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The Laboratory of Tree-Ring Research (LTRR) at the University of Arizona currently houses approximately 2,000,000 wood research specimens and their associated records, photographs, analyses, etc. As the oldest dendrochronology laboratory in world, the LTRR’s collections are unparalleled in size. The continuously expanding multi-taxon collection contains records of life on earth that are an irreplaceable source of biological and human information, built over the past 100 years.

To ensure the long-term viability of the Collection, and its future growth, an appropriate set of policies and procedures must be clearly stated and adhered to closely, while accounting for the necessary degree of flexibility associated with a multidisciplinary field that rapidly advances, such as dendrochronology. 


The Collection only exists as a result of decades of research, and should function to support current and future science, education and outreach.




The LTRR exclusively curates dendrochronological specimens, associated materials and documentation (including soil, leaves, photographs, digital images, data, field notes, etc.).

As dendrochronology involves many fields of research, each project may have different analytical requirements, reflected in sample preparation and its long-term curation needs. Common specimens are cores, sections (or portions thereof), and archaeological remains which are often irregular in size and shape. The LTRR is dedicated to providing the best care possible for any and all forms of current and future dendrochronological samples.

Samples for dendrochronological analysis come from a combination of living trees (“green” samples), remnant wood, charcoal and archaeological contexts. Although the Collection currently does not contain any, waterlogged specimens (remnant and archaeological), these are likely to become more common in the near future and can also be curated at the LTRR. Future research will inevitably lead to new materials that need curation, which will be addressed at that time.