regeneration

Many tree fern taxa have a skirt, an encircling structure of persistent dead fronds or stipes around the growing crown at the top of the trunk. Page and Brownsey (1986) hypothesised that the function of these skirts was to protect tree ferns against damage from large epiphytes, hemiepiphytes, and climbing plants. Tree fern trunks provide both suitable establishment surfaces for a range of woody epiphytes and hemiepiphytes in New Zealand, as well as attachment surfaces for climbing rātā (Metrosideros spp.).

Tree fern trunks provide establishment surfaces and habitat for a range of plant taxa including many understorey shrubs and canopy trees. The importance of these habitats for augmenting forest biodiversity and woody plant regeneration processes has been the subject of conjecture but has not been robustly assessed.

The population structure of red beech (Nothofagus fusca) is described for four forest stands situated at different altitudes on Mount Colenso. Data on red beech seedling densities and frequency distributions of living and dead tree diameters (d.b.h.) are presented. Red beech seedlings are shown to be more numerous, and on average larger, on decaying red beech logs than elsewhere. This seedling site preference could lead to, a 'regeneration cycle', and explain the 'regeneration gaps' and bimodal d.b.h. frequency distributions commonly found in red beech forest in the Ruahine ranges.

[First paragraph...]
The Hunua Range consists of approximately thirty square miles of dense mature rain forest and an equal area of scrub and second growth. It is situated nearly thirty miles south-east of Auckland City on the western edge of the Firth of Thames (Fig. 1.) The range comprises a group of deeply dissected, up-faulted blocks of Mesozoic greywacke. The upland region is sharply delimited from the rolling lowlands by four well-defined fault lines in the east, south and west. To the north the area dips gradually into the Tamaki Strait and the Papakura-Clevedon lowland.

New Zealand forests have been substantially modified by introduced red deer over the past century. New Zealand’s indigenous forest managers need to know if regeneration of palatable tree species can be restored following control or eradication of browsing ungulates. Aorangi Forest, Wairarapa, suffered dramatic changes in forest understorey composition by the 1950s after more than seven decades of colonisation by red deer (Cervus elaphus), feral goats (Capra hircus) and pigs (Sus scrofa).

This study uses data from forty-nine 20 m × 20 m permanent plots measured in 1976, 1982, 1989 and 1997-2002 in Wakatipu Forest, western Otago. We relate changes in red (Nothofagus fusca), silver (Nothofagus menziesii) and mountain beech (Nothofagus solandri var. cliffortioides) forest vegetation to the presence of fallow deer (Dama dama). Vegetation composition is likely to have been altered prior to plot establishment, and results show that there was little change in vegetation composition during the study.

Totara-matai forests are an under-represented forest type in Westland, relative to their original extent, and require protection and enhancement where possible. This study examined the regeneration of totara on gorse-covered river terraces of the Whataroa and Waiho Rivers, on a site grazed by cattle at Whataroa, and ungrazed sites at both locations. Totara is regenerating prolifically at all sites. Tall-seedling densities were significantly higher at the grazed Whataroa site than at the ungrazed Whataroa site.

Making use of existing fences as ready-made exclosures, this study aimed to assess the long-term effects of cattle grazing on forest margins. Results indicated: 1) that cattle browsing and trampling has an impact on vegetation species composition, structure and regeneration; 2) that the effects of a particular grazing regime may take many decades to dissipate; and 3) that the impacts of cattle change with stock intensity. Some plant species appeared to be highly palatable to cattle and only occurred on sites without cattle.

Aspects of the production and vegetative performance of Calluna vulgaris (heather) were examined in four areas of New Zealand between 1981 and 1983; Tongariro National Park in the North Island, together with Mount Cook National Park, the Wilderness Scientific Reserve, and Ben Callum peat bog in the South Island. The height and height/width quotient of Calluna bushes, the diameter increment of woody stems and the amount of flowers/stem all decreased with altitude.

The amount of conspicuous canopy dieback in all central Westland southern rata-kamahi forests east of the Alpine Fault, between 500 m altitude and treeline, was assessed and mapped from aerial photographs taken in 1984-85 and verified by aerial reconnaissance of selected areas in 1988. At least 20% of all canopy trees, predominantly southern rata (Metrosideros umbellata) and Hall's totara (Podocarpus hallii), were dead in 1984-85.