The Cairncross Sisters' Conservation Gift
How a 1941 family donation preserved 55 hectares of intact subtropical rainforest
Mary Cairncross Reserve is fifty-five hectares of intact subtropical rainforest preserved in the Blackall Range hinterland. It exists because in 1941 — well before mainstream conservation movements — three sisters chose to gift family land for permanent protection rather than sell it for timber or grazing. This is the story of that gift and why it still matters.
The 1941 donation
In 1941 — during the Second World War, decades before the modern conservation movement — sisters Mabel, Mary, and Jean Thynne donated fifty-five hectares of intact subtropical rainforest near Maleny to the Landsborough Shire Council. The land was named in memory of their mother, Mary Cairncross Thynne. The condition of the gift: the rainforest must remain permanently protected for community benefit.
Mary Cairncross Reserve is now managed by Sunshine Coast Council and is one of the largest accessible remnants of subtropical rainforest in south-east Queensland. The boardwalk that wheelchair-accessible visitors walk today follows essentially the same path the Cairncross sisters used to walk before the war.
Who the sisters actually were
The Thynne family had owned the Maleny property since the late 1800s. Mary Cairncross Thynne (the matriarch) had raised her daughters with what would now be called a strong environmental ethic — a recognition that the rainforest itself was the family's most valuable asset, not the timber it could produce.
When their mother died and the sisters inherited the property, they had options. Logging the bunya pines, red cedar, and other rainforest timbers would have been highly profitable in 1941. Clearing for grazing was the standard hinterland practice of the era. The sisters chose neither.
What 55 hectares of intact rainforest means in 2026
Most of the Blackall Range was cleared for timber and dairy farming through the late 1800s and early 1900s. Intact rainforest remnants of any significant size are rare. Fifty-five hectares preserved continuously since 1941 is genuinely uncommon — it has allowed ecosystems and species (the red cedars, the bunya pines, the dependent fauna including pademelons) to remain ecologically functional rather than degraded fragment patches.
Bunya pines are particularly significant. The bunya groves in this region were the focus of major triennial Aboriginal gatherings — Jinibara people hosting visitors from across what's now Queensland and northern New South Wales — going back tens of thousands of years. Mary Cairncross Reserve preserves not just the trees but the cultural landscape they anchor.
Why the story still matters
It's easy to assume conservation always required environmental policy frameworks, EPBC Acts, government reserves systems. Mary Cairncross predates all of that. Three women made a personal decision to gift land for permanent protection because they understood what the rainforest was. Eighty-five years later it's still there.
Visitors walking the 240-metre boardwalk today often don't realise the depth of the history. The bunya pines they walk under are the same trees the Cairncross sisters walked under in 1941. The acknowledgement of Country we read at the start of the walk recognises a cultural connection that goes back tens of thousands of years before that.