This short vignette provides a contextualized example of usage of fire size and FMO functions from the alfresco package, specifically fsdf and fmo_cb_reduction. See the help documentation for these and other associated functions for details.

Cumulative burn reduction results are compared for different fire management scenarios applied to multiple historical JFSP ALFRESCO model runs. Results are based on a two-factor experimental design. Each factor has a control and three treatment levels covering zero, 25, 50 and 75 percent maximum suppression applied to ALFRESCO fire sensitivity and ignition factor input maps, respectively. The status quo fire management scenario involves both controls: no suppression applied to either input map.

Setup

Load the required packages.

library(alfresco)
library(dplyr)
library(ggplot2)

Then prepare the data from the historical_fsv.rds file. After using fsdf and fmo_cb_reduction, make some additional changes in a new data frame for better plotting.

file <- "C:/github/jfsp/data-raw/historical_fsv.rds"
d <- fsdf(file)
d2 <- fmo_cb_reduction(d)

lev <- c("Control", "Tx: 50s/75i")
dex <- select(d, 7:10) %>% filter(FMO %in% c("fmo00s00i", "fmo50s75i")) %>% 
    mutate(FMO = factor(ifelse(FMO == "fmo00s00i", lev[1], lev[2]), levels = lev), 
        FS = FS/1000, CBA = CBA/1000)

Results

Table 1. shows results from all treatments. Below, figure 1. shows a comparison of one selected treatment with the control. In table 1., The % Sensitivity and % ignition show the treatment factors. These refer to the maximum percentage suppression applied to the ALFRESCO fire sensitivity and ignition factor input maps. For example, 25% sensitivity means that regions of the fire sensitivity map experienced no greater than 25% reduction in sensitivity for the model run.

The following mean, lower and upper percent change columns describe the mean and associated lower and upper bounds for the percent change from the status quo control run for a given fire management treatment level. These correspond to the last three columns of cumulative burn area means and minimum and maximum bounds across 32 ALFRESCO simulations. The period for comparison of treatments is 1950 - 2013.

Table 1. 1950 - 2013 cumulative burn reduction by FMO treatment.
% Sensitivity % Ignition Lower % Change Mean % Change Upper % Change Min Area Mean Area Max Area
No sensitivity suppression
0 0 -4.6 0.0 5.2 140,030 146,851 154,438
0 25 -9.2 -3.4 8.8 133,270 141,816 159,821
0 50 -15.4 -7.2 2.8 124,180 136,289 151,021
0 75 -19.1 -10.9 -2.1 118,855 130,791 143,750
Max 25% sensitivity suppression
25 0 -15.7 -10.7 -2.5 123,730 131,184 143,250
25 25 -19.7 -13.1 -7.0 117,976 127,619 136,627
25 50 -22.7 -15.4 -3.7 113,460 124,207 141,398
25 75 -25.9 -18.1 -8.5 108,792 120,261 134,396
Max 50% sensitivity suppression
50 0 -26.6 -20.0 -11.3 107,721 117,505 130,213
50 25 -26.1 -21.2 -15.2 108,545 115,736 124,487
50 50 -32.6 -23.6 -14.4 98,930 112,224 125,763
50 75 -35.8 -26.6 -14.9 94,275 107,790 124,966
Max 75% sensitivity suppression
75 0 -72.6 -69.1 -66.1 40,182 45,331 49,775
75 25 -75.9 -71.6 -68.0 35,390 41,664 47,062
75 50 -77.2 -74.2 -70.2 33,542 37,957 43,771
75 75 -80.9 -77.0 -73.5 28,067 33,766 38,871
Figure 1. 1950 - 2013 cumulative burn vs. fire size.

Figure 1. 1950 - 2013 cumulative burn vs. fire size.