Aluminium and Acacia plant growth on coal mine dumps

Colonising native and introduced plant species present on old abandoned dumps in the Collie coal field in south-west Western Australia provide a potential resource for rehabilitation. Coal waste dumps are more acidic than the surrounding forest soils, indicating a potentially toxic presence of aluminium. Some plants exhibit tolerance, and may accumulate, avoid or exclude aluminium. Excluders restrict translocation of the metal bound in root cells. Evolution of tolerance to metal stress may be comparatively rapid and although aluminium has many adverse affects on growth, plants tolerant of its presence also tend to be drought tolerant, an advantage for survival on dumps over dry summers. Progeny of a dump population of Acacia decurrens are contrasted with a non-dump population. Seedlings were subjected to varied concentrations of aluminium in solution and harvested at 10 weeks. A. decurrens tolerated low levels of applied aluminium but severe effects on growth were observed at 500 ppm. Plants of dump origin failed to produce greater plant biomass than non-dump plants. However, dump origin plants took up less total aluminium than non-dump plants, indicating an avoidance mechanism. Dump progeny held more of the absorbed aluminium within roots, translocating lower quantities to foliage, suggesting an exclusion mechanism. Decreased tissue nitrogen, phosphorus and calcium coincided with increased aluminium supplied. Calcium decline was the most severe. Trace element and manganese concentrations increased with added aluminium. Despite an inability to out-perform non-dump progeny, the pattern of nutrient uptake indicates a real difference between the two accessions. In the long run survivors are likely to persist and reproduce if they have successfully avoided uptake of deleterious elements beyond the root systems. It is therefore recommended that collection of seed for use on coal-mine rehabilitation sites should be made from established plants growing on dumps

Changes to tuart woodland in Yalgorup National Park over four decades

The condition of the tuart tree (Eucalyptus gomphocephala), a coastal southwestern Australian woodland species, has declined dramatically within parts of its distribution over the last decade, particularly within Yalgorup National Park. Prior to the park being gazetted in 1968, some of the woodlands were used for cattle grazing. Frequent, light, understorey burns were carried out to encourage grass fodder growth. Earlier, Aboriginal use is believed to have involved a similar regime to facilitate hunting and access. Since gazettal, the majority of the park has either been excluded from fire, or burnt infrequently by wildfire and prescribed fire. Consequently, from 1968 to the present, most fires are thought to have been more intense due to increased fuel loads. Alterations in disturbance patterns (particularly fire) elsewhere, have been linked with vegetation changes (composition and structure) and in some instances, declining tree health. For tuart woodland, it has been proposed that increased abundance and vigour of the lower storey peppermint tree (Agonis flexuosa) and a decline in the health of tuart trees are consequences of reduced fire frequency. Sample plot data from the mid – late 1970s and photographs from 1957 are contrasted with the 2003/2004 situation to describe changes in tuart woodland. Declining tuart health, changes in the health and abundance of some understorey species (for example, fewer Banksia attenuata) and a shift towards peppermint dominance are revealed. The contribution of changing fire regimes to these trends is explored. While a link between fire and changes to the woodland may be established, factors underlying the loss of tuart dominance remain to be determined. An integrated research project is in progress to examine the range of decline factors

Pengaruh variasi ukuran biji terhadap perkecambahan Acacia fauntleroyi (maiden) maiden and blakely

The aim of this study was to investigate to what extent are germination of A. fauntleroyi affected by seed size. Does pre-treatment improve germination? Under what temperature regime does most seed germinate? Three seed size classes (small, medium and large)were chosen. Seeds were pre-treatments either at ambient, 50 °C, 75 °C or 100 ° C and incubated at 15 ° C or 30 °C. Then, number of seed that germinate and speed of germination were measure. Five seeds representing each of small, medium and large seed sizes were also selected and the seed coat thickness measured. Seed size, pre-treatment temperature and incubation temperature all affected the number of seed that germinated. Pre-treatment temperature affected germination more than incubation temperature. Incubation temperature affected germination more than seed size. The interaction of seed size and pre-treatment temperature was stronger than that between seed size and incubation temperature. Small seeds produce less germination than medium or large seeds, however small seed germinated sooner. Seed coat thickness varied among seed sizes. Thinner seed coats occur in smaller than larger seeds. Acacia; Germination; Incubation; Pre-treatment; Seed siz

Sandalwood seed nursery and plantation technology

Le CIRAD-Forêt et l'ACIAR ont organisé cet atelier afin de valoriser les travaux réalisés sur toute la filière de production du Santa

Tree performance and Root-zone salt accumulation in three dryland Australian plantations

Doubts exist about the effectiveness of establishing trees near saline discharge areas on farmland to manage dryland salinity. These centre on low rates of water uptake from saline water tables, salt accumulation in tree root zones and the consequent poor growth and survival of trees. Despite this, trees still survive in many plantations established adjacent to saline discharge areas and land-holders often favour such locations, as they do not compete for arable land such as that occurs with plantings in recharge areas. Tree performance and salt accumulation were assessed in three experimental plantations established adjacent to saline discharge areas 20 1325 years ago. These were all in the 400 13600 mm rainfall zone of south-western Australia. Mean soil salinity, within 1 m of the surface, ranged from 220 to 630 mS m"121, while permanent ground-waters occurred within 2 135 m of the surface and had electrical conductivities ranging from 175 to 4150 mS m"121. The study confirmed the low growth rates expected for trees established over shallow, saline water tables in a relatively low rainfall environment, with estimated wood volumes in Eucalyptus cladocalyx, E. spathulata, E. sargentii, E. occidentalis and E. wandoo of between 0.5 and 1.5 m3 ha"121 yr"121. Values of up to 3 m3 ha"121 yr"121 were obtained on soils with low salinity (70%) of several Eucalyptus species confirms that discharge plantations species can persist, despite increasing soil salinity. However, the long-term sustainability of such plantings (50 13100 years) without broader landscape treatment of the present hydrological imbalance must be questioned

Sandalwood seeds for oleochemical industry: Sustainability in Sandalwood agroforestry

Western Australian Sandalwood (S. spicatum R.Br.) is a hemi-parasitic arid tree which depends upon a host tree throughout its life. Large scale plantations have been established to cater for the future global demand as a valuable timber crop. Sandalwood takes several years to yield quality timber. Seeds are considered as a secondary income from plantations situated in the semi-arid areas of Western Australia. Seeds are large and contain a hard shell. Kernel is rich in oil which consists of a rare fatty acid, namely Ximenynic acid. Use of this seed oil in oleochemical industry has been envisaged. Current studies will report on the effect of geographical source, seed size, storage time and host trees on sandalwood seed oil