As in the 8th Edition TFM requires the calculation of (TAa - TAr) that is, the trunk area of the appraised tree less the trunk area of the replacement size tree. The 8th Edition did not define the result of the equation.
9th Edition introduces (first on p.71 #12, then on pages 74 & 75 #12) a new term, TAincr, to describe the trunk area increase.This is sraight forward enough.
But rather than simply using the simple equation terms constently, 9th edition uses other descriptive labels as well. These are presented in bold face as if they are meant to be defined terms, while the equation terms are not.
First on page 71 #12 as "APPRAISED TREE SIZE INCREASE."
Next on page 72 as "TRUNK AREA INCREASE of the appraised tree."
Next on pages 74 & 75 #12 as "APPRAISED TREE TRUNK INCREASE."
After flipping back and forth among the pages it seems clear that the equations are constant in describing the term to be calculated and used. But the inconsitent descriptive labels are confusing at first. It is also likely that different appraisals will use on or another of the three desccriptive labels differently causing confusion when appraisals are compared by both appraisers and appraisal users. Since the only constants are the equation terms it might be best to stick to them:
