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Importance Values of 1974 and 1996 - Compared
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From the 1974 AND 1996 data, Phytosociological Tables were generated for the purpose
of a comparison of the forest composition, then and now. The variables that we were
interested in were basal area (m3) that was calculated from the DBH, the density of trees
that was calculated as number of trees per hectare, and frequency - i.e. how many of each
species are found on each transect. Individual percentages of these three variables by
species as compared to their totals was then calculated, and these percentages were summed
and divided by three, generating what we were defining as an "Importance Value". This
importance value weighted the species, so a species with a few large trees would have a
similar importance as a species with more individuals per hectare but not as large dbh.
For fun, we decided to generate a host of Phytosociological tables for both 1996 data and
1974 data, in the following catagories:
1974
The following links are to the raw data for the 1974 phytosociological tables that have been sorted in the
following manner:
All
Live
Live greater than 10 cm
Live less than 10 cm
North - All
North - Live
South All
South Live
North Live greater than 10 cm
North Live less than 10 cm
South - Live greater than 10 cm
South - Live less than 10 cm
1996
The following links are to the raw data for the 1996 phytosociological tables that have been sorted in the
following manner:
All
Live
Live greater than 10 cm
Live less than 10 cm
North - All
North - Live
North Live greater than 10 cm
North Live less than 10 cm
South All
South Live
South - Live greater than 10 cm
South - Live less than 10 cm
1974 Summary Table of Importance Values - Comparison
1996 Summary Table of Importance Values - Comparison
Phytosociology Conclusions