Assessing the effects of ecosystem disturbance on aboveground biomass in tropical forest reserves of Ghana
Dan Wanyama, University of Oklahoma, wanyama@ou.edu (Presenter)
Michael Wimberly, University Of Oklahoma, Norman, mcwimberly@ou.edu
Russell Doughty, University of Oklahoma, russell.doughty@ou.edu
Long-term records from optical remote sensing are commonly used to monitor forest change but have limited capacity to measure the vertical distribution of tree canopy which is necessary for assessing the effects of different disturbances on forest structure and function and tracking the recovery after disturbances. This study integrated spaceborne Global Ecosystem Dynamics Investigation (GEDI) LiDAR data with disturbance histories obtained from Landsat times series analysis, and active fire points from VIIRS and MODIS to assess changes in aboveground biomass density (AGBD) associated with non-fire disturbance and forest canopy recovery. The study was conducted in tropical forest zones in Ghana which follow a precipitation gradient from wet evergreen to moist evergreen to moist semideciduous. Fire-associated disturbance was identified and excluded. We generated time series graphs of AGBD against time since the last event (either forest loss, degradation, or canopy recovery) for reserves in each zone. We observed that forest loss had the greatest and longest lasting effect on aboveground biomass. Across all zones, deforested locations had significantly lower AGBD in relation to undisturbed locations throughout the 16-year period. In contrast, AGBD was higher in degraded forests but was still lower compared to the undisturbed locations. Unlike the deforested locations, AGBD at degraded locations recovered to pre-disturbance levels in some zones, taking 14 years in the wet evergreen and 16 years in the moist semideciduous (southeast) zones. Except for the moist semideciduous (northwest) zone, we observed that after forest canopy recovery, AGBD was still lower than pre-disturbance levels but increased gradually over time and was similar to undisturbed forests after 5-10 years. These results provide evidence that the fusion of data from GEDI LiDAR and optical sensors like Landsat can more effectively and comprehensively track and characterize responses of forest structure and functions after disturbances or recovery. Such information can aid in planning the sustainable use and effective restoration of tropical forests in Ghana and similar tropical regions.
Associated Project(s):
Poster Location ID: 1-20
Presentation Type: Poster
Session: Poster Session 1
Session Date: Tue (May 9) 5:00-7:00 PM
CCE Program: TE