Southern Yellow Pine
Description
Dioecious small tree up to 10 m tall and 60 cm dbh, with spreading branches and a rounded crown; in exposed settings (such as alpine areas), it often forms a tight, rounded, cypress-like shrub. Bark silver-grey, peeling away in small thick flakes to reveal a reddish-brown inner layer. Branches stout, clothed with persistent leaves; branchlets 3-4 mm diameter, 4-sided. Has distinct juvenile and mature foliage, although branchlets of mature trees often revert to the juvenile form. Juvenile leaves spreading, linear, 10-20 × 1.5-3 mm, narrowed into a short, twisted petiole; midvein usually distinct; stomatal lines evident. Mature leaves scale-like, densely imbricate, closely pressed, 2 mm long, blunt, very thick with translucent margins, prominently keeled on the back. Pollen cones solitary, about 4 mm long, at the tips of branchlets. Ovules ovoid, compressed. Epimatium adnate to carpidium at base, coriaceous, surrounding the pendent inverted ovule; integument membranous. The seed (which appears to form at very irregular intervals and takes about twelve months to reach maturity) is solitary or rarely in pairs, oblong, blunt, striate, compressed, 2-3 mm long, in an orange aril. Wood is pink and sweet-smelling; tight-grained, it is possibly the most durable of New Zealand native woods (Allan 1961, Dallimore et al. 1967, Salmon 1996).
Distribution and Ecology
New Zealand, from the volcanic plateau of the North Island south to Stewart Island, at elevations from sea level to 1,400 m. Rare in the north, it is more plentiful in the south, often occurring in small local stands on rich soils in high-rainfall areas. On the southern slopes of Mt Ruapehu it is found occasionally in the forests and, above the bush line, around bogs with H. bidwillii (Salmon 1996). Within its range, mean annual temperature is 8.8°C, with an average minimum in the coldest month of -0.6°C, and a mean annual precipitation of 3009 mm (Biffin et al. 2011, Table S5).
Hardy to Zone 8 (cold hardiness limit between -12.1°C and -6.7°C) (Bannister and Neuner 2001).