My name is Dan Crawford, and I’m a research scientist in the Environment & Natural Resources Institute at the University of Alaska - Anchorage. My path to dendro was an unexpected one to say the least. I started college at the University of Minnesota towards a degree in aerospace engineering. However, my connections with my professors and peers in this area left me feeling unfulfilled, and my mental health and transcript were paying the price. I found myself in a geography course with Scott St. George, and the material spoke to me in a way I wasn’t yet accustomed to in my young college career. By the end of the semester I found myself working alongside Scott, Kurt Kipfmueller, and some amazing grad students in the tree-ring lab; thus began my path in dendrochronology.
Fast forward to my current day-to-day at the lab, and I’m focused on generating tree-ring data for the Forest Inventory and Analysis (FIA) arm of the U.S. forest service. Field crews collect hundreds of cores each summer from forests in Alaska, which we are tasked with prepping, sanding, imaging, measuring, and crossdating to create reliable time series. These data can provide key demographic and “forest-level” insight that may be absent from traditionally targeted tree-ring studies.
In my current position, I’ve found that surface quality and high-resolution images are key for generating high-quality tree-ring data. Each FIA sample that comes through our lab is sanded to at least 1200-grit, which is a requirement for resolving most cellular-scale anatomy and aids in the identification of micro rings and other notable sub-annual features. In such sanding, I find the performance of Klingspor stearate aluminum oxide sanding sheets with a quarter-sheet power sander as an unmatched combination! For final hand polishing I swear by 3M Imperial Micro-finishing paper (sourceable from jewelry supply outlets).
A perfect surface is for naught without sufficient imaging capabilities; I was privileged to contribute to the gigapixel macrophotography approach while at the University of Minnesota, and maintain that these images surpass microscope quality when it comes to resolution, magnification, and accessibility (see dendro.elevator.umn.edu for proof-of-concept). My current setup relies on an Epson flatbed scanner capable of 6400 dpi resolution, and the open-source Hugin panorama stitcher for large cross-sections that require multiple scans.
I have a deep appreciation for dendrochronology and the unique insights into our world that it can provide, and feel incredibly grateful to have this community as part of my lifelong learning journey.
Thank you Dan for the very useful post. I am mesmerized by the gigapixel images!