Close to 150 acres (60 hectares) of woodland were devastated before dawn in Puerto Rico by a fire in Adjuntas Forest in the central part of the island.
The chief of the Puerto Rican Fire Department, Angel Crespo, said the blaze damaged some 40 percent of the forest and that National Guard helicopters were used to put out the flames.
Though the cause of the fire has not been confirmed, Crespo said that "in all probability" it was deliberately set.
"The fire spread so quickly it seems to indicate that someone started it," biologist Arturo Massol Deya of the environmentalist Casa Pueblo de Adjuntas told Efe.
The area will take decades to recover, he said.
Forest fires in Puerto Rico cause millions in losses every year and affect the survival of endangered species.
A blaze at the end of last month in Boqueron State Forest, an area of great ecological value in the southwestern part of the island, caused the destruction of 30 acres (12 hectares) of protected land and harm to endangered species like the brown pelican, peregrine falcon and dry forest anole lizard, among others.
To date this year, forest fires have destroyed more than 2,000 acres (800 hectares) of woodland in Puerto Rico. EFE