Sensitive vs. Complacent Tree-Ring Growth


sensitive and complacent samples
sensitive tree site "Sensitive" tree growth:
  • High degree of annual variation
  • Wide and narrow rings intermixed through time
  • Limiting growth factor (e.g., rainfall) is highly variable year to year
  • Especially true for harsh sites (steep/rocky for moisture sensitivity; see figure at left)
  • Reasonably sensitive ring growth is good:
    • Matching patterns of relatively wide and narrows rings across trees is
      easier when ample variation exists
complacent tree site "Complacent" tree growth:
  • Low degree of annual variation
  • Rings are roughly the same for many years consecutively
  • limiting growth factor is not variable from year to year
  • Especially true for benign sites (flat with deep soil for moisture complacency; see figure at left)
  • Complacent ring growth can be difficult to crossdate:
    • matching patterns of relatively wide and narrows rings across trees is
      harder when not much variation exists
    • depending on the level of complacency and the length of a sample (number
      of rings), a sample might not be crossdateable

When you try skeleton plotting for yourself, you can:
Change the sensitivity of your virtual core with scroll bars, as on the right:
  • Mouse click on the arrows of the "Sensitivity" scroll bar
    • The lower the number, the higher the ring-width sensitivity
    • The higher the number, the higher the ring-width complacency
    • Mouse click the "Restart a New Core" button
  • Important point: You may also need to change the number of rings:
    • A longer tree-ring series may be needed to crossdate complacent series
    • Mouse click on the arrows of the "Number of Rings" scroll bar
    • Mouse click the "Restart a New Core" button
sensitivity and ring options



Paul R. Sheppard
Laboratory of Tree-Ring Research, The University of Arizona
Tucson, Arizona 85721 USA
office: (520) 621-6474, fax: (520) 621-8229
Comments to: sheppard@ltrr.arizona.edu