Summary statistics for inferred outbreaks
Arguments
- x
An obr object after running
outbreak()
Value
A data frame with descriptive statistics for each outbreak event
determined by outbreak(), including:
"start" -- first year of outbreak
"end" -- last year of outbreak
"duration" -- length of outbreak (in years)
"n_df_start" -- number of trees defoliated at the start
"perc_df_start" -- percent of trees defoliated at the start
"max_df_obr" -- maximum number of trees in the outbreak during a single year
"yr_max_df" -- year with the maximum number of trees defoliated
"yr_min_ngsi" -- year with the lowest mean normalized growth suppression index (NGSI)
"min_gsi" -- minimum growth suppression index
"min_ngsi" -- minimum normalized gsi
Note
Certain statistics will be set to NA for the final
outbreak event if there was an ongoing defoliation event (in which
series_end_event = TRUE in defoliate_trees()). This is because the end
of the outbreak remains unknown, so statistics such as duration cannot be
calculated. Statistics pertaining to the start of the event are provided.
Examples
data("dmj_obr")
outbreak_stats(dmj_obr)
#> start end duration n_df_start perc_df_start max_df_obr yr_max_df yr_min_ngsi
#> 1 1680 1699 20 1 33.3 3 1690 1692
#> 2 1753 1769 17 6 46.2 7 1754 1755
#> 3 1825 1840 16 11 78.6 12 1831 1826
#> 4 1849 1865 17 7 46.7 13 1852 1853
#> 5 1881 1895 15 8 53.3 14 1886 1885
#> 6 1959 1970 12 7 41.2 15 1960 1965
#> 7 1987 NA NA 9 52.9 15 NA NA
#> min_gsi min_ngsi
#> 1 0.121 -2.407
#> 2 0.343 -1.611
#> 3 0.500 -1.304
#> 4 0.252 -1.994
#> 5 0.262 -1.945
#> 6 0.328 -1.830
#> 7 0.378 -1.640