Must read: Marijuana goes up in smoke in wildfire above Los Angeles

LOS ANGELES - The wildfire that has ravaged a national forest near Los Angeles has burned one plant species that authorities were happy to see go: marijuana, lots of it.

The fire destroyed an untold number of marijuana plantations in the Angeles National Forest, a growing hub for pot-growing operations in California.

Three marijuana cultivation areas identified just before the fire are believed to have burned, Los Angeles County Sheriff's Lt. Phil Abner said, and many more are assumed to have been destroyed.

Sheriff's officials don't know how many plants were in the three burned grow areas. Because marijuana is grown in a hodgepodge style and the plants are concealed by tall brush, it is hard to gauge from helicopters the size of each grove. Groves can host anything from several hundred to several thousand plants.

'I don't doubt that some burned that we hadn't identified,' said Abner, who heads up a multi-agency force tasked each growing season with eradicating marijuana. 'It could be one (growing area), it could be 50.'

Cultivation of marijuana, often by Mexican drug cartels, is rife in California's national forests, and the steep, scrub-covered canyons only a short drive from Los Angeles are no exception. Even before the blaze, authorities had removed record amounts of pot with an estimated street value of more than $2 billion.

In the days the fire was burning most ferociously, several apparent pot plantation laborers were spotted spilling from the forest and walking down highways away from the flames, Abner said.

'With no clear explanation as to why they were,' he said. 'The educated speculation is they came out of the marijuana groves.'

And it appears they are already starting to return to the forest.

On Saturday, a team of hotshot firefighters working near a popular and badly burned recreational area high in the rugged San Gabriel Mountains found singed water lines with new ones already lying alongside them. Fearing for their safety, the firefighters called the sheriff's department, whose deputies arrested a Mexican national found hiding out with a .22-caliber rifle, Abner said.