This collection contains oven-dried canopy foliage collected from NEON terrestrial sites (NEON sample class: cfc_chemistrySubsampling_in.archiveSampleID). Each NEON site conducts canopy foliage sampling once every 5 years and is scheduled to begin within ± 2 weeks of the anticipated midpoint of the Aerial Observation Platform (AOP) flight window at the site. A subset of the 40 x 40 meter Distributed Base Plots located across the study area are used for canopy foliage sampling. In forest and shrubland sites, these plots overlap with those used for Vegetation Structure (VST) monitoring. In sites dominated by woody cover (e.g., forests and shrubland), the general procedure is to sample at least one individual of each species found in the site-level, sunlit canopy. For the more common species, replicates are taken, spanning whatever gradients are relevant to a site (topography, aspect, soil type, stand age, etc.). In high-diversity sites, rare species are sampled, but only where feasible (e.g., target taxa with sunlit foliage present in a CFC plot). Each site has a target sample number proportional to its canopy diversity, as assessed using stem counts. Target taxa lists including per-species sample numbers have been generated by NEON Science and are included in the Sampling Support Library (SSL). In systems dominated by herbaceous vegetation, bulk herbaceous plant biomass is harvested from a set of assigned plots using clip strips. Subsamples for archive are oven-dried at 65 degrees Celsius for at least 48 hours then ground in a Wiley mill to 20 mesh size (sieve opening size = 0.0331 in). Archived samples are stored at room temperature in 20 mL HDPE scintillation vials. See related link below for protocol.