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Abstract: Forest ecosystems have been subjected to continuous dynamics between deforestation and forestation. Assessing the effects of these processes on biodiversity could be essential for conservation planning. We analyzed patterns of species richness, diversity and evenness of plants and birds in patches of natural forest of Quercus spp. and in stands of native Pinus pinaster and exotic Eucalyptus globulus in NW Portugal. We analyzed data of forest and non-forest species separately, at the intra-patch, patch and inter-patch scales. Forest plant richness, diversity and evenness were higher in oak forest than in pine and eucalypt plantations. In total, 52 species of forest plants were observed in oak forest, 33 in pine plantation and 28 in eucalypt plantation. Some forest species, such as Euphorbia dulcis, Omphalodes nitida and Eryngium juresianum, were exclusively or mostly observed in oak forest. Forest bird richness and diversity were higher in both oak and pine forests than in eucalypt forest; evenness did not differ among forests. In total, 16 species of forest birds were observed in oak forest, 18 in pine forest and 11 in eucalypt forest. Species such as Certhia brachydactyla, Sitta europaea and Dendrocopos major were common in oak and/or pine patches but were absent from eucalypt stands. Species-area relationships of forest plants and forest birds in oak patches had consistently a higher slope, at both the intra and inter-patch scales, than species-area relationships of forest species in plantations and non-forest species in oak forest. These findings demonstrate the importance of oak forest for the conservation of forest species diversity, pointing the need to conserve large areas of oak forest due to the apparent vulnerability of forest species to area loss. Additionally, diversity patterns in pine forest were intermediate between oak forest and eucalypt forest, suggesting that forest species patterns may be affected by forest naturalness. [Copyright &y& Elsevier]

In situ analysis of lignin by 2D NMR of whole plant material was carried out by swelling finely ball-milled samples in deuterated dimethylsulfoxide (DMSO- d6) and sonicated so that a gel was formed in the NMR analysis tube. Solution HSQC NMR spectra of different plant materials representative for hardwood ( Eucalyptus globulus), softwood ( Picea abies), and non-woody plants ( Agave sisalana) are presented here. The spectra show signals corresponding to those of the main plant constituents, such as lignin and polysaccharides. The lignin signals were assigned by comparing the HSQC spectra of the whole plant materials with the HSQC spectra of their respective milled-wood lignins (MWLs). In general terms, the major lignin structural features, such as the relative abundances of the main lignin substructures, the syringyl/guaiacyl ratios and the extent of γ-acetylation of the lignin side-chain observed in the HSQC spectra of the whole plant materials, matched those obtained from the HSQC spectra of the isolated MWLs. Therefore, this technique, which needs only minor amounts of lignocellulosic material and minimal sample preparation, can be useful for the rapid screening of plant lignins without the need for tedious and time-consuming lignin isolation procedures. [ABSTRACT FROM AUTHOR]

While habitat fragmentation is a central issue in forest conservation studies in the face of broad-scale anthropogenic changes to the environment, its effects on contemporary mating patterns remain controversial. This is partly because of the inherent variation in mating patterns which may exist within species and the fact that few studies have replication at the landscape level. To study the effect of forest fragmentation on contemporary mating patterns, including effective pollen dispersal, we compared four native populations of the Australian forest tree, Eucalyptus globulus. We used six microsatellite markers to genotype 1289 open-pollinated offspring from paired fragmented and continuous populations on the island of Tasmania and in Victoria on mainland Australia. The mating patterns in the two continuous populations were similar, despite large differences in population density. In contrast, the two fragmented populations were variable and idiosyncratic in their mating patterns, particularly in their pollen dispersal kernels. The continuous populations showed relatively high outcrossing rates (86–89%) and low correlated paternity (0.03–0.06) compared with the fragmented populations (65–79% and 0.12–0.20 respectively). A greater proportion of trees contributed to reproduction in the fragmented ( de/d≥ 0.5) compared with the continuous populations ( de/d = 0.03–0.04). Despite significant inbreeding in the offspring of the fragmented populations, there was little evidence of loss of genetic diversity. It is argued that enhanced medium- and long-distance dispersal in fragmented landscapes may act to partly buffer the remnant populations from the negative effects of inbreeding and drift. [ABSTRACT FROM AUTHOR]

Abstract: The way how sterols, the main lipophilic compounds present in eucalypt kraft pulp, are eliminated by an enzymatic stage using the laccase-mediator system was evaluated. With this purpose laccase-mediator stage (L) was applied on an Eucalyptus globulus pulp under different operation conditions following a three-variable (laccase dose, mediator dose and reaction time) sequential statistical plan, to optimise the removal of sterols. The decrease in pulp sterol content during the enzymatic treatment was related to the decrease in kappa number and to brightness increase, as well as with the increase in some oxidation products of sitosterol (namely 7-oxositosterol and stigmasta-3,5-dien-7-one). The increase in reaction time from 1 to 5h strongly reduced the sterol content, while no more sterols were eliminated during the 5–7h period. Increasing the laccase dose from 1 to 20Ug−1 of pulp produced a high reduction in pulp sterols, whereas the increase in mediator (1-hydroxybenzotriazole) dose (from 0.5 to 2.5% of pulp weight) had only a slight influence in removing sterols. Therefore, at 16Ug−1 laccase dose, 0.5% mediator dose, 4h of reaction, practically all the sterols were removed. Finally, it was demonstrated that sterols were more sensitive to a L stage (practically 100% of sterols were eliminated) than to a chlorine dioxide stage (54% of sterols eliminated). [Copyright &y& Elsevier]

Research into the effects of seven management techniques on survival and growth of eucalypt seedlings planted on farmland is reviewed. The techniques include: pre- and post-planting weed control; soil cultivation; fertiliser; mulch; tree guards/shelters; and irrigation. The initial and ongoing effects of each technique are discussed—including the effects of timing, type and quantity. Consideration is given to site, species and climatic influences. A statistical analysis of the published survival rates is then presented, to provide information on the relative importance of, and interactions between, practices. The analysis shows that maximum survival may be achieved by using one or two management techniques. Combining this result with the insights gained from the review suggests that the use of soil cultivation and post-planting weed control are likely to achieve the greatest improvements in early eucalypt survival and growth. [ABSTRACT FROM AUTHOR]

Abstract: Eucalyptus polybractea (blue mallee) is the key species used in the commercial production of pharmaceutical-grade (>70% 1,8-cineole) eucalyptus oil in Australia. The establishment of plantations based on clones of selected, elite oil-producing plants has been recognized as the best means by which to increase oil and cineole yields. Blue mallee can be micropropagated using axillary bud proliferation of explants collected from the coppicing lignotubers of decapitated plants. To date, this has been successful for ortets from three different ontogenetic stages: 8-month-old ‘seedlings’, 4-year-old ‘saplings’ and ‘mature’, biannually harvested plants of indeterminate age. The issue of ontogenetic control of oil quality and quantity is an important consideration when selecting ortets for cloning and also when examining the success of a cloning programme. Our aim is to examine if clones derived from ortets of the three different ages reflect their respective ortets, in terms of oil quantity and quality (cineole proportion), and to appraise at what age the clones best reflect the ortets for these traits. Our results suggest that the age of ortets prior to explant collection does not influence micropropagation success or clonal consistency, and that clones generally exhibit the leaf oil traits of their respective ortets. Leaf oil quantity accumulation in ramets followed the ontogenetic trajectory of a relatively rapid increase to a maximum between 3 and 9 months, followed by a period of relative constancy for at least 12 months before beginning to gradually decrease after 21 months. Although oil quality of ramets reflected their corresponding ortets relatively well after 9 months, apparent ontogenetic constraints to cineole accumulation suggest that harvesting at a time between 9 and 21 months may better reflect the ortets for both traits. It appears likely that the proliferation of selected blue mallee genotypes using micropropagation will result in selection gains for key oil traits, thus potentially increasing cineole yields in future plantations. [Copyright &y& Elsevier]

