Sample Parameter File
You can download the actual file to run with SORTIE-ND in the downloads area. The file includes a parameter file and an output file created with it. Choose the sample file that goes with your version of SORTIE-ND (6.04 or later). This file is also set up to create a detailed output file, which has not been included in the download because of size.
Note: If you load and run the parameter file for yourself, you may wish to change the output file paths before running the file. Put the output files in a specific directory on your computer or they will end up in your home directory and may be hard to find.
Source of parameters
Most of the parameters in the sample file come from published papers. The tables below list the parameter sources.
Species list:
- FAGR = beech (Fagus grandifolia)
- TSCA = eastern hemlock (Tsuga canadensis)
- ACSA = sugar maple (Acer saccharum)
- ACRU = red maple (Acer rubrum)
- BEAL = yellow birch (Betula alleghaniensis)
- PIST = white pine (Pinus strobus)
- QURU = red oak (Quercus rubra)
- PRSE = black cherry (Prunus serotina)
- FRAM = white ash (Fraxinus americana)
Plot Parameters
| Parameter Name | Value | Comment |
|---|
| Number of Timesteps | 100 | -- |
| Random Seed | 0 | A standard choice, meaning a new random seed is chosen each run. |
| Number of years per timestep | 5 | Pacala et al 1996, p. 5: "Experiments with intervals of 2.5 and 1 yr produced results indistinguishable from 5 yr." Other forest systems may require different timescales. |
| Plot Length in the X (E-W) Direction, in meters | 300 | Minimum useful plot size is 9 ha (Pacala et al 1996). |
| Plot Length in the Y (N-S) Direction, in meters | 300 | -- |
| Plot Latitude, in decimal degrees | 41.92 | -- |
| Mean Annual Precipitation, mm | 0 | This is not needed for any behaviors used in this parameter file. |
| Seasonal Precipitation | 0 | This is not needed for any behaviors used in this parameter file. |
| Water Deficit | 0 | This is not needed for any behaviors used in this parameter file. |
| Mean Annual Temperature, degrees C | 0 | This is not needed for any behaviors used in this parameter file. |
| Annual Nitrogen Deposition | 0 | This is not needed for any behaviors used in this parameter file. |
| Plot title | Default parameter file-use for testing only | -- |
Tree population parameters
| Parameter Name | Value | Comment |
|---|
| New Seedling Diameter at 10 cm | 0.2 | Pacala et al. 1996 |
| -- | ACRU | ACSA | BEAL | FAGR | TSCA | FRAM | PIST | PRSE | QURU | -- |
|---|
| Minimum Adult DBH | 10 | 10 | 10 | 10 | 10 | 10 | 10 | 10 | 10 | -- |
| Max Seedling Height (meters) | 1.35 | 1.35 | 1.35 | 1.35 | 1.35 | 1.35 | 1.35 | 1.35 | 1.35 | This was the original definition of a seedling - having a height less than 1.35 meters. |
| Initial Density (#/ha) - 0-1.0 cm DBH | 25 | 25 | 25 | 25 | 25 | 25 | 25 | 25 | 25 | Pacala et al. 1996 |
Allometry Parameters
| Parameter Name | Value | Comment |
|---|
| -- | ACRU | ACSA | BEAL | FAGR | TSCA | FRAM | PIST | PRSE | QURU | -- |
|---|
| Adult Height-Diameter Function | Std | Std | Std | Std | Std | Std | Std | Std | Std | -- |
| Sapling Height-Diameter Function | Std | Std | Std | Std | Std | Std | Std | Std | Std | -- |
| Adult Crown Radius-Diameter Function | Std | Std | Std | Std | Std | Std | Std | Std | Std | -- |
| Sapling Crown Radius-Diameter Function | Std | Std | Std | Std | Std | Std | Std | Std | Std | -- |
