The Beech Forests.
The beech forests (fig. 18
), incorrectly called "birch" by the settlers, consisting of species of Nothofagus
, are quite distinct from all those of which we have hitherto treated, although they have some species in common. The dense growth of the evergreen foliage shuts out a large percentage of light, and in consequence the undergrowth is scanty. Some South Island subalpine forests of pure mountain-beech (N. cliffortioides
) contain in many parts little but seedling beech-trees. Woody lianes, too, are wanting,*
as are the more highly organized perching-plants. Nor are ferns nearly so plentiful as in the mixed taxad forest, though one, Polystichum vestitum
, is frequently abundant (fig. 19
). The tree-trunks are frequently covered completely with a black fungus (Antennaria
). Parasitic on the beech-trees are two mistletoes, the one, Elytranthe tetrapetala
, having most showy scarlet flowers, and the other, E. flavida
, having yellow flowers. A small club-moss, Lycopodium jastigiatum
, is sometimes very abundant on the forestfloor. In moist places there are frequently large colonies of the giant moss (Polytrichum dendroides
), looking rather like a pine-tree in miniature. Where the forest comes to an abrupt termination in the subalpine region it is invaded by some of the shrubs of that zone. At lower altitudes, and in the south of the North Island, various species of beeches and other forest-trees are mixed together, as in the Day's page 48
Fig. 18.—Gully passing through a Mountain-beech Forest (Nothofagus cliffortioides). Mount Torlesse, Canterbury.
[Photo, L. Cockayne.
Bay bush near Wellington; or a mixed taxad-Nothofagus
forest such as fringes the West Coast Sounds, or is common in Nelson, may occur.
There are six species of beech in New Zealand. Elsewhere the genus occurs in the south of South America, Tasmania
, and, eastern Australia. Of the New Zealand species, N. fusca
and N. Menziesii
Fig. 19.—The Fern Polystichum vestitum at outskirts of a Mountain-beech Forest. Fronds 3 ft. in length. Base of Big Ben, Canterbury.
[Photo, L. Cockayne.
called respectively the red and silver beeches, have toothed leaves, those of the first named being thinner, larger, and of a more vivid green. It also has distinct plank-buttresses on the trunk, and is at times a tree of huge dimensions. The other species have entire leaves; but only two—the mountain-beech (N. cliffortioides
) and the entireleaved beech (N. Solandri
are common. These two much resemble each other, except in the seedling stage.