RELEASE-2023

Coarse Downed Wood bulk density samples are collected from terrestrial sites with qualifying logs where repeat CDW Survey sampling is performed. CDW Bulk Density sampling is implemented twice per site, the first time within the first three years of data collection at a site, and the second time 5-6 years after the first sampling event. When possible, the same logs are targeted for sampling at both sampling time points. Sampling may occur in up to 20 Distributed Plots and all Tower Plots, and unlike all other NEON TOS sampling, collection of disks may also occur outside of NEON plot boundaries, due to the sparsely distributed nature of target logs. Logs sampled for bulk density are parsed into five decay categories that broadly match existing USFS definitions, three size categories (2-5 cm, 5-10 cm, and greater than 10 cm diameter), and are identified to the highest taxonomic resolution possible according to the USDA Plants database. The bulk density sampling effort is inherently variable from site to site, as it is driven by the number of 'decayClass x sizeCategory x taxonID' (DST) combinations, which is strongly dependent on site-level tree diversity. For each site, sampling is considered complete once all rank-ordered DSTs that cumulatively make up 80% of the total tallies have been sampled. Target disk sample size per DST is n=10 for DSTs >= 10 cm diameter, and n=5 for DSTs < 10 cm diameter. Instrumentation: