Red Iron Bark - Eucalyptus tricarpa
Origin of the species name
Eucalyptus from Latin meaning well-covered and describes the cap on the flower bud; tricarpa from Greek meaning three fruit.
Family
Myrtaceae
Date planted
June 2010 and later.
Lifespan
Trees of this species can live over 35 years.
General description
This is a medium sized to tall evergreen tree which usually has a single trunk. It has deeply fissured bark that is red-brown to brown-black and very hard. The leaves are a dull green and thick. The flowers hang in clusters of three and can vary from white through pink to red. Height 25m Spread 20m.
Natural distribution and habitat
The species is native to south eastern New South Wales and Victoria, Australia. It grows mainly in the open forests on the hilly and undulating terrain of the foothills of the Great Dividing Range.
Conservation status
It is not classified as a threatened species.
Planting pattern
Forests 98 and 99 are planted in a regular square grid with plantings on the far eastern and western ends turned on an angle. Both C. maculata and E. tricarpa are present in both forests. Forest 101 is not currently involved in the research project.
Uses
It produces a dense, durable wood that has been used for a range of heavy duty applications such as bridges, buildings and railway sleepers. It was also used by Aboriginals to make weapons and tools. The flowers are used for honey production. The trees at the Arboretum are being used for research by the Australian National University.
Further reading
Boland DJ, MIH Brooker, GM Chippendale, N Hall, BPM Hyland, RD Johnston, DA Kleinig, MW McDonald and JD Turner (2006) Forest Trees of Australia (5th Edition) CSIRO Publishing.
About the ANU Research Project
A major reason for the inclusion of Eucalyptus tricarpa at the Arboretum is because it is one of the eucalypts that have evolved adaptations for survival in a relatively dry climate. It is classified as a 'drought tolerator' because it is able to rely on good stomatal control to prevent loss of water from the leaves when ground water is limited. Once the stomata are closed, transpiration ceases and the trees essentially stop growing. Consequently they may not be fast growing.
Forests 98 and 99 are designed so that E. tricarpa can be treated with variable amounts of water. Automated sensors will measure how these trees respond to different water levels, particularly the way parts of the tree start or stop growth at different watering thresholds. Ground sensors will monitor the soil water and temperature in other parts of the environment to allow comparisons with the alternative eucalypt adaptations to drought like those adopted by Corymbia maculata (see below). This information will help scientists and natural resource managers to understand how these trees will respond to variation in climate and may also help to identify individual trees or genes that will be more robust and more able to survive climate extremes.
Spotted Gum - Corymbia maculata
Other common names
Spotted iron gum.
Origin of the species name
Corymbia a Latin word derived from Greek meaning a cluster of flowers, where all flowers branch from the stem at different levels but ultimately terminate at about the same level; maculata from a Latin word meaningspotted, referring to the appearance of the trunk.
Family
Myrtaceae
Date planted
May 2010
Lifespan
Trees of this species can live over 100 years.
General description
This is a medium sized to tall evergreen tree. It has a distinctive single cream trunk which is blotched with patches of old bark. The mature leaves are up to 20 cm long and are a dark shiny green with distinctive parallel side-veins. The small white flowers are fragrant and are followed by brown, and distinctively barrel-shaped fruits. Previously known as Eucalyptus maculata. Height 25m Spread 20m.
Natural distribution and habitat
The species is native from south-eastern Queensland, through to south-eastern New South Wales and eastern Victoria where it grows mostly on valley slopes along coastal areas, in open forest and often in fairly pure stands. It grows on a range of soils and commonly sandstone sites.
Conservation status
It is not classified as a threatened species.
Planting pattern
Forests 98 and 99 are planted in a regular square grid with plantings on the far eastern and western ends turned on an angle. Both C. maculata and E. tricarpa are present in both forests. Forest 101 is not currently involved in the research project.
Uses
It has very strong timber which has been exploited commercially for a range of construction uses. It is also used for boat building and is well known for its use as tool handles. The trees are used for honey production. The trees at the Arboretum were planted as part of a research project by the Australian National University into forest growth.
Further reading
Boland DJ, MIH Brooker, GM Chippendale, N Hall, BPM Hyland, RD Johnston, DA Kleinig, MW McDonald and JD Turner (2006) Forest Trees of Australia (5th Edition) CSIRO Publishing.
About the ANU research project
A major reason for the inclusion of Corymbia maculata at the Arboretum is because it is one of the eucalypts that have evolved adaptations for survival in a relatively dry climate. It is classified as a 'drought avoider' because the species essentially relies on an extensive and efficient root system to harvest any available water from considerable depth and distance from the tree. The tree can therefore continue to actively transpire and grow, even when rain has not fallen for long periods. However, the species does have relatively poor stomatal control, so it loses water through its leaves when rainfall becomes too limited for its extensive root system.
Forests 98 and 99 are designed so that blocks of C. maculata can be treated with variable amounts of water. Automated sensors will measure how these trees respond to these different water levels, both in the way parts of the tree grow or change, but also how they respond to natural variations in soil water and temperature or other parts of the environment around them. This information will help scientists and natural resource managers to understand how these trees will respond to variation in climate and may also help to identify individual trees or genes that will be more robust and more able to survive climate extremes.