Help Page

Table of Contents

  1. Getting Started
  2. Data Transfer Methods
    1. Manual Entry
    2. File Upload
  3. Interacting with the Chart
  4. Additional Features
  5. Troubleshooting

1. Getting Started

The Site-Potential Tree Height Calculator requires three types of data: tree species, tree height (in ft), and tree age (in years). Refer to WDFW’s “Procedure for Determining a Site Index from Field-Based Measurements” for the methods to be used when collecting these data. The SPTH200 can provide an estimate of site-potential tree height at age 200 years (SPTH200) for each of the tree species in your data.

2. Data Transfer Methods

There are two ways to transfer data to the SPTH200:

  1. Manual Entry: Enter data directly through the keyboard.
  2. File Upload: Upload a data file in CSV format.

Select one by clicking on the corresponding button.

Getting Started Image

a. Manual Entry

To manually enter data:

  1. Select the Manual Entry option.
  2. Choose a species from the dropdown menu labeled Select a species.
  3. Enter the tree's Height and Age in the provided fields.
  4. Click the Add Tree button to add the data to the chart and table.
  5. The adjacent graph is updated each time you enter another tree. This update includes a new estimate of the average SPTH200 for the selected tree species.
  6. Repeat the process to add more trees if needed.
  7. To start a new table for the same species, click the Clear button.
  8. To start a new table for a different species, click the Back button.
Manual Entry Image

b. File Upload

To upload data using a CSV file:

  1. The data file must be a comma-delimited CSV file with a “.csv” file extension. The first line of the file should be the column headings. Three of the columns should be labeled “SpeciesCode”, “Age”, and “Height”. Tree heights should be in feet and tree ages in years. The file may also contain other columns such as species name or tree diameter, but these extra columns will be ignored.
  2. Use the following species codes in your CSV file:
    3. Common Name Scientific Name Species Code
    Douglas-fir Pseudotsuga menziesii DF
    Western Hemlock Tsuga heterophylla WH
    Western Redcedar Thuja plicata RC
    Sitka Spruce Picea sitchensis SS
    Pacific Silver Fir Abies amabilis SF
    Ponderosa Pine Pinus ponderosa PP
    Western Larch Larix occidentalis WL
    Grand Fir Abies grandis GF
    Lodgepole Pine Pinus contorta LP
    Rocky Mountain Douglas-fir* Pseudotsuga menziesii var. glauca RM
    Black Cottonwood Populus balsamifera ssp. trichocarpa CW
    Red Alder Alnus rubra RA

    * Also known as interior Douglas-fir or inland Douglas-fir.

  3. Ensure your CSV file follows the correct format. For example:
    4. SpeciesCode,Age,Height
DF,80,150
DF,82,145
PP,60,110
DF,79,148
  4. Select the File Upload option.
  5. Click the Choose File button and select your CSV file.
  6. After uploading, select a species from the dropdown menu to analyze the data. Selecting “all species” in the dropdown menu produces estimates of SPTH200 for all species in the data file and determines which species has the tallest SPTH200.
  7. To start a new analysis for a different species, click the Back button.
CSV Upload Image

3. Interacting with the Chart

The chart offers interactive features to enhance your data analysis:

  • Hover Over Data Points: View detailed information about each data point in the chart.
  • Display Control: Toggle on/off data point visibility by clicking on the three legend items.
  • Chart Title: When tree data is present, it will display the species name, average Site-Potential Tree Height (SPTH) at 200 years, and a 95% confidence interval for the average SPTH. For example, a title might read: Douglas-fir - Average SPTH: 139 ft (95% CI: 120 ft - 158 ft).
Chart Interaction Image

4. Additional Features

  • Delete Entries: Remove single rows in the tree data table by clicking the Delete button.
  • Clear Data: Use the Clear button to remove all tree data and restart the data table.
  • Full-Screen View: Expand the chart to full-screen for a better view. To exit full-screen view, press the Esc key.
  • Export Options: Export the chart as an image or as a PDF using the chart's export menu, which is located in the upper right corner of the chart. A PDF file is obtained by “printing” to a PDF.

5. Troubleshooting

If you encounter any issues, consider the following:

  • Ensure all required fields are filled out correctly.
  • Verify that the age and height values are within acceptable ranges (Age: 1-200 years).
  • Check your CSV file for correct formatting and data consistency.
  • Ensure you're using the correct species codes as listed above.
  • Refer to any error messages displayed in the application for guidance.
  • If problems persist, contact support at WDFW: ken.muir@dfw.wa.gov.

Purpose

The Site-Potential Tree Height Calculator (SPTH200 Calculator) calculates site-potential tree height at age 200 years (SPTH200) for a specific site. SPTH200 is WDFW’s recommended width for riparian management zones (RMZs). See WDFW’s PHS management recommendations for riparian ecosystems for more information.

The SPTH200 uses tree age and tree height data entered by the user. Refer to WDFW’s “Procedure for Determining a Site Index from Field-Based Measurements” for the methods to be used when collecting tree age and tree height data.

