All Ruckered out    Edward Frank    Apr 25, 2004 10:10 PDT  Bob and others, Rucker Index Terminology There has been a number variants of the original Rucker Site Index proposed and experimented with in the last few months. It is important that some sort of a standard terminology be determined so that the various incarnations of "Rucker" not be confused. Colby Rucker for example is actually a person and not an index at all!! Rucker Site Index: The average height of the ten tallest individuals of each of the ten tallest species on a site. Commonly referred to as simply the Rucker Index. http://www.nativetreesociety.org/measure/rucker_site_index.htm Rucker Combined Index: The average of the height times cbh of the ten largest individuals of each of the ten largest species on a site. http://www.nativetreesociety.org/measure/pushing_the_envelope.htm Rucker Site Iteration Table: This would consists of a table of multiple Rucker Site Index iterations made for a particular site. Colby Rucker, March 6, 2004 writes: The first iteration is a measure of both maximum height potential and the diversity of the dominant species. Ten species is high enough to offset the high numbers associated with the emergent giants, and low enough so that few sites are pressed into averaging numbers from interface species that are much smaller than the shorter species on a site with greater dominant diversity.   Higher numbers in succeeding iterations are correlated to large acreage and second growth monotony. http://www.nativetreesociety.org/measure/iterations.htm Rucker Species Index: The average height of the ten tallest individuals of a particular species on a site. Concept mentioned first in a post by d-@comcast.net Apr 17, 2004 14:51 PDT  Rucker Species Average Index: The average of the ten highest Rucker Species Indexes for a particular site. Concept mentioned first in a post by d-@comcast.net Apr 17, 2004 14:51 PDT  (I understand this is not how it was used in a table recently forwarded to me.) One of the strengths of the Rucker Site index is that it uses the same criteria for all sites, i.e. 10 species. Some of the recent discussions have considered the ramifications if the number of species in these indexes were increased from 10 to 13, 14, or whatever the data would support. I think these ideas have valid arguments in their favor and some drawbacks as well, but certainly the options should be explored. I myself have posted suggesting a Rucker 20 Site Index incorporating the tallest 20 species in order to encourage measurement of a wider variety of species.     I propose that for sake of consistency and to allow valid comparisons to be made between the possible variations, the base Index name be reserved for those including 10 individuals or averages, no more or no less. If a number other than 10 is used that number should be included in the index title or abbreviation. For example if the index was expanded to include 14 species rather than the base ten for a site that would be referred to as a Rucker 14 Site Index, or Rucker 14 Index. A species average index including 13 species, such as appeared on a table sent to me for MTSF, would be referred to as a Rucker 13 Species Average Index. This would standardize the terminology and allow someone to easily differentiate between possible variations.   Home