Spring 2020 saw us carry out an innovative restoration of indigenous biodiversity in our forest. Several years in the planning, this involved epiphytes – plants that grow on other plants. Usually unnoticed and unappreciated because they are often out of sight from casual observation, epiphytes are an important part of the forest ecosystem.

AFP chose two initial species of shrub epiphytes to restore. Pittosporum kirkii, which is classified as At Risk – Declining, and Pittosporum cornifolium. Both species can grow into spreading shrubs or even small trees, many meters off the ground.

The natural process for how they come to grow where they do in the host tree’s canopy plays out over many, many years. Initially, mosses and leaves collect in the forks of major branches. These provide purchase for astelias that cling by their roots to the host tree. Slow-growing and flax-like, astelias eventually form ‘nests’, collecting leaf detritus. Large nests can contain considerable organic material, which absorbs water like a sponge. These nests make ideal nurseries for the seeds of shrub epiphytes that arrive via our native birds.

If their precarious lifestyle and niche ecological requirements were not enough, they are also vulnerable to possum browse. Pittosporum kirkii has fleshy leaves and seems particularly tasty, hence its current conservation status.

Having carried out predator control in the forest since 2006 and with the flourishing of birds like rifleman and robin, AFP are also keen to restore all parts of the forest flora that have disappeared. The decision to try shrub epiphytes was the brainchild of our chairperson James Denyer: “We knew it wasn’t easy, but this was something that no-one else was doing.”

Passionate about New Zealand’s native flora, he further explained: “It’s great that revegetating marginal land with natives is now commonplace, but planting natives on bare land is invariably restricted to colonising and tall forest species, not the more unusual plants that only thrive in old-growth forests. We are still losing some of that biodiversity.”

The first job was to source the seeds. Given where the plants grow, this wasn’t going to be easy. Adding to that, AFP considered eco-sourcing seeds from as close as possible to the restoration area was important. Luckily, James found suitable plants growing towards the top of the Kaimai. Even better, the wind-battered and stunted forest in which they were growing put some within reach of harvesting by hand. A keen eye was still required to sift the leaf litter and pick out the tiny black seeds. DOC gave approval to collect the seeds first, before James germinated and grew them on until a suitable size for planting.

A large puriri tree on the Short Loop track was selected. Abundant in nest epiphytes of Astelia solandri and Astelia hastata, there were multiple sites into which the shrub epiphytes could be transplanted. Even better, the tree with is spreading branches above the track was in the perfect spot for future visitors to see the results of the restoration project.

Expert tree climbers Scott Sambell and Emma Cronin were called in to hoist the plants into their new homes. The highest planting spot was almost 25 metres above the ground and the climb was not for the faint-hearted. Thanks to their rope skills and a couple of handy buckets, the shrubs were carried up and planted over the course of several hours.

We look forward to monitoring the plants and seeing them grow. Once established and big enough, we’d like to add signage to tell the story for visitors to the forest.