Seasonal growth patterns of southern rata (Metrosideros umbellata), Camp Creek, Westland, New Zealand
Shoot and diameter growth of southern rata (Metrosideros umbellata Cav.) were measured at four south-aspect sites (1982-1983 and 1983-1984) covering the altitudinal range of the species in Camp Creek, and at two higher altitude north-aspect sites (1981-1982 to 1983-1984). Shoot growth in canopy tree...
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Veröffentlicht in: | New Zealand journal of botany 1989-01, Vol.27 (1), p.13-26 |
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Format: | Artikel |
Sprache: | eng |
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Zusammenfassung: | Shoot and diameter growth of southern rata (Metrosideros umbellata Cav.) were measured at four south-aspect sites (1982-1983 and 1983-1984) covering the altitudinal range of the species in Camp Creek, and at two higher altitude north-aspect sites (1981-1982 to 1983-1984). Shoot growth in canopy trees at all sites was limited to the expansion of leaf primordia present in the overwintering bud. Where vigorous seedlings retained an apical meristem over winter, shoots grew continuously throughout the next growing season. Rata seedlings began growth earlier, grew more rapidly, and completed extension growth ahead of canopy foliage in mature trees. Shoot extension followed the pattern of prevailing temperature, with bud growth starting when mean weekly temperatures reached 5-6°C. The start of growth in spring was delayed by 3.5 to 4.0 days for each 100 m increase in altitude. Cooler temperatures in spring 1982 delayed bud break at high altitude sites by about 4 weeks, but had little effect at the lowest site. Shoots elongated rapidly after bud break and completed growth before temperatures became limiting for growth. Growth of new leaves continued well into autumn and, at high altitude sites, was subject to damage from early winter frosts when bud break was delayed. Diameter growth rates (≤2.0 mm per annum) decreased with altitude, with some trees at high altitude sites making no measurable growth (< 0.1 mm) over two growing seasons. |
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ISSN: | 0028-825X 1175-8643 |
DOI: | 10.1080/0028825X.1989.10410140 |