Search

The present study aimed to investigate the allelopathic effects of leaf aqueous extracts of introduced Eucalyptus gomphocephala L. (donor species) were collected during different growing seasons at different concentrations (0, 25, 50, 75, and 100% v/v) on germination percentage, average germination time, plumule and radical length, dry weight of radical and plumule and seedling vigor index (SVI) of native Ceratonia siliqua L. (recipient species) seedlings under laboratory conditions. Results suggested that the germination percentage and all growth parameters of C. siliqua were significantly reduced gradually with the increase of aqueous extract concentration levels and the reduction was varied and could be extract concentration and growing season dependent. The highest phytotoxic effect on germination and seedling growth was exhibited by E. gomphocephala aqueous extract at 100% concentration, followed by 50% concentration. Generally, it is concluded that the allelopathic effect of introduced E. gomphoracephala trees on native Ceratonia siliqua trees has been weak or no effectiveness in some cases under laboratory conditions. Keywords: Eucalyptus gomphocephala; Introduced species; Libya; Allelopathy; Ceratonia siliqua

The objective of this study was to investigate the species identification, chemical composition and the antimicrobial activity of tuart (Eucalyptus gomphocephala DC) fruits and leaves. The essentia...

The objective of this study determination total storage of carbon content weight for three tree species namely Eucalyptus gomphocephala, Casuarina equisetifolia and Casuarina glauca during 2019. On this concerning carbon content decreased in available merchantable portions which decreased carbon content as environment balance region and economic value. E. gomphocephala and C. equisetifolia have recorded total tree biomass values (378.49 and 327.95 kg/tree) respectively which were significantly higher when compared to C. glauca (148.95 kg/tree). On the other hand evaluating total weight of carbon content on merchantable fewer portions had stayed on the same area. E. gomphocephala and C. equisetifolia had significantly enhanced carbon content weight values on merchantable fewer portions (146.45 and 138.34 kg/tree) respectively compared to C. glauca (32.99 kg/tree) more fourfold increment approximately. The investigated study was carried out at the Experimental Farm of El-Kassasin Horticulture Research station, Horticulture Research Institute, Agriculture Research Center, Giza, Egypt.

We used molecular profiling with 454 pyrosequencing to identify ectomycorrhizal, arbuscular mycorrhizal fungi, and other fungal communities associated with containerized Eucalyptus gomphocephala seedling roots. We found a higher proportion of ectomycorrizal fungi associated with seedling roots grown in soil collected from sites with healthy trees, and of arbuscular mycorrhizal fungi from seedling roots grown in soil collected from sites with declining trees. We also found a relatively high proportion of pathogenic fungi present in roots from declining sites compared to healthy sites. This research should be extended to the field to further investigate mycorrhizal and pathogenic fungal populations associated with tree declines.

To study the impact of soil pollution on plant growth, our work focused on soil polluted by heavy metals. This soil was taken from the municipal landfill of Jendouba (North of Tunisia). We have undertaken to study the morphological behavior of a forest specie “Eucalyptus gomphocephala”. Two treatments are chosen (substrate containing 100% and 50% of soil taken from municipal solid waste of Jendouba) compared to a control (pilot soil). Morphological Parameters (stem height, root length, leaf area, the ratio of the stem/root and biomass) was measured. The plants grown on substrates based on an S1 (100% soil taken from municipal waste) and S2 (50%), exhibit morphological appreciable contribution to the control soil.

Four experiments were established on the semi-arid west coast plain of South Africa during the 1990s. The trails tested the survival and growth of several eucalypt species and hybrids, some of which were established in a climate that is drier than their natural distribution range. The aridity indices (AI; defined as mean annual precipitation [MAP]/mean annual potential evapotranspiration) ranged from 0.21 to 0.36 and MAP from 228 to 423 mm. The driest trial site (AI = 0.21 and MAP = 228) had high levels of mortality. However, a number of species (in particular, Eucalyptus gomphocephala, E. camaldulensis and E. tereticornis, as well as individual hybrids of the latter two species with E. grandis) survived and grew well at the remaining sites. Eucalyptus cladocalyx survived well and attained competitive growth rates only on the wettest site in the group (AI = 0.36). The dominant height of the top-performing genotypes at age 5 ranged between 9 and 10 m on the two wetter sites. This corresponded to mean annual increment values in excess of 10 m3 ha−1 a−1, which is comparable to volume obtained at more favourable aridity indices in the summer rainfall zone of South Africa and exceeds the growth rates obtained in several other arid zone studies globally. The E. grandis × E. camaldulensis hybrid ranked among the top performers in two trials,but its susceptibility to recently introduced pests and relatively poor wood quality makes it a less attractive choice for planting. The high density and durability of timber, acceptable growth rate (given the low rainfall conditions), and low pest and disease incidence make E. gomphocephala and E. cladocalyx the species of choice for planting in the drier and relatively wetter sections of the semi-arid zone, respectively.Keywords: agroforestry, dryland forestry, Eucalyptus, Western Cape coastal plain