The spotted gum species complex represents a group of four eucalypt hardwood taxa that have a native range that spans the east coast of Australia, with a morphological cline from Victoria to northern Queensland. Of this group, Corymbia citriodora subsp. variegata (CCV) is widespread in south-eastern Queensland and northern New South Wales. It is currently the most commonly harvested native hardwood in Queensland. However, little basic knowledge of the reproductive biology of the species is available to inform genetic improvement and resource management programmes. Here we take an integrative approach, using both field and molecular data, to identify ecological factors important to mating patterns in native populations of CCV. Field observation of pollinator visitation and flowering phenology of 20 trees showed that foraging behaviour of pollinator guilds varies depending on flowering phenology and canopy structure. A positive effect of tree mean flowering effort was found on insect visitation, while bat visitation was predicted by tree height and by the number of trees simultaneously bearing flowers. Moreover, introduced honeybees were observed frequently, performing 73% of detected flower visits. Conversely, nectar-feeding birds and mammals were observed sporadically with lorikeets and honeyeaters each contributing to 11% of visits. Fruit bats, represented solely by the grey-headed flying fox, performed less than 2% of visits. Genotyping at six microsatellite markers in 301 seeds from 17 families sampled from four of Queensland's native forests showed that CCV displays a mixed-mating system that is mostly outcrossing (tm = 0.899 ± 0.021). Preferential effective pollination from near-neighbours was detected by means of maximum-likelihood paternity analysis with up to 16% of reproduction events resulting from selfing. Forty to 48% of fertilising pollen was also carried from longer distance (>60 m). Marked differences in foraging behaviour and visitation frequency between observed pollinator guilds suggests that the observed dichotomy of effective pollen movement in spotted gums may be due to frequent visit from introduced honeybees favouring geitonogamy and sporadic visits from honeyeaters and fruit bats resulting in potential long-distance pollinations. [ABSTRACT FROM AUTHOR]

Achieving a well-stocked stand at time of planting is important to compartment productivity and yield in clonal eucalypt stands for pulpwood production. The window period in which individuals that replace those that died after initial planting (blanks) still contribute meaningfully to final yield is set by the competition dynamics between individuals within the stand. The longer the period between planting and blanking, the greater the advantage achieved by original plantings in dominating site resources (light, water and nutrients) and suppressing blanks. A blanking trial was established to determine growth differences of blanked and original individuals and productivity per unit area. Factorial combinations of blanking period after planting, mortality pattern and extent of mortality were tested. Analysis of measurements at four years showed that the period before blanking is the only factor that significantly accounts for the variation in plot volume between treatments, although the percent mortality and pattern of mortality by percent mortality together also have influence on plot volume. Late blanking results in a higher proportion of suppressed trees that contribute little to total volume. Asymmetric competition is more pronounced where late blanking is carried out and where mortality is spread, rather than clumped. [ABSTRACT FROM AUTHOR]

We report the results of recent monitoring of the impacts of logging in karri (Eucalyptus diversicolor) and jarrah (E. marginata) forest. Avifaunal composition of logged and unlogged karri forest was the most similar so far, 21 years after logging took place, but species richness and total abundance remained higher in unlogged karri forest. In jarrah forest, species composition in four treatments (two logged, two unlogged) had not closely converged after 10 years. Graphs of the abundance of each bird species against time for each treatment in karri and jarrah forest are presented. We recommend that monitoring of these forests be continued, and plots relating to an earlier study in karri forest be re-activated. The data accrued so far provide an important baseline for assessing future impacts from changing climate, and any associated changes in fire regimes and infection by animal disease and Phytophthora cinnamomi, as well as for evaluating the ecologically sustainable basis of forest management. [ABSTRACT FROM AUTHOR]

Leaf biochemical traits indicating early symptoms of plant stress can be assessed using imaging spectroscopy combined with radiative transfer modelling (RTM). In this study, we assessed the potential applicability of the leaf radiative transfer model Fluspect-Cx to simulate optical properties and estimate leaf biochemical traits through inversion of two native Australian eucalypt species: Eucalyptus dalrympleana and E. delegetensis. The comparison of measured and simulated optical properties revealed the necessity to recalibrate the refractive index and specific absorption coefficients of the eucalypt leaves' biochemical constituents. Subsequent validation of the modified Fluspect-Cx showed a closer agreement with the spectral measurements. The average root mean square error (RMSE) of reflectance, transmittance and absorptance values within the wavelength interval of 450–1600 nm was smaller than 1%. We compared the performance of both the original and recalibrated Fluspect-Cx versions through inversions aiming to simultaneously retrieve all model inputs from leaf optical properties with and without prior information. The inversion of recalibrated Fluspect-Cx constrained by laboratory-based measurements produced a superior accuracy in estimations of leaf water content (RMSE = 0.0013 cm, NRMSE = 6.55%) and dry matter content (RMSE = 0.0036 g·cm−2, NRMSE = 21.28%). The estimation accuracies of chlorophyll content (RMSE = 8.46 µg·cm−2, NRMSE = 24.73%), carotenoid content (RMSE = 3.83 µg·cm−2, NRMSE = 30.82%) and anthocyanin content (RMSE = 1.69 µg·cm−2, NRMSE = 37.12%) were only marginally better than for the inversion without any constraints. Additionally, we investigated the possibility to substitute the prior information derived in the laboratory by non-destructive reflectance-based spectral indices sensitive to the retrieved biochemical traits, resulting in the most accurate estimation of carotenoid content (RMSE = 3.65 µg·cm−2, NRMSE = 29%). Future coupling of the recalibrated Fluspect with a forest canopy RTM is expected to facilitate retrieval of biophysical traits from spectral air/space-borne image data, allowing for assessing the actual physiological status and health of eucalypt forest canopies. [ABSTRACT FROM AUTHOR]

• Forest experimentally treated with thinning and recent burning did not ignite in wildfire. • Fuel hazard reduction benefits extend for at least three years after fuel treatments. • Active management of fuels reduces wildfire risk and wildfire severity. • In-field measures of fuel hazard strongly correlate with wildfire severity. • Field assessed fire severity strongly correlates with remote sensed fire severity. Climate change is increasing the area of seasonally dry forests burnt by wildfire in many parts of the world, compelling a revision of management strategies to reduce risk and improve the resilience of forest ecosystems. While prescribed burning is a common strategy used to reduce bushfire risk, mechanical thinning has not been as widely applied in Australia's temperate forests in comparison with the USA and Europe. In this study we report results from a prescribed burning and mechanical thinning experiment in a 37-year-old naturally regenerated Eucalyptus open forest that was burnt through by wildfire in January 2020, providing an opportunity to determine how pre-wildfire fuel status and burning and thinning treatments influenced wildfire severity. Fuel hazard assessments in the experimental forest, made prior to the wildfire, indicated that untreated forest, and thinned forest, had very high to extreme fuel hazard scores, while forests treated with prescribed burning, or with thinning plus burning, had low fuel hazard scores. These fuel hazard scores explained more than 70% of the variation in wildfire severity, indicating that the fire was largely fuel driven and responsive to fuel reduction measures. Forest areas treated with thinning only recorded extreme fuel hazard, largely due to the increase in forest floor residues, which were ignited by the wildfire resulting in a high fire severity ranking. Forest areas treated with thinning and prescribed burning, or with high intensity prescribed burning, did not ignite from the advancing front of the wildfire, clearly demonstrating the effectiveness of fuel reduction management under low to moderate forest fire danger weather. Fuel hazard reduction benefits extend for at least three years after the application of fuel modification treatments in Eucalyptus sieberi forests. The results from this forest experiment demonstrate that the active management of fuels, including thinning with prescribed burning, can reduce wildfire risk and fire severity. [ABSTRACT FROM AUTHOR]

