You might wish to investigate some of these web sites with tree-ring data or information about other dendrochronology laboratories around the world:

• The Laboratory of Tree-Ring Research, University of Arizona, Tucson
• The International Tree-Ring Data Bank (ITRDB)
• The Swiss Federal Institute for Forest, Snow, and Landscape Research (WSL)–Tree Ring Research
• The Climatic Research Unit, University of East Anglia, Norwich, England

• University of Cambridge | Dept. of Geography | Climate & Environmental Dynamics

• Oxford Dendrochronology Laboratory
• Tree-Ring Lab, Lamont-Doherty Earth Observatory at Columbia University.
• The University of Arkansas Tree-Ring Laboratory

• University of St. Andrews | Tree-Ring Laboratory

• OLDLIST: a database of ancient trees and their ages
• University of Minnesota Griffin Lab – dendrochronology, climate science, global change

• Swansea University |  Environmental Dynamics Research Group | Tree Ring Research Group

• The DendroHub webpage provides links to many other dendro labs around the world