(8) The Forest.
Distribution of the Forest Areas.—In pre-European times Banks Peninsula was clad with dense forest, except on the hills overlooking the plains and between Timutimu Head and Birdling's Flat, where the forests were chiefly confined to valleys and hilltops. From Lyttelton Heads to Kennedy's Bush there were no large forests, and between Kennedy's Bush and Little River the forests were not continuous. The hills on the southern side of Lyttelton Harbour were also in part bare; from Little River to Akaroa, and from Akaroa along the outer bays to Port Levy, there was an almost continuous sheet of forest. Here and there the bald heads of some of the higher peaks rose above the forest line, as in the case of Mount Herbert and Mounts Sinclair and Fitzgerald; but elsewhere the forest wave swept over the hilltops, and was continuous except where broken by cliffs. Certain trees abundant on the western ranges, which probably require a rainfall of 50 in., are conspicuously absent from the area: such are Metrosideros lucida, Weinmannia racemosa, and Phyllocladus alpinus.
Types of Forest.—The forest is of two main types—(a) the podocarp forest, and (b) the beech forest.* The podocarp forest can again be subdivided as to altitude into the lower podocarp and the upper podocarp-cedar
[Footnote] * This is not further described here, but see R. M. Laing, Trans. N.Z. Inst., vol. 46, p. 58, 1914.
forest. It is characterized by the presence of certain taxads—viz., Podocarpus totara, Podocarpus spicatus, and in smaller quantity Podocarpus dacrydioides, as chief timber-trees. In the upper podocarp forest, on the tops of the ridges above 2,000 ft. P. totara is replaced by P. Hallii, P. dacrydioides is absent, and Libocedrus Bidwillii is found. This upper forest is found chiefly on the tops and sides of the ridges between Kaituna Valley and the Akaroa — Le Bon's dividing ridge. Here it passes into the beech forest.
The Lower Podocarp Forest.—The lower podocarp forest is remarkably uniform throughout, and cannot be further subdivided by reference to the common species. The localization of some of the rarer, species suggests, however, a further subdivision into a seaward area lying between Port Levy and Akaroa, and a landward area lying between Lyttelton and Little River. The former of these areas is somewhat warmer and moister than the other. Here are to be found, though not uniformly distributed throughout the area, Corynocarpus laevigata, Rhopalostylis sapida, Coprosma lucida (large-leaved form), Cyathea medullaris, and a form of Sophora tetraptera approaching to but different from the East Cape S. grandiflora With the exception of Cyathea medullaris, these are plants which find their southernmost limit here. On the landward side these species are absent, but at one time Dacrydium cupressinum seems to have occurred. Certain rare species also occur here more commonly than on the eastern side. Thus both at Mount Pleasant and at Lake Forsyth there occur the following species, which do not reappear again together, so far as I know, elsewhere on the peninsula: Olearia fragrantissima, Teucridium parviflorum, Nothopanax anomalum, and Microlaena polynoda. Other localized species no doubt exist in the peninsula lowland forests, though it is difficult now to be sure that they were not at one time more widely distributed. Amongst these may be mentioned Pseudopanax ferox, now chiefly confined to the western area; Australina pusilla, in both areas; and Parietaria, in both areas. The distinctions of areas here made are not intended to be rigidly insisted on; they are, however, suggestive of some differences in primitive vegetation. But it is too late now to endeavour to define them more accurately, as we are not sufficiently well acquainted with the distribution of the species of sixty years ago. Certain species have undoubtedly disappeared since Raoul's time, and others have become very rare. These may be determined from the accompanying list.
The taxads are the only large timber-trees common in the lower podocarp forest. Griselinia littoralis, however, often forms short, knotted trunks, sometimes 4 ft. through, but generally hollow. As the altitude increases, the forest-trees become somewhat smaller. Podocarpus spicatus, though not confined to the lower portion of the forest, is at its best and most abundant below 1,500 ft. Large trees of Podocarpus totara (sometimes in association with P. Hallii) are found up to 2,500 ft.; but in the upper parts of the “bush” Griselinia tends to replace the pines, and on the ridges and towards the summit Podocarpus Hallii and Libocedrus Bidwillii appear. The former is known on the peninsula as “mountaintotara,” and, though much valued as a timber, is considered inferior to P. totara. The white-pine is not, I think, found above 1,500 ft. Towards the upper limit of the forest the number of species is reduced and the specimens are stunted, until it finally gives place to a poorly developed subalpine scrub.