| Adult Crown Height-Height Function | Std | Std | Std | Std | Std | Std | Std | Std | Std | -- |
| Sapling Crown Height-Height Function | Std | Std | Std | Std | Std | Std | Std | Std | Std | -- |
| Seedling Height-Diameter Function | Std | Std | Std | Std | Std | Std | Std | Std | Std | -- |
| Slope of DBH to Diameter at 10 cm Relationship | 0.75 | 0.75 | 0.75 | 0.75 | 0.75 | 0.75 | 0.75 | 0.75 | 0.75 | These values are not parameterized from field data but represent a reasonable estimate. |
| Intercept of DBH to Diameter at 10 cm Relationship
| 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | These values are not parameterized from field data but represent a reasonable estimate. |
| Maximum Tree Height, in meters | 25.7 | 24.8 | 23.2 | 34.6 | 29.6 | 32.4 | 38.4 | 30.8 | 33.6 | Pacala et al 1996, Table 2, H1. |
| Slope of Asymptotic Height | 0.063 | 0.0623 | 0.063 | 0.0353 | 0.0243 | 0.056 | 0.033 | 0.045 | 0.042 | This value combines the original Pacala et al 1996 H1 and H2 parameters as B = H2 / H1; from Table 2. |
| Slope of Height-Diameter at 10 cm Relationship | 0.03 | 0.03 | 0.03 | 0.03 | 0.03 | 0.03 | 0.03 | 0.03 | 0.03 | These values are not parameterized from field data but represent a reasonable estimate. |
| Slope of Asymptotic Crown Radius | 0.108 | 0.107 | 0.109 | 0.152 | 0.1 | 0.095 | 0.087 | 0.116 | 0.119 | Pacala et al 1996, Table 2, C1. |
| Crown Radius Exponent | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | Original equation form had no exponent - setting the exponent to 1 matches the original SORTIE equation |
| Maximum Crown Radius (Standard) (m) | 10 | 10 | 10 | 10 | 10 | 10 | 10 | 10 | 10 | This was a hard-coded limit in the original SORTIE equation. Now it is a parameter |
| Slope of Asymptotic Crown Height | 0.49 | 0.58 | 0.54 | 0.664 | 0.846 | 0.319 | 0.413 | 0.37 | 0.413 | Pacala et al 1996, Table 2, C2. |
| Crown Height Exponent | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | Original equation form had no exponent - setting the exponent to 1 matches the original SORTIE equation |
Light parameters
| Parameter Name | Value | Comment |
|---|
| Beam Fraction of Global Radiation | 0.5 | -- |
| Clear Sky Transmission Coefficient | 0.65 | -- |
| First Day of Growing Season | 120 | -- |
| Last Day of Growing Season | 270 | -- |
| Number of Azimuth Sky Divisions for Quadrat Light Calculations | 18 | -- |
| Number of Altitude Sky Divisions for Quadrat Light Calculations | 12 | -- |
| Minimum Solar Angle for Quadrat Light, in rad | 0.779 | -- |
| Height at Which GLI is Calculated for Quadrats, in meters | 0.675 | -- |
| Height of Fisheye Photo | Mid-crown | -- |
| Number of Azimuth Sky Divisions for GLI Light Calculations | 18 | -- |
| Number of Altitude Sky Divisions for GLI Light Calculations | 12 | -- |
| Minimum Solar Angle for GLI Light, in rad | 0.779 | -- |
| -- | ACRU | ACSA | BEAL | FAGR | TSCA | FRAM | PIST | PRSE | QURU | -- |
|---|
| Amount Canopy Light Transmission (0-1)
| 0.399 | 0.399 | 0.399 | 0.064 | 0.064 | 0.399 | 0.399 | 0.399 | 0.566 | Source: Pacala et al. 1996. Table 2. |
Growth parameters
| Parameter Name | Value | Comment |
|---|
| -- | ACRU | ACSA | BEAL | FAGR | TSCA | FRAM | PIST | PRSE | QURU | -- |
|---|
| Adult Constant Area Growth in sq. cm/yr | 0.3 | 0.3 | 0.3 | 0.3 | 0.3 | 0.3 | 0.3 | 0.3 | 0.3 | Teck and Hilt 1991. |