As growing economies – in particular in the Gulf region – use extreme and growing amounts of desalinated seawater for municipal purposes the use of produced waste waters is in the focus of science. The fixation of atmospheric carbon-dioxide by a safe cultivation of trees using this slightly salty water sources is of increased importance in times of ongoing climate change. Unfortunately, existing research relies on irrigation of trees in arid lands using ground water, any kind of precipitation, seasonal events like river flooding or a mix of them. To date no data support the biomass or tree production in total absence of natural precipitation and complete lack of ground water. In this study, seven timber and fuelwood tree species, namely, Eucalyptus occidentalis En., Eucalyptus tereticornis Smith, Eucalyptus camaldulensis Dehnh., Eucalyptus gomphocephala DC., Eucalyptus grandis Hybr. Hill ex Maid, Tamarix aphylla (L.) Karst., Tamarix nilotica (Ehrenb.) Bunge were tested for carbon sequestration and biomass-production. Above-soil and sub-soil parts were determined under two levels of drip-irrigation water supply: 25% and 50% of Evapotranspiration (ETo) over a period of two years and four months from planting to harvest. The trees were cultivated under hyper-arid climatic conditions using brackish irrigation water (3.5 dS m-1) on a research and development station in Arava, Israel. Purified waste water from a seawater desalination plant (reverse osmosis) was applied after municipal use. Eucalyptus gomphocephala DC. delivered the highest yields and had the highest water use efficiency, producing 70 t of Dry Matter (DM) /ha/a under the higher irrigation level. Compared with the other species, E. gomphocephala DC. showed a 32% to 65% superior performance . Whereas, lower amounts of saline irrigation water were favoured by E. camaldulensis and T. aphylla – both producing more than 50 t of DM/ha/a. Nevertheless, Tamarix, as a halophyte specialist plant, needed 30 % less water for this growth. Both Eucalyptus varieties mentioned before form a closed tree stand and reached a height of almost 10 m, two years after planting. Regardless of the particular use of the produced timber, about 15 – 25% of the trees’ total DM, approximately equal to the carbon-content, remains in the soil as long-term carbon-storage after harvesting the above ground biomass. Fast growing fuelwood tree species ensure a safe long-term biological fixation of carbon Irrigated with small amounts of saline waste water.

Southern Africa, and specifically its western parts is dominated by low rainfall areas, and it is expected that the rainfall in most of these parts will in future decrease further due to climate change. Woodlots of fast-growing, non-invasive tree species can provide the opportunity to produce wood and release the pressure on natural woodlands, while creating much needed income to inhabitants. Over the last two decades several trials of Eucalyptus species that could potentially withstand arid conditions were established on the South African west coast. The three most promising genotypes according to their volume growth were selected among 46 pure and hybrid species from two 20-year-old trials for further evaluation. These included 10 Eucalyptus grandis × Eucalyptus camaldulensis hybrid trees, 9 Eucalyptus gomphocephala trees, and 9 Eucalyptus cladocalyx trees for a total of 28 trees. The objective of the study reported here was to investigate the within-tree and between species variability of selected physical and processing properties determining the suitability of these three species for lumber production. The density, microfibril angle, spiral grain angle, MOE, MOR, radial and tangential shrinkage, twist, bow, splitting, and collapse were measured in a radial and longitudinal gradient. Valuable insights were gained which could provide decision support for planting, processing and further research on these species when grown in arid conditions. The E. grandis × camaldulensis hybrid was inferior in terms of most relevant properties to the other two species evaluated. The main shortcoming of both E. gomphocephala and E. cladocalyx was the high levels of twist in lumber.

Forest canopy loss due to plant pathogens, insect or abiotic factors significantly alters habitat and resource availability for animals, which has flow-on effects for whole ecosystems. The tuart (Eucalyptus gomphocephala) has been in decline throughout its geographic range; this is likely associated with watertable and salinity changes, although a plant pathogen (Phytophthora multivora) has also been implicated. We examined the relative abundance of common brushtail possums (Trichosurus vulpecula) across 12 sites (each 0.72 ha) selected on the basis of the health of dominant tuart trees (six ‘healthy’ and six ‘declining’ sites). Habitat variables (understorey, tuart dimensions and density, tree hollows, tree-to-trap distance) and tuart tree health (crown loss, epicormic regrowth) were compared with possum abundance. Possums were detected at most sites. There was no significant difference between brushtail possum numbers at ‘healthy’ or ‘declining’ sites, although marginally more possums were recorded at declining sites (5.7 ± 1.5 (s.e.), n = 6 sites) compared with healthy sites (3.3 ± 0.7; Cohen’s effect size d = 0.80). Slightly higher abundance of possums was associated with sites that had a greater density of smaller-diameter but taller tuart trees. ‘Declining’ sites, with more epicormic regrowth and greater tree densities, may provide more palatable food resources for possums.

[EN] The aim of this work was to determine the microwave drying kinetics of Eucalyptus Gomphocephala wood and to investigate the influence of intermittent and continuous heating processes on the end quality of dreid samples. The average moisture content evolution and temperature of wood samples under different microwave powers were analyzed in terms of drying time and internal temperature level. Results show that the increase of microwave power level decreses the drying time and increases the internal wood temperature. Based on qualitative observations on the state of dried samples, the intermittent microwave powers intensity process present the optimal processing parameter in microwave drying of Eucalyptus wood species., Our thanks go to Abderrazak Zaaraoui from the LETTM, Sara Ghariani from INRGREF and for both of Sameh Hannachi and alaeddine garali from CETIBA for their technical assistance and help in carrying out the experiments.

Natural regeneration is a critical component of forest ecosystems sustainability. Local extinction can occur without adequate regenerationor seedling recruitment prior to adult senescence. The urban and peri-urban environment is particularly challenging for recruitment. For example, although many forest species have specific requirements involving fire events, few opportunities associated with fire exist in contemporary urban and peri-urban environments. For our study species, Eucalyptus gomphocephala, en masse recruitment can occur in ashbeds following a hot fire. However, this may not occur following low-intensity, fuel reduction burns that are prescribed for many E. gomphocephala woodlands and forests. Nevertheless, ashbeds could be created by constructing and burning coarse woody debris (CWD) piles. In a series of collaborative case studies involving community groups, NGOs and Local and State Government agencies, we investigated whether seedling recruitment could be facilitated through broadcast seeding after: a) creating CWD piles prior to a low intensity, prescribed burn; b) naturally-occurring ashbeds following a hot summer wildfire; and c) creating CWD piles and then burning the piles only. We found that regeneration of this post-fire, canopy gap regenerator can be facilitated by broadcast seeding naturally occurring or created ashbeds. However, it seems that protection from seed harvesters and herbivores is vital. These case studies provide tools that can be used to preserve the natural demographics in populations with specific regeneration requirements in a range of environments by leveraging natural recruitment processes and community involvement. Importantly, it is the conservation of these urban and peri-urban ecosystems that will be vital in maintaining connection between people and the environment into the future.

