Agathis microstachya description

Agathis microstachya Bailey & C. White

Common Names

Atherton kauri (Silba 1986), kauri pine, bull kauri, bull pine (Boland et al. 1985).

Taxonomic notes

Description

Tree: Usually a straight single trunk, not buttressed, with little taper below the base of the crown. Height to 50 m, dbh to 270 cm. Monoecious (Boland et al. 1985).
Bark: Brown to grey-brown, coarsely flaky, inner bark ('outer blaze') mixed pink and brown with a milky bark exudate and a faint odor of pinene (Boland et al. 1985).
Branches:
Shoots: Primary (orthotropic) shoots with spirally inserted leaves, secondary (plagiotropic) with opposite to subopposite leaves (Boland et al. 1985).
Leaves: Linear to elliptic, 2-9 × 0.5-2.5 cm, stiff, with fine, longitudinal, subparallel veins, on 1-2 mm long petioles. Seedling leaves ovate-lanceolate, acute, 5-8 × 1.5-2.5 cm, venation and peioles similar to adult (Boland et al. 1985).
Cones: Globular to ovoid, 7.5-11.5 × 6.5-10 cm (Boland et al. 1985).
Cone scales: Size to 2.6-3.5 × 3.3-4.5 cm, numbering 160-210, generally glaucous at the apex (Boland et al. 1985).
Pollen cones: Shortly pedunculate or almost sessile, 1.1-1.6 × 0.6-0.8 cm, with 400-500 scales. Each scale has 2-5 pollen sacs on the abaxial side. Cones mature in December (Boland et al. 1985).
Seeds: Cordate, winged (Boland et al. 1985).
Wood: Heartwood cream to pale brown, growth rings usually inconspicuous, about 480 kg m^-3 (Boland et al. 1985).
Other features: Cotyledons 2, oblong or ovate, 2.5-3 × 1-1.5 cm, almost sessile, slightly stem-clasping, with fine, indistinct, longitudinal, sub parallel veins (Boland et al. 1985).
Similar species:

Range

Australia: N Queensland. Almost entirely confined to rainforests of the Atherton Tableland, at latitude 17-18° S and elevations of 400-900 m. The mean maximum temperature of the hottest month is 30°C and the mean minimum of the coldest month is 10°C (data for Atherton station). Precipitation is 1400-3300 mm, concentrated in the summer months, reaching a minimum of 25 mm in the driest month (August or September). Soils are deep loams to clays on varied silicic substrates. As with most species of Agathis, it grows as a rainforest emergent in a canopy composed of hundreds of different tree species (Boland et al. 1985).

Big Tree

Said to attain heights of 50 m and diameters of 270 cm (Boland et al. 1985). The "twin kauris" at Lake Barrine, Crater Lakes National Park in North Queensland, are quite famous as the largest conifers in Australia. In 2002 they were 205 cm dbh and 41.2 m tall, and 198 cm dbh and 40.2 m tall. Another, seen along Gillies Road on the way down to Cairns, is nearly as big: 196 cm dbh and 38.4 m tall (Robert Van Pelt e-mail, 27-Jan-2003).

Oldest

Dendrochronology

It has apparently not been examined, probably due to its very limited distribution.

Ethnobotany

The timber is soft, light, easy to work and polishes well. It is not durable in contact with the ground, but is used for house framing, flooring, and joinery (Boland et al. 1985).

Observations

See "Big Tree" above.

Remarks

This species is listed as 'LR/cd' (lower risk, conservation dependent) by the WCMC, which adds: "As with A. atropurpurea, this timber species is found in low densities in localised lowland rainforest. Logging is heavy where the forest is unprotected. Before 1985 the population had been halved by logging but 70% of the forests are now protected."

The specific epithet microstachya derives from the Greek micros (small) and stachys (ear of corn or a flower spike), alluding to the small male strobili (Boland et al. 1985).