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Severe storms and blow-down disturbances in the Amazon forest

Fernando Del Bon Espirito-Santo, Institute for the Study of Earth, Oceans and Space (EOS), Complex System Research Center (CSRC), Morse Hall, University of New Hampshire, Durham NH., fernando@guero.sr.unh.edu (Presenting)
Michael Keller, Institute for the Study of Earth, Oceans and Space (EOS), Complex System Research Center (CSRC), Morse Hall, University of New Hampshire, Durham NH.,, michael.keller@unh.edu
Robby Braswell, Institute for the Study of Earth, Oceans and Space (EOS), Complex System Research Center (CSRC), Morse Hall, University of New Hampshire, Durham NH., rob.braswell@unh.edu
Gilberto Vincente, NOAA, Product Implementation Branch, Camp Springs, MD., gilberto.vicente@noaa.gov
Steve Frolking, Institute for the Study of Earth, Oceans and Space (EOS), Complex System Research Center (CSRC), Morse Hall, University of New Hampshire, Durham NH., steve.frolking@unh.edu

Large (area ≥ 1 ha) natural disturbances in old-growth tropical forests are caused by a variety of processes such as landslides, fires, wind, and cyclonic storms. We analyzed the pattern of large forest disturbances apparently caused by severe winds (blow-downs) in a mostly unmanaged portion of the Brazilian Amazon using a longitudinal transect of Landsat images (27 scenes) between Lat/long 643W 6850S and 216W 5151S, respectively and daily precipitation estimates based on NOAA satellite data. We found 170 blow-downs with an average area of 3 km2. Most blow-down disturbances occurred in Western Amazon between longitudes 67 and 58 W. A map of heavy rainfall ( ≥ 20 mm d-1) showed that the maximum frequency of heavy daily rainfall (~80 days y-1) occurred around at the longitude 63 in our study region. We found a close relation between the frequency of heavy storms and the occurrence of blow-down disturbances events. This result suggests a close relation between severe weather and the rate of forest turnover caused by blow-down disturbances. The forest turnover time calculated for these disturbances in 9 Eastern Landsat scenes studied was almost 9000 years whereas for the 18 scences in the Western Amazon, turnover time was closer to only 1200 year. Large disturbance may have a significant influence on spatial pattern of forest dynamics and productivity of the Amazon.

Science Theme:  CD (Carbon Dynamics)

Session:  1A: Remote Sensing and the Carbon Cycle

Presentation Type:  Oral (view presentation (21852 KB))

Abstract ID: 33

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