Canopy Foliage Chemistry and Leaf Mass Per Area Measurements NEON is interested in quantify changes in canopy nutrient stocks over time, and using the isotopic compositions of leaves (as well as leaf litter, roots, and soils samples collected in aforementioned protocols) to follow how the sources of nutrients to and metabolism of the ecosystem at SRER changes over the life of the Observatory. This dataset is generated in collaboration with the AOP, which is largely responsible for mapping plant chemical and physical characteristics using spectral and LiDAR measurements. Ground-based data will be used, in part, to ground-truth the airborne measurements as well as to extend the airborne data to create maps of canopy N. Canopy foliar samples are collected at SRER in a subset of Tower (n = 4) and Distributed Plots (n = 6) once every five years. A subset of additional Distributed Plots (n = 10) may be selected for additional canopy chemistry sampling. Sampling will occur within ± 2 weeks of AOP flights. Page 1 of 1