Understanding the environmental parameters that drive adaptation among populations is important in predicting how species may respond to global climatic changes and how gene pools might be managed to conserve adaptive genetic diversity. Here, we used Bayesian FST outlier tests and allele-climate association analyses to reveal two Eucalyptus EST-SSR loci as strong candidates for diversifying selection in natural populations of a southwestern Australian forest tree, Eucalyptus gomphocephala (Myrtaceae). The Eucalyptus homolog of a CONSTANS-like gene was an FST outlier, and allelic variation showed significant latitudinal clinal associations with annual and winter solar radiation, potential evaporation, summer precipitation and aridity. A second FST outlier locus, homologous to quinone oxidoreductase, was significantly associated with measures of temperature range, high summer temperature and summer solar radiation, with important implications for predicting the effect of temperature on natural populations in the context of climate change. We complemented these data with investigations into neutral population genetic structure and diversity throughout the species range. This study provides an investigation into selection signatures at gene-homologous EST-SSRs in natural Eucalyptus populations, and contributes to our understanding of the relationship between climate and adaptive genetic variation, informing the conservation of both putatively neutral and adaptive components of genetic diversity.

Tree declines are increasingly being reported around the world. Since the 1990’s Eucalyptus gomphocephala (tuart) has suffered a significant decline in the Yalgorup region, approximately 100 km south of Perth Western Australia. The complexity of many tree declines makes diagnosis difficult. Robust tools are needed to help identify factors contributing to tree declines. Two experiments tested the effect of trunk applied phosphite, nutrients and combined phosphite and nutrient treatments on wild declining E. gomphocephala. Treatment efficacy was tested as a management option to mitigate crown decline and as an explorative tool to help determine disease causality. Experiment 1 assessed the efficacy of combined treatments of trunk injections of different phosphite concentrations, trunk nutrient implants of different compositions and combined phosphite and nutrient treatments. Experiment 2 assessed the efficacy of different phosphite concentrations. In Experiment 1, phosphite, together with nutrient treatments, increased the average crown condition by 21 %, as measured using a crown health score (CHS) averaged over 4 years, with the greatest improvements evident 6 months after application. Injection of 25 g phosphite/L combined with 0.3 g zinc sulphide gave the greatest increase. In Experiment 2, application of 75 to 375 g phosphite/L increased the CHS compared to the control treatment, with the greatest improvements in trees injected with 150 g phosphite/L. Foliar analysis for Experiment 2 confirmed a significant uptake of phosphite for all phosphite treatments. The increase in the CHS and significant flushes in new growth resulting from phosphite and nutrient treatments highlight the possible involvement of Phytophthora species in the decline, as Phytophthora species are known to be controlled by phosphite application. Further work on combined phosphite and nutrient applications, with a particular emphasis on zinc, is required to help understand and potentially mitigate the E. gomphocephala decline.

The health of Eucalyptus gomphocephala is declining within its natural range in south-western Australia. In a pilot study to assess whether changes in mycorrhizal fungi and soil chemistry might be associated with E. gomphocephala decline, we set up a containerized bioassay experiment with E. gomphocephala as the trap plant using intact soil cores collected from 12 sites with E. gomphocephala canopy condition ranging from healthy to declining. Adjacent soil samples were collected for chemical analysis. The type of mycorrhiza (arbuscular or ectomycorrhizal) formed in containerized seedlings predicted the canopy condition of E. gomphocephala at the sites where the cores were taken. Ectomycorrhizal fungi colonization was higher in seedling roots in soil taken from sites with healthy canopies, whereas colonization by arbuscular mycorrhizal fungi dominated in roots in soil taken from sites with declining canopies. Furthermore, several soil chemical properties predicted canopy condition and the type of mycorrhizal fungi colonizing roots. These preliminary findings suggest that large-scale studies should be undertaken in the field to quantify those ectomycorrhiza (ECM) fungi sensitive to E. gomphocephala canopy decline and whether particular ECM fungi are bioindicators of ecosystem health.

Quantifying dieback in forests is useful for land managers and decision makers seeking to explain spatial disturbances and understand the cyclic nature of forest health. Crown condition is assessed as reference to dieback in terms of the density, transparency, extent and in-crown distribution of foliage. At 20 sites in the Yalgorup National Park, Western Australia, a total of 80 Eucalyptus gomphocephala crowns were assessed both in situ (2008) and using two acquisitions (2008 and 2010) of airborne imagery. Each tree was assessed using four crown-condition indices: Crown Density, Foliage Transparency, the Crown Dieback Ratio and Epicormic Index combined into a single index called the Total Crown Health Index (TCHI). The airborne imagery is like value calibrated then classified and modelled using in situ canopy condition assessments resulting in a quantification of crown-condition change over time. Comparison of Normalized Difference Vegetation Index (NDVI), Soil-Adjusted Vegetation Index (SAVI) and a novel...

