Calculating the Lower Basal Wedge - Alternate Method

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Calculating the Lower Basal Wedge - Alternate Method

Post by M.W.Taylor » Fri Sep 29, 2017 4:22 pm

The attached is an alternate method for computing the lower basal wedge volume using the ground perimeter instead of the horizontal offset of high side ground level vs. low side ground level. In some cases the perimeter with a tapeline is easier to obtain. In other cases as with older data, only the perimeter data was taken so this is a way to update old data sets with the improved lower basal wedge model without needing to go back to the tree to get a horizontal offset. The equation gets rather ugly so a numeric solution is needed. See attached write-up and spreadsheet with visual basic to solve the complex equation.

Michael Taylor

slant frustum perimeter solution-RevB.docx
write up on new alternate method
(62.06 KiB) Downloaded 41 times
slant frustum numeric perimeter solver.xlsb
spreadsheet with visual basic embedded. Enter perimeter instead of horizontal offset in cells AH1 instead of offset in AF1. Then press the black button to solve for horizontal offset. minor and major axis of the base will also be calculated. Cells with red borders should not be changed.
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Re: Calculating the Lower Basal Wedge - Alternate Method

Post by dbhguru » Fri Sep 29, 2017 6:50 pm


Great work. We've come a long way from the days when tree volume was calculated through log volumes taken over a well behaved section of trunk.

Robert T. Leverett
Co-founder, Native Native Tree Society
Co-founder and President
Friends of Mohawk Trail State Forest
Co-founder, National Cadre

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