The endangered brush-tailed rock-wallaby (Petrogale penicillata) has declined significantly across its range in south-eastern Australia. Several catchments in north-eastern New South Wales (NSW) represent the last strongholds for the species in the wild. Appropriate management of these populations is of critical importance. This thesis outlines an investigation of the efficacy of current management of brush-tailed rock-wallabies in the Green Gully section of Oxley Wild Rivers National Park (OWRNP).

Plant species diversity on the North-West Slopes of New South Wales is threatened by pastoral management activities, both past and present. Native vegetation has been extensively cleared for livestock grazing, which has created a landscape in which only remnants of original vegetation are retained. However, large areas of derived native pasture have been retained on private grazing land, providing habitat for many native flora and fauna. This thesis investigates the patterns of plant species distribution across the region to determine the contribution of each of the major land uses to regional plant diversity. A particular focus was on the impact of land management at broad (landscape and regional) spatial scales.

In Australia, substantial ecological restoration of farmland is undertaken in conjunction with community-based natural resource management agencies, with the objective of balancing agricultural land use and biodiversity conservation through revegetation with native species. Across the North-West Plains of New South Wales (NSW), both large-scale and small-scale restoration efforts are frequently required. However, fragmented agricultural landscapes, the lack of sufficient scientific information on the seed ecology of native species and the environmental conditions associated with the region's vertosol soils are major challenges for revegetation. This thesis investigated germination traits in 73 plant species that are important components of endangered vegetation communities in north-western NSW to produce information useful for plant propagation and ecological restoration. In order to identify the optimum combination of environmental conditions to maximise the percentage and rate of germination in 14 'Eucalyptus' seedlots of ten species from north-western NSW, germination responses to seasonal temperature regimes and light were examined, and the relationship between these factors and seed size investigated. The effect of three alternating day/night temperature treatments (spring, summer, winter) and two light treatments (light/dark, dark) was investigated in growth cabinets. Germination patterns varied between species and seedlots. In general, the presence of light and winter and spring temperatures resulted in higher average germination than darkness and summer temperatures. However, some seedlots germinated consistently well under all treatments. Germination of small seeds was higher in the presence of light while larger seeds germinated better under continuous darkness. Time to germination was about threefold faster in response to summer and spring temperatures than winter temperatures. The seeds of many acacias, which are important in ecosystem regeneration due to the ability of 'Acacia' species to fix nitrogen, have a physical dormancy that must be broken prior to their use. In order to identify convenient methods to break seed dormancy in ten 'Acacia' species from north-west NSW, seed response was investigated to three dormancy-breaking treatments and two incubation temperatures. Mechanical scarification (two intensities) and hot water were applied as seed pre-treatments and seeds incubated under two temperature/light-controlled treatments in germination cabinets. The results varied with species but the three dormancy-breaking treatments significantly increased germination percentage or reduced the time to germination in all but one species. Temperature had an effect on only one species. Germination was greater or more rapid after mechanical scarification than after hot-water treatment. North-western NSW is one of Australia's biodiversity 'hotspots' due to the number of endemic plants and diversity of species, some of which lack seed ecology information for restoration and conservation purposes. Seeds of 49 species were investigated to identify limitations to germination, the pre-treatments needed to overcome such limitations, and determine the suitability of these species for direct seeding or propagation from seed. Seed viability, germination under different seasonal temperatures (winter, spring/autumn, summer) and a requirement for seed pretreatment to promote germination were all assessed experimentally in germination cabinets. Seed viability varied widely among the 49 species; temperature determined germination success in 27 species and various seed pre-germination treatments were effective in increasing germination percentage in 22 species. The results will be useful in propagating these species in the nursery and for direct seeding in the field. The decline in eucalypt-dominated woodlands across the wheat–sheep belt of southern and inland eastern Australia is of concern, and revegetation targets have been set to restore woody vegetation cover in over-cleared landscapes. In order to provide guidelines for direct-seeding eucalypts in large-scale revegetation of cracking clay soils in north-western NSW, seedling emergence was investigated in relation to moisture regime, sowing depth and seed size in six species of 'Eucalyptus' in a glasshouse experiment. Seedling emergence was low despite high seed viability and provision of optimum temperatures and soil moisture. All six species exhibited greatest emergence when sown at 0–6-mm depth, with seed size being less important than moisture (except under dry conditions) and proximity to the surface. Species responded differently to the three watering treatments. Success in direct-seeding these species in vertosol soils in the region may be unreliable. The findings of this research should contribute to seed management and direct seeding in large-scale revegetation projects on cracking clay soils in the agricultural districts of north-western NSW. The research variously examined the seed viability, quality, persistence and germination response of seeds in a range of species to light, temperature and sowing depth. It aimed to determine where release of germination constraints was necessary, as well as cost-effective techniques that can be applied to large quantities of seed required in broad-acre revegetation.

