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Beech (Nothofagus spp.)

Last Modified: 21-2-2019 9:03

Beech forest on the Queen Charlotte Track
Beech forest on the Queen Charlotte Track

Several Nothofagus species make up New Zealand's collection of trees that bear the name 'beech'. This genus is restricted to the southern hemisphere, and while classified as 'beech' is evergreen in New Zealand unlike the northern hemisphere trees of the genus Fagus. In addition to New Zealand, closely related species are found in Tasmania, eastern Australia, South America, New Caledonia, and Papua New Guinea.

Much of Marlborough is too dry to support beech forest, and large areas of formerly forested land have been cleared by accidental and deliberate fires. European colonisation was accompanied by massive deforestation as large areas of forest were milled, or cleared for farming. In spite of this significant areas of original and regenerated forest remain. North of the Wairau River, much of the Richmond Range is covered in beech forest, along with some small remnants of mixed beech and podocarp forest. In the Pelorus valley a popular conservation reserve is set aside with mixed podocarp and beech forest. Parts of the Marlborough Sounds also have significant areas of beech forest.

Black beech N. solandri is a tree up to 25m high found up to about 700m altitude generally in drier sites. It's difficult to distinguish from mountain beech N. solandri var.cliffortioides which grows to the highest altitude of any New Zealand tree, reaching 1800m in the Branch River valley in Marlborough. These are the highest trees in the country. This is not a very high tree line for a latitude of 42 degrees, but reflects the maritime climate of New Zealand. Mountain beech grows to a height of about 20m and flowers a month later than black beech. Crimson stamens on the tiny male flowers can colour a whole tree of either variety.. Some localities: Black- Marlborough Sounds, Pelorus, Isolated Hill, Oaro. Mountain- Richmond Range, upper Wairau and tributaties, Inland Kaikoura Range.

Unlike the foregoing species with entire (untoothed) leaves, red beech N.fusca has serrate (toothed) leaves. It reaches a height of 30m and the often buttressed trunks may have a diameter of 2m. This tree grows up to about 900m altitude in Marlborough and prefers wetter sites, particularly valley bottoms. Straw coloured stamens on male flowers. Some localities: Pelorus, upper Wairau

Hard beech N.truncata has slightly different leaf serrations from red beech. It grows to 25m in Marlborough and inhabits drier sites than red beech. On the east coast it reaches its southern limit in northern Marlborough. The male flowers have prominent red stamens. Some localities: Pelorus, Marlborough Sounds

Silver beech N.menziesii occupies a separate group within the genus. Unlike the others it does not form hybrids. It has small serrate leaves and grows to 25m. It is a colder climate tree inhabiting high rainfall areas. In Marlborough it is found above 1000m on the Richmond Range. On Mt Richmond it forms the timberline. The flowers are tawny bunches up to 6cm across.

The beeches are parasitised by a scale insect which feeds on sap. The only visible part of the insect is normally a long white hair ending with a drop of honeydew obtained from the phloem. This provides food for honeyeaters such as bellbird, tui, stitchbird, kaka, and bees. In the late 1950s the German wasp Vespa germanica reached Marlborough from the North Island after hitchhiking there in a crate of aircraft parts fom Europe. The wasp thrived on the honeydew of the Marlborough beech forests, becoming a noxious pest for humans and depleting the food supply for bees and native birds. The German wasp has since been largely supplanted by an even more aggressive stowaway- the common wasp Vespa vulgaris. Research on methods of biological control has seen the introduction of a small insect predator which has had a minor impact on wasp numbers. Visitors to beech forests need to be prepared with appropriate first aid for stings in summer and autumn. As the scale insect is uncommon above 600m there is no problem at altitude.

The sooty mould seen on beech trunks and branches feeds on the honeydew excreted by the scale insect. This, and the sweet odour of honeydew will be the first indication to a newcomer to our beech forests that they have arrived.

Beech honey is available from local apiarists.

Beech trees flower prolifically in the spring following a hot summer. The male flowers of black and mountain beech are so numerous that the forest appears dark red even from a distance. Beech nuts provide food for kakariki (parakeet), rats and mice. The explosion in rodent numbers in causes an increase in their predators- stoats. When the rodent numbers decline the stoats attack birds. So one of these 'mast years' causes profound ecological changes to the forest. Numerous beech seeds lie on the forest floor awaiting light to stimulate germination. When forest giant falls or there is a slip, light enters the gap and a dense mass of seedlings shoots up. Soon these become a 'pole stand' - very difficult to penetrate. Eventually a few mature trees survive.

NZ  beeches support the semiparasitic mistletoes Peraxilla (red flowering) and Alepis (yellow flowering). Both these attractive mistletoes have been much reduced by the Australian possum.

Why the colorific names for the beeches? 'Red' and 'silver' may refer to the timber but this is very variable. 'Black' must be the sooty mould.

There is no beech timber milling in Marlborough now, though several individuals have planted woodlots. Early timber men such as Brownlie clear felled the forests wastefully and burning for farms or sheer entertainment was the norm. Beech timber is strong and durable above ground but it is prone to twisting and splitting. In ideal conditions a red beech tree can reach a trunk diameter of 1m in 80 years.

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