• Resprouter forests are comprised by trees which resprout basally and epicormically. • They are assumed to be reliable carbon stores as the trees are rarely killed by fire. • We found that wildfire substantially reduces aboveground carbon in these forests. • After controlling for aridity, short-interval fires further reduced carbon stocks. • Therefore, fire-tolerant forests may not be as resilient carbon stocks as assumed. Forests play a key role in mitigating global climate change through carbon storage and sequestration. Wildfire affects forest carbon through combustion and by influencing forest mortality and regrowth, which are also influenced by a forest's growth environment. Wildfires are becoming more severe and frequent in many temperate regions but the impacts of such changes–in association with projected warmer, drier climates–on forest carbon stocks, remains under-quantified in many temperate biomes. We compare the impacts of a single high-severity wildfire and two high-severity wildfires within a short interval (six years) on carbon stocks 2–3 years after the last wildfire in multiple carbon pools of fire-tolerant eucalypt forests in temperate, south-eastern Australia. These forests are assumed to contain relatively resistant carbon stores because the dominant eucalypts are rarely killed by fire, reliably resprouting after most fires. Mean carbon stocks in the principal aboveground pools were decreased by one, and particularly two, high-severity wildfires after controlling for site aridity, which was negatively related to aboveground carbon stocks. On average, the percentage of aboveground carbon stocks in live biomass decreased from 76% at Unburned sites to 62% at Single-burned and 47% at Double-burned sites, contributing to increases in standing deadwood carbon stocks from 11% at Unburned sites to 42% at Double-burned sites. As such, the proportion of carbon in large, living trees (an indicator of carbon stability and carbon-recovery capacity) was decreased after short-interval wildfires. Soil carbon stocks to 10-cm depth were also significantly reduced at all wildfire sites (likely due to erosion), which could also delay post-fire recovery of productivity. Overall, our findings indicate that both single and short-interval wildfires can significantly reduce the amount of carbon stored in fire-tolerant eucalypt forests, and that the potential for carbon-stock recovery could be compromised by predicted warmer and drier (i.e., more arid) future climates, and by soil feedbacks to productivity. Actively managing carbon stocks in fire-tolerant eucalypt forests could be required in the coming decades to mitigate these risks. [ABSTRACT FROM AUTHOR]

Ecological restoration using seedling tubestock is challenging under a Mediterranean-type climate of hot, dry summers. We investigated the ecophysiological effects of plastic tree guards and shadecloth tree guards during seedling establishment of four co-occurring tree species that differ in leaf morphology. Average temperature was 6.7°C higher in plastic guards than controls over a summer, with a maximum of 53.5°C compared to 47.9°C in controls. Light levels were 2-fold lower in both tree guard treatments relative to control. In spring, photosynthesis and specific leaf area were significantly elevated in shadecloth tree guards relative to other treatments. In summer, photosynthetic rate was significantly lower, and midday photochemical efficiency was significantly higher, in both tree guard treatments relative to controls. The effect of elevated temperature in plastic tree guards may partially explain our results of higher mortality of seedling in plastic tree guards. The relatively elevated spring photosynthesis of seedlings in shadecloth tree guards may partially explain the result of reduced mortality and increased growth in this treatment. We conclude that shadecloth tree guards create a microclimate more favorable for seedling establishment in a Mediterranean-type environment than plastic tree guards and control treatments. Our results may have wide applicability to the range of restoration settings where seedling tubestock is planted, except in environments where low temperature is limiting to plant growth. [ABSTRACT FROM AUTHOR]

Abstract: The Murray-Darling Basin covers 1Mkm2 and occupies most of inland, south-eastern, mainland Australia. Large areas have been cleared and are now used for agriculture. In this paper, estimates are made of the minimum area of Eucalyptus globulus plantation forests needed to be established in the Basin to supply 2.25M oven-drytyr−1 of firewood annually, the amount of firewood harvested presently from the native forests which remain in the Basin. If plantations were established in higher rainfall areas along the eastern and southern boundaries of the Basin, it was estimated that a minimum of just over 200,000ha of plantations would be required, grown on a 10-yr rotation. If plantations were restricted to less productive areas of lower rainfall (<900mmyr−1), or to areas where land clearing for agriculture has been particularly intensive, a minimum of just under 350,000ha would be required, grown on an 11-yr rotation. If planting was restricted to soils in the Basin at high risk of salinisation from agriculture, which are generally in areas of lower rainfall, a minimum of about 600,000ha would be required, grown on a 20-yr rotation. It is considered that the practicalities of plantation establishment in the Basin would require appreciably larger areas of plantations than these minima. [Copyright &y& Elsevier]

Abstract: The Murray-Darling Basin is a 1millionkm2 agricultural region of south-eastern Australia, although 29% of it retains native forests. Some are mallee eucalypt types, whilst the ‘principal’ types are dominated mainly by other eucalypt species. One-third of the 6–7 million oven-dry tonne of firewood burnt annually in Australia is obtained from these forests, principally through collection of coarse woody debris. There are fears that removal of this debris may prejudice the floral and faunal biodiversity of the Basin. The present work considers what silvicultural management practices will allow the long-term maintenance of the native forests of the Basin and their continued contribution to its biodiversity. It then estimates that the maximum, long-term, annual, sustainable yield of firewood which could be harvested, by collection of coarse woody debris, from principal forest types of the Basin would be 10millionoven-drytonneyr−1. An alternative, harvest of firewood from live trees by thinning the principal forests and clear-felling mallee forests, would be able to supply 2.3milliontonneyr−1 sustainably. Whilst coarse woody debris harvests could supply far more than the present demand for firewood from the Basin, they would lead to substantial reductions of the debris remaining in the forests; this may be detrimental to biodiversity maintenance. Live tree harvest does not lead to this problem, but would barely be able to supply existing firewood demand. [Copyright &y& Elsevier]

Tree cavities are an important shelter site for a variety of vertebrate species, including birds, reptiles and mammals. Studies indicate that in most taxa favoured tree hollows are those in larger trees and higher from the ground, generally thought to be related to decreased predation risk and a more optimal thermal environment. However, neither of these ideas has been tested definitively. Here, we investigate the microclimate of daytime den sites in tree hollows of common brushtail possums in tropical northern Australia. We compare tree and hollow characteristics of dens known to be used by possums, and those not known to be used, to determine whether possums choose trees with microhabitats with a more favourable daytime microclimate. Possums chose to den in tree hollows which were on average 1.6 °C cooler during the day, and were more buffered from temperature extremes, than other potential den locations. Important factors explaining daytime temperatures between hollows included height of the hollow, entrance width and tree diameter. Tropical arboreal marsupials have been identified as being particularly vulnerable to climate change and there are calls to identify and preserve natural refuges, such as tree hollows, which could buffer them from extreme temperatures. Our results highlight the value of older, larger hollow-bearing trees as refuges from extreme temperature, the importance of which may become critical for some temperature-sensitive species under the combined effects of continuing habitat loss and climate change. [ABSTRACT FROM AUTHOR]

