Q |
What are the functions of the VDYP7 core programs |
A |
Functionally, VDYP7 Attribute Adjustment starts by creating a file structure, or ‘Template File’ containing the forest inventory information required by subsequent processing. Yield predictions are then made for adjustment by calling the following six VDYP7 core programs:
- FIPSTART – creates the stand description needed to project a FIP polygon.
- VRISTART – creates the stand description needed to project a VRI polygon.
- VRIYOUNG – used to advance the age and grown heights of short stands (less than 6-8 m) to a sufficient height so that a stand description can be produced.
- VRIADJST – produces additional adjusted attributes to the stand description and harmonizes these attributes in relation to the standard 11 attributes adjusted in the VRI analysis.
- VDYP7 Growth Projection Model – is a growth and yield model that projects the stand description forward in time.
- VDYP7BACK – moves the stand description backward in time using interpolation procedures.
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Q
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How does VDYP7 interact with the adjustment process? |
A |
The adjustment process in VDYP7 ensures that VRIADJST adjusted polygon information for an administrative unit (such as a TSA) sum to the sample based estimates for that unit. The adjustment process directly uses the revised values, then modifies other variables as required to make the description plausible for all species, utilization classes and volume types. This ensures that the predictions of BA, volume and selected attributes, when summed across polygons in a unit, agree with the totals obtained from the unbiased VRI phase 2 ground samples. |