An HPLC–PDA–ESI/MS/MS method was developed to identify the phytoconstituents of the EtOAc fraction of Eucalyptus gomphocephala DC. The antioxidant effect of the EtOAc fraction together with its sub-fractions was determined in vitro . The cytotoxicity was evaluated on different cell lines. The EtOAc fraction exhibited strong antioxidant activity, reduced the viability of all cell lines and was more active on MCF-7 and HepG-2 cell lines. Subsequently, the cytotoxicity of the sub-fractions and the isolated compounds were tested on MCF-7, HepG-2. The EtOAc fraction possessed potential antitumour promoting properties. It inhibited the stimulated NO (20%), 5-LOX (48.0%) and COX-2 (49.7%) respectively (at concentration of 20 μg/ml). This study suggests that this fraction is a source of different antioxidant and cytotoxic compounds with potential chemopreventive properties that might prevent different stages of the carcinogenesis process.

The fine roots and ectomycorrhizae system of 18 declining Eucalyptus gomphocephala trees, in the Yalgorup region, approximately 100 km south of Perth, Western Australia, were exposed using an air spade and the relationships between the crown health and the fine root and ectomycorrhizal total density scores (TDS) were determined. Crown health was significantly correlated with the fine root and ectomycorrhizal TDS and trees with crown decline symptoms had significantly fewer fine roots and ectomycorrhizae than trees with healthy crowns. In addition, E. gomphocephala seedlings were grown in-situ within the exposed fine root mats adjacent to the 18 woodland trees and the relationships between seedling and tree health was assessed. Seedling survival, height and foliar health were significantly correlated with the crown health of the adjacent woodland trees. Seedling survival was also significantly correlated with the ectomycorrhizal TDS of the adjacent woodland trees. The relationships between reduced seedling health and reduced crown health and ectomycorrhizal density of the woodland trees indicates that decline symptoms may be associated with the absence of ectomycorrhizae. The study demonstrates new techniques for assessing the fine root and ectomycorrhizal densities of large woodland trees and their relationships to crown health.

th , 2012; revised July 10 th , 2012; accepted July 25 th , 2012 Ecosystems in Mediterranean climate regions are projected to undergo considerable changes as a result of shifting climate, including from extreme drought and heat events. A severe and sudden dieback event, occurring in regionally significant Eucalyptus gomphocephala woodland in Western Australia, coincided with extreme drought and heat conditions in early 2011. Using a combination of remote sensing and fieldbased approaches, we characterized the extent and severity of canopy dieback following the event, as well as highlighted potential predisposing site factors. An estimated 500 ha of woodland was severely affected between February and March 2011. Tree foliage rapidly discolored and died over this period. In the affected portion of the woodland, approximately 90% of trees greater than 20 cm DBH were impacted, while in the adjacent unaffected woodland 6% showed signs of damage. Tree density in the unaffected area had approximately 4.5 times more trees than the affected woodland. Precipitation drainage patterns are thought to explain the difference between affected and unaffected woodland. Dropping groundwater levels, a relatively shallow soil profile, and extreme drought and heat in 2010-2011 are thought to predispose water-shedding sites to drought-triggered canopy dieback during extended periods of dryness. Tracking forest health changes in response to severe disturbance is an important key to deciphering past and future vegetation change.

Phytophthora multivora is associated with the rhizosphere of declining Eucalyptus gomphocephala, Eucalyptus marginata and Agonis flexuosa. Two pathogenicity experiments were conducted. The first experiment examined the pathogenicity of five P. multivora isolates and one Phytophthora cinnamomi isolate on the root systems of E. gomphocephala and one P. multivora isolate on the root system of E. marginata. In the second experiment, the pathogenicity of P. multivora to E. gomphocephala and E. marginata saplings was measured using under-bark stem inoculation. In Experiment 1, the P. cinnamomi isolate was more aggressive than all P. multivora isolates causing significant loss of fine roots and plant death. Two P. multivora isolates and the P. cinnamomi isolate caused significant losses of E. gomphocephala fine roots 0–2 mm in diameter and significantly reduced the surface area of roots 0–1 mm in diameter. One P. multivora and the P. cinnamomi isolate significantly reduced the surface area of roots 1–2 mm in diameter. Two of the P. multivora isolates significantly reduced the number of E. gomphocephala root tips. In E. marginata, the length and surface area of roots 0–1 mm in diameter and number of root tips were significantly reduced by P. multivora infestation. Rhizosphere infestation with the P. multivora isolates and P. cinnamomi isolate on E. gomphocephala, and one P. multivora isolate on E. marginata, did not significantly influence the foliar nutrient concentrations. In Experiment 2, under-bark inoculation with P. multivora caused significant lesion extension in E. gomphocephala and E. marginata saplings, compared to the control. We propose that P. multivora is inciting E. gomphocephala and E. marginata decline by causing fine root loss and subsequently interfering with nutrient cycling throughout the plant. The impact of fine root loss on the physiology of plants in sites infested with P. multivora requires further research.

Inoculation with beneficial soil microorganisms has the potential to enhance success of restoration, particularly in harsh Mediterranean-type ecosystems (MTEs). We investigated the effects of microorganisms (mycorrhizal fungi and root nodule bacteria) and planting material (seed and nursery-raised seedlings) on early establishment and growth of two key postdisturbance colonizing species with different life histories, life forms and functional types (Eucalyptus gomphocephala and Acacia saligna) under field conditions. Establishment and growth were monitored at 13months, following the first MTE drought period. For E. gomphocephala, establishment was higher for seedlings (81%) than for seeding (7.5%). Inoculation with ectomycorrhizal fungal spores was not beneficial. For A. saligna, establishment was also higher for seedlings (84%) than for seeding (42.5%). Mycorrhizal fungal inoculum had no effect on establishment or growth. This study has shown that in harsh MTE conditions, the use of seedlings is more effective than seeding in degraded woodlands even when attempting to reintroduce key colonizing species. The microorganism treatments tested did not result in significant improvement in establishment or growth.