Psyllids are one most widespread group of pests, causing severe damage on agricultural and forestry systems. The recently discover about occurrence of red gum lerp psyllid Glycaspis brimblecombei Moore (Hemiptera: Psyllidae), in Brazil is, nowadays a serious problem in Eucalyptus forests, mainly in E. camaldulensis. The psyllid specific parasitic wasp Psyllaephagus bliteus Riek (Hymenoptera: Encyrtidae) is the main biological control agent of this pest. Thus, the adequate monitoring of both species by efficient sampling method would facilitate a future decision making. Due to economic importance, this study aimed to evaluate G. brimblecombei and P. bliteus populations in Eucalyptus camaldulensis plantation, using yellow traps to determinate population fluctuation with weather interactions (temperature and rainfall). The study of the pest and parasitoid population (53 sampling dates) was carried out on E. camaldulensis plantations in 19ha area in Luíz Antônio municipality (SP, Brazil), with quarterly samplings, between January and June, 2005 (ten sampling dates). This research indicated that populations had an inversely proportional correlation subject according to the temperature. However, there is no correlation between both species with the rainfall in the evaluated period. [ABSTRACT FROM AUTHOR]

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Abstract: The aim of this study is to improve our knowledge of the temporal and spatial variations of soil water repellency following wildfire, in particular for the eucalypt stands that now dominate the landscape of north-central Portugal. Topsoil water repellency was monitored on 21 occasions over a 10-month period, starting in September 2005, six weeks after a moderately severe wildfire. This was done, on mostly alternating dates, in two neighbouring commercial eucalypt plantations, one with an undisturbed and one with a ploughed soil profile, in the foothills of the Gralheira Massif in north-central Portugal. Water repellency severity was measured in situ at soil depths of 2–3 and 7–8 cm using the ‘Molarity of an Ethanol Droplet’ (MED) test, and accompanied by soil moisture measurements using a ThetaProbe™ or, at a few occasions, sample analysis in the laboratory for gravimetric content. The results show a broadly seasonal pattern of overall very high water repellency in dry periods and reduced or no repellency following prolonged rainfall. This was more pronounced at the undisturbed compared to the ploughed site, as the latter exhibited strong to extreme water repellency at almost all sampling dates. Significant changes in repellency severity, including major increases, occurred within periods as short as 6–7 days, suggesting that the sampling intervals used here may have not captured the full dynamics of topsoil repellency. Repellency severity was consistently lower at greater soil depth, in particular when considering the whole study period. Soil moisture was found to relate to the temporal variations in repellency. As found in previous studies, however, soil moisture alone was not sufficient to predict the temporal variations in water repellency. [Copyright &y& Elsevier]

Eucalyptus globulus is the main eucalypt species grown in Australian plantations. The focus on seedling deployment systems, coupled with exploitation of large, open-pollinated base populations for breeding purposes over the last two decades, has required a detailed understanding of the reproductive biology of this species. We review our research on the reproductive biology of E. globulus, with a focus on its breeding system and advances made in seed production systems. While most improved seed is still obtained from open-pollinated seedling or grafted seed orchards, the development of the one-stop/single-visit pollination procedure has revolutionised the breeding and deployment of this species. The reduced costs of controlled pollination has meant full pedigree-control can now be maintained in large advanced-generation breeding populations and E. globulus is one of the few eucalypt species where large-scale production of manually pollinated seed for family forestry is being undertaken. [ABSTRACT FROM AUTHOR]

Neopolycystus sp. is the only primary egg parasitoid associated with the pest beetle Paropsis atomaria in subtropical eucalypt plantations, but its impact on its host populations is unknown. The simplified ecosystem represented by the plantation habitat, lack of interspecific competition for host and parasitoid, and the multivoltinism of the host population makes this an ideal system for quantifying the direct and indirect effects of egg parasitism, and hence, effects on host population dynamics. Within-, between- and overall-egg-batch parasitism rates were determined at three field sites over two field seasons, and up to seven host generations. The effect of exposure time (egg batch age), host density proximity to native forest and water sources on egg parasitism rates was also tested. Neopolycystus sp. exerts a significant influence on P. atomaria populations in Eucalyptus cloeziana. plantations in south-eastern Queensland, causing the direct (13%) and indirect (15%) mortality of almost one-third of all eggs in the field. Across seasons and generations, 45% of egg batches were parasitised, with a within-batch parasitism rate of around 30%. Between-batch parasitism increased up to 5–6 days after oviposition in the field, although within-batch parasitism rates generally did not. However, there were few apparent patterns to egg parasitism, with rates often varying significantly between sites and seasons. [ABSTRACT FROM AUTHOR]

Eucalyptus urophylla (Timor mountain gum) is an economically important plantation species that occurs naturally in a series of disjunct populations on the volcanic slopes of seven islands in eastern Indonesia. Twelve microsatellite markers were used to investigate the distribution of nuclear genetic diversity among 19 geographically defined E. urophylla populations. High levels of gene diversity were observed throughout the geographic range ( H E = 0.703 to 0.776). The level of genetic differentiation among populations was low ( F ST = 0.031), but the amount of differentiation increased with geographic distance. A phenogram produced by a neighbor-joining analysis illustrated that populations clustered according to islands. However, a Bayesian clustering approach revealed a more cryptic population structure comprising two genetically homogeneous groups. Gene flow among the populations is likely responsible for the apparent weak influence of geographic insularity on the genetic diversity and structure of the island species. These findings provide direction for conservation and breeding strategies in E. urophylla. [ABSTRACT FROM AUTHOR]

Concentrations of solutes, and thus leaf osmotic potential (Ψπ), often increase when plants are subject to drought or sub-zero (frost) temperatures. We measured Ψπ and concentrations of individual solutes in leaves of 3-year-old Eucalyptus camaldulensis Dehn., E. globulus Labill., E. grandis W. Hill ex Maid. and 29 hybrid clones on a site subjected to both summer drought and winter frost. We sought to characterize seasonal and genetic variations in Ψπ and to determine whether Ψπ or leaf turgor is related to bole volume increment. Leaf osmotic potential at full turgor (Ψπ(100)) was 0.7 MPa more negative in winter than in late summer, and this trend was uniform across genotypes. Soluble carbohydrates were confirmed as key contributors to Ψπ, accounting for 40–44% of total osmolality. The seasonal trend in Ψπ(100) was facilitated by changes in leaf morphology, such as reduced turgid mass:dry mass ratio and increased apoplastic water fraction in winter. Cell wall elasticity increased significantly from winter to summer. Our results suggest that elastic adjustment may be more important than osmotic adjustment in leaves exposed to drought. Although Ψπ(100) was a reasonable predictor of in situ osmotic potential and turgor, we found no relationship between any physiological trait and bole volume increment. Clone-within-family variation in Ψπ(100) was small in both summer and winter and was unrelated to bole volume increment. We conclude that, for the study species, tree improvement under water-limited conditions should concentrate on direct selection for growth rather than on indirect selection based on osmotic potential. [ABSTRACT FROM AUTHOR]

Abstract: In this study approximately 420 of the described species of Eucalyptus were examined for cyanogenesis. Our work has identified an additional 18 cyanogenic species, 12 from living tissues and a further six from herbarium samples. This brings the total of known cyanogenic species to 23, representing approximately 4% of the genus. The taxonomic distribution of the species within the genus is restricted to the subgenus Symphyomyrtus, with only two exceptions. Within Symphyomyrtus, the species are in three closely related sections. The cyanogenic glycoside was found to be predominantly prunasin (1) in the 11 species where this was examined. We conclude that cyanogenesis is plesiomorphic in Symphyomyrtus (i.e. a common basal trait) but has probably arisen independently in the other two subgenera, consistent with recent phylogenetic treatments of the genus. The results of this study have important implications for the selection of trees for plantations to support wildlife, and to preserve genetic diversity. [Copyright &y& Elsevier]

