Fires are now more numerous in Brazil's Cerrado region, a vast tropical savanna, than in the Amazon rainforest, data published Wednesday by the National Institute for Space Research show.
The government's monitoring agency reported 8,012 fires in the Cerrado region and 7,457 fires in the Amazon region in the first 10 days of September.
The Cerrado is always hot and dry at this time of the year, and fire is often used by farmers to clear land and pastures. But flames are advancing particularly fast, as temperatures have risen unusually high in the last few days, experts said.
In Santa Catarina state, fires had destroyed over 500 hectares (about 1,235 acres) of vegetation by Wednesday morning in the Serra do Tabuleiro state park, online news portal G1 said Wednesday. Officials issued an emergency call Tuesday requesting reinforcement to combat the flames in this protected area.
"This is all manmade," said Carlos Nobre, a University of Sao Paulo climate scientist.
He said there was no evidence any of the fires had been caused naturally. "The dry weather, hotter and less humid, induces greater propagation of the fires," he said.
In recent weeks, fires across Brazilian forests have spread at a pace unseen since 2010, stirring an international outcry. Worries have been particularly high over fires in the Amazon rainforest area, because of its role in absorbing heat-trapping carbon dioxide from the atmosphere.
So far in 2019 the number of fires across Brazil has surpassed 100,000, which is about 45% more than during the same period a year ago.