Fig. 5

Line and box plots for reconstructed Engelmann spruce pollen accumulation rates (PAR) calibrated to carbon biomass (t/ha) at Emerald Lake (panel a) and Blue Lake (panel b). Lower plots shows the ratio of spruce to fir, which is indicative of disturbances that preferentially cause spruce mortality. The shaded boxes highlight periods of documented disturbances that favored spruce mortality, such as settlement-era logging and a spruce beetle outbreak. Box plots indicate the range of variability recorded over the length of the sediment records, 10,500 cal yr BP for Emerald Lake and 5000 cal yr BP for Blue Lake, to facilitate comparison with the historical range of variability (post-1800 CE)