November in the hills with Barbara Mitcalfe and Chris Horne
Fuscospora solandri, tawhai rauriki, black beech
Tawhai means beech, and rauriki means small leaved. Māori used the name tawhai rauriki for both black beech and mountain beech because both have small leaves. You will be relieved to know that black beech is easy to distinguish from the big-leaved beeches which we have been describing to you recently, and after this, there's only one more beech species to learn!
Fuscospora solandri, black beech, was named after Daniel Solander, 1733–1783, a Swedish botanist who sailed with Captain Cook on his first voyage to New Zealand.
In the North and South islands, black beech grows in lowland and lower-montane forest, but like all our other NZ beeches, it is absent from Mt Taranaki. It is uncommon north of the Volcanic Plateau and East Cape. In the South Island, it extends to South Westland.
Unlike silver, red and hard beech leaves, black beech leaves have no serrations, and remain mid-green all year round. At 10-15 mm x 5-10 mm, they are elliptic, noticeably smaller, and have rounded tips. Their texture is firm, almost leathery, and their hairless upper surface has plump bulges between deeply impressed veins. Young leaves have dense white hairs underneath.
As with the other NZ beech species, black beech flowers are minute, but, en masse, their crimson stamens can make the whole tree appear crimson. Flowering is in spring and summer, followed by tiny 'nuts' c. 6 mm. long.
Black beech and mountain beech are fairly similar in appearance, and when they are in the same area, they frequently hybridise with each other. So if you're tramping in montane beech forests, and you're finding it difficult to identify black beech, it may be because this is happening. Mountain beech is the subject of next month's article, so we shall be devising a table to help you distinguish one from the other, just as we did for red and hard beech.
Although at the time of writing, no rongoā uses for black beech are known to us, this species has played, and is still playing, a vital role in our industrial history. Despite its high silica content which blunted many a saw, its timber was used for an extraordinary variety of products ranging from bridges, railway sleepers, flooring, panelling and cartwheel spokes, to suites of fine furniture, and even paper. As with other NZ beech species, a solution made from its bark was much used by the tanning industry because of its high tannin content.
In the forest, sooty moulds blacken the bark, which gives the tree its common name. That very same black, furrowed bark is also the favourite home of the sap-sucking insect, Ultracoelostoma assimile, that produces honeydew, one of our prestigious, high-value exports. It is a favourite food of wasps as well. When you're tramping in beech forest, always remember to have fresh anti-histamine in your First Aid kit to counteract wasp stings.
Black beech make handsome, long-lived, evergreen specimen trees, their foliage being often attractively layered. Their maximum height is c. 23 metres, and their maximum trunk diameter is just over 1 metre.