The smaller trees of the forest are the same all over the peninsula to a remarkable extent, and, indeed, most of them are common as far south
as the Bluff. Griselinia littoralis, Melicylus ramiflorus, Carpodetus serratus, Pennantia corymbosa, Sophora microphylla, Nothopanax arboreum, Schefflera digitata, Aristotelia racemosa, Fuchsia excorticata, Pittosporum eugenioides, P. tenuifolium, and Hedycarya dentata are amongst the most abundant. These support an abundant growth of climbers, which in some places render the forest almost impenetrable. The most frequent are species of Rubus, Parsonsia, Clematis, and Muehlenbeckia; less common are Rhipogonum, Tetrapathaea, and Metrosideros hypericifolia. In the scrub which is found interspersed with the forest-trees are Drimys colorata, various species of Coprosma, Myrtus obcordata, Melicope simplex, and a few other plants. On the forest-floor are Blechnum discolor, and Polystichum vestitum in large quantities. By the side of the forest-streams Blechnum fluviatile, Blechnum lanceolatum, Asplenium bulbiferum, and Blechnum capense are the most abundant species of ferns. In the darker creeks Leptopteris hymenophylloides and Blechnum Patersoni appear. As a tree-parasite Loranthus micranthus is abundant, while Tupeia antarctica is much less common. There are, too, as in all parts of New Zealand, many epiphytic ferns: Cyclophorus serpens, Asplenium falcatum, Asplenium flaccidum, and Polypodium diversifolium are common in such situations. On exposed windy ridges the forest tends to pass out into the heath.
The Upper Podocarp-Cedar Forest.—Through the centre of the peninsula, at an altitude of somewhat over 2,000 ft., runs a narrow belt of forest in which Podocarpus Hallii and Libocedrus Bidwillii are the predominant species. At its upward edge in places— e.g., Mounts Fitzgerald and Sinclair—this passes into a still narrower belt of subalpine scrub, probably not more than 100 or 200 yards in width, and not well defined. The absence of lowland trees, such as Myoporum, Dodonaea, and tree-ferns further differentiates this forest from that of the lowland area; otherwise it is very similar. Griselinia littoralis, Drimys colorata, Fuchsia excorticata, Nothopanax arboreum, and certain species of Coprosma are here in increased abundance, along with several species of Rubus.
The Destruction of the Forest.—Unfortunately, however, there are only scraps of the forest left. Most of it has been destroyed with the advance of settlement. Possibly 10 per cent. of the big trees were used for timber, and the rest wastefully burnt. Of the extensive and almost continuous forest that once blanketed the peninsula from Little River round the coast to Pigeon Bay only scraps are left in the valleys and on the tops of the ridges, and practically everywhere these remnants are run through by cattle. This means that all the forest will be destroyed except for a few small and imperfect reserves. The destruction took place in the half - century between 1850 and 1900, and it is now practically complete. The largest area still forested is on the southern side of Mount Herbert. It is some two miles in length, and lies at an altitude of from 1,500 ft. to 2,500 ft. It is in too high and too bleak a situation to show the lower podocarp forest at its best, but it contains well-preserved areas of the podocarp-cedar forest and the subalpine scrub.
Replacement of Vegetation in Forest Areas.—Where the bush land has not been sown with cocksfoot, but natural causes have been allowed to provide a secondary growth, considerable areas of bracken soon appear, and this in its turn is often replaced by heath, consisting chiefly of the two common species of manuka. Such areas are best seen where the bush was early destroyed by Maoris, settlers, or even by accident, as in Barry's Bay, Duvauchelle's Bay, Little River, Kaituna, and Port Levy.
Where the bush was partly burnt, or burnt patches occurred in the middle of the forest, fire weeds such as Aristotelia racemosa, Solanum aviculare, Erechtites prenanthoides, Plagianthus betulinus, and other fast-growing plants appeared, but, owing to the complete destruction of the forest, patches containing these second-growth species have now also disappeared.