Abstract: Paropsis atomaria is a recently emerged pest of eucalypt plantations in subtropical Australia. Its broad host range of at least 20 eucalypt species and wide geographical distribution provides it the potential to become a serious forestry pest both within Australia and, if accidentally introduced, overseas. Although populations of P. atomaria are genetically similar throughout its range, population dynamics differ between regions. Here, we determine temperature-dependent developmental requirements using beetles sourced from temperate and subtropical zones by calculating lower temperature thresholds, temperature-induced mortality, and day-degree requirements. We combine these data with field mortality estimates of immature life stages to produce a cohort-based model, ParopSys, using DYMEX™ that accurately predicts the timing, duration, and relative abundance of life stages in the field and number of generations in a spring–autumn (September–May) field season. Voltinism was identified as a seasonally plastic trait dependent upon environmental conditions, with two generations observed and predicted in the Australian Capital Territory, and up to four in Queensland. Lower temperature thresholds for development ranged between 4 and 9°C, and overall development rates did not differ according to beetle origin. Total immature development time (egg–adult) was approximately 769.2±S.E. 127.8DD above a lower temperature threshold of 6.4±S.E. 2.6°C. ParopSys provides a basic tool enabling forest managers to use the number of generations and seasonal fluctuations in abundance of damaging life stages to estimate the pest risk of P. atomaria prior to plantation establishment, and predict the occurrence and duration of damaging life stages in the field. Additionally, by using local climatic data the pest potential of P. atomaria can be estimated to predict the risk of it establishing if accidentally introduced overseas. Improvements to ParopSys’ capability and complexity can be made as more biological data become available. [Copyright &y& Elsevier]

Abstract: Divergent paralogs can create both obstacles and opportunities for phylogenetic reconstruction. Phylogenetic relationships among eucalypt genera have been incongruent among datasets in previous studies, where morphological characters supported monophyly of the genus Corymbia, while intergenic spacers of the nuclear ribosomes (ITS) and chloroplast loci (trnL, trnH, psbA) showed Corymbia as either equivocal or paraphyletic. Ribosomal DNA occurs in multiple copies in a genome. We cloned and sequenced the nrITS to investigate if gene duplication was the cause of incongruence among trees in the eucalypts. Three ITS riboforms, two of them widespread, were recovered within some genomes. One of the ITS riboforms recovered a robust phylogeny showing Corymbia as a monophyletic genus, corroborating the evidence from morphology, fossil data, a recent ITS/ETS dataset and microsatellites (SSRs). Compelling evidence suggested that this divergent riboform is a pseudogene, i.e., non-functional paralog: comparatively lower GC content suggesting lower structural stability, deamination-like mutations at potential methylation sites, lack of conserved helices and hairpins and conspicuously lower thermodynamic stability in secondary structures. Phylogenies from the apparently functional riboform retained Corymbia as paraphyletic. We show here that pseudogenes can recover a well-corroborated phylogeny whereas their functional paralogs show misleading hypotheses. We explain that phylogenetic signals may be obscured when functional constraints in ITS necessitate compensatory mutations in the secondary structure helices involved in RNA transcription, whereas pseudogenes mutate under neutrality. [Copyright &y& Elsevier]

Abstract: Information about fine root dynamics before and after harvest is scarce in eucalypt plantations. Knowledge of root system functioning is important to achieve sustainable production of these fast-growing species. This work evaluated fine root turnover in 9-year-old Eucalyptus grandis stands growing on a loamy soil (RED) and in a sandy soil (QTZ). On each soil type, the experimental area was divided into three plots that corresponded to the following time sequence: mature forest before harvesting (MF), after harvesting in summer (HS) and after harvesting in winter (HW). Fine roots (diameter<3mm) were sampled by sequential coring. Root length was obtained by imaging processing, distinguishing fine roots with diameter<1mm (FR1) and diameter between 1 and 3mm (FR2). Fine root decomposition was estimated with litter bags incubated in three plots per soil. Root length density was higher for FR1 in QTZ than in RED for all plot types. There was a significant seasonal difference in FR1 density (FRD1) at a depth of 0–10cm in RED (from 2.3 to 4.4cmcm−3) and QTZ (from 5.7 to 8.2cmcm−3), in winter and summer, respectively. Fine root dynamics was significantly altered after harvesting, mainly in the surface layer in both soils. An approx. 50% decrease in FRD1 was observed 60 days after harvesting in the two soil types. Root mass loss in litter bags was faster in RED than in QTZ. Decomposition of fine roots was faster after harvesting, which was directly related to altered environmental conditions (water availability, soil temperature). [Copyright &y& Elsevier]

Summary: Results from a paired catchment project measuring the water balance of native eucalypt forest and the change caused by conversion of one catchment to radiata pine are presented. The results are from 1975 to 1987 and from 1997 to 2006. The project measured the water yield from three small, steep, contiguous, forested catchments carrying similar native eucalypt vegetation in south-eastern Australia. One of the catchments was converted to radiata pine in 1980. Data from the untreated catchment showed that annual water yield was substantially a function of annual rainfall, and that annual rainfalls below 900mm generated little runoff. The conversion to radiata pine led to an increased water yield of up to 300mm per annum immediately after clearing. This response has declined but in general the runoff from the pine catchment is still higher than that of the eucalypt catchment except for “drought” years. Combination of these results with other Australian results gave a simple model of radiata pine water use (relative to the native eucalypt vegetation) as a function of age and annual rainfall. Older trees and low-rainfall years are associated with a higher water use by the radiata pine than the native forest, but conversely younger trees and higher rainfalls give lower water use. Extrapolation of the results to grassland showed that reforestation of grassland sites would lead to diminished yields. The relationships generated may be useful for estimation of the net change in streamflow caused by afforestation with radiata pine in larger catchments. [Copyright &y& Elsevier]

The tropical savanna landscape of northern Australia is perhaps the most extensive and flammable ecosystem in the world. Like savannas worldwide, there still remains uncertainty as to the functioning of much of this system and the mechanisms maintaining a state between open grassland and woodland. We use the development of a process-based model to examine the processes operating on the eucalypt dominated tree component of the northern Australian savannas, focussing on the interaction of water availability and fire. A process-based, tree population dynamics model (Flames) has been developed to understand the interactive effects of fire and rainfall variability on trees in Australian savanna ecosystems where there has been limited modelling to date. This paper shows that the model is capable of simulating the range of tree populations found in northern Australia by considering soil properties (texture and depth) and rainfall distribution. The model indicates that seasonal variability and inter-annual variability in rainfall is critical in defining the structure and density of tree stands in northern Australia. We also show that fire plays an important role in defining tree structure by removing the most sensitive (the very young and old) trees and that frequent fronting fires will lead to ongoing reductions in tree populations. While fire is an important factor in northern Australia, the model indicates its effects on tree populations at a sub-continental scale are secondary to the impact of rainfall variability. [Copyright &y& Elsevier]

Increasingly stringent effluent quality limits for bleached kraft pulp mills pose a great challenge to mill wastewater system managers since these limits can require levels of chemical oxygen demand (COD) removal efficiency rarely reported for biological treatment of these types of effluents. The present study was therefore undertaken to better understand the nature of recalcitrant COD in bleached kraft pulp effluents that persists through the biological treatment system. Bleaching effluents from a Brazilian eucalypt bleached kraft pulp mill were collected and treated in a bench-scale sequencing batch reactor. Organic matter in raw and treated effluents was characterized before and after separation into low and high molecular mass fractions. Biological treatment removed 71% of the COD, with 83% removal of the low molecular mass COD but only 36% removal of the high molecular mass COD. Microorganisms capable of degrading the recalcitrant COD were isolated from enrichment cultures of the original activated sludge fed on fractions of the bleaching effluent that presented low biodegradabilities. Use of a microbial consortium composed of ten of these isolates to treat the biologically treated effluent removed a further 12% of the effluent COD, all from the high molecular mass fraction. Results of this research indicate that microorganisms with potential for degrading recalcitrant COD are present in activated sludge, but that these are not metabolically active during normal activated sludge treatment of mill effluents. The use of biological selectors in the treatment system to promote growth of such microorganisms may enhance removal of recalcitrant organic matter. [ABSTRACT FROM AUTHOR]

