Over dinner one night in March 1832, George Augustus Robinson, “chief protector of Aborigines”, was told about three white stockkeepers in Van Diemen’s Land (now Tasmania) who chased an Indigenous woman up a tree and then shot her to death.

“Every time the shot took effect she pulled the leaves off the tree and thrust them into the wounds, till at last she fell lifeless to the ground,” he wrote in his diary. “It was … a practice with the stockkeepers to get two or three of the women together and shoot them.”

Currently on display as part of Tasmanian artist Julie Gough’s first major retrospective, the horrifying image is one of many which land on the visitor like a punch in the stomach.

Julie Gough stands in front of a work displayed as part of Tense Past, which looks back at 25 years of the artist’s videos, sculptures and design. Photograph: Alistair Bett

Gough’s Tense Past opened earlier this month at the Tasmanian Museum and Art Gallery (TMAG) as part of Hobart’s winter festival, Dark Mofo. Curated by Mary Knights, it combines 25 years of Gough’s acclaimed creative work – videos, sculptures, text work and design – responding to what she refers to as her “life’s journey”: her forensic combing through diary entries, news reports and official government records to track the murders and massacres of Indigenous men, women and children during the black war.

It’s important to make sure you’re not completely erased from a place Julie Gough

In the early 1800s, the state’s Indigenous population numbered around 6,000; a generation later, it was just a few hundred. The names of the dead and circumstances of their murders have been largely excised from Tasmania’s story, but Gough has spent her career doing everything within her power to rediscover and preserve them.

“I think I just keep doing the same artwork, sometimes,” she says deprecatingly, of the varied pieces that surround us. “I don’t want to keep beating my head against the wall.”

Julie Gough’s work is displayed among artefacts from the genocidal black war, in an exhibition that lands like a punch in the stomach. Photograph: Alistair Bett

The chilling proof of colonial genocide on display comes part from Gough’s own research (Gough holds three arts degrees, but also trained as an archaeologist) and part from her interrogation of other institutional archives – including TMAG’s own. Taken together, along with her artistic responses, the effect is overwhelming, and sickening.

An 1830 news report tells of “one of the blacks” being speared by a pitchfork through the chest. Another talks of 17 “miserable black natives” being shot in cold blood. We read of a young man boasting about killing “three crows”; of Gough’s own ancestor Dalrymple Briggs, who survived being stolen from her parents and shot by her master; and of many, many children who were stolen, abused, killed.

The site of the exhibition adds an extra tension. The TMAG collections were established in the 1840s by the Royal Society of Van Diemen’s Land – but before then, two of its buildings served as both the bond store and the commissariat during the black war.

Gough describes them as “haunted buildings … this museum has held the bones, the skeletons, of a lot of Aboriginal people”. It’s situated in Hobart among other “heritage” buildings like the Hope & Anchor pub across the road, which celebrates its status as a “colonial bar and restaurant” and displays artefacts of British colonialism. After an afternoon spent among Gough’s work, it’s difficult to understand why anyone would want to broadcast that history.

“Yeah, the whole island is that,” says Gough, a descendant of the Trawlwoolway people of north-east Tasmania. “‘Heritage Tasmania’ automatically means non-Aboriginal heritage … things are really askew here.”

In We Ran/I Am (2007) by Julie Gough. The artist recreated the trousers given to Indigenous people by ‘chief protector’ George Augustus Robinson, who praised them as ‘excellent things [that] confines their legs so they cannot run’. Photograph: Alistair Bett

Gough’s artistic practice talks back to these wilful gaps in history. In her video series Hunting Ground, she overlays images of bucolic landscapes with historical text about the massacres that occurred there. When Gough visited some of those sites, she posted notices in situ for the public to find, informing passersby of the head counts.

The impulse to “bring hidden histories to light” is one she says she has always had.

“When I was a child we moved house a bit,” she tells the Guardian. “One time I pulled off the plastic of one of those long doorstoppers, and left a big letter inside, about who we were when we lived in this house … I think it’s important to make sure you’re not completely erased from a place, or a story.”

Her work has, at times, been risky. For the video piece Observance, she hid in the bushes to film groups of ecotourists who pay a private company $2,400 for the pleasure of tramping across her maternal country, Tebrikunna in north Tasmania. The voyeuristic footage makes any non-Indigenous viewer who has walked blithely across country feel shame and complicity.

“There’s this constant procession of visitors,” Gough says. “It feels like the number of footsteps – the air breathed, and the people’s dreams – could eventually overtake ours and our ancestors … it disrupts the energy of a place.”

The Gathering (2015, 2019) features stones Gough took from outside Tasmanian colonial estates. Photograph: Alistair Bett

For The Gathering, Gough drove past scores of Tasmanian colonial estates with a camera trained at the fences and gates that shut her out. She then jumped out of the car to steal back a piece of stone from each.

Many of these properties have been converted into luxury accommodation and wineries. Some still belong to the colonists’ descendants.

“In my head sometimes I feel I might go ‘missing’ – killed, yeah,” Gough says, with a half-smile that suggests she’s only half-joking. “I don’t know the state of mind of some of these [colonial] families that have been here for so long. They’re like a kingdom upon themselves.”

Gough’s 2008 artwork, titled Some Tasmanian Aboriginal Children Living With Non-Aboriginal People Before 1840. Photograph: Alistair Bett

In another room, a bundle of half-finished spears are trapped in the seat of a chair, which is suspended on a wall. On each spear is carved the name of a Tasmanian Aboriginal child who was orphaned or stolen from his or her parents during the black war. Gough has spent decades attempting to recover these children’s names and stories.

“I’ve now [found the stories of] 185 children … but that’s just the ones who are recorded,” Gough says. “I’ve exhausted birth, death, marriage notices; [lists of] orphan, asylum and children requiring education; newspaper reports, inquest reports. It feels sad … there are probably five times more than that.”

For the temporary exhibition Missing or Dead – a companion to Tense Past – Gough created 185 posters summarising everything she could find out about these 185 children. She pinned them to 185 trees in Queens Domain for Dark Path, Dark Mofo’s night-time outdoor installation.

The memorial was expansive, compelling the viewer to meander off the main track as they read about each one, lest any child be forgotten again.

“Without the Mofo effect, the work wouldn’t be up,” Gough says of the funding and audience the festival could offer. But the theme this year was “forest”, a word which “sets off an acid reflux” for Gough.

“That idea of a forest is totally European – the fairytale forest world is not Australian. And for a lot of Tasmania the word ‘forest’ is aligned entirely with Forestry Tasmania, which is about the decimation of our country.”

A memorial to 185 Indigenous children, titled Missing or Dead, was installed by Julie Gough as part of Dark Mofo’s outdoor exhibition Dark Path. Photograph: Rémi Chauvin

The true history of Tasmania continues to be glossed over. When she was studying tourism, Gough remembers being placed on a historic Port Arthur tour where “you’re not allowed to mention Aboriginal people at all”. (The agency responsible explained to the Guardian that “until further discussions with our local Aboriginal communities occur, we do not believe we are well equipped to interpret Aboriginal history at our sites”.)

And while Gough believes education is getting better, particularly among younger people, she says, “I think it’ll be another 50 years before things really change.”

She adds a bleak rejoinder: “I don’t think we’ll have a planet then anyway.”

• Julie Gough’s Tense Past, presented by Dark Mofo, is on at the Tasmanian Museum and Art Gallery until 3 November

• The Guardian was a guest of Dark Mofo and Tourism Tasmania