A flood of bidders from Europe and America was largely responsible for prices rising tenfold – more in some cases – over the previous decade.

In the middle of the previous decade local auction houses reported that more than 50 per cent of sales of Aboriginal art came from overseas.

In 2006, Emily Kame Kngwarreye's painting, Earth Creation, sold for $1.056 million at a Lawson-Menzies auction. She was the first indigenous artist to crack the million-dollar barrier.

A year later Clifford Possum Tjapaltjarri's Warlugung sold for a staggering $2.4 million at a Sotheby's auction in Melbourne. The buyer was the National Gallery of Australia.

Then, with the arrival of the global financial crisis a few months later, prices crashed along with a lot of hopes for future profits. Only now is there a sense that things may be slowly improving.

On May 11, Bonhams held a single-owner sale of Aboriginal art at the Byron Kennedy Hall in Sydney's Moore Park, with the emphasis of paintings on bark. This significant collection had been accumulated, mainly in the 1980s, by Sydney psychiatrist Milton Roxanas and his wife Alma. Some pieces are regarded as museum-quality.

Results were impressive, with total sales of $613,702 (including buyers premiums) and 89 per cent sold by lot and 133 per cent by value.

Bidding was especially enthusiastic for a range of work by Yirawala, usually described as “the Picasso of Arnhem Land”. He was a ceremonial leader who preserved his father's sacred designs, songs and stories on bark. He believed in sharing his art with non-indigenous people. Perhaps this is why he is so keenly collected these days.

Typical is a work called Lumaluma, painted on eucalyptus bark around 1970, which sold for $25,620 including buyers premium, well above estimates of $8000 to $12,000. Other examples, also executed around the 1970 period, sold above estimates for $23,180, $17,080 and $12,200.

Yirawala died in 1976 but appears to have been very much rediscovered.

Other strong results on the night included Deaf Tommy Mungatopi's c.1965 work Coral Designs, sold for $24,400 including buyers premium, and a collaborative piece by Wandjuk Marika and Mawalan II Marika, fetching $23,180 including buyers premium.

The top ten results were all above the $10,000 mark, but many more sold in the $2000 to $5000 entry level range, with a few going for less.

Lot 109, a 1949 depiction of Fish of Gulf of Carpentaria from Groote Eylandt, sold for $1037 including buyers premium. The artist is unknown. Down in the bargain basement it's still possible to pick up significant pieces on bark for under $500.

Bonhams specialist Francesca Cavazzini says that barks have only recently taken off on the secondary market because they were previously under-valued by collectors who perceived them as tourist shop souvenirs rather than serious art.

This is no longer the case.

In November last year Bonhams sold the Clive Evatt collection of 320 bark paintings, again with strong results. This auction was 96 per cent sold by lot and 99 per cent by value.

Evatt was the former director of the Hogarth Galleries in Paddington where Milton Roxanas sourced some of his first pieces. As Cavazzini suggests, one successful sale tends to lead to another and she is currently planning more bark sales for later this year. She notes that single-owner collections always sell better, especially ones with solid provenance.

A lot of those investors who had their fingers burnt in the boom of the 2000s are now much more careful to confirm authenticity. Official recognition also helps. The current Old Masters exhibition of bark paintings at the National Museum in Canberra (on until 20 July) has no doubt boosted interest in this area of art.