This is good content - not theoretical at all. In the PNW, this is how
we cruise. Yes, a forester had better know what his findings mean in
the "real world" of non-mensurationists, on the other hand, he had
better be able to explain his procedures professionally too. If photo
cruises can do that for you back east, fine. That's not done often here,
except for cursory overviews. Partly that's because of the way we sell
timber - we have a lot of cash sales rather than stumpage sales and
values had better be nailed down to a few percent.

Back to the original question: having to derive a sample area when
using a relaskop is not kosher, but its done all the time to estimate
the number of plots needed before a cruise. Then sampling intensity is
adjusted in the field, depending on the findings. An BAF of 40 in large
timber is approximately equivalent to a 0.2 acre fixed plot for
estimating purposes only. As to whether one would actually DO a fixed
area plot, the advantages of using variable plots are so great in this
region (see that caveat?) that fixed plots are used only for
regeneration or research.