1. Comparisons of adult and juvenile plant stages are often confounded by other factors such as differences in height between plants. However, these factors can be teased apart using common garden experiments and appropriate sampling designs. 2. Using paired sampling of upper and lower canopies of Eucalyptus nitens trees, which were growing in a common environment trial and only one of which had undergone the transition to adult foliage, this study assessed the effects of ontogeny and canopy position on the feeding preferences of Common Brushtail Possums ( Trichosurus vulpecula) in captive feeding trials under choice conditions. 3. Possums preferred juvenile foliage over adult foliage. In contrast, canopy position did not influence preferences. 4 Adult foliage contained significantly less sideroxylonals (a compound known to deter herbivory by Brushtail Possums), but was significantly tougher (with thicker cuticle, more fibre, more lignin and a higher percentage dry mass) than juvenile foliage, suggesting that leaf toughness was more significant than defensive chemistry in influencing intake by possums. Adult foliage did not differ significantly from juvenile foliage in nitrogen, total phenolics or essential oil concentration. 5. Greater resistance to herbivory of adult foliage compared with juvenile foliage by a significant browser of eucalypt tree foliage could contribute to selection for an earlier change from juvenile to adult foliage in areas that are heavily browsed by possums. [ABSTRACT FROM AUTHOR]

Noisy Miners ( Manorina melanocephala) are aggressive Australian honeyeaters that dominate many areas of remnant vegetation and forest edges from which they competitively exclude small birds. A similar domination can also occur in planted wildlife corridors. The aim of this study was to determine which corridor plantings encouraged the presence of small native birds in regions where Noisy Miners dominate. Six vegetation mixes were investigated in the main study: eucalypts with and without shrubby understorey; acacia with and without shrubby understorey; exotic conifer; and exotic deciduous trees. A supplementary study then examined sites with a mixture of eucalypt and acacia trees with a shrubby understorey. The findings showed that Noisy Miners dominated corridors of eucalypts, virtually excluding small birds, whereas native acacias, exotic conifer and exotic deciduous corridors had small birds and no resident Noisy Miners. The greatest abundance and richness of small birds occurred in plantings combining eucalypts with at least 15% acacias, in this case bipinnate species. Given these results, it is recommended that eucalypt plantings should be supplemented with both acacias (preferably bipinnate) and a shrubby understorey. [ABSTRACT FROM AUTHOR]

Abstract: Defoliation from herbivores can reduce growth of affected plants, and this has been demonstrated for plantation-grown Eucalyptus globulus. We undertook a field study to examine: (1) the influence of severity, pattern and frequency of defoliation on E. globulus stem growth, (2) whether fertiliser application influences growth responses to defoliation and (3) whether rate or timing of fertiliser application is important in determining growth responses. Two rates of nitrogen (N) (100 or 300kgha−1) were applied either pre- or post-defoliation or both. Defoliation treatments examined the effects of pattern, frequency and severity of defoliation on growth. In the absence of fertiliser, removal of 25% of leaf area from throughout the crown reduced diameter and height increment over the following 20 months. Removal of all leaf area from the upper 50% of crown had a much more dramatic effect on stem growth than did removal of all leaf area from the lower 50% of crown. More frequent defoliation increased the effect of defoliation on stem growth, and there was more of an effect following defoliation of the upper rather than lower crown. While there was no fertiliser response in undefoliated trees at the site, pre-defoliation fertiliser application maintained diameter and height increment of defoliated trees at a level similar to that of undefoliated trees. The growth response to fertiliser following defoliation was greater with pre- than post-defoliation applications of N, although there was still a significant response to post-defoliation applications. While foliar N content increased with rate of N application in undefoliated trees, defoliation generally reduced foliar N content and total phenolics. It was concluded that fertilising with N, even on sites with no discernible N deficiency, is a potential management tool for dealing with defoliation events. Management implications of the results are discussed. [Copyright &y& Elsevier]

Abstract: High salt levels in mine spoils have been identified as one of the major chemical limitations to plant establishment after coal mining in central Queensland. Soil solution extracts from spoils indicated that EC levels of up to 26dS/m could be encountered. Glasshouse trials examined the emergence and growth of Eucalyptus citriodora, Eucalyptus camaldulensis and Eucalyptus populnea provenances and Acacia salicina subjected to such EC levels. Relatively low levels of salt (100mM NaCl, or 11dS/m) with respect to the levels encountered on mine spoils, were enough to substantially reduce the rate and percentage emergence of all eucalypt provenances. A. salicina was found to be superior to the eucalypts in its ability to emerge and survive under saline conditions. It was the only species to have seedlings emerge and survive at 200mM NaCl (20dS/m), and the effect of salt on decreasing seedling dry weight was less pronounced for A. salicina than for any of the eucalypts. Established plants survived the range of salt treatments far better than emerging seedlings, with survival of established plants being reduced only at 300 and 400mM NaCl (28 and 36dS/m, respectively). A. salicina performed significantly better at 300 and 400mM NaCl than most of the eucalypts studied. [Copyright &y& Elsevier]

Greenhouse trials with containerized Eucalyptus globulus and E. urophylla seedlings were made to determine effective inoculum spore densities (Scleroderma cepa from temperate Australia, and S. citrinum from sub-tropical China) and spore storage conditions (fresh spores or spores stored for 5 years at room temperature or at 4 °C; S. albidum, S. areolatum and S. cepa from Western Australia). Inoculation with 106 or 108 spores/seedling increased eucalypt growth by up to 46% in height and 42% in dry weight compared to non-inoculated seedlings at 12 weeks after inoculation. Mycorrhizal formation was poor at 102 spores/seeding. Spores stored at 4°C for 5 years were as effective in forming mycorrhizas as freshly collected spores when a standard density of 106 spores/seedling was applied. It is recommended that spore densities ⩾104 be used for inoculation of containerised eucalypts and that spores be stored at 4 °C until use. [ABSTRACT FROM AUTHOR]

Abstract: In eucalypts the reduction in CO2 assimilation and total leaf area at low phosphorus (P) supply is not associated with lower leaf total P concentrations. We tested the hypothesis that the leaf concentration of inorganic phosphorus ([Pi]) may be a better indicator of P nutrition status in Eucalyptus grandis W. Hill ex Maiden by growing seedlings in P deficient soil supplemented with P supplies ranging from 3 to1000mgkg−1. Height, biomass accumulation, gas exchange, chlorophyll fluorescence and concentrations of total P ([Pt]), organic P ([Po]) and [Pi] of the last fully expanded leaves were measured when harvested at 19 weeks. All parameters of growth increased with larger applications of soil P with most becoming saturated at additions of 500mgPkg−1 soil. Soil P supply had larger effects on biomass and canopy leaf area, by both increased in leaf initiation and expansion, than on CO2 assimilation (A). Leaf [Pt] and [Po] concentrations were largely invariant to soil P supply and were not correlated with any of the measured growth and photosynthetic parameters. By contrast, leaf [Pi] increased from 171 to 398mgkg−1 with increasing soil P supply. Furthermore, number of leaves, total leaf area and seedling biomass increased exponentially with leaf [Pi], while individual leaf area and A increased linearly with leaf [Pi], and quantum yield of photosystem II similarly increased, and non-photochemical quenching decreased, with increasing leaf [Pi]. The response of A to internal CO2 concentration (C i) indicated that at lower P supplies A became increasingly restricted by limitations associated with Rubisco and RuBP regeneration. Stomatal limitation may in part be masking the full effect of P supply on A as C i declined with either increasing soil P or leaf [Pi] supply. We conclude that leaf [Pi] was a potentially better indicator than [Pt] or [Po] for correlating the effects of soil P supply on growth and photosynthesis of E. grandis. Furthermore, as A achieved at saturating C a increased with increasing P supply leaf [Pi], these findings suggest that a greatly increased rate of canopy assimilation could be achieved at higher P supply in response to the expected increase in global CO2 levels. [Copyright &y& Elsevier]