Fire regimes in temperate forests and woodlands have changed significantly in Australia since European settlement. We hypothesised that an absence of fire leads to the increased development of woody understorey/ midstorey and that this may be correlated with decreased water and/or nutrient availability in overstorey temperate eucalypts currently declining in health. Sites with a history of being long unburnt or recently (and frequently in the case of Eucalyptus gomphocephala woodland) burnt (relative to median fire intervals for the vegetation type) were established in E. gomphocephala woodland in Western Australia and in Eucalyptus delegatensis forest in Tasmania. In long unburnt sites in both E. gomphocephala woodland and E. delegatensis forest, there was greater percent cover of understorey/midstorey and eucalypts had higher water use efficiency, indicative of greater soil water limitation, as estimated by foliar carbon isotope ratios. In E. gomphocephala woodland foliar Cu and Zn were significantly lower in eucalypts of long unburnt, relative to frequently burnt, sites. In E. gomphocephala woodland, understorey/midstorey (shrub) cover was positively correlated, and foliar copper and zinc levels were negatively correlated to health of overstorey trees. In E. delegatensis forest foliar phosphorus (P) was significantly lower in eucalypts of long unburnt, relative to recently burnt, sites. In E. delegatensis forest moss cover was positively correlated and foliar P was negatively correlated to health of overstorey trees. The understorey/midstorey that develops in the long absence of fire may alter ecological processes that lead to less favourable water- and nutrientrelations in E. gomphocephala woodland and E. delegatensis forest that are associated with decline in crown health. However this study does not definitively show a link between understorey/midstorey vegetation and overstorey tree water- and nutrient-relations. This link will be investigated in future research.

The objective of this study was to investigate how the management practices of prescribed fire and understorey vegetation removal affect water and nutrient relations of old, yet prematurely declining Eucalyptus gomphocephala. Long unburnt sites were established in Yalgorup National Park, Western Australia, adjacent to frequently burnt state forest sites. Trees were allocated to vegetation clearing, prescribed fire or no prescribed fire treatments. Prescribed fire was achieved in only one long unburnt national park site so that the results were pseudoreplicated but analysed accordingly. Soil chemistry, plant nutrient availability and tree foliar carbon and nitrogen isotope ratio and nutrient concentration were investigated. No effects of vegetation clearing were found. Prescribed fire sites were associated with sky exposure and bare ground whereas no prescribed fire sites were associated with shrub and litter cover and litter depth. Foliar carbon isotope ratios were significantly more negative in prescribed fire, relative to no prescribed fire, treatments on long unburnt sites. Soil exchangeable Zn and Mn and plant available (estimated by charged resin beads) Mg were higher on prescribed fire, relative to no prescribed fire, long unburnt sites. Seedling bioassays indicated elevated P and Cu availability on prescribed fire, relative to no prescribed fire, treatments. In overstorey E. gomphocephala, foliar N levels were elevated (but not to excessive levels), and there was a trend toward elevated foliar Mn, in prescribed fire relative to no prescribed fire treatments on long unburnt sites. In the context of our large-scale pseudoreplicated case study, prescribed fire provided a pulse of water and N, (with some indications towards provision of elevated Mn, Cu and Mg) availability to E. gomphocephala in decline on sites with a history of a long absence of fire that may in part underpin observations of elevated tree health on sites that have a history of relatively frequent fire.

This study investigates whether tree decline in Eucalyptus gomphocephala (tuart) is associated with the functional diversity of soil bacterial communities. We selected 12 sites with different stages of decline and assessed crown health [Crown density (CD), Foliage transparency (FT), Uncompacted live crown ratio (ULCR), Crown dieback ratio (CDR) and Epicormic index (EI)] and soil bacterial functional diversity based on Biolog EcoPlates™ incubation [Average well colour development (AWCD), Shannon diversity (H'), richness (S) and Shannon evenness (E)]. Crown health indices differed between sites with EI being the most robust indicator of decline in crown health followed by CDR and CD (P

Management interventions are needed to reverse the decline of Tuart (Eucalyptus gomphocephala) woodland in the Yalgorup area of south-west Western Australia where the largest intact remaining example of this ecosystem is located. Although the cause of the decline is uncertain and several factors may be involved, management action should not be withheld because the decline process is not fully understood. We contend that the reduction in fire frequency over the last 50 years has led to an increase in understorey density, particularly of Western Australian Peppermint (Agonis flexuosa), resulting in greater competition for resources, which may in turn have increased the susceptibility of healthy woodland to decline. In contrast to Tuart regeneration, which is usually tied to fire, Western Australian Peppermint can establish readily in unburnt woodland. Further, once Western Australian Peppermint seedlings develop to the lignotuberous stage, they can resprout vigorously after fire. Therefore, a combination of fire and the physical removal of understorey in sites where this species has formed extensive thickets is required to: (i) provide an opportunity for regeneration of Tuart in both healthy and declining stands; (ii) improve the chances of sustained recovery of Tuart trees in declining stands; and (iii) ensure heterogeneity in the vegetation at multiple scales, a recognized strategy for conserving biodiversity and increasing ecosystem resilience. We propose that this approach may also be relevant to other tree decline syndromes in southern Australia. However, fostering community support for active intervention using thinning and fire in conservation reserves and staging the operations within an experimental framework will be important for such action to gain both the social and scientific acceptance necessary for it to be applied widely.

