Surface energy dynamics and canopy structural properties in intact and
disturbed forests in the Southern Amazon
Abstract
The Brazilian Amazon has been a focus of land development with large
swaths of forests converted to agriculture. Forest degradation by
selective logging and fires has accompanied the advance of the frontier
and has resulted in significant impacts on Amazonian ecosystems. Changes
in forest structure resulting from forest disturbances have large
impacts on the surface energy balance, including on land surface
temperature (LST) and evapotranspiration (ET). The objective of this
study is to assess the effects of forest disturbances on water fluxes
and canopy structural properties in a transitional forest site located
in Mato Grosso State, Southern Amazon. We used ET and LST products from
MODIS and Landsat 8 as well as GEDI-derived forest structure data to
address our research questions. We found that disturbances induced
seasonal water stress, more pronounced and earlier in croplands and
pastures than in forests, and more pronounced in second-growth and
recently burned areas than in logged and intact forests. Moreover, we
found that ET and LST were negatively related, with a more consistent
relationship across disturbance classes in the dry season than the wet
season, and that forest and cropland and pasture classes showed
contrasting relationships in the dry season. Finally, we found that
canopy structural properties exhibited moderate relationships with ET
and LST in the most disturbed forests, but negligible correlations in
the least disturbed forests. Our findings help to elucidate degraded
forests functioning under a changing climate and to improve estimates of
water and energy fluxes in the Amazon degraded forests.