tolerant species Wisconsin I = 18.187 – 0.097BA Michigan I = 13.899 – 0.050BA Mid-tolerant species Wisconsin I = 4.603 – 0.035BA Michigan I = 4.903 – 0.048BA + 0.01N Shade-intolerant species Wisconsin I = 7.622 – 0.059BA Michigan I = 9.024 – 0.085BA BA=basal area (ft2/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 mid- tolerant 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 ft 3). 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 Softwoods Hardwoods (inches) 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
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
38 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 y y i i H species log i1 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 y y H j log j size j1 y y
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