Farm Forestry New ZealandPohutukawa does not generally have a form suitable for timber production, but reasonable growth rates, adaptability to harsh conditions and excellent timber properties suggest the species is a good contender for work on selection for straight form. Pohutukawa and its hybrids can be clonally propagated (grown from cuttings) so selection and propagation of vigorous straight-formed trees should be fairly straight forward.
Anecdotal evidence suggests that straight, single-stemmed pohutukawa occur naturally in Northland as hybrids with northern rata. A range of named hybrid clones are also available and are grown as ornamental trees. However, these have not been tested for form and site requirements in a plantation forestry setting.
Annual diameter growth of up to 2 cm is possible on good sites, which is good for a native tree species. Average growth rates of 50 cm diameter in 50 years can be expected.
A range of Graham Platt's hybrid selections are available, including Mistral, Sirocco, Hauparapara, Mercer Bay and Waikakariki, which are reputed to be straighter and faster growing than the pure species. The pohutukawa clones Maori Princess and Pink Lady also have a reputation for good form.
Health: Susceptible to browsing by possums. A range of indigenous insects feed on pohutukawa but do not impact significantly on tree health.
Timber: very dense, strong, hard and durable. Cuts out red but ages to a rich reddish-brown colour.
| Species | Density, dry (kg/m3) | Bending strength, MoR (MPa) | Stiffness, MoE (GPa) | Hardness, Janka (kN) |
|---|---|---|---|---|
| Rata x Pohutukawa hybrid | 880 | 114 | 11.4 | NA |
Siting: Resilient to both poor soil conditions and strong winds. However, growth rates would be expected to be slow in such conditions. Seedlings are frost tender and vulnerable to dessication by wind and drought. Young trees need to be free of weed competition. Does not cope with waterlogging.
Steep slopes: Perhaps the most suitable of the native species for exposed eroded slopes. A coppicing species, i.e. the roots do not die but the stump stays alive after felling and re-sprouts. Coppicing species hold the soil from slipping even after harvest.
Species characteristics: Reasonable growth rates, excellent timber properties and adaptability to harsh conditions offers potential for production forestry on exposed eroding slopes deficient in topsoil.
Recommended regime: Plant clonal selections at 800 stems per hectare, interplanted with 800 stems manuka per hectare for honey production and as a nurse crop to draw the Metrosideros upwards. Epicormic shoots are likely to result from pruning open-grown trees.
Key message: Hybrids grow straighter and faster than pohutukawa. Research is required to trial hybrid selections and develop management techniques.
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