Natural pastures, which are dominated by native plant species, occupy an extensive proportion of Australia (432 M ha, or 56% of the continental landmass). Traditional grazing methods (continuous set-stocking) can lead to low levels of herbage mass, litter mass and ground cover, which in turn leads to high surface runoff, high soil evaporation, and poor pasture growth. A key component of designing a sustainable grazing system for these pastures includes a sound knowledge of the impact of that system on the hydrological balance. A grazing management experiment was established at Springmount near Barraba on the North-West Slopes to study the effect of five grazing treatments on pasture characteristics while monitoring the associated impact on selected components of the hydrological balance. The grazing treatments included: continuous grazing (4 and 6 sheep/11a), continuous grazing with subterranean clover and fertiliser applied (8 sheep/ha), and rotational grazing (4 sheep/ha) with pastures grazed for four weeks and rested for four weeks (two paddock rotation) or rested for 12 weeks (four paddock rotation). The continuous grazing treatments had significantly lower mean levels of herbage mass (1500-1800 kg DM/ha), litter mass (1)0-110 kg DM/ha) and ground cover (70-73%) compared with either rotational grazing or over-sowing with subterranean clover (3000-3500 kg DM/ha, 210-260 kg DM/ha, and 83-90% for herbage mass, litter mass and ground cover, respectively).

'Farmscapes' are farming landscapes that comprise combinations of forests and scattered remnant vegetation (trees), natural and improved grasslands and pastures and crops. Scattered eucalypt trees are a particular feature of Australian farmscapes. There is a growing need to assess carbon and biomass stocks in these farmscapes in order to fully quantify the carbon storage change in response to management practices and provide evidence-based support for carbon inventory. Since tree trunk diameter, more formally known as diameter at breast height (DBH), is correlated with tree biomass and associated carbon stocks, DBH is accepted as a means inferring the biomass–carbon stocks of trees. On ground measurement of DBH is straightforward but often time consuming and difficult in inaccessible terrain and certainly inefficient when seeking to infer stocks over large tracts of land. The aim of this research was to investigate various avenues of estimating DBH using synoptic remote sensing techniques. Tree parameters like crown projected area, tree height and crown diameter are all potentially related to DBH. This thesis first uses on–ground measurements to establish the fundamental allometric relationships between such parameters and DBH for scattered and clustered Eucalyptus trees on a large, ~3000-ha farm in north eastern part of New South Wales, Australia. The thesis then goes on to investigate a range of remote sensing techniques including very high spatial resolution (decicentimetre) airborne multispectral imagery and satellite imagery and LiDAR to estimate the related parameters. Overall, the research demonstrated the usefulness of remote sensing of tree parameters such as crown projection area and canopy volume as a means of inferring DBH on a large scale.

