B is for Basal Area

When the basal area of trees starts to add up, so does the monetary value.

Defined, basal area is a measure of the cross-sectional area of a tree bole measured 4½ feet above the ground on the uphill side of the tree.  The cross-sectional area is often expressed in square feet.

To get a picture of basal area think of a deck of cards and then spread them out.  The coverage on the flat surface is what basal area looks like in a forest.  Now think about putting a one, two, three, maybe four decks of cards on each of the individual cards that you spread out.  A few cards spread out with decks on them, not many cards, a lot of cards spread out in the same area with decks on them, a lot more cards.

The same idea applies to trees and the forest.  Using specialized and calibrated forestry tools calculation of basal area (BA) is fast and combined with tree volume equations the relationship, volume/ BA, is a quick way to estimate the volume of a tree or a forest.  A forest with about the same height trees with 400 square feet of BA per acre will have more volume than one with 100 square feet of BA per acre.  

Knowing the volume is one of the initial factors in determining the monetary value of trees and a forest.  So when basal area starts to add up so does the dollar value of the forest.