Indigenous forest restoration via pine plantations research

A new study by ecologist Meg Graeme for Tāne’s Tree Trust and Ministry for Primary Industries (MPI) shows that pine plantations across erosion-prone hill country in Tairāwhiti already host an understory that is 98% native species – dominated by kawakawa, māhoe, hangehange and coprosmas.

The study sampled 45 plots across 24 radiata pine stands, analysing how factors such as stand age, canopy density, seed source proximity, and browsing pressure influence native understory regeneration.

It found older, more open pine stands support richer, more diverse native growth and higher carbon storage. But without pest control and strong native seed sources, big canopy trees may struggle to establish – leaving gaps filled by shrubs or wilding pines.

The good news? Pine plantations may act as “nurse crops” that help bring back permanent native forests. Successful transition to mature native forest will require active management of these stands across tens of thousands of hectares that cannot be sustainably harvested.

Key interventions required include: (a) pest control to allow seedlings to reach canopy height; (b) ensuring access to diverse native seed sources; and (c) thinning or modifying pine canopies to accelerate succession. These measures will be essential not only for biodiversity recovery but also for soil stabilisation, climate resilience, carbon sequestration, and reducing downstream impacts on communities and ecosystems.

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Source: Tāne’s Tree Trust (via LinkedIn)