DOI: 10.5061/dryad.qrfj6q5b6
title: Supporting data for increasing fire activity reinforces shrub conversion in Southwestern US forests

description: Fire-exclusion in historically frequent-fire forests of the southwestern
 United States has altered forest structure and increased the probability
 of high-severity fire. Warmer and drier conditions, coupled with dispersal
 distance limitations are limiting tree seedling establishment and survival
 following high-severity fire. Post-fire conversion to non-forest
 vegetation can be reinforced by subsequent fire events. We sought to
 determine the influence of fire probability on post-fire vegetation
 development in a severely burned landscape in New Mexico, USA. We used
 LANDIS-II to simulate three fire probability scenarios—contemporary mean
 fire return interval (CMFRI), and 1.5 times and 2 times CMFRI—with
 contemporary climate. As fire probability increased, the mean size of the
 largest fires and the mean landscape fire severity increased. These
 changes in fire characteristics resulted in a net decrease in total above
 ground biomass and photosynthetic capacity on the landscape. Additionally,
 the distribution of individual species biomass shifted, with early
 successional species, especially those that resprout after fire,
 increasing as a fraction of total biomass with increasing fire occurrence.
 Continued increases in fire frequency are likely to favor resprouting
 species and result in a loss of forest biomass and ecosystem productivity
 in this southwestern forest landscape.
description: These data are outputs of a set of simulations using the
 LANDIS-II (v6.2) model with the PnET Succession extension (v.2.1.1) and
 the Dynamica Fuels and Fire System (v2.1)<br> extension. We used
 current climate data from Daymet and atmospheric CO2 data from the Mauna
 Loa observatory. We ran the model with three fire ignition probability
 scenarios; these are labelled 'Low or LO', 'Medium or
 MED', and 'High or HI'. Our study objective was to examine
 differences in post-fire vegetation recovery under<br> variable fire
 regimes. Our simulation area was the footprint of the 2011 Las Conchas
 fire in New Mexico, USA. We ran 30 replicate
 simluations for each scenario; the length of each was 50 years. We
 summarized most data by calculating the mean and standard deviation of the
 30 replicates. Mean and standard deviation for fire severity data were
 calculated for all years/replicates together. We present the data sets
 (raw and final) and code for creating figures in Keyser et al.
 The parameter files for the PnET succession and Dynamic Fire and
 Fuels extensions are also included.
description: The data is organized as follows: The
 directory includes folders for 1) Fire Size and Severity, 2) Resprouter
 Probability,<br> 3) Vegetation Distribution, and 4) Photosynthesis. 
 The directory also includes a folder with the parameter files for the PnET
 succession and Dynamic Fire and Fuels extensions.
 Within each directory is R code for creating figures and the data
 used to create each figure. <br> 1) Area Burned
 and Fire Size Distributions:<br> Files<br>
 'CAB_allScen.csv'       contains summarized data for cumulative
 area burned for all<br>                         scenarios. (Figure
 1) 'bigFireLO2.csv'        contains a subset
 of the summary log records for the Low fire<br>
                         scenario. The subset is the top 25% of fires by
 size. The field<br>                         TotalSitesBurned is the
 number of 1ha pixels that burned in the<br>                        
 fire event. The logAB field is the log of area burned.
 'bigFireMED2.csv'       contains the same as above, but
 for the Medium fire scenario.
 'bigFireHI2.csv'        contains the same as above, but
 for the High fire scenario.
 'bigFireALL2.csv'       contains all records in the
 above three files. This file is used<br>                         to
 create the combination figure. The individual fires are<br>
                         require for statistical analyses. (Figure
 2) 'FireSizeDistributionsAndAreaBurned.html' 
 contains the code for creating figures. 1) Fire
 Severity:<br> Files<br> 'muFSevAllScen2_df.csv'
 contains the mean fire severity data for all scenarios, years,<br>
                         and replicates. (Figure 5)
 'FireSeverity.html'     contains the code for creating
 figures. <br> 2) Resprouter Probability<br>
 Directories:<br> LOfire, MEDfire, HIfire               Each of these
 contains the year 50 values for aboveground<br>
                                       biomass (AGB) for each species in
 *.csv format for each of<br>                                      
 30 replicates. At the top of each directory is a *.csv with<br>
                                       the mean number of fire counts for
 all replicates at each<br>                                      
 site.<br>                                       <br>
 Files<br> 'sproutsProbAll2_df.csv'              contains
 final data for the probability that the fraction of<br>
                                       total aboveground biomass in a site
 composed of<br>                                       resprouting is
 greater than or equal to 50%, at year<br>
                                       50 for all scenarios. (Figure
 3) 'ResprouterProbability.html           contains
 R markdown code for calculating the probability that<br>
                                       the site biomass will be greater
 than 50% resprouters and<br>                                      
 code for creating the figures.<br>
                                        <br> 3)
 Vegetation Distribution: Files:<br>
 'sppAGByr0.50fireCntLMH_hiLow.csv'   contains data for the
 fration of mean aboveground<br>                                     
 biomass of resprouting species and obligate seeders by<br>
                                      number of times sites burned at years
 0 and 50. All<br>                                      scenarios are
 combined in one data frame. Number of<br>
                                      fire occurrences are binned.
 (Supplementary Figure)
 'sppAGByr0.50fireCntLMHdiffs.csv'    contains the
 difference in aboveground biomass between<br>
                                      years 0 and 50 (0minus50) for all
 species grouped by<br>                                      by fire
 count bin, for all scenarios. (Suppl. Figure)
 'fuelCntBYfireCnt_df.csv'            contains data for
 fractional coverage of fuel types<br>
                                      by fire count bin, for all scenarios.
 (Figure 4) <br>
 'VegetationDistributionPlots.html'   contains code for making
 manuscript and supplementary<br>
                                      plots. <br>
 4) Photosynthesis<br> Directories:<br> LOfire, MEDfire,
 HIfire                Each of these contains the mean annual
 photosynthesis<br>                                        records
 for each species in *.csv format Example file name:
  <br> 'abieconc_PSNmuDataFrame.csv'          Each file
 prefix is the 8 letter genus species code<br>
                                        with the same suffix.
 'CumulativePhotosynthesis.html'        contains the
 code to read in each species annual<br>
                                        photosynthesis output, calculate
 annual and cumulative<br>                                       
 sums, calculate the difference between scenarios, and<br>
                                        plot Figure 6 from the
 manuscript.