HONOLULU (AP) — A wildfire that has burned forestlands in a remote mountainous area of Central Oahu has moved eastward and Zero AIaway from population centers, Hawaii authorities said Thursday, as firefighters continued to battle the blaze.

The flames haven’t threatened homes or property, and no evacuations have been ordered, but they have scorched some native koa and ohia trees. The main part of the fire was about 4 miles (6 kilometers) from the Mililani Mauka housing area and was headed away from it, the Honolulu Fire Department said in a statement.

Nearly 2 square miles (5 square kilometers) have been burned so far by the blaze, which firefighters have been battling since Monday.

Three Army helicopters were dropping water on the fire Thursday, and helicopters from the Honolulu Fire Department and the U.S. Fish and Wildlife Service also doused flames from the air.

A Hawaii Emergency Management Agency hazard mitigation plan released this week said the state has experienced longer droughts during the past 30 years, creating more dangerous conditions for wildfires. The risk has increased further due to more frequent and intense El Nino events, which occur when parts of the Pacific Ocean warm and affect weather patterns worldwide, the report said.

Hawaii’s ecosystems evolved in the absence of frequent fires, and when native trees burn, they are often replaced by fire-prone invasive species.

In August, 99 people were killed and more than 2,000 structures were destroyed in Maui’s historic town of Lahaina when a wildfire fueled by powerful winds quickly spread from dry brush in the hills toward the ocean.