LANDFIRE 2001 Refresh Forest Canopy Base Height (CBH) HI

LANDFIRE’s (LF) 2001 Canopy Base Height (CBH) product describes the lowest point in a stand where there is sufficient available fuel (greater than or equal to .25 in diameter) to propagate fire vertically through the canopy. Specifically, CBH is defined as the lowest point at which the canopy bulk density is greater than or equal to 0.012 kg m3. A spatially explicit map of canopy base height supplies information used in fire behavior models such as FARSITE (Finney 1998) to determine the point at which a surface fire will transition to a crown fire. The CBH mapping process began by deriving field referenced estimates of canopy characteristics through LFRDB plot analysis. Approximately 50,000 plots were acquired throughout the U.S. for estimating CBH in LF 2001. Utilizing these plots, field referenced CBH values were calculated for each plot using the canopy fuel estimation software FuelCalc (Reinhardt et al. 2006b). Using the information gleaned from the statistical analysis it was decided to map CBH values using an average Look Up Table (LUT) approach based on plot level combinations of Existing Vegetation Height (EVH), Cover (EVC), and Type (EVT). To assign averages using these variables, various grouping combinations of EVT, EVC, and EVH were tested to determine which would map CBH values most logically. For each grouping, a set of LUTs were calculated enabling CBH to be mapped with the Fuels Change Mapping Tool, or ToFu Delta. These maps were analyzed, peer reviewed and tested to determine which performed best. The CBH data represented in the resultant layer are continuous from 0 to 9.9 meters (to the nearest 0.1 meter). Some stands dominated by broadleaf species which typically do not permit initiation of crown fire (e.g. Populus spp.) are coded with a CBH of 10 meters. Since crown fire is rarely observed in most hardwood stands, the highest CBH value possible was used to prevent false simulation of crown fire in these areas. Similarly, all non-forest values, including herbaceous, and shrub systems and non-burnable types such as urban, barren, snow and ice and agriculture, were coded as 0. Finally, certain types of agriculture that are deemed burnable were assigned a value by ToFuDelta based on region and vegetation type.

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  "010:12"
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[
  "geospatial"
]