I’ve got a confession to make: I cannot reliably tell a miro from a mataī, or a karaka from a kohekohe. I wish I could positively identify tawa or kāmahi or maire. But I’ve always struggled to tell trees apart. I’m botanically challenged. Packing for a recent tramping trip, I was reluctant to add the weight of a field guide to all the gear and food I was carrying. If only, I thought, there was a phone version.

There was. In fact, AUT University’s NZ Trees app had just been updated—and it also worked offline. I used my last scrap of cellphone service to download it, holding my phone up to the sky on the east coast of Stewart Island/Rakiura.

The app allows you to search for trees by leaf shape, edge, surface, tip, base and arrangement, whittling down species until one matches the pictures and description. It wasn’t a failsafe identification method—I still don’t know the difference between an elliptic and an ovate leaf—but I enjoyed the process. I learned that the fewer characteristics I selected, the easier it was to figure out a species, given my propensity for misidentifying apetiolate leaf bases as round ones. If the tree was flowering or fruiting, that made it easier. I enjoyed it so much that I started to wish the app extended to shrubs, but it’s tree-only—for now.