Identification Information Citation Originator: USDA Forest Service, Geospatial Technology and Applications Center, BAER Imagery Support Program Publication Date: 2017-09-18 Title: Burned Area Reflectance Classification (BARC) Data Bundle for the Chetco Bar Fire occurring on the Rogue River-Siskiyou NF - 2017 Publication Information Publication Place: Salt Lake City, Utah, USA Publisher: USDA Forest Service Geospatial Data Presentation Form: raster digital data Description Abstract: These data products are preliminary burn severity assessments derived from Sentinel 2 and Landsat 8 data. Sentinel 2 data has a nominal spatial resolution of 20m and Landsat 8 has a nominal spatial resolution of 30m. Therefore the Sentinel 2 imagery was resampled to 30m prior to creation of burn severity products. The pre-fire and post-fire subsets included were used to create a differenced Normalized Burn Ratio (dNBR) image. The dNBR image attempts to portray the variation of burn severity within a fire. The severity ratings are influenced by the effects to the canopy. The severity rating is based upon a composite of the severity to the understory (grass, shrub layers), midstory trees and overstory trees. Because there is often a strong correlation between canopy consumption and soil effects, this algorithm works in many cases for BAER teams whose objective is a soil burn severity assessment. It is not, however, appropriate in all ecosystems or fires. It is expected that BAER teams will adjust the thresholds to match field observations to produce a soil burn severity. Purpose: These data were created by the USDA Forest Service Geospatial Technology and Applications Center (GTAC) to support Burned Area Emergency Response (BAER) teams. Product List Chetco_Bar_perim_geomac_20170915.shp Burned area boundary downloaded from the Geomac and current to 9/15/2017. The boundary was unmodified. Chetco_Bar burn severity products.kmz Google Earth format file that contains the burn severity (BARC4) layer and the fire perimeter. mask_hotspots_ChetcoBar.shp Shapefile showing the hotspots in the imagery. These areas generally show up as high severity, but should not be interepreted as such, since they represent active fire hotspots. chetcobar_l82016257_s22017256_barc4.tif: BARC4, Four category preliminary estimate severity classification. BARC4 burn severity classification Chetco Bar.jpg A JPEG version of the BARC4 da chetcobar_l82016257_s22017256_barc256.tif: BARC256, 256-class (0-255); continuous image representing preliminary estimate of burn severity. This dataset can be adjusted by the user, if needed, to refine the thematic BARC4 product and/or define a new BARC4. It is anticipated that users will adjust the breakpoints between classes, then recode to their desired 3 or 4 classes. chetcobar_l82016257_s22017256_dnbr.tif: Continuous dNBR product scaled by 1000; theoretical range of values is -2000 to 2000 L8_2016257_refl_clip.tif: Pre-Fire Landsat 8 reflectance image subset, acquired on 09/13/2016. Bands 1-5 and 7. Prefire image L8 2016-09-13.jpeg JPEG version of the prefire Landsatimage S2_2017256_refl_b12_b8a_b5_30m.tif Post-Fire Sentinel 2 reflectance image subset, acquired on 09/13/2017. Band order (1-3): SWIR, NIR, Red (Sentinel 2 bands 12, 8a, 5). Postfire image S2 2017-09-13.jpeg JPEG version of the postfire Sentinel image BARC256 Thresholds: 0-80 Unburned 81-114 Low 115-193 Moderate 194-255 High All files are projected in UTM Zone 10N, WGS84 Contact: Justin Epting jepting@fs.fed.us (801) 975-3755 ******************************************************************************** The following section should be completed after the BARC has been field validated by the BAER team and this entire metadata file should be returned to GTAC with the Soil Burn Severity data. BAER Assessment Completion Date:10/11/2017 BAER Team GIS Analyst: Thomas, Dorothy -FS BAER Team Leader: Chatel, John C -FS ; Soil Burn Severity Analyst(s): MacDonald, Christopher D -FS , Ochoa, Lizeth - FS ; Thomas, Dorothy -FS Soil Burn Severity thresholds: Unburned / Undetectable: 0-71 Low: 72-140 Moderate:141-254 High:255 Sequence of steps used to create Soil Burn Severity data: Chetco Bar recieved multiple BARC acquisitions we primarily used the 9/13 product, because of the striping on the later Landsat BARC. 1) We Adjusted the BARC threshold drastically between High and Moderate all the way down to 255. We moved all the threshold to higher value except between Low and unburned. 2) 9/13 image reclass based on thresholds listed, run majority filer (3) to eliminate single pixels 3) 9/24 image reclass based on original thresholds, run majority filer (3) to eliminate single pixels 4) Combined 9/13 and 9/24 image, reclassed to maintain Low, Moderate, and High severity from 9/13 image, and only keep High, moderate, and low from 9/24 image in Unburned 9/13 image This allowed up to caputre areas that burned after the 9/13 image was acquired. 5) Reproject to Oregon Washington Albers, and mask to fire perimeter. Additional Comments: Field Survey data was collected in Survey123 (points linked to photos), these points were used live to verify and validate soil burn severity classification mapping. Included in zip are geotagged photos, and the geodatabase of field data collected. Path to layerfile T:\FS\NFS\RogueSiskiyou\Project\RRS\rrsChetcoBarBAER2017\GIS\LayerFile\FieldReconPhotoHotLinks.lyr Here’s or rationale for our BARC adjustment – which was rather significant: Although vegetation burn severity was well-correlated with the BARC dataset, soil burn severity was lower in both moderate and high burn severities. We believe this is because the fire made very substantial “runs” as rolling crown fire as indicated in the fire progression map. Soil quality indicators that we assessed throughout the burned area indicated that soil aggregate stability was maintained in most high burn severity and all moderate burn severity since fine and medium roots and fungal mycelia remained intact in many areas. Organic matter in the soil was not consumed to the point where aggregate stability was lost. There did not appear to be any fire-induced soil hydrophobic conditions. We did, however find strong soil hydrophobic conditions in many areas within the fire perimeter, including unburned areas, so background soil hydrophobic conditions exist throughout the burned area. It is possible that moist moss and ground cover may have protected the soil and contributed to the lack of soil scorching in areas mapped as high severity.