The work was carried out at the Experimental Farm of El-Kassassin Horticulture Research Station, Horticulture Research Institute to study the effects of various sewage sludge application rates (0, 10%, 20%, 30% and 40%) on growth and Cd, Pb and Ni content in the roots, stems and leaves of two Eucalyptus species, Eucalyptus citriodora and E gomphocephala . Also, to study the possibility of using specific transplants for bioaccumulation some heavy metals on new reclaimed soils in semi arid areas using treated municipal sewage sludge. The highest value of plant height and stem diameter obtained from Eucalyptus gomphocephala with 30% or 40% of sewage sludge application. High amount of Ni was observed in leaves of the studied plants

A new Phytophthora species, isolated from rhizosphere soil of declining or dead trees of Eucalyptus gomphocephala, E. marginata, Agonis flexuosa, and another 13 plant species, and from fine roots of E. marginata and collar lesions of Banksia attenuata in Western Australia, is described as Phytophthora multivora sp. nov. It is homothallic and produces semipapillate sporangia, smooth-walled oogonia containing thick-walled oospores, and paragynous antheridia. Although morphologically similar to P. citricola, phylogenetic analyses of the ITS and cox1 gene regions demonstrate that P. multivora is unique. Phytophthora multivora is pathogenic to bark and cambium of E. gomphocephala and E. marginata and is believed to be involved in the decline syndrome of both eucalypt species within the tuart woodland in south-west Western Australia.

Eucalyptus gomphocephala (tuart) is a tree native to the southwest coast of Western Australia, where, in some areas, there is a significant decline in the health of tuart. Botryosphaeriaceous taxa have been isolated as endophytes and canker pathogens from numerous hosts in many parts of the world and have been implicated in the decline of E. gomphocephala. In the present study, endophytic fungi were isolated from a wide variety of native woody plant species (Acacia cochlearis, A. rostellifera, Allocasuarina fraseriana, Agonis flexuosa, Banksia grandis, E. gomphocephala, E. marginata and Santalum acuminatum), at two locations in native E. gomphocephala woodland; a site in decline at Yalgorup National Park and a healthy site at Woodman Point Regional Park. Of the 226 isolates obtained, 154 were botryosphaeriaceous taxa, 80 % of which were found to be Neofusicoccum australe, isolated from all hosts at both collection sites. Four new species are described, Dothiorella moneti, Dothiorella santali, Neofusicoccum pennatisporum, and a species belonging to a genus only recently included in the Botryosphaeriaceae, Aplosporella yalgorensis. The other species isolated were Botryosphaeria dothidea on the new hosts A. rostellifera, A. cochlearis and E. marginata and Dichomera eucalypti, on the new host E. marginata. None of the new species formed lesions on excised stems of their host species, E. gomphocephala, or a common plantation species, E. globulus. However, Neofusicoccum australe formed lesions on excised stems of E. globulus and E. gomphocephala.

Isohydric and anisohydric regulations of plant water status have been observed over several decades of field, glasshouse and laboratory studies, yet the functional significance and mechanism of both remain obscure. We studied the seasonal trends in plant water status and hydraulic properties in a natural stand of Eucalyptus gomphocephala through cycles of varying environmental moisture (rainfall, groundwater depth, evaporative demand) in order to test for isohydry and to provide physiological information for the mechanistic interpretation of seasonal trends in plant water status. Over a 16 month period of monitoring, spanning two summers, midday leaf water potential (psi(leaf)) correlated with predawn psi(leaf), which was correlated with water table depth below ground level, which in turn was correlated with total monthly rainfall. Eucalyptus gomphocephala was therefore not seasonally isohydric. Despite strong stomatal down-regulation of transpiration rate in response to increasing evaporative demand, this was insufficient to prevent midday psi(leaf) from falling to levels below -2 MPa in the driest month, well into the region likely to induce xylem air embolisms, based on xylem vulnerability curves obtained in the study. However, even though midday psi(leaf) varied by over 1.2 MPa across seasons, the hydrodynamic (transpiration-induced) water potential gradient from roots to shoots (delta psi(plant)), measured as the difference between predawn and midday psi(leaf), was relatively constant across seasons, averaging 0.67 MPa. This unusual pattern of hydraulic regulation, referred to here as isohydrodynamic, is explained by a hydromechanical stomatal control model where plant hydraulic conductance is dependent on transpiration rate.

International audience; Effects of polluted sea-spray on leaves of Acacia cyanophylla Lindl. and Eucalyptus gomphocephala Dc. in Tunisian coast. A deterioration of the coastal vegetation of the Cape Bon in Tunisia has been observable for these two last decades. In many points of the coast, the peuplement of Acacia cyanophylla Lindl. and Eucalyptus gomphocephala Dc. are touched. The sheets of the damaged trees present a marked reduction of their relative content water compared to that of the healthy sheets, with deterioration of their surface on the epicuticular waxes. These deterioration are related to the recent presence in the marine spray of several pollutants like anionic surfactants. The experiences results in laboratory confirm hypothesis that when the sea-spray contains the surfactant and hydrocarbons, they then have a very significant impact on the sheets with in particular a deterioration of the cuticle. Indeed Na+ and Cl- ions and the pollutants present in the spray can then largely cross the cuticular barrier and exert their deleterious effects on leaf tissues.; Un dépérissement de la végétation côtière du Cap Bon en Tunisie est observable depuis ces deux dernières décennies. En de nombreux points de la côte, les peuplements d'Acacia cyanophylla Lindl. et d'Eucalyptus gomphocephala Dc. sont touchés. Les feuilles des arbres dépérissants présentent une réduction marquée de leur teneur relative en eau par rapport à celle des feuilles saines, avec des altérations de leur surface au niveau des cires épicuticulaires. Ces dépérissements sont liés à la présence récente dans les embruns marins de plusieurs polluants comme des tensioactifs anioniques. Les résultats d'expériences en laboratoire confirment l'hypothèse que lorsque les embruns marins contiennent des tensioactifs et des hydrocarbures, ils ont alors un impact très important sur les feuilles avec en particulier une altération de la cuticule. En effet les ions Na+,Cl- et les polluants présents dans les embruns peuvent alors franchir largement la barrière cuticulaire et exercer leurs effets néfastes sur les tissus foliaires.