Wood density influences both the physiological function and economic value of tree stems. We examined the relationship between phosphorus (P) supply and stem wood density of Eucalyptus grandis Hill ex Maiden seedlings grown with varying soil P additions and determined how changes in wood anatomy and biomass partitioning affect the relationship. Plant height, stem diameter and total biomass increased by 400–500% with increasing P supply. Stem wood density decreased sharply from 520 to 380 kg m−3 as P supply increased to 70 mg P kgsoil−1. Further increases in P supply to 1000 mg P kgsoil−1 had no effect on wood density. The increase in wood density at low soil P supply arose principally from enhanced secondary wall thickening of stem fiber cells. Cell wall thickness increased from 3.6 to 4.5 μm as soil P supply decreased. Because fiber cell diameter was independent of soil P (12 μm ± 0.3), the proportion of the stem occupied by cell wall material increased as P supply declined. The enhanced secondary wall thickening of stem fiber cells at low P supply was not associated with changes in whole-plant biomass partitioning. Instead, low P supply appeared to alter biomass partitioning within the stem in favor of secondary wall thickening. Thus, increased wood density in E. grandis seedlings grown at low P soil supply was associated with inhibited stem cambial activity, resulting in an increased proportion of photoassimilates available for secondary wall thickening of fiber cells. [ABSTRACT FROM PUBLISHER]

Eucalyptus species are the native and major plant group in Australian landscapes. Since European settlement, eucalypt trees heavily decline in the tablelands of New South Wales. Tree recruitment bog down and the landscape ecosystem hardly recovers to the original state. This paper introduces the history of eucalypt trees and native shrubs decline, analyzes reasons of seedling recruitment decrease in this region, such as clearing grazing, fire, competition from exotic species, dieback, insects, drought and so on, and summarizes the probable conditions of eucalypt tree recruitment, such as suitable conditions of seedling survival, sufficient seed supply, keep from predation, suitable germination conditions, non-grazed environment, mechanical treatment, weed control, fire regime, disease control etc, lending suggests how to preserve and encourage eucalypt trees recruitment in the area. [ABSTRACT FROM AUTHOR]

Abstract: Alpha-cypermethrin is widely used in Australian forestry to control defoliating beetle pests but no information exists on its efficacy against beetle pests or impacts on non-target arthropods. To address this deficiency I quantified the short-term impacts of single commercial applications of the insecticide alpha-cypermethrin on populations of both defoliating beetle pests and beneficial arthropods over 12 months in two southwestern Australian eucalypt plantations. A single application of alpha-cypermethrin (24g a.i./ha) in October or November reduced beetle pest populations to near zero levels. Beetle recovery began immediately after spraying but high populations of eucalyptus weevil and chrysomelid beetles, and high defoliation levels did not eventuate until 10–12 months later. Despite the success of alpha-cypermethrin in controlling defoliating beetle pests, the broad-spectrum nature of the insecticide led to nearly complete mortality of all beneficial arthropods immediately after spraying. Spiders were the main group of beneficial arthropods present after spraying probably because some individuals occupy a concealed and protected habitat. Populations of Anaphes nitens (Girault), the important eucalyptus weevil egg parasitoid, also partly survived the spray because they were protected within weevil egg masses. Post-spray recovery of both beetle pests and beneficial arthropods occurred gradually in the following 12 months, presumably through immigration from outside the plantation. [Copyright &y& Elsevier]

With high quality petroleum running out in the next 50 years, the world governments and petrochemical industry alike are looking at biomass as a substitute refinery feedstock for liquid fuels and other bulk chemicals. New large plantations are being established in many countries, mostly in the tropics, but also in China, North America, Northern Europe, and in Russia. These industrial plantations will impact the global carbon, nitrogen, phosphorus, and water cycles in complex ways. The purpose of this paper is to use thermodynamics to quantify a few of the many global problems created by industrial forestry and agriculture. It is assumed that a typical tree biomass-for-energy plantation is combined with an efficient local pelleting facility to produce wood pellets for overseas export. The highest biomass-to-energy conversion efficiency is afforded by an efficient electrical power plant, followed by a combination of the FISCHER-TROPSCH diesel fuel burned in a 35%-efficient car, plus electricity. Wood pellet conversion to ethanol fuel is always the worst option. It is then shown that neither a prolific acacia stand in Indonesia nor an adjacent eucalypt stand is “sustainable.” The acacia stand can be made “sustainable” in a limited sense if the cumulative free energy consumption in wood drying and chipping is cut by a factor of two by increased reliance on sun-drying of raw wood. The average industrial sugarcane-for-ethanol plantation in Brazil could be “sustainable” if the cane ethanol powered a 60%-efficient fuel cell that, we show, does not exist. With some differences (ethanol distillation vs. pellet production), this sugarcane plantation performs very similarly to the acacia plantation, and is unsustainable in conjunction with efficient internal combustion engines. [ABSTRACT FROM AUTHOR]

Development of ovular structures in the `eucalypt group' (Eucalyteae, Myrtaceae) was investigated using scanning electron microscopy and light microscopy. Different modes of placental expansion account for the variation in initiation and arrangement of ovules and ovulodes. In Eucalyptus sensu stricto placental elongation proceeds proximally and the distally-positioned ovulodes develop from the first primordia initiated (congenital ovulodes). In Angophora, Corymbia, Arillastrum, Allosyncarpia and Stockwellia placental elongation is bi-directional and the ovulodes develop from last-initiated primordia (residual ovulodes). Bi-directional elongation and residual ovulodes are present in the outgroup taxon Lophostemon confertus and is presumably plesiomorphic. This suite of characters is potentially informative for resolving relationships for several key taxa: E. microcorys (subgenus Symphyomyrtus) has proximal placental expansion and congenital ovulodes, which is consistent with most Eucalyptus; E. curtisii (subgenus Gaubaea) has the plesiomophic condition and may be sister to all other species of Eucalyptus. [ABSTRACT FROM AUTHOR]

The complete nucleotide sequence of the chloroplast genome of the hardwood species Eucalyptus globulus is presented and compared with chloroplast genomes of tree and non-tree angiosperms and two softwood tree species. The 160 286 bp genome is similar in gene order to that of Nicotiana, with an inverted repeat (IR) (26 393 bp) separated by a large single copy (LSC) region of 89 012 bp and a small single copy region of 18 488 bp. There are 128 genes (112 individual gene species and 16 genes duplicated in the inverted repeat) coding for 30 transfer RNAs, 4 ribosomal RNAs and 78 proteins. One pseudogene (ψ-infA) and one pseudo-ycf (ψ-ycf15) were identified. The chloroplast genome of E. globulus is essentially co-linear with that of another hardwood tree species, Populus trichocarpa, except that the latter lacks rps16 and rpl32, and the IR has expanded in Populus to include rps19 (part of the LSC in E. globulus). Since the chloroplast genome of E. globulus is not significantly different from other tree and non-tree angiosperm taxa, a comparison of hardwood and softwood chloroplasts becomes, in essence, a comparison of angiosperm and gymnosperm chloroplasts. When compared with E. globulus, Pinus chloroplasts have a very small IR, two extra tRNAs and four additional photosynthetic genes, lack any functional ndh genes and have a significantly different genome arrangement. There does not appear to be any correlation between plant habit and chloroplast genome composition and arrangement. [ABSTRACT FROM PUBLISHER]