Frequent fires have been suggested to result in a decline in plant species composition and structure in Australian plant communities. This is especially apparent in regions in northern NSW thought to have had a history of frequent low intensity fires, primarily due to accidental ignitions and ignited to promote grass for cattle grazing. The aim of this study was to investigate recent fire regimes and their impacts on the vegetation composition and structure to address future fire management planning. The study was undertaken in Guy Fawkes River National Park in northern NSW, through compiling a fire history by integrating hard-copy fire records and filling gaps with multi-temporal satellite imagery. The 25-year fire history provided the stratification variables for a survey of the current vegetation patterns in relation to a number of fire frequency attributes including number of fires, shortest inter-fire interval and time since last fire. The results from the vegetation study demonstrated that shrub and tree species richness declined with increasing number of fires and shorter inter-fire intervals. This was particularly evident in the Tablelands area of the study region where the fire history was more varied and the environmental variation more constrained. The study also revealed a sharp decline in the abundance of woody shrubs and an accompanying simplification of the structure of the vegetation community with increasing number of fires and shorter intervals between fires. Complementary soil seed bank studies were undertaken to compare the impacts of high and low fire frequency. A reduced abundance of shrub species was apparent in the seed bank of sites with a history of frequent fires. Shrub species, such as Acacia irrorata, were predominantly found in the seed bank of long unburnt sites. The information from these studies was used to develop a management framework based on fire thresholds for species and vegetation community conservation. Plant species data compiled from these plus other studies provided information on regenerative mechanisms following fire, the time to reproductive maturity and longevity. Fire thresholds were determined for the majority of communities in the study region, above and below which plant species were likely to decline. This framework of fire thresholds was used to identify areas where the minimum recommended time period between fires had been exceeded in the 2000/01 fire season. Five vegetation communities were identified with 80% or more of the total area exceeding the recommended fire threshold, indicating that a decline in plant species richness was possible due to recent fire regimes. The study provided the first fire ecology study in this region and a baseline on which to build future research. The integration of fire ecology information into spatially explicit fire management guidelines was demonstrated, providing the basis for future planning for the preservation of plant species and vegetation communities in large conservation areas.

Various anthropogenic transformations and modifications have continuously modified and/or changed the land cover for centuries for different forms of human productions. These ultimately impacted or changed the biodiversity, nutrient and hydrological cycles as well as global environment and climate, especially in the developing world. Australia has a great variety of native vegetation ranging from rainforests, alpine habitats, wetlands, grasslands, eucalypt forests and woodlands reflecting the diversity of species, habitats and ecosystems found across the country. The destruction of habitat due to native vegetation clearing has been identified as the greatest single threat to biodiversity in New South Wales (NSW), Australia. The clearing has mainly taken place in grassy woodlands areas for pasture improvement by the application of fertilizers, ploughing and the sowing of introduced grasses and clovers. This research explored the potential of a range of remote sensing and modelling techniques to assist in the investigation of suitability of land cover mapping in terms of time-period, methods, and seasonal and long term land cover change in the north-eastern parts of NSW, Australia. The overall aim of this research was to investigate the potential of remote sensing, GIS and modelling techniques in detailed investigations of seasonal and nearly four decadal land cover change analysis and assessment of long term pattern of land cover change for future change predictions. The research also aimed at assessing the impact of land cover change on terrestrial habitat configurations.

Extensive bushfires have been a recurring feature in the forests and woodlands of south-eastern Australia and the threat from fire to both the community and the environment is forecast to grow as the incidence of fire and drought is predicted to increase due to climate change. Notwithstanding the loss of life and property caused by these fires and demands from the community for protection from fire by increasing the area of hazard reduction burning, the effects of such burning on fauna, flora and wildlife habitat have not been fully considered. This omission assumes greater importance as attrition of fauna habitat attributes from the landscape has been exacerbated by clearing, urbanisation and other forms of habitat destruction and modification. Thresholds for burning vegetation communities in New South Wales (NSW) are based on plant species' responses to fire and do not consider multi-factorial issues such as drought, site attributes or fauna requirements. The aim of the research reported in this thesis was to investigate knowledge gaps concerning the impact of fire on habitat features of open forests and woodlands on the Northern Tablelands and North-West Slopes of NSW, to extend understanding of the nexus between fire and species diversity to encompass environmental variables at a landscape scale and to consider the adequacy of the theory of fire management based on traits of flora species' fire responses. The consequences of managing fire at broader scales are complex and this study tests ideas concerning the incorporation of severe drought and landscape attributes into fire planning and biodiversity conservation beyond the use of fire as a single issue management tool.

