DOI: 10.48443/pgdv-wd42
title: Non-herbaceous perennial vegetation structure (DP1.10045.001)
title: RELEASE-2021

description: This data product contains the quality-controlled, native sampling resolution data from in-situ structural measurements of live and standing dead non-herbaceous perennial plants, from all terrestrial NEON sites with qualifying vegetation. Non-herbaceous perennial plants include agave, cactus, ferns, ocotillo, palms, xerophyllum and yucca species. The exact measurements collected per individual depend on growth form, and these measurements are focused on biomass and productivity estimation, when suitable allometries exist, and estimation of volume. Tree Palms are the only non-herbaceous perennial individuals that are consistently mapped; smaller palms such as Serenoa repens may be mapped if no taller overstory is present in a given plot. Tagging is also generally dependent on growth form and species; qualifying individuals are tagged when tags can be efficiently relocated to enable longitudinal data collection. For example, palms are always tagged, large-stature cactus are tagged, small-stature cactus are not tagged, and ferns are never tagged. Individuals of all growth forms except tree palms may be subsampled according to a nested subplot approach in order to standardize the per plot sampling effort. Structure and mapping data are reported per individual per plot; sampling metadata, such as per growth form sampling area, are reported per plot. For additional details, see the user guide, protocols, and science design listed in the Documentation section in this data product's details webpage.

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.

nst_perindividual:  90

vst_perplotperyear:  300
description: Non-herbaceous perennial vegetation structure data are collected from distributed and tower plots. Each distributed plot is sampled in a given bout if at least one tree palm is present. If tree palms are absent, smaller qualifying non-herbaceous perennial vegetation is considered together with smaller qualifying woody vegetation; both non-herbaceous perennial and woody vegetation are sampled if all qualifying individuals of both types comprise ≥ 10% aerial cover of the plot. For example, a distributed plot with 10% aerial cover comprised of a mix of small shrubs and yucca would be sampled for yucca even if total yucca cover is < 10% aerial cover. Ferns, Xerophyllum, and Yucca have additional sampling criteria within distributed plots: These three growth forms are not measured when the NLCD vegetation type of the plot is Deciduous Forest, Evergreen Forest, or Mixed Forest. In addition, when Distributed plot NLCD vegetation type is not forest, ferns are only sampled when aerial cover is ≥ 50% within the plot. Tower plots are sampled if at least one tree palm is present in ≥ 10% of tower plots, or if smaller qualifying non-herbaceous perennial individuals plus smaller qualifying woody vegetation comprise ≥ 10% of aerial cover averaged across all tower plots. Within distributed and tower plots, tree palms are mapped and measured throughout the plot sampling area. If stem density thresholds are met, smaller qualifying individuals may be measured within nested subplots to standardize the sampling effort across plots.

At all sites at which qualifying non-herbaceous perennial vegetation is present, distributed plots are sampled every 5 years. At sites with qualifying vegetation, a spatially-balanced subset of n=5 tower plots are sampled annually, and the full complement of tower plots is sampled every 5 years. Ferns are only sampled in Tower plots when all Tower plots are sampled every 5 years; that is, ferns are not measured annually in the n=5 Tower plot subset. At desert sites with sensitive vegetation and soils, there is no annual tower plot measurement and non-herbaceous perennial vegetation in the full complement of tower plots is measured every 5 years only (i.e., MOAB, JORN, SRER, ONAQ).

At all sites, distributed plot sampling and ‘full’ tower plot sampling is scheduled in a staggered manner such that sites generate data either from all distributed plots or all tower plots every 2-3 years. Sites that do not have qualifying vegetation are surveyed every 5 years to determine whether ingrowth of qualifying vegetation has occurred.

At sites with seasonal senescence, the onset of sampling in a given year is triggered by senescence of canopy or understory individuals, and must be completed before growth begins the following season and within 4 months of sampling onset. At sites with no distinct season, sampling begins within ± 2 weeks of the same date, and must be completed within 60 days of sampling onset. See NEON.DOC.000987 for more details.