Gigapixel macro photography of tree rings

Abstract
High quality specimen digitization is becoming standard across the sciences, is relevant for curation of natural history collections, and must become a priority for dendrochronology. Here, ultra-high resolution images of tree-ring specimens are presented. Our gigapixel images of polished specimens have proven effective for digital analyses, archiving, and education, and we believe macro photography may prove a lower cost and more broadly accessible digitization alternative to microtomy and X-rays. We advocate for gigapixel macro photography as one accessible and adaptable paradigm to elevate reflected light imaging standards in dendrochronology.

Description
Two ultra-high resolution images of tree rings are available as TIFF files. Tree-ring specimens are Pseudotsuga macrocarpa from California and Quercus macrocarpa from Minnesota sampled in June 2016 and March 2019, respectively. These gigapixel macro photographs were created using a professional-grade camera body, the GigaMacro imaging system, and computational post-processing. Image comparison from a flatbed scanner and the GigaMacro system are shown (Figure 1), and visual aids illustrate the mechanics of gigapixel macro photography (Figure 2). Specific questions about these tree-ring images and about access to additional materials may be addressed to Daniel Griffin ([email protected]).

Funding information
Sponsorship: National Science Foundation Division of Environmental Biology, Award: 1655144; National Science Foundation Division of Atmospheric and Geospace Sciences, Award: 1602633; National Science Foundation Division of Atmospheric and Geospace Sciences, Award: 1903504