Since European settlement,Eucalyptusbox woodlands have been substantially modified by agricultural practices, and in many areas in southern Australia are now restricted to scattered or clumped trees. We report here on a study to examine the impact of trees on water flow (infiltration) in an agricultural landscape with substantial areas of extant native vegetation. We examined infiltration through coarse- and fine-textured soils within four landscape strata, the zones belowEucalyptus melliodoraandCallitris glaucophyllacanopies, the intertree zone dominated by perennial grasses and a landscape homogenized by cultivation and dominated by annual crops. We measured sorptivity, the early phase of water flow, and steady-state infiltration with disc permeameters at two supply potentials. These different potentials enabled us to separate infiltration into (i) flow through large (biopores) and small pores and (ii) flow through small pores only where biopores are prevented from conducting water. On the fine-textured soils, both sorptivity and steady-state infiltration were significantly greater (approximately fivefold) under the timbered strata compared with the grassy slopes or cultivation. Differences were attributable to the greater proportion of macropores below the tree canopies compared with the nontimbered strata. The lack of a significant difference on the coarse-textured soils, despite their macropore status, was attributed to differences in surface litter and plant cover, which would maintain continuous macropores at the surface and thus conduct large amounts of water. The tendency of slopes covered by cryptogamic crusts and grasses to shed run-off and for the trees to absorb substantial quantities of water reinforced the important ecological service provided by trees, which moderates large run-off events and captures small amounts of water leaking from the grassy patches. In the absence of these‘ecosystem wicks’, run-off would find its way into regional groundwater and contribute to rising salinity. [ABSTRACT FROM AUTHOR]

Climate models use broad definitions of vegetation-based biophysical parameters that may not represent the continentally-specific nature of Australian vegetation well. This paper explores the impact on the January simulation of climate over Australia of this common simplification. First, we map the Australian distribution of vegetation types onto the default classification used in one high-resolution climate model. Second, through a search of the literature we chose replacement values for the biophysical parameters to better reflect the properties of eucalypts. Third, we choose several sets of biophysical parameters and allow these to vary regionally. We assess the impact of these changes on simulated rainfall, temperature and latent heat flux over an ensemble of six different Januaries. We find that the model simulates rainfall and temperature reasonably well over Australia in January and that replacing the default parameter set with a single set of more appropriate values degrades model performance slightly. Allowing the biophysical parameters to vary regionally leads to some small improvements in the simulation of temperature and precipitation. We find large impacts on the simulated latent heat flux. Overall, the model is not substantially improved by careful selection of eucalypt parameters. We comment that given the shortage of observed data on eucalypts and the almost total absence of biophysical parameters for other Australian vegetation types, this lack of sensitivity to the biophysical parameters is reassuring since it implies that the lack of data is not presently seriously limiting to our particular modelling capability. [Copyright &y& Elsevier]

Plant resistance to herbivores can be influenced not only by the independent effects of plant genotype and environmental variation, but by interactions between the two. The main aim of this study was to assess the effects of environmental variability (nutrient treatment) on the known genetic-based expression of resistance and defensive chemistry ofEucalyptus globulusto browsing by the generalist mammalian herbivoreTrichosurus vulpecula. In a captive feeding trial, we measured intake of seedlings from one relatively resistant (Blue Gum Hill) and one relatively susceptible (St Helens) population ofE. globulusgrown under two nutrient treatments (no fertiliser, plus fertiliser). There was a significant genotype×fertiliser interaction effect on intake ofE. globulusfoliage byT. vulpecula, and the predicted genetic-based resistance of the two populations was expressed only for the non-fertilised treatment. Expression of resistance largely reflected the combined and inverse effects of nitrogen and condensed tannin concentrations. The expression of plant secondary metabolite concentration differed between compounds, but in all cases the effects of plant genotype and fertiliser treatment were independent. The formylated phloroglucinol compounds differed significantly between genotypes but not between fertiliser treatments. In contrast, the effect of plant genotype on the expression of condensed tannins was weak but they were significantly reduced by fertiliser. Essential oils were influenced by both plant genotype and fertiliser treatment and were significantly higher in the fertilised seedlings than in the non-fertilised seedlings. This study highlights interactive effects of plant genotype and environment in influencing the phenotypic expression of resistance in a eucalypt species to a mammalian browser. It also demonstrates that this interactive effect is the net result of independent effects of genotype and environment on plant chemistry and finally, that different groups of compounds within a plant can respond very differently to variation in environmental conditions. [ABSTRACT FROM AUTHOR]

1 Eucalyptus globulus Labill. exhibited consistent intraspecific variation in oviposition choice by Mnesampela privata (Guenée) (Lepidoptera: Geometridae) in field surveys of host plants that had been designated, based on the prior season's defoliation levels, as resistant or susceptible to M. privata. At both field sites significantly fewer egg batches were found on resistant compared to susceptible trees. 2 In cage bioassays we demonstrated a significant oviposition preference by M. privata, with over two-fold greater number of egg batches laid on foliage sprigs from susceptible compared to resistant trees. Despite differences in tree oviposition choice, we found no evidence in the field or the laboratory of adult females adjusting egg batch size in accordance to oviposition preference. 3 Caged larval survival, development times and pupal weight did not vary significantly between resistant and susceptible trees. Similarly, in a laboratory feeding experiment, neonates utilized resistant and susceptible foliage equally. 4 Larval mortality in the field attributed to natural enemies did not vary significantly between resistant and susceptible trees, nor did the percentage of Telenomus sp. parasitism of M. privata eggs within a batch and batches per tree. 5 Failure to associate either larval performance or natural enemy efficacy with the observed intraspecific variation in E. globulus susceptibility to M. privata oviposition indicates that some other unidentified factors drive the evolution of host selection for oviposition. [ABSTRACT FROM AUTHOR]

Soil water repellency can enhance overland flow and erosion and may be altered by fire. The Christmas 2001 bushfires near Sydney allowed investigation of the relationship between fire severity, water repellency and hydrogeomorphological changes. For two sub-catchments with differences in fire severities in Nattai National Park, south-west of Sydney, this paper considers: (1) the links between fire severity based on SPOT image analysis and ground observation of fire severity and repellency; (2) the textural and organic/minerogenic characteristics of eroded sediment; and (3) erodibility, erosion and deposition of soils in both catchments. Ground surveys show that image analysis reflects well the degree of vegetation consumption by fire, but cannot adequately predict the degree of ground litter consumption, associated soil heating and repellency effects. Fire had varying effects on repellency, leaving it unchanged, destroying it or enhancing it, depending on the soil temperature reached. The main post-fire hydrogeomorphological changes have been widespread erosion and colluvial and alluvial deposition of topsoil in foot-slope locations and river systems, but only localised redistribution of the highly erodible, repellent sandy subsurface layer. The fire did not trigger major geomorphological change in the study area, but fires probably cause important topsoil and nutrient depletion and may also affect water quality. [ABSTRACT FROM AUTHOR]