One of the key forest canopy species in lowland coastal forest in the North Island and Marlborough Sounds is kohekohe (Dysoxylum spectabile). It's quite an unusual tree. It belongs to a genus of tropical trees from Asia, with seeds making their way here countless thousands of years ago, adapting to the cooler climate experienced here. It is usually never found more than 5km from the coast.
As Manawa Karioi is only 1.5km from the nearest coastline, kohekohe would have been one of the main canopy species, growing to 15 metres tall. The further inland you go, the fewer kohekohe you will find, and it becomes a sub-canopy species as taller trees become dominant. It often grows in association with tawa.
You can find a remnant of kohekohe/tawa forest on the southern slopes of Johnston Hill in Karori, and there is a good stand of kohekohe on the Serpentine Walk that winds up behind the Dell in the Wellington Botanic Garden. It is also found along the Kaiwharawhara stream. In south Wellington, we are aware of only one mature kohekohe in Tawatawa Reserve just over the ridge from Manawa Karioi. And there are five known old trees on the Miramar peninsula.
For most of the year kohekohe blends in with other trees, but it really stands out when it is in flower. It's one of the few trees to flower in winter, and to have flowers coming straight out of the trunk and main branches.
Flowering begins around late June in Wellington, and lasts until late August. During this time they are an important nectar source for smaller forest birds. The seed capsules develop slowly, taking about one year. They bear three seeds surrounded by a orange-red fleshy structure called an aril. The larger native birds eat the arils, dispersing the seeds in the process.
Over the last 17 or so years, dozens of kohekohe have been planted at MK. Many are 4-5 metres tall but aren't flowering yet, despite being over 15 years old. The only one we have seen flowering at MK is only 3 metres tall and was planted around 2005/6. It's growing right next to the main track cutting across Seed Source Gully.
Here's a close-up shot of the flowers of this tree, taken late July.
Over the last couple of years we have been planting kohekohe from seed collected from the remaining five trees in Miramar. This year we will be planting several at each working bee this month, in three different locations.
As with every working bee this month we meet on Sundays and we depart 1pm sharp from the interpretation board shelter in the Tapu Te Ranga Marae carpark. This is up the driveway signposted at the end of Danube St, Island Bay. All trees, tools and gloves are provided. We will be planting regardless of weather, so bring appropriate clothing, shoes and a raincoat. If the weather is bad we can plant in the sheltered areas.
If you are late or can't find us, call 0221 277361.
Written By Ross Gardiner.
A tree enthusiast and an ex-resident of Island Bay. Vanessa brings her digital skills to the volunteer team at Manawa Karioi - one of the oldest reforestation projects in Wellington.
With over 17 years experience volunteering with Manawa Karioi, Ross has a detailed knowledge of the project.
Paul Blaschke is an environmental consultant and part-time university lecturer. He loves living and working in Wellington’s southern suburbs, whether in the Owhiro catchment, the Town Belt near his home, or on the slopes at Manawa Karioi.
Chris and his partner and their 3 children were at the dawn planting of the first tree in 1991. He has maintained his involvement in the project ever since and gets great satisfaction now from seeing how much the trees have grown and how the associated native ecosystems have developed over those 26 years. Chris emphasises that providing tracks to enable the public to enjoy Manawa Karioi, and carbon sequestration, are both integral parts of the project.