DOI: 10.48443/kmc7-8g05
title: Plant foliar traits (DP1.10026.001)
title: RELEASE-2022

description: This data product contains the quality-controlled, native sampling resolution data from NEON's measurement of foliar traits in sun lit, georeferenced vegetation samples. Trait measurements include leaf mass per area, leaf water content, chlorophyll, carbon and nitrogen concentrations and stable isotopes, major and minor elements, and lignin. Whenever possible, foliar data are collected in conjunction with overflights of the NEON Airborne Observation Platform (AOP), and starting in 2020 polygon shapefiles are provided to link sampled crowns to airborne imagery. For additional details, see the user guide, protocols, and science design listed in the Documentation section below. Queries for this data product will return field collection data, physical and chemical measurements, and crown polygons (where available) on a per sample basis. Several items are available in the expanded data package, including summary tables of external lab precision and accuracy as well as information on woody sample geolocation.

Latency:
The expected time from data and/or sample collection in the field to data publication is as follows, for each of the data tables (in days) in the downloaded data package. See the Data Product User Guide for more information.

bgc\_CNiso\_externalSummary:  30

cfc_carbonNitrogen:  270

cfc_chemistrySubsampling:  90

cfc_chlorophyll:  120

cfc_chlorophyllParameters:  30

cfc_chlorophyllSummary:  30

cfc_elements:  180

cfc_elementsSummary:  30

cfc_fieldData:  90

cfc_lignin:  180

cfc_LMA:  90

cfc_shapefile: 90

lig_externalSummary:  30

vst_mappingandtagging: 120
description: For sites with predominantly forest/shrubland cover, spatial collection methods differed during early operations (2016‐2018) compared to 2019 and onward. The earlier method involved sampling the top three dominant species present in each of 14 pre‐assigned plots, 4 Tower and 10 Distributed. However, with input from the community, the design shifted away from plots and towards a site‐based approach focused on sampling the full spectrum of canopy biodiversity present at the site. Many of the individuals sampled are monitored in the Vegetation Structure (VST) protocol, and all are georeferenced, either using stem offsets (prior to 2020 as well as smaller individuals) or polygon shapefiles of sampled crowns mapped on top of recent AOP spectrometer data while in the field (2020 and onward for larger individuals).

For grassland sites, the design has remained consistent. Foliage is sampled from 20 plots; all aboveground material in one or two (depending on plot size), randomly selected  0.1 X 2 m clip strips is harvested and homogenized, yielding 20-24 samples per bout. Traits are measured on species mixtures that represent community composition of the clip strip. In sites with both woody and herbaceous cover, a combination of the two sampling approaches is employed.

Foliar sampling occurs once every five years per site during the period of historic peak greenness. Whenever possible, sampling also occurs within two weeks of the AOP overflight and aopCollectDate for each sample is included in the data. Chlorophyll subsamples are immediately frozen after collection, and additional processing of samples, including scans for leaf mass per area and initiation of sample drying for leaf water content and chemical analyses, occurs within 1-5 days of collection. During the same year that foliar traits are measured, other biogeochemical pools and fluxes are as well (e.g., soil chemistry, DP1.10086.001; litter chemistry, DP1.10033.001; root biomass and chemistry, DP1.10067.001) with coincident data at a subset of plots.