get_1000h_coeffs: 1000-hour coefficients

In danfosterfire/Rfuels: Estimate Fuel Loads from Brown's Transects for Sierra Nevada Conifers

Description

Van Wagtendonk et al. (1996) tables 3, 6, and give the average quadratic mean diamter, secant of acute angle, and specific gravity of woody fuel particles of 21 Sierra Nevada conifers. Following Stephens et al. (2001), we estimate the average SEC (secant of acute angle) and SG (specific gravity) by taking a weighted average of the species-specific values. The various coefficients are weighted by the proportion of total plot basal area occupied by each species. Note that for 1000-hour fuels, we assume that the sum-of-squared-diameters have been observed and recorded in the data, so we don't need to estimate QMD based on the species. For more details, see the vignette.

Usage

get_1000h_coeffs(dataset, species_list, type)

Arguments

dataset	A tidy data table with a row for each observation (brown's transect), and columns for the plot identifier ('plot_id'), the inventory date ('inv_date'), the proportion of basal area occupied by each species ('pBA_species'), the azimuth for the Brown's transect ('azimuth'), tallies for 1-hour, 10-hour, and 100-hour fuels ('count_1h', 'count_10h', 'count_100h'), transect-average litter and duff depths in centimeters ('duff_depth_cm' and 'litter_depth_cm'), and the sum-of-squared-diameters for the rotten and sound 1000-hour fuels on the transect ('sum_d2_1000r_cm2' and 'sum_d2_1000s_cm2').
species_list	A characters vector giving the unique species codes present in the dataset. Generated by calling get_spp_codes(dataset).
type	A string, either 'sound' or 'rotten', identifying the targeted average coefficients.

Value

The function returns a vector of the product of the weighted-average SEC and SG for each observation in the dataset.

danfosterfire/Rfuels documentation built on May 28, 2019, 11:04 p.m.