Agathis robusta

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Agathis robusta
Arobusta.jpg

Agathis robusta

Systematics
Subdivision : Seed plants (Spermatophytina)
Class : Coniferopsida
Order : Conifers (Coniferales)
Family : Araucarias (Araucariaceae)
Genre : Kauri trees ( Agathis )
Type : Agathis robusta
Scientific name
Agathis robusta
( C.Moore ex F.Muell. ) FMBailey

Agathis robusta , also known as Queensland Kauri spruce , is a species of the Kauri tree ( Agathis ) in the Araucariaceae family. It is native to Australia and Papua New Guinea .

bark
Branch with leaves.

description

Agathis robusta grows as an evergreen tree that reaches heights of up to 50 meters with trunk diameters of up to 180 centimeters. More than half of the upright trunk of the fully grown tree is knotless; the treetop is dense. The bark of the trunk is orange-brown to brown or gray-brown; it is very smooth or at most slightly flaky. The inner bark is colored from red and pink to brown. The secretion of the bark is transparent to slightly milky.

Main branches and side branches are different. The leaves on the main shoots are spiraling, while the leaves on the side branches are more or less opposite. The leaves are entire; the petiole is 3 to 10 millimeters long. The linear to elliptical leaves are dark green, 5 to 13 inches long and 1 to 4 inches wide; they are thick and rigid and have fine longitudinal, more or less parallel leaf veins . The leaves on young trees are oblong-lanceolate, glossy green on top, 6 to 7 inches long and 1 to 2 inches wide.

The seedling has 2 sessile almost seated cotyledons ( cotyledons ) which are elongated to egg-shaped; they are 3 to 4 inches long and 1 to 1.5 inches wide with fine, more or less parallel leaf veins .

Agathis robusta is single sexed ( monoecious ). The male cones are short-stalked to sessile. They are cylindrical, 4 to 8.5 (rarely up to 10) centimeters long and 0.7 to 0.9 centimeters wide and contain 600 to 1300 microsporophylls, each of which has 2 to 8 pollen sacs on the underside. The female cones are spherical to cylindrical and about the size of a tennis ball; they are 9 to 15 inches long and 8 to 10.5 inches wide. They have 340 to 440 cone scales; the centrally located scales measure 3.4 to 4.1 by 3.9 to 4.6 centimeters. The seeds are almost heart-shaped and winged. The ripening period is from July to September.

The wood of Agathis robusta is white to pale brown and is relatively similar to that of the species Agathis microstachya . The density of the wood is 435 to 480 kg per m³.

Similar species
  • The leaves of the New Zealand Kauri tree ( Agathis australis ) are only about half the size.
  • The smooth bark and the large male and female cones are helpful in distinguishing them from other species of the genus Agathis .

Distribution and location

The home of this species is in the coastal areas of the Australian Queensland as well as in the eastern Papua New Guinea .

The distribution area in Queensland consists of two disjoint sub-areas:

One area is in South Queensland between Tewantin and Maryborough and on Fraser Island . This area has a humid, subtropical climate; in January the average temperature is 30 to 32 ° C, in July 6 to 8 ° C. The species is mainly associated with Flindersia schottiana , Pseudoweinmannia lachnocarpa , Brachychiton acerifolius , Backhousia myrtifolia , Flindersia bennettiana and Rhodamnia trinervia .

The other area in North Queensland is between the Herbert River and the Big Tableland near Cooktown. Here the climate is humid and tropical; the mean temperature in January is 30 to 32 ° C, in July 13 to 19 ° C. The species is particularly associated with Flindersia ifflaiana , Flindersia bourjotiana , Argyrodendron trifoliolatum , Musgravea heterophylla , Pseudoweinmannia lachnocarpa , Brachychiton acerifolius , Backhousia hughesii , Eucalyptus torelliana , light walnut tree ( Aleurites costana ) and Rhodamana costana .

The annual rainfall at the Australian locations is about 1100 to 3500 mm.

Systematics

The botanist Charles Moore described this species in 1860 under the name Dammara robusta ; its description was given in a work by Ferdinand Jacob Heinrich von Mueller : Quart. J. Trans. Pharm. Soc. Victoria , 2, p. 173 published. The botanist Frederick Manson Bailey presented the species in Syn. Queensl in 1883. fl. , p. 498 under the currently valid taxon Agathis robusta into the genus Agathis .

The population in Papua New Guinea has been partially described as the variety Agathis robusta var. Nesophila ; sometimes it is also regarded as a separate species Agathis spathulata .

use

The wood is used for forestry with a rotation period of 50 to 60 years. The core is straw-colored to reddish brown, the sapwood is lighter. The wood is used for furniture, musical instruments, drawing implements and butter dishes as well as in boat interiors, as plywood and in paper production.

Special specimens

From reports, specimens on Fraser Island with a trunk diameter of 255 centimeters (chest height) are known, but they have long been felled. The northern Australian population was also decimated by massive felling actions; In 2002 a specimen with a trunk diameter of 137 centimeters and a height of 43 meters was measured at the Skyrail mountain station on Red Peak above Cairns .

In the meantime, some of the specimens planted as ornamental trees are already as large as the surviving specimens from the natural sites. In Yatton Park, Tauranga , New Zealand, a trunk 191 centimeters in diameter and 32 meters in height was measured on a specimen.

swell

Individual evidence

  1. ↑ Dammara robusta in the Germplasm Resources Information Network (GRIN), USDA , ARS , National Genetic Resources Program. National Germplasm Resources Laboratory, Beltsville, Maryland.
  2. ↑ Agathis robusta in the Germplasm Resources Information Network (GRIN), USDA , ARS , National Genetic Resources Program. National Germplasm Resources Laboratory, Beltsville, Maryland.

Web links

Commons : Agathis robusta  - album with pictures, videos and audio files