John Navas wrote:

> The empirical studies I've seen are anything but conclusive.

I don't know what studies you are referring to but
http://www.radyn.com/Papers/gmc/Foliage_Attenuation.pdf might interest you.

This is particularly a millimeter wave study but pages 8-9 and
particularly paragraph 4 on page 9 are relevant and compare results from
several studies which were within 1 dB of each other.

From these, I would say it is conclusive that there is a significant
frequency dependency to attenuation through foliage.

g