Uses

WDFW’s Site-Potential Tree Height Mapping Tool presents on-line maps of SPTH200 for Washington, and enables a user to determine SPTH200 values for a particular location. The data source for tree productivity (i.e., site index) in the mapping tool is NRCS soils surveys. However, NRCS soils surveys have spatial gaps in coverage; most notably in urban areas and some public lands. With the SPTH200 and tree age and tree height data collected by the user, those data gaps can be filled.

Under some circumstances, empirical verification of the SPTH200 value provided by the SPTH Mapping Tool for a particular site may be desired. With the SPTH200 and data collected from that site, SPTH200 values can be verified.

References

  • Alexander, R.R. 1966. Site indexes for lodgepole pine, with corrections for stand density: instructions for field use. USDA, Forest Service. Rocky Mountain Forest and Range Experiment Station Research Paper RM-24.
  • Barnes, G.H. 1962. Yield of even-aged stands of western hemlock. USDA, Forest Service. Pacific Northwest Forest and Range Experiment Station Technical Bulletin 1273.
  • British Columbia Forest Service (BCFS). 1977. Site index curves for cottonwood (as adapted by Sauerwein, W.J.). pp. 852-853 in Pocket Woodland Handbook. U.S. Department of Agriculture, Soil Conservation Service, Portland, Oregon.
  • Cochran, P.H. 1979a. Gross yields for even-aged stands of white or Douglas-fir and white or grand fir east of the Cascades in Oregon and Washington. USDA, Forest Service. Pacific Northwest Forest and Range Experiment Station Research Paper PNW-263.
  • Cochran, P.H. 1979b. Site index and height growth curves for managed, even-aged stands of Douglas-fir east of the Cascades in Oregon and Washington. Res. Pap. PNW-251. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Forest and Range Experiment Station. 16 p.
  • Cochran, P.H. 1985. Site index, height growth, normal yields, and stocking levels for larch in Oregon and Washington. USDA, Forest Service. Pacific Northwest Forest and Range Experiment Station Research Note PNW-424.
  • Hegyi, F., J.J. Jelinek, J. Viszlai, and D.B. Carpenter. 1979. Site index equations and curves for the major tree species in British Columbia. B.C. Min. For., Victoria, B.C. For. Inventory Rep. No. 1.
  • Hoyer, G.D. and F.R. Herman. 1989. Height-age and site index curves for Pacific silver fir in the Pacific Northeast. USDA, Forest Service. Pacific Northwest Experiment Station Research Paper PNW-RP-418.
  • King, J.E. 1966. Site index curves for Douglas-fir in the Pacific Northwest. Weyerhaeuser Company, Forestry Research Center. Forestry Paper 8.
  • Kurucz, J.F. 1978. Preliminary, polymorphic site index curves for western redcedar (Thuja plicata Donn) in coastal British Columbia. Forest Research Note No. 3. MacMillan Bloedel, Nanaimo, B.C.
  • Meyer, W.H. 1961. Yield of even-aged stands of Ponderosa pine. USDA Technical Bulletin 630. (revised 1961).
  • Meyer, W.H. 1937. Yield of even-aged stands of Sitka spruce and western hemlock. USDA, Forest Service. Pacific Northwest Forest Experiment Station Technical Bulletin 544.
  • Monserud, R.A. 1985. Applying height growth and site index curves for inland Douglas-fir. USDA, Forest Service. Intermountain Research Station Research Paper INT-347.
  • Schmidt, W.C., R.C. Shearer, and A.L. Roe. 1976. Ecology and silviculture of western larch forests. USDA, Forest Service Technical Bulletin 1520.
  • Wiley, K.N. 1978. Site index tables for western hemlock in the Pacific Northwest. Weyerhaeuser Company, Western Forestry Research Center Forestry Paper No. 17.
  • Worthington, N.P., F.A. Johnson, G.R. Staebler, and W.J. Lloyd. 1960. Normal yield tables for red alder. USDA, Forest Service. Pacific Northwest Forest and Range Experiment Station Research Paper No 36.
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For questions about the SPTH200, contact Muir Ken.

For questions about the procedure for collecting tree height and tree age data, contact Brandon Austin.

For questions about the SPTH Mapping Tool, contact Terry Johnson.

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Welcome to the Site-Potential Tree Height Calculator (SPTH200 Calculator) Web App, a tool designed for foresters and ecologists to estimate the growth potential of trees in riparian areas. By inputting current tree age and height data, users can predict the average height that trees will reach at 200 years of age, known as the site-potential tree height (SPTH200).

The SPTH200 Calculator assists in ecological management and planning by providing insights into the long-term growth potential of various tree species. This information is vital for understanding how trees in riparian zones contribute to the health of adjacent aquatic ecosystems

Please start by selecting a data entry method. For more detailed instructions, please refer to the Help section

Data Entry Method: Manual Entry File Upload

Please select a tree species from the dropdown:

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