Claire Concannon hits the Central Otago hills with Botany PhD student Ben Teele to imagine the landscape as it use to be, and to follow the clues to find leftover pockets of tōtara trees.

The hillsides of Central Otago are known for their golden grass and tussock slopes with scattered low-lying shrubs. But once this landscape was covered in tōtara forest. Now only a few trees remain, cryptic and scattered across the large region, and Ben Teele is on the hunt for as many of them as he can find.

Follow Our Changing World on Apple Podcasts, Spotify, Stitcher, iHeartRADIO, Google Podcasts, RadioPublic or wherever you listen to your podcasts.

University of Otago Botany PhD student Ben Teele is mapping and 'health-checking' the remaining tōtara tree populations. Some large, some small, some regenerating well, but others struggling.

Clues are key to him finding the trees in this vast landscape, and he finds them in all kinds of nooks and crannies - tōtara sightings from geologists, botanists or hill walkers, environmental reports to local authorities and even historical gold mining records describing where tōtara grew.

Ben is looking for the thin-barked tōtara species well adapted to this semi-arid environment. Once widespread, they are now restricted to rocky bluffs high on the hills, which helped them survive the fires that swept across the region after human arrival.

Ben wants to collect the seeds and grow some cuttings from these Central Otago survivors to ensure good genetic diversity, and to figure out what the optimal conditions might be to help them regenerate, and spread back down the hills to the lowers slopes they once inhabited. His research is funded by the Ministry for Primary Industries One Billion Trees programme, with the aim of planning one billion trees across Aotearoa by 2028. Ben hopes that at least some of those trees planted will be thin-barked tōtara in Central Otago and imagines a future where this landscape could look very different.

Go to this episode on rnz.co.nz for more details