Resurrecting PAGEPLOT for Tree-Ring Analysis

Technology #ua16-065

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Zachary Wilder
Paul Sheppard
Associate Professor, Tree Ring Lab
Managed By
Lewis Humphreys
Licensing Manager (520) 626-2574

Title: Software for the Dating and Study of Tree Rings


Invention: Software used for crossdating tree rings using skeleton plotting, allowing more accurate dating than ring counting alone.


Background: Ensuring accurate dating by counting each individual tree ring can prove difficult due to calendar year vs. time to grow a ring, absent rings, false rings, and other various factors. Matching ring-growth characteristics across many samples  to crossdate rings allows the exact year of each ring to be identified. This software, while still in development, focuses on modernizing outdated skeleton plotting and mainframe software so that their benefits are applicable in the current computing world.



  • Interdisciplinary dendrochronological research and course work (ecology, climatology, geology, anthropology, hydrology, etc.)
  • The lumber industry (product quality and source and future of the industry)
  • Art history and museums (verification of acquisition legitimacy)



  • Crossdating samples provides more accurate tree ring dating than counting alone
  • Skeleton plots provide an excellent visual aid for pattern matching
  • Coupling sample skeleton plots with a master chronology grants greater insight into patterns for enhanced dating characteristics


Licensing Manager: 

Lewis Humphreys

(520) 626-1213