In 1996 , a Sir Herbert Beerbohm Tree fell in the Bolivian Amazon , jamming up a river like a chicken bone lodge in a waste pipe . 119,000 acres of forest died in the catastrophic flooding that result . Twenty geezerhood afterwards , newfangled enquiry has conclude that this was n’t a one - off event : So - predict ‘ logjam ’ are invariably remold immense swath of western Amazonia .
That ’s according to Umberto Lombardo , a geographer and geomorphologist at the Pompeu Fabra University in Barcelona , Spain , who first became concerned in how logjam were affecting landscapes several years back . He was play around with Google Earth timelapse , and notice certain Amazonian rivers comport “ in a very singular way . ”
“ I became very curious , ” he told Earther .
That oddment led Lombardo to hunt for papers key what could be stimulate river to clot up suddenly , spilling their contents into the beleaguer forest . All he could find out was a work from 1996 describing a logjam in the Cuberene River in Bolivia that caused a declamatory area of forest to die off and regenerate as savanna , a grassland peppered with tree .
Another bailiwick by the same author explored how satellite imagery can be used to describe logjam , but Lombardo could incur no follow - up enquiry detailing how prevalent these natural event actually are in the tropics .
To find out , Lombardo downloaded Landsat artificial satellite imagery of a 9,300 - square - mile swath of the Bolivian rainforest , captured from 1984 to 2016 . He name 22 river that showed signboard of logjam - bring on implosion therapy , and analyzed eight of them in item , tallying up the full number of logjam and explore how these events impacted the hem in wood .
The results , published recentlyin Earth System Dynamics , show that logjam induced floods are “ a major driver of forest disturbance in the Bolivian Amazon , ” strike one C of acres of forest , often on an annual base . Logjams affect rivers in characteristic ways , drying up the downstream channel and diverting water supply into the forest in a v - shaped area .
The forest then drowns , and is often replaced by savanna . In one of the areas Lombardo studied , the Cuberene river , the 46,000 Akko of timber perturbation due to logjam was “ comparable to the current rates of disforestation driven by the expanding farming frontier . ”
This is just a individual explorative study , of course . Much more inquiry is needed to suss out how prevalent logjams are throughout the tropical zone , and how the ever - increasing human footprint in rainforests , including deforestation , affects these innate events .
In the Bolivian Amazon at least , Lombardo think logjam serve forge woodland writing , and drive re-formation . When you ’re out in the rainforest , he says , the force of these river clog are n’t subtle .
“ It was telling , ” he say , describe a visit to a forest that had been flooded by a logjam . “ The ground was covered with fluvial sediments , the Tree had no foliage because they were all dead , and the Lord’s Day ’s rays make the terra firma . It look like a forest that had been glow down but without ash or charcoal . ”
And you thought a single tree could n’t make a difference of opinion .
skill
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