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.