DOI: 10.5061/dryad.k6djh9wh2
title: Data from: New methods provide a 300–year perspective on modern area burned in two wilderness areas of the southwest United States

description: Climate change and increased fuels from fire exclusion drive recent
 increases in area burned and fire severity in dry conifer forests of the
 western United States. Recent increases in area burned are occurring
 against the backdrop of a large fire deficit caused by over a century of
 fire exclusion. A key land management question is whether fire regimes can
 be restored – i.e., can the fire deficit be paid off? Accurate estimates
 of historical area burned prior to fire exclusion (circa 1900) are
 difficult to derive and have rarely been calibrated or validated against
 modern fires, leaving their accuracy uncertain. In this study, we applied
 multiple time-series methods to tree-ring fire-scar data for the first
 time, including a multi-model ensemble, time-varying predictor subset
 calibration, and multiple measures of model uncertainty and validation. We
 focused on two southwestern U.S. wilderness areas – Saguaro National Park
 (SAGU) and the Gila Wilderness (GILA) – that have abundant and
 well-documented modern fires due to decades of active fire restoration,
 allowing us to test whether the area burned has been restored to
 historical levels. Our ensemble of ten fire-scar models accurately
 estimated area burned by modern fires with no consistent biases. While
 individual models did not differ significantly from mapped fires, the
 ensemble solution reduced overall bias and uncertainty. Each member model
 has distinct strengths that make them suitable for specific applications
 (e.g., the synchrony model is easily applied, and Thiessen polygons
 provide spatially explicit estimates). The accurate reconstruction of the
 modern area burned from relatively sparse fire scar data at GILA suggests
 that dense grids are not necessary for accurate reconstructions. Our
 findings reveal that despite dropping to near zero in the early 20th
 century, the area burned in recent decades is within historical levels at
 GILA and trends toward historical levels at SAGU. These results highlight
 the magnitude of the post-1900 fire deficit and demonstrate that fire
 management can restore the historically prevalent, ecologically important
 process of widespread, frequent, low- to moderate-severity fire in dry
 conifer forests.
description: # Data from: New methods provide a 300–year perspective on modern area
 burned in two wilderness areas of the southwest United States
 **Description of the data and file structure** These files contain all
 spatial layers (in ArcGIS shapefile format) used to conduct this study,
 including the fire atlas data maps, fire ignition point files, and the
 study area boundaries. They are organized by study area into two
 directories -- GILA and SAGU. The fire perimeter data were obtained from
 Saguaro National Park, and the Gila National Forest. **SPATIAL DATA:**
 These files contain all spatial layers (in ArcGIS shapefile format) used
 to conduct this study, including the fire atlas data maps, fire ignition
 point files, and the study area boundaries. They are organized by study
 area into two directories: SAGU Directory: * SAGU_CoreStudyArea.zip – the
 outline of the SAGU study area. It has XML which is ArcGIS metadata for a
 shapefile named SAGU_CoreStudyArea, describing its creation, lineage,
 distribution, spatial structure, and attributes. It documents processing
 history (like field deletions and exports), file location, data format
 (shapefile), and feature schema for GIS usage. Attributes:          AREA:
 Area of the study area in square meters          PERIMETER: Perimeter of
 the study area polygon in meters * SAGU fire polygons through 2013.shp–
 fire atlas data for the study area between 1937 and 2013, as described in
 Hunter et al. (2013):          Attributes:          FIRE_NAME: Official
 name of the fire          YEAR: Calendar year the fire burned         
 AREA: Area of individual fire polygons in square meters         
 PERIMETER: length of individual fire polygons in meters * Rx
 burns_93_2005.shp – this file contains management-ignited prescribed burns
 that were not included in the SAGU fire polygons through 2013.shp shapefil
          Attributes:          NAME: Official name of the prescribed fire
          YEAR: Calendar year the fire burned          Area: area of
 individual prescribed burn polygons in square meters   * Deer
 Head_2014_Finaly_poly_u12nad83.shp – A wildland fire polygon from 2014
 that burned after the *SAGU fire polygons through 2013.shp *was compiled
 in 2013.          Attributes:          FireName: Official name of the fire
          YEAR: Calendar year the fire burned * Fire_points_through
 2012.shp– point file of fire ignition locations in Saguaro National Park.
 These include all fires that were too small to be mapped or for which maps
 are lacking.            Attributes:          FIRE_NAME: Official name of
 the fire          YEAR: Calendar year the fire burned          T_Acres:
 Reported acres (populated by Saguaro National Park staff) GILA Directory:
 * Gila_all_fires through 2013.shp – Fire atlas data for the Gila National
 Forest used in Hunter et al. (2014). Attributes:           FIRE_NAME:
 Official name of the fire          FIRE_YEAR: Calendar year the fire
 burned          AREA: Area of individual fire polygons in square meters *
 Gila_Fires_2014-2016.shp – Fire atlas data between 2014 and 2016 obtained
 from the Gila National Forest Attributes:           FIRENAME: Official
 name of the fire          FIREYEAR: Calendar year the fire burned         
 AREA: Area of individual fire polygons in square meters *
 FirePoints1970-2016.shp – Ignitions points for fires in the Gila National
 Forest (obtained from Gila National Forest in 2016).  These include fires
 that were too small to be mapped or for which maps are lacking.
 Attributes:           FIRENAME: Official name of the fire         
 FIREYEAR: Calendar year the fire burned          TOTALACRES: Reported
 acres (populated by Gila National Forest) * GILA_core_study_area.shp – The
 study area boundary, which is the White Creek Watershed on the Gila
 National Forest Attributes:           ha: Hectares of the watershed
 polygon