A New South Wales Aboriginal artist is reviving the lost art of carved trees used to mark special places.

Long before European settlement, Aboriginal clans across NSW used the trees, which were known as dendroglyphs.

There was a time the ornate dendroglyphs could be seen across eastern Australia, from northern Victoria to southern Queensland.

Once the bark was stripped back, Aboriginal people would inscribe the tree trunks with patterns and designs.

Aboriginal artist Warwick Keen began making his own contemporary dendroglyphs a few years ago at his studio at Nowra, on the state's south coast.

Aboriginal artist Warwick Keen began making his own contemporary dendroglyphs a few years ago at his studio at Nowra, on the New South Wales south coast. ( ABC: Bridget Brennan )

His dendroglyphs have now gone on permanent display in Sydney.

"Aboriginal people used to carve them as signposts for burial poles and they would also be carved for initiation ceremonies when people came together," Mr Keen said.

"Where I come from in Gunnedah there was 80 or so of these different trees originally in this one spot so there were big mobs of people travelling a long way to get together so that they could go through all of their ceremonies."

The dendroglyphs are vast artworks measuring up to three metres tall, carved from iron bark and blackbutt eucalypts.

Mr Keen's collection of 24 dendroglyphs was bought by the Mosman Art Gallery in Sydney.

The gallery's director John Cheeseman said the poles have gone on permanent display outside the gallery.

"We want to make sure that the first thing that people see when they come to Mosman Art Gallery is Aboriginal art so this is a magnificent statement," he said.

Mr Cheeseman said the huge artworks were difficult to manoeuvre.

"It was massive. When we first talked about it I thought it would be a simple process but it actually took cranes and all sorts of drilling exercises," he said.

Very few dendroglyphs left standing

Some traditional dendroglyphs can still be seen at Molong, near Orange in the state's central-west, where the elder Yuranigh is buried.

Yuranigh was a Wiradjuri man who acted as a guide to the explorer Sir Thomas Mitchell in 1845.

While Mr Keen was researching dendroglyphs, he discovered that there are very few other sites still standing in NSW.

"Most of the others you'll find them in museums," he said.

"They've been lost to floods, fires, there's stories of people that have cut them down and keep them for their own, as a talking piece. They put them in their homesteads."

Mr Keen said dendroglyphs are a "lost art", which is why he thinks the carvings are an important tradition to preserve.

"Nobody that I'm aware of sort of has continued on with that practice of carving dendroglyphs for a long time.

"So this was an opportunity to bring that out into the open as a talking point, as a discussion to acknowledge and promote New South Wales Aboriginal art."

Historical photos of dendroglyphs, carved by Aboriginal cultures of western NSW can be viewed in the State Library of New South Wales archives.