Millions of landmines were laid in Cambodia during the country's nearly three-decade civil war, which ended in 1998, causing tens of thousands of casualties.
Deminers found the three landlines that had been installed in the tree, which then grew around them, during their mine-clearance operation in northwestern Banteay Meanchey province on Wednesday, Heng Ratana, the director general of the Cambodian Mine Action Centre, told AFP.
He said it was not the first time that his deminers had found a landmine in a tree.
"But this time, it's a bit surprising to see many landmines laid on a tree," he said, adding that the explosive devices had been safely removed.
"During the war, soldiers laid these landmines with trip wire to ambush their enemies."
Cambodia is littered with discarded ammunition and arms from decades of civil war from the 1960s.
Deaths from mines and unexploded ordnance are common, with around 20,000 fatalities since 1979, and twice that number injured in accidents involving landmines and unexploded ordnance.
In August last year, thousands of pieces of unexploded ordnance left over from the war were unearthed inside a school in the country's northeast.
And in 2018, an Australian and a Cambodian were killed when war-era ordnance exploded during a de-mining training exercise in southern Cambodia.
The government has vowed to clear all mines and unexploded ordnance by 2025.