| Asymptotic Diameter Growth (A) | 0.167 | 0.125 | 0.169 | 0.152 | 0.229 | 0.226 | 0.23 | 0.249 | 0.266 | Source: Pacala et al. 1996. Table 2. |
| Slope of Growth Response (S) | 0.027 | 0.159 | 0.137 | 0.075 | 0.051 | 0.025 | 0.019 | 0.064 | 0.022 | Source: Pacala et al. 1996. Table 2. |
| Relative Michaelis-Menton Growth - Diameter Exponent
| 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | No exponent used on diameter. |
Mortality parameters
| Parameter Name | Value | Comment |
|---|
| DBH of Maximum Senescence Mortality Rate, as an integer in cm | 100 | -- |
| -- | ACRU | ACSA | BEAL | FAGR | TSCA | FRAM | PIST | PRSE | QURU | -- |
|---|
| Mortality at Zero Growth | 0.99 | 0.998 | 0.555 | 0.014 | 0.077 | 0.999 | 0.268 | 0.998 | 0.985 | Kobe et al. 1995 |
| Light-Dependent Mortality | 6.64 | 4.79 | 2.67 | 0.2 | 5.97 | 5.15 | 4.67 | 4.85 | 9.38 | Kobe et al. 1996 |
| Senescence Mortality Alpha | -20 | -20 | -20 | -20 | -20 | -20 | -20 | -20 | -20 | This value is set to give no additional mortality to adult trees as they grow. |
| Senescence Mortality Beta | 0.135 | 0.135 | 0.135 | 0.135 | 0.135 | 0.135 | 0.135 | 0.135 | 0.135 | This value is set to give no additional mortality to adult trees as they grow. |
| DBH at Onset of Senescence, in cm | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | This value is set to give no additional mortality to adult trees as they grow. |
| Adult Background Mortality Rate | 0.01 | 0.01 | 0.01 | 0.01 | 0.01 | 0.01 | 0.01 | 0.01 | 0.01 | Pacala et al 1996 |
| Juvenile Background Mortality Rate | 0.01 | 0.01 | 0.01 | 0.01 | 0.01 | 0.01 | 0.01 | 0.01 | 0.01 | Pacala et al 1996 |
Disperse parameters
| Parameter Name | Value | Comment |
|---|
| Seed Distribution | Deterministic | -- |
| -- | ACRU | ACSA | BEAL | FAGR | TSCA | FRAM | PIST | PRSE | QURU | -- |
|---|
| Minimum DBH for Reproduction, in cm | 10 | 10 | 10 | 10 | 10 | 10 | 10 | 10 | 10 | Ribbens et al 1994. |
| Canopy Function Used | Weibull | Weibull | Weibull | Weibull | Weibull | Weibull | Weibull | Weibull | Weibull | Pacala et al 1996. |
| Weibull Canopy Annual STR | 0.09 | 0.09 | 0.09 | 0.036 | 0.09 | 0.09 | 0.09 | 0.09 | 0.09 | Scaled from Pacala et al 1996. |
| Weibull Canopy Beta | 2 | 2 | 2 | 2 | 2 | 2 | 2 | 2 | 2 | Ribbens et al 1994. |
| Weibull Canopy Theta | 3 | 3 | 3 | 3 | 3 | 3 | 3 | 3 | 3 | Ribbens et al 1994. |
| Weibull Canopy Dispersal | 3.62E-04 | 7.44E-04 | 1.00E-07 | 3.41E-04 | 6.87E-03 | 9.23E-05 | 1.03E-04 | 7.75E-04 | 1.46E-03 | Ribbens et al 1994. Note: values are incorrectly reported in Table 1. They must be multiplied by 10 to correct. |
Citations
Kobe, R. K., S. W. Pacala, J. A. Silander, Jr. and C. D. Canham. 1995. Juvenile tree survivorship as a component of shade tolerance. Ecological Applications 5:517-532.
Pacala, S. W., C. D. Canham, J. Saponara, J. A. Silander, Jr., R. K. Kobe, and E. Ribbens. 1996. Forest models defined by field measurements: II. Estimation, error analysis and dynamics. Ecological Monographs, 66:1-43.
Ribbens, E., Pacala, S. W. and Silander, J. A. 1994. Recruitment in forests: calibrating models to predict patterns of seedling dispersal. Ecology 75:1794-1806.
Teck, R.M., and D.E. Hilt. 1991. Individual-tree diameter growth model for the northeastern United States. U.S. Department of Agriculture Forest Service Research Paper NE-649.
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