Adjusting Forest Vegetation Simulator (FVS) predictions of reforested ponderosa pine stands

This tool allows managers to adjust uncalibrated Forest Vegetation Simulator projections of reforested ponderosa pine stands managed under only basic site preparation, herbicide, young stand fertilization, or combined herbicide and fertilization. 

The increasing scale and severity of wildfire in California is creating an urgent demand for more effective reforestation practices. However, managers face barriers to the incorporation of key practices, such as herbicide and young stand fertilization, into environmental planning. This tool allows managers to adjust uncalibrated Forest Vegetation Simulator (FVS) projections of reforested ponderosa pine stands managed under only basic site preparation, herbicide, young stand fertilization, or combined herbicide and fertilization. 

This model is based on data from the Garden of Eden study. This study evaluated ponderosa pine growth under four different treatments (with or without herbicide and/or fertilizer addition) for 20 years. This manager tool was developed by calibrating FVS predicted variables with measured field data from the Garden of Eden study. First, bare ground FVS simulations were run for each variant, initiated using the PLANT keyword, with 1 year old 0.3m tall Ponderosa pine seedlings, no resprouting, and a uniform spatial distribution. Then, we compared simulated basal area (BA), quadratic mean diameter (QMD), and top height (TopHt) to measured values from the Garden of Eden experimental plots, for each variant and site at approximately 10 and 20 years after planting. Those prediction accuracy values are used in this manager tool to allow users to adjust FVS predictions of BA, QMD, and TopHt to compare and contrast reforestation outcomes under herbicide, fertilization, and no-action treatment alternatives.

Instructions:

1. Click the download button. Two options are available: ‘Open’ or ‘Save As.’

• Choose ‘Save As’ to put the file in a known location. Choosing ‘Open’ causes an automatic download to a deeply buried Windows folder.

2. In either case, navigate to the zipped file in Windows Explorer.

3. Double click the zipped file to uncompress.

4. Double click the resulting Excel file to open.

5. The file will open to a README worksheet with a security warning that macros are disabled at the top.

• The user can peruse the various worksheets, scroll, and even enter input values but clicking the calculate button will result in an error message if macros are not enabled.

6. Click “Enable Content.”

• You must enable macros to use the tool.