The chemical composition of the essential oil from the leaves of Eucalyptus camaldulensis, Eucalyptus camaldulensis var. obtusa and Eucalyptus gomphocephala grown in northern Egypt was analysed by using GC-FID and GC-MS techniques. The antibacterial (agar disc diffusion and minimum inhibitory concentration methods) and antioxidant activities (2,2'-diphenypicrylhydrazyl) were examined. The main oils constituents were 1,8-cineole (21.75%), β-pinene (20.51%) and methyleugenol (6.10%) in E. camaldulensis; spathulenol (37.46%), p-cymene (17.20%) and crypton (8.88%) in E. gomphocephala; spathulenol (18.37%), p-cymene (19.38%) and crypton (16.91%) in E. camaldulensis var. obtusa. The essential oils from the leaves of Eucalyptus spp. exhibited considerable antibacterial activity against Gram-positive and Gram-negative bacteria. The values of total antioxidant activity were 70 ± 3.13%, 50 ± 3.34% and 84 ± 4.64% for E. camaldulensis, E. camaldulensis var. obtusa and E. gomphocephala, respectively. The highest antioxidant activity value of 84 ± 4.64% could be attributed to the high amount of spathulenol (37.46%).

Objective: To evaluate the in vitro antibacterial activities of two extracts (Aqueous extract and ethanolic extract) from the leaves of fourteen medicinal plants found in Zerhoun (central Morocco) on the growth of six strains of Pseudomonas aeruginosa. Methodology and Results: The method of diffusion in solid and macromethod of dilution in liquid medium from active extract were used for antibacterial testing. The results showed that aqueous extracts were more active than the ethanol extracts. The plant extracts were more active against pigmented strains (pyocyanin) than against non-pigmented strains. Eight plants showed antibacterial activity against one or more bacterial strains. The aqueous extract of Eucalyptus gomphocephala presented the highest anti Pseudomonas aeruginosa activity against all strains tested with zones of inhibition between 16 and 18.5 mm, having an MIC value (6.25-12. 5mg/ml) and MBC (6.25-25mg/ml). Conclusion and Application: According to this study results, water was the best solvent in the concentration of the active ingredients of the plants. In addition, the antibacterial activities of the extracts from the leaves of eucalyptus in this study could justify the therapeutic use of this plant in traditional medicine in the treatment of many bacterial infections.Keywords: antibacterial activity; aqueous extracts; ethanol extracts; Pseudomonas aeruginosa; eucalyptus gomphocephala.

The vegetation of Kings Park, near the centre of Perth, Western Australia, once had an overstorey of Eucalyptus marginata (jarrah) or Eucalyptus gomphocephala (tuart), and many trees still remain in the bushland parts of the Park. Avenues and roadsides have been planted with eastern Australian species, including Eucalyptus cladocalyx (sugar gum) and Eucalyptus botryoides (southern mahogany), both of which have become invasive. The present study examined the effect of a recent burn on the level of herbivory on these native and exotic eucalypts. Leaf damage, shoot extension and number of new leaves were measured on tagged shoots of saplings of each tree species in unburnt and burnt areas over an 8-month period. Leaf macronutrient levels were quantified and the number of arthropods on saplings was measured at the end of the recording period by chemical knockdown. Leaf macronutrients were mostly higher in all four species in the burnt area, and this was associated with generally higher numbers of canopy arthropods and greater levels of leaf damage. It is suggested that the pulse of soil nutrients after the fire resulted in more nutrient-rich foliage, which in turn was more palatable to arthropods. The resulting high levels of herbivory possibly led to reduced shoot extension of E. gomphocephala, E. botryoides and, to a lesser extent, E. cladocalyx. This acts as a negative feedback mechanism that lessens the tendency for lush, post-fire regrowth to outcompete other species of plants. There was no consistent difference in the levels of the various types of leaf damage or of arthropods on the native and the exotic eucalypts, suggesting that freedom from herbivory is not contributing to the invasiveness of the two exotic species.

Land available for afforestation in the Western Cape Region has largely been subordinate to agriculture. Eucalypt species have never been tested intensively along the West Coast. Climatic matching suggests planting of species from West Australia as native habitat introductions, or from seed sources in the Mediterranean region where eucalypt species have been tried successfully, such as Morocco and Israel. Promising growth of eucalypt hybrids on marginal sites in the summer rainfall areas of South Africa prompted the inclusion of local as well as some hybrid seedlots obtained from Morocco. The terrain of the trial site is an almost flat old dune area (slopes 35oC). The sandy soils have a coarse texture within the normal rooting depth. During winter water tables were observed on all soils within 2-3 m from the soil surface. The trial was planted during the winter of 1991. It consisted of ten local hybrid families of different species involving Eucalyptus grandis, 14 E. camaldulensis seedlots from Australia, Morocco and Israel, 7 hybrid lots from Morocco, 4 E. grandis ex Morocco and 11 other species including E. gomphocephala and E. cladocalyx. The results indicate the potential for correct species/provenance selection. Potential yields of 8 to 10 m3 / annum / ha are predicted on the assumption that good genetic stock and correct silvicultural procedures are used. Most notable was the expected performance of the well known West Australian species (E. gomphocephala, E. cladocalyx). The group of 14 E. camaldulensis seedlots can be regarded as representing a series of provenances from Australia, except for three from Israel and one from Morocco. As expected, the different provenances survived well but performed variably, generally ranking in the bottom 50 %. However, two seedlots - the provenance from Lake Albacutya and the seedlot from Morocco - are worth noting as they actually ranked among the top ten for index score. Generally, the provenances from Queensland (e.g. Petford) and New South Wales that normally do well in summer rainfall regions did not do well. As the relevant parent species originate in summer rainfall regions, the phenomenal growth rate of many of the hybrid families came as a surprise in this trial. The yield of the best E. grandis x E. camaldulensis (GXC) family would have been equivalent to that of E. gomphocephala if the survival was equally good. The E. grandis x E. tereticornis (GXT) family did survive and performed equally well. The second best GXC family would have yielded even better than the GXT if it had a better survival. The GXC and GXT families were all within the top 50 % of the trial. Southern African Forestry Journal No.191 2001: 9-20

