Bob, I assume the question was partially directed at me as well as the rest of the ENTS members. I like the concept you are presenting here. One index, your Historical Rucker Index, HRI, is the Rucker Index including the tallest trees of the tallest ten species ever measured at a site. Your Present Rucker Index PRI, includes only the heights of tree as they exist at the present time. I like the ratio you propose comparing the two indexes. I really don't care for your nomenclature.
When you say Historical Rucker Index, I think of it as meaning the RI at some discrete point in the past. In general I have always considered the basic Rucker Index to represent the average of the largest trees recorded at the site, and their maximum height, whether or not they were still at their maximum height, or whether or not they were still standing. Others may have interpreted this value differently. I would recommend that the standard Rucker Index be defined in this way explicitly, then the term "Historical" would not need be used. This would clarify the meaning of the value and avoid future confusion For your PRI, you are talking about the index of the contemporaneous trees growing at the site at this particular time - the present. What strikes me is that if you call "Present" then it practically begs to ask what date does present mean? If someone would look back from fifty years in the future, then they would want to know the date of the "Present" in the index. Still, though have wracked my brain, I can think of no word or letter more appropriate for the 'snapshot in time' idea you have proposed. In May 2006 http://www.nativetreesociety.org/measure/rucker/to_rucker_or_not_to_rucker.htm We had a discussion about the nomenclature of the various Rucker Index. I proposed a structure that I thought would be good for the long-term for how the information should be ordered. The idea was to avoid confusion as we added more and more variations of the Rucker Index to the repertoire. I would like to encourage the adaptation of this idea of a Present Rucker Index to that format. It isn't that I proposed this structure, it is because I think a uniform naming pattern will make things easier to deal with over time. The structure I proposed was of the format for example: RHI10-xx where: 1) Type of Index (R = Rucker) 2) Parameter of Index (H = Height,) code letters for other types of indexes like girth, crown spread, etc would go here. 3) Number of trees in the Index (10, 05, 20, etc) 4) Other Information (for example the 15th iteration would be represented as I15) In the case of the basic rucker height index with 10 trees, the notation could be simplified to just RI, if another type of index was used, or if the basic height index was used in conjunction with another parameter, then the full notation would be required. For your Present Rucker Height Index, the full notation I would suggest would be RHI10-P2008. This would mean Rucker- Height Index - 10 tree - Present - 2008. In the discussion there is no reason it could not be simplified to RI-P. In the tables I would suggest the full notation. In your ratio, the RI (HRI in your notation) would always be greater than the RI-P (PRI) in your notation. This ratio may be informative about the current versus maximum heights on a site. Over a long period of time you may also compare the RI-P from different times and see how these values changed over that period of time. That is one reason why the RI-P should have a date also in tables or compilations. The format for dates should be just the year- I don't see time resolution beyond that being practical or useful. Ed Frank Join me in the Eastern Native Tree Society at http://www.nativetreesociety.org and in the Primal Forests - Ancient Trees Community at: http://primalforests.ning.com/ ----- Original Message ----- From: [EMAIL PROTECTED] To: [email protected] Sent: Friday, October 03, 2008 6:35 PM Subject: [ENTS] PRI, HRI, and PRI/HRI ENTS, Today John Knuerr and I tracked down the champion white ash in Trout Brook and remeasured it. Its prior height as determined by John Eichholz a couple of years ago was 151.5 feet, tops in the Northeast. However, the top sprig appears dead. We got 149.3 feet after multiple measurement attempts. There is still a lot of understory that blocks vision, so we can't absolutely rule out a higher point. We'll return in about a month when the crown will be more visible. However, at present, the tree drops out as the tallest of its species for MTSF and in its place is the other 150-footer on the south side of Clark Ridge. This brings me to a point. Trees can die and drop out of the RHI for a site. Other trees can come into the list. Still other trees can gain or lose height and still remain in the list. What this inevitable change of the index means is that we can lose sight of the potential of the site to grow tall trees, which is partly what we are attempting to measure with the RHI or RI for short. We are, of course, also taking instantaneous shots of the forest, capturing status at a moment in time. The following tables show the historical and present indices of MTSF. When I report a site index in the future, I will include its historical Rucker Index HRI along with its present RI, called a PRI (present Rucker Index) for properties where the more detailed level of reporting is warranted. That would generally be the case for properties that are visited frequently like MTSF. I would hope Dale will do the same for Cook Forest, Tom Diggins for Zoar Valley, and Will for the GSMNP. One way we might implement the concept is to show the two indices in ratio form: PRI/HRI. For MTSF that form would yield 136.1/136.8. Thoughts, anyone? Bob --~--~---------~--~----~------------~-------~--~----~ Eastern Native Tree Society http://www.nativetreesociety.org You are subscribed to the Google Groups "ENTSTrees" group. 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