| Eusideroxylon | |
|---|---|
| Young tree of Eusideroxylon zwageri | |
| Scientific classification | |
| Kingdom: | Plantae |
| (unranked): | Angiosperms |
| (unranked): | Magnoliids |
| Order: | Laurales |
| Family: | Lauraceae |
| Genus: | Eusideroxylon Teijsm. & Binn. |
| Species | |
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9, including:
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Eusideroxylon is a genus of evergreen trees belonging to the Laurel family. The genus includes nine species of plant in the family Lauraceae. The genus is present in coastal rainforest and montane rainforest of Southeast Asia They are evergreen hardwood trees, reaching up to 40 meters in height. The wood is very prized.
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The natural habitat is forest which are cloud-covered for much of the year. Trees of large size of the lowland tropical forests, Attaignant 50 meters high and 220 centimeters in diameter of trunk. The genus is found in areas with high humidity and stable and mild temperatures, in a climate regime with well defined seasons, but lacking in sharp contrast. Also in laurel forest habitat.
Eusideroxylon zwageri, the species most named by its commercially valuable timber, is also known by the common names Borneo Ironwood and Belian. This hardwood trees grows up to 100 feet tall. Eusideroxylon zwageri is a renowned wood of the Borneo rain forests. The wood is impervious to termites, and the cut wood can last up to 100 years. Borneo Ironwood has been extensively harvested and, in some areas, destroyed. Conservation efforts are underway, with several countries banning imports of wood of those valuable trees. Widely exploited for its timber, A tree is 90 to 110 m3 of wood, species of Eusideroxylon genus are threatened with extinction because of overcut and deforestation. Listed as vulnerable in the IUCN Red List of IUCN. The heartwood is basically brown to yellow, without streaks. Prohibition on export restrictions in Indonesia and Sarawak for its preservation.
The latin name of the genus means "new iron tree". They are canopy tree species with extremely durable and decay-resistant wood distributed in tropical rain forests of South-East Asia: Borneo, Java, Malaysia, Sumatra, Philippines, In lowland tropical forest (Senami forest), Jambi, Indonesia. It is native to the Malesia floristic region.
The color of the flowers is pale yellow to yellow. The flower is hermaphrodite, actinomorfic. Present Inflorescences composed of hermaphroditic flowers, with perigonium. With 6 tepals, distribuited in two whorls at first and second whorl,imbricate.The pedunculus of the flower is colored from dark reddish brown to dark yellow brown. This genus is monoecious. The pollination is done by bees and other insects. They have berries named drupes.
The seed is a drupe varied in size and shape from oblong to ovate or sub-cylindrical to sausage shape or date shape. It could be asymmetric elongated or rounded. 8-13 cm long, diameter 4-5 cm weights 90-170 grs. Seed dispersal by vertebrate animals. The fruits are a very important food source for birds and other wildlife, like reptils, rodents, muntjacs, monkeys and bats.
They are leafy canopy tree with erect or spreading branches. The tree produce sprouts. The thick, leathery leaves are dark green, lauroide type. Odour indistinct or absent. mature leaves are dark green 26-29 cm long, 10-11 cm width. Young leaves reddish brown to yellowish red. Laurophyll or lauroide leaves are characterized by a generous layer of wax, making them glossy in appearance, and narrow, pointed oval in shape with an apical mucro, or 'drip tip', which permit the leaves to shed water despite the humidity, allowing perspiration and respiration from plant. Plants of the laurel forests must adapt to high rainfall and humidity. The trees adapted by developing leaves that repel water.
It was dated the life span and growth rate of Borneo ironwood (Eusideroxylon zwageri). Timber segments collected from 15 logged stumps in Kubah National Park, Sarawak, Malaysia, and found that Eusideroxylon zwageri can live more than 1000 years[1] y and that the growth rate of this species is very slow, with a mean radial growth rate of 0ยท058 cm y-1. The life span is much greater and the growth rate is much slower than those observed or estimated for trees of Dipterocarpaceae, the dominant family in this tropical forest. Eusideroxylon are trees of mature laurel forests, they are trees of slow growing and very long-lived, having a dense tree canopy, and low light levels at the forest floor. When the tree grows with its shadow is eliminating its competitors, needing a long time to establish itself as the dominant tree. The cutting of old trees causes that the species are replaced by other faster growing difficulting its regeneration in the habitat. The long life span of this species may be caused by wood durability with a high specific gravity and abundant defensive compounds. Given equal carbon allocation, the high density and carbon-based defensive compounds may result in a reduced growth rate.