get_litterduff_coeffs: Calculate coefficients

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

Description

Van Wagtendonk et al. (1998) table 7 gives the fitted coefficients for a linear relationship predicting measured fuelbed weight (kg / m^2) for the litter and/or duff of 19 Sierra Nevada conifers as a function of litter and/or duff depth (cm). Following Stephens et al. (2001), we estimate the linear coefficient between litter/duff depth and litter/duff fuelbed weight by taking the average of the coefficients for each species present on the plot. The various coefficients are weighted by the proportion of total plot basal area occupied by each species. For more details, see the vignette.

Usage

get_litterduff_coeffs(dataset, species_list, fuel_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).
fuel_type	A string, either 'duff_coeff' or 'litter_coeff', identifying the targeted average coefficient.

Value

A weighted-average coefficient to predict litter or duff weight from litter or duff depth for each observation, based on the overstory present for that observation.

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