Vegetation of the Aorangi range,Southern Wairarapa

Abstract

In primeval times the Aorangi Range supported an almost continuous forest cover broken only by occasional slips and young stream terraces. Forest still form the most extensive cover in the area. It can be broadly classified into four main types: mahoe-hinau-rewarewa forest en the more stable slopes and flats up to an altitude of 1,700–1,900 ft; black beech forest on the drier, more exposed spur sites up to 1,600 ft; red beech forest on the mid slopes between 1,400 ft and 1,900 ft; and silver beech forest along the ridges between 2,000 ft and the highest points of the range. In recent times the vegetation of the area has been modified by fire, browsing, and erosion. Erosion has favoured the extension of seral plant communities such as are found on slips, in gully heads, and on aggrading river terraces. Burning has given rise to tall kanuka scrub at lower altitudes and to subalpine scrub and tussock grassland at higher altitudes. Browsillg mammals have considerably altered the composition of cach forest type and have modified succcession on bared areas. The first section of this paper briefly describes the physical nature of the range; the second deals with the distribution, structure, and composition of the main forest types, and the third describes how erosion, fire, and hrowsing have altered these to produce the present seral and subclimax communities.