Both the common and generic names imply that this genus is found only in the Southern Hemisphere. This is so, and it can therefore be contrasted to the closely related genus of beeches, Fagus, found only in the Northern Hemisphere. At one time the southern beeches were thought to have had an origin around the Antarctic not only because of fossil records there but also because of the southerly latitudes of the living forests in South America, Australia, and New Zealand. In the last one or two decades, forests have been discovered at high altitudes in New Guinea and New Caledonia. While the species of trees in these have been identified as a different section of the genus, nevertheless they are southern beeches. In addition, possible fossil pollen records are now coming forward from the Northern Hemisphere. There is a quickened interest in the whole genus.
New Zealand has four species, one of them with two distinct varieties which are connected by a gradation of intermediates. These four species are all evergreen (Fagus species are all deciduous). Two of them have smallish toothed leaves, red beech (N. fusca) and hard beech (N. truncata), the former reaching heights of 100 ft and diameters of 3–4 ft. The latter is a somewhat smaller tree. Silver beech (N. menziesii), a tree with small, thick, double-toothed leaves and a cherry-like bark on the branches and young trees, reaches heights of about 100 ft and diameters of 2–3 ft. The other species, N. solandri or mountain beech, has small entire leaves. One of its varieties (var. cliffortioides) is no more than a dwarf tree at timber line but reaches much larger dimensions; at the other end of the scale, the second variety (var. solandri) or black beech, reaches heights of 80 ft in lowland forests.
The main forests formed by these species extend from about latitude 38° to the south of the South Island, mostly at higher latitudes and in the drier climates. Pockets of N. truncata are found as far north as latitude 35°. Hybrids between all species, excluding N. menziesii, are common where more than one species is present in a forest.
Forests formed by southern beeches are distinctive in so far as they are more or less pure associations of species. Thus they are a contrast to the mixed hardwood podocarp forests which were the main forests of lowland New Zealand and in which many species are present. Regeneration is gregarious, arising from periodic, bountiful seed years. It has the same habit as Fagus and this characteristic has enabled European foresters to introduce very intensive management into the European beech forests. It will therefore be possible for New Zealand foresters to follow their ideas with southern beeches.
The timbers are useful to commerce and about 12 million board feet or 1.7 per cent of the total timber cut finds its way on to the market each year. The timber from each species has its own special characteristics and between them they have a wide range of uses. Silver beech from forests in the south is an all-purpose timber, but particularly suited for furniture. Red beech is generally durable and is used for railway sleepers and bridge timbers. It is also good general building and furniture timber. True black beech is a very durable timber and was widely used for fence posts when and where available. Mountain beech, its counterpart, is nondurable, but is a good, mild timber that is easily worked.
by Alec Lindsay Poole, M.SC., B.FOR.SC., F.R.S.N.Z., Director-General of Forests, Wellington.