The trees, about 12 miles from Alice Springs in Australia's Northern Territory, were reduced to ashes, The Australian reported Friday.
A spokeswoman from the Territory's Department of Lands, Planning and the Environment said a department employee found the destruction Thursday during a routine check. Police said the trees were burned down several days earlier.
Northern Territory Indigenous Advancement Minister Alison Anderson said the trees were a "special place" for residents, art lovers, historians and tourists, The Australian said.
"The ghost gums featured in many of his [Namatjira's] works and were easily accessible on the road to Hermannsburg, where he was born in 1902," Anderson said. "The twin ghost gums were a wonderful reminder of his connection to the land and many who visited the site would have felt a connection to this great Territorian."
Namatjira painted for nearly 20 years after his first exhibition in 1938. He died in 1959.