Looking for published material about calculating the crown volume of an individual tree. Found some interesting formulae on an Australian National University web site for conoid, paraboloid and hemisherical crowns. Somewhere in my boxes of stuff I seem to recall a simplified model involving a truncated cone... maybe in one of the well known tree ordinances... but I can't find it. Anybody have any references?

Some of us recently got e-mails from an Austrian software company with a program that would calculate crown area or volume from a photo. Might be interesting, but I'm looking for the underlying math.

Thanks.