Trip Reports/Rucker Indexes/Future   Edward Frank
  Mar 03, 2005 17:13 PST 


I have been looking over our large accumulation of trip reports compiled
over the last several years by ENTS members. Let say upfront that I think
a good detailed description of a particular site is as important as getting
tree measurements. I will continue to encourage people who visit a
worthwhile site to post a description of the site to the discussion list,
even if they did not take any tree height or girth measurements.

One of the goals of the group however is still to document tall trees on
these sites using our accurate measurement methodologies. A stalwart
measure we try to compile for a site is a Rucker Index (RI). This is the
average height of the tallest individual of each of the ten tallest species
found on the site. Measurement of additional trees allows us to look in
greater detail at each of these sites. We can caculate multiple iterations
of the RI, and look at how other shorter species fit into the picture of
the site.

I started looking at the trip reports published on the website. I choose
Georgia as a test example, basically because we had only a few trip reports
from the area. Of the thirteen sites for which we had reports. ten had
tree measurements. A pretty good percentage, especially considering that I
crop out, even a mention of a different site written as an aside, as a
separate page on the website. Of the remaining ten sites, only three had
sufficient numbers of measurements to calculate a 10 species Rucker Index.
I went back through the reports to see how many would support a limited
rucker index consisting of five species (RI5). Four additional sites, plus
the three with 10 species index, had sufficient measurements to calculate a
RI5 index. Of the remaining three sites, two of them had measurements of
just 4 species. The last had five species, but did not include the tallest
on the site. I started a table for Pennsylvania, but it is not finished yet.

I actually would like to see a broader measurement where possible that
includes as large a number of species as possible from a site. I am
joining the measurement club and will try my best to paractice what I preach.

I want to suggest that we try to calculate RI5 indexes for all sites for
which we have sufficient measurements, and continue to calculate standard
RI for all site for which we have sufficient measurements. The addition of
the RI index would allow a comparison of a wider number of sites. What do
the rest of you think?

Ed Frank