Fig. 5
Correlation scatterplots for field estimates (data collected in 2015 and 2016) of total fuel density (TFD; kg m−3) and canopy bulk density (CBD; kg m−3) compared to LANDFIRE (LF) estimates of CBD extracted for our 61 field plot locations within the Superior National Forest, Minnesota, USA. Estimates of TFD (all coniferous fuel above ground level) and CBD (coniferous fuel ≥2 m above ground) based on weighted canopy gap fraction are denoted T and C, respectively, while numbers 1, 12, and 123 refer to zenith angle ranges (0 to 7°, 0 to 23°, and 0 to 38°, respectively) of the LAI-2200C instrument. FuelCalc-based field estimates of CBD are denoted FC. Pearson correlation coefficients with corresponding P-value significance codes (*** for 0 to 0.001; ** for >0.001 to 0.01; * for >0.01 to 0.05; · for >0.5 to 0.1; and no symbol for >0.1 to 1) are shown above the diagonal, while the diagonal shows distributions of fuel density estimates. Bivariate scatter plots with fitted lines are below the diagonal. Linking field fuel estimates and satellite sensor data facilitates ground-to-satellite calibration of fuel models for fuel mapping purposes