Eucalyptus ‘Urrbrae Gem’ is an attractive amenity tree which is believed to be a spontaneous F1 hybrid with Eucalyptus erythronema var. erythronema the known female parent. Previous observations based on adult morphology led to suggestions that either E. gomphocephala or E. stricklandii could be the male parent. Multivariate analysis of 54 adult morphological characters placed E. ‘Urrbrae Gem’ between E. erythronema var. erythronema and E. stricklandii, with minimum spanning tree values of 0.21 and 0.27, respectively. Controlled hybridisation between E. erythronema var. erythronema and both E. stricklandii and E. gomphocephala were undertaken, and the resulting seedlings were compared to each other, and to open pollinated seedlings of the putative parent species and of the F1 and second generation E. ‘Urrbrae Gem’ trees. Based on 14 morphological characters, seedlings clustered into eight groups, with E. erythronema var. erythronema × E. stricklandii seedlings most similar to open pollinated seedlings of the F1 and second generation E. ‘Urrbrae Gem’ trees. In contrast, E. erythronema var. erythronema × E. gomphocephala seedlings clustered into a number of groups, with the majority close to E. gomphocephala open pollinated seedlings. The results indicated that E. stricklandii is the male parent of E. ‘Urrbrae Gem’.

The leaf oils of Eucalyptus globulus Labill., E. camaldulensis Dehn., E. gomphocephala A. DC, E. sideroxylon A. Cunn. ex Wolls, E. robusta Smith, E. tereticomis Smith and E. viminalis Labill. isolated by steam distillation were analyzed by GC/MS. All the species contained α-pinene (2.8–24%), β-pinene (0.2–3.6%), limonene (1.5–4.5%), myrcene (0.1–1.1%), 1,8-cineole (3.5–81%), allo-aromadendrene (0.1–8.8%) and globulol (0.2–5.7%) as principal leaf oil components

The parentage of ‘Urrbrae Gem’, an ornamental hybrid Eucalyptus, was investigated using RAPD-PCR. The female parent was known to be E. erythronema var. erythronema but previous opinion, based on adult morphological characters, placed the male parent as either E. stricklandii or E. gomphocephala. Samples of DNA, extracted from leaves of different individuals within each species, were amplified with six different 10-mer primers to produce RAPD fingerprints. These were used to generate a UPGMA dendrogram based on genetic similarities, and an ordination plot, derived by multi-dimensional scaling (MDS), and minimum spanning tree (MST) to show the relative dissimilarities between the individuals tested. The UPGMA dendrogram divided the samples into three clusters, with the hybrid slightly closer to E. stricklandii than E. gomphocephala. The MDS ordination and MST placed the hybrid between E. erythronema var. erythronema and E. stricklandii, supporting E. stricklandii as the male parent.

Rehabilitation with native plant species of an experimental titanium dioxide residue containment pond on dune swales at Capel, Western Australia was undertaken in 1990. The treated residue comprised unreacted ilmenite, coking coal, metal hydroxides, gypsum and lime inerts, and titanium dioxide. It was an inert, insoluble, non-toxic, clay-like material. This paper describes the growth and establishment of terrestrial vegetation in the residue material after five years and its associated symbiotic root fungi and ant communities. The total number of plant species present after five years was comparable to a nearby Eucalyptus gomphocephala woodland and dune vegetation. Vegetation cover was similar to the dune site but less than the woodland. Litter cover was similar to the burnt dune site. Mycorrhizal infection rates were similar in the roots of plant examined in experimental and control sites. Ant species richness was approaching levels in control sites. Soil analysis showed that topsoil in the resi...

†Background and Aims Few phylogeographic studies have been undertaken of species confined to narrow, linear coastal systems where past sea level and geomorphological changes may have had a profound effect on species population sizes and distributions. In this study, a phylogeographic analysis was conducted ofEucalyptusgomphocephala (tuart), a tree species restricted to a 400 × 10 km band of coastal sand-plain in south west Australia. Here, there is little known about the response of coastal vegetation to glacial/interglacial climate change, and a test was made as to whether this species was likely to have persisted widely through the Last Glacial Maximum (LGM), or conforms to a post-LGM dispersal model of recovery from few refugia. †Methods The genetic structure over the entire range of tuart was assessed using seven nuclear (21 populations; n ¼ 595) and four chloroplast (24 populations; n ¼ 238) microsatellite markers designed for eucalypt species. Correlative palaeodistribution modelling was also conducted based on five climatic variables, within two LGM models. †Key Results The chloroplast markers generated six haplotypes, which were strongly geographically structured (GST ¼ 0.86 and RST ¼ 0.75). Nuclear microsatellite diversity was high (overall mean HE 0.75) and uniformly distributed (FST ¼ 0.05), with a strong pattern of isolation by distance (r 2 ¼ 0.362,P ¼ 0.001). Distribution models of E. gomphocephala during the LGM showed a wide distribution that extended at least 30 km westward from the current distribution to the palaeo-coastline. †Conclusions The chloroplast and nuclear data suggest wide persistence of E. gomphocephala during the LGM. Palaeodistribution modelling supports the conclusions drawn from genetic data and indicates a widespread westward shift ofE.gomphocephala onto the exposed continental shelf during the LGM. This study highlights the importance of the inclusion of complementary, non-genetic data (information on geomorphology and palaeoclimate) to interpret phylogeographic patterns.