Fig. 1: Status of tree mortality in California from individual dead trees detected from NAIP aerial images in 2020.
From: Scattered tree death contributes to substantial forest loss in California
In panel a, the orange circles denote the total count of dead trees in each national forest. Supplementary Table 3 provides the lookup table for national forest abbreviations. The underlying map represents the percentage of tree mortality, which is the count of detected dead trees against the count of all trees in 2011 within 240 × 240 m grids43. Only forests, shrublands, and grasslands that are contained in the National Land Cover Database 201963 and ESA WorldCover 202064 are included in the mapping (Methods). b Total number of dead trees and spatial coverages for 16 main logical ecological groupings of forest types in California44. c Box plots of percentages of tree mortality per ha for each forest-type group. The boxes represent the interquartile range (IQR) which is between the 25th and the 75th percentile of the percentages of tree mortality. The whiskers represent 1.5 times the IQR. The white lines inside the boxes represent the medians. The notches inside boxes represent the 95% confidence intervals for the medians. Random selection of 30% of the pixels per forest-type group was applied to mitigate the spatial auto-correlation. The colour scheme used in panels a, b is consistent with the forest-type group map (Supplementary Fig. 7), representing different forest-type groups.
