What if the leaves of the humble tī kōuka (cabbage tree) could be used for a greener, more sustainable and profitable future?

That’s the question Yiting Su from Breens Intermediate explored in his winning science project at the 2025 Wrybill Trophy Awards event hosted by us.

His project, ‘From Tree to Treasure’, investigated the ways the tough fibrous leaves from the tī kōuka could be repurposed. These leaves can’t be put into our green waste bin but can be disposed of in the red bin (landfill) or at an Ecodrop for a fee. To reduce filling up our landfill bins with these leaves, Yiting thought of a way to put them to better use.

From backyard problem to science project