They're one of the biggest pests facing New Zealand, and you probably haven't heard of them.
Wilding pines were introduced back in the 1960s as erosion control. Now it's the thing that needs controlling.
Around 7 percent of New Zealand is already infested by wilding pines, and left unchecked it'll be 20 percent within two decades.
Once they've taken hold, the trees grow so thick they choke the life out of native life.
They already cost us billions, and if we don't do something soon, they'll cost us even more.
Watch the video for the full Story report.