Abstract. Forest disturbance and regrowth are key processes in
forest dynamics, but detailed information on these processes is difficult to
obtain in remote forests such as the Amazon. We used chronosequences of
Landsat satellite imagery (Landsat 5 Thematic Mapper and Landsat 7 Enhanced
Thematic Mapper Plus) to determine the sensitivity of surface reflectance
from all spectral bands to windthrow, clear-cut, and clear-cut and burned
(cut + burn) and their successional pathways of forest regrowth in the
Central Amazon. We also assessed whether the forest demography model
Functionally Assembled Terrestrial Ecosystem Simulator (FATES) implemented
in the Energy Exascale Earth System Model (E3SM) Land Model
(ELM), ELM-FATES, accurately represents the changes for windthrow and
clear-cut. The results show that all spectral bands from the Landsat satellites
were sensitive to the disturbances but after 3 to 6 years only the
near-infrared (NIR) band had significant changes associated with the
successional pathways of forest regrowth for all the disturbances
considered. In general, the NIR values decreased immediately after disturbance,
increased to maximum values with the establishment of pioneers and
early successional tree species, and then decreased slowly and almost
linearly to pre-disturbance conditions with the dynamics of forest
succession. Statistical methods predict that NIR values will return to
pre-disturbance values in about 39, 36, and 56 years for windthrow,
clear-cut, and cut + burn disturbances, respectively. The NIR band captured the
observed, and different, successional pathways of forest regrowth
after windthrow, clear-cut, and cut + burn. Consistent with inferences from the NIR
observations, ELM-FATES predicted higher peaks of biomass and stem density
after clear-cuts than after windthrows. ELM-FATES also predicted recovery of
forest structure and canopy coverage back to pre-disturbance conditions in
38 years after windthrows and 41 years after clear-cut. The similarity of
ELM-FATES predictions of regrowth patterns after windthrow and clear-cut to
those of the NIR results suggests the NIR band can be used to benchmark forest
regrowth in ecosystem models. Our results show the potential of Landsat
imagery data for mapping forest regrowth from different types of
disturbances, benchmarking, and the improvement of forest regrowth models.