Authorities have discovered thousands of marijuana plants growing in Redwood National Park.

Park rangers detained four men and a woman near the area where the growing operation was found near Schoolhouse Peak. They were taken to Eureka for questioning about their possible involvement.

The plants were cut down and removed by helicopter after agents discovered the marijuana growing on four to five acres of park land Wednesday. Agents from several state and federal agencies helped destroy the plants.

While marijuana has been found growing on public lands for years, officials say they're finding larger, more damaging operations — many of them connected to gangs with ties to Mexico.