General Account

Communities similar to the one described occupy all scrub land sites where the slope is steep, the drainage free, the soil shallow, and the exposure not extreme. They comprise about half of the vegetation of the scrub zone. Their characteristic feature is the dense storey of shrubs, mainly Olearia colensoi, with groups of taller Dracophyllum traversii. Dracophyllum longifolium is usually present, and on drier or warmer sites, such as slight spurs and terrace faces, it may rise to dominance.

On exposed ridges, especially those with northerly aspect, Olearia colensoi scrub passes gradually into communities dominated by Dracophyllum uniflorum. There is a corresponding decrease in height of the scrub, and an increase in the proportions of certain species, notably Dracophyllum longifolium, Olearia lacunosa, Gaultheria rupestris and Coprosma serrulata. On southerly faces low-growing communities of nearly pure Olearia colensoi intervene between tall scrub and grassland.

Occasional slipping of the substratum may explain the occurrence of scattered plants of Hoheria glabrata and Olearia ilicifolia. Gaps often contain herbfield inclusions with Aciphylla (?) colensoi, Celmisia coriacea, Danthonia flavescens (usually the very broad-leaved form), Astelia cockaynet and Phormium colensoi.

In a downhill direction, with the entry of Libocedrus bidwillii, Olearia colensoi scrub passes into high altitude forest. The following pH values were obtained from a soil supporting a community in which Olearia colensoi and Dracophyllum longifolium share dominance:

(C.f. shrub composite scrub of Southern Alps and mountains of north-western district, Cockayne, 1928, p. 278).

Dracophyllum Uniflorum Scrub

Typical Community. Altitude, 3,800ft Slope, 43°. Aspect, N. E. Steep ground on the crest of a ridge.

Shrub Storey. Dense clumps of Dracophyllum uniflorum 2–3 feet tall.

Ground Cover. Mainly Blechnum minus and large moss (genus Dendroligotrichum.) Also Gaultheria sp., Suttonia nummularia, and Schoenus pauciflorus. Occasional clumps of Phormium colensoi, Danthonia flavescens (2 forms), and Celmisia coriacea.

Regeneration. Seedlings of Dracophyllum uniflorum were not seen; but the bushes are propagating by “downhill layering”. One chance seedling of Hoheria glabrata seen.