spherical densiometers?

[Eric M. Nielsen]

Hey again.

  Does anyone have any opinion on the utility of spherical
crown densiometers for use in estimating leaf area index in
boreal forests?  I'm thinking that the typical narrow crowns of
boreal trees might make the method fairly bogus, but haven't
got any other options at this point, other than using
allometries.
  If they are useful, which would be better, convex or
concave?  Also, is there a reasonably priced source for them
that can deliver quickly (walnut case not required) ??
  Please e-mail me at emn8c at virginia.edu as soon as you can!

  thanks,   Eric