Revegetation in agricultural regions across the globe has intensified over past decades in an effort to reverse widespread land degradation and conserve natural ecosystems and the biodiversity they contain. Biodiversity is essential for the physical, economic, social and cultural dimensions of human well-being, but agricultural intensification has resulted in the loss of millions of hectares of forests and natural vegetation globally. In Australia, a brief, but intense history of land clearing has resulted in the loss of 50% of forest ecosystems, with over 80% of eucalypt-dominated woodlands and forests having been altered by human endeavour. The situation on the Northern Tablelands of New South Wales reflects land clearing practices throughout the country with an estimated loss of tree cover of 50% to date. Although land clearing has eased in the past decade, tree decline continues due to recurrent episodes of rural dieback. To address this problem, substantial efforts have been made by revegetation organisations, practitioners and landholders to re-establish native trees in the region, but plantings often fail. This research was conducted to identify and reverse ecological barriers preventing the success of revegetation in temperate upland pastures. The work focused on tubestock plantings and direct seeding.
The first study was conducted to determine if existing native shelterbelts can be evaluated in terms of survival and growth to identify the environmental stresses influencing planted eucalypt establishment and growth on the Northern Tablelands. Most ‘on-ground’ revegetation is designed and implemented with no thought given to follow-up scientific monitoring. Monitoring is important not only to justify the large amounts of public funding directed into revegetation activities, but also because it demonstrates whether targets have been achieved, and provides opportunities to learn from and improve upon past failures. Six-year old shelterbelt plantings consisting of Eucalyptus nitens, E. pauciflora and E. viminalis were examined to identify potential biotic and abiotic stresses influencing tree performance. Topographic position, altitude, slope, temperature, soil type, soil moisture and weed control were measured and modelled in relation to tree survival and growth (height). The information theoretic approach was used to select the best-fitting model from a set of competing models. Poor weed control and subzero temperatures were identified as the predominant stresses affecting eucalypt survival during the monitoring period. Subzero temperatures also significantly influenced tree growth.
Given these results, the second study compared the performance of five native tree and shrub species grown in tall Corflute® tree guards and milk cartons at three landscape positions (lower slope, mid slope and upper slope) in an open temperate pasture. Seedlings in tall guards survived better than seedlings in milk cartons at mid and upper-slope landscape positions. Height was also greater for seedlings in tall guards than milk cartons at all landscape positions. Eucalypts in particular benefited from tall guards, with height growth up to three times greater than in milk cartons. Tall guards increased the temperature surrounding seedlings inside the guards, extending the growing period.
Next, the efficacy of direct seeding as a revegetation technique was investigated. Prior to conducting this investigation, three trial sites were established and monitored for 3–6 months at Bingara, Ben Lomond and Invergowrie. Recruitment and subsequent establishment was so poor that the trials were considered a failure. This study compared the effects of three sowing methods (KB seeder, modified Chatfield planter and hand sowing) and three bulking materials (rice, chicken crumble and smoked vermiculite) on the recruitment of direct-seeded acacias and eucalypts. Recruitment was highest with the KB seeder followed by the Chatfield seeder and hand-sown methods. There were no significant differences in recruitment among bulking materials. Eucalypt recruitment was low compared to the recruitment of acacias. Recruitment peaked in mid May (8 weeks post-sowing) for acacias and in early July (15 weeks post-sowing) for eucalypts, but declined markedly for both genera during the reminder of the study. Some seedling losses were incurred following the first heavy frost, but most were attributed to an invasion of rat’s tail fescue (Vulpia myuros) in late winter, and waterlogging in the lower areas of the site due to above-average rainfall between May and August.
Based on the results of the previous study two subsequent investigations were designed and implemented. To address the problem of weed invasion in direct-seeded revegetation, the effect of eight herbicide oversprays on the survival of 11 native tree and shrub species was examined. Seedling survival was assessed at 1, 2, 7 and 8 weeks post-spraying. Survival was greatest in seedlings treated with imazethapyr and isoxaflutole, and least in seedlings treated with diflufenican and glyphosate. There were also significant differences in survival between species, with Dodonaea viscosa, Acacia pendula and Senna artemisioides exhibiting the highest tolerance to the greatest range of herbicides, and Atriplex nummularia, Casuarina cristata and Einadia nutans exhibiting the lowest tolerance. Species varied in their tolerance of different herbicides, due to the selective nature of the different modes of action of the active ingredients and their differential uptake, translocation and metabolism between species.
To address the problem of poor eucalypt recruitment, the effects of three seed-coating treatments (coated seed, seed coated with MycoApply® and uncoated seed), four watering regimes (30 mL per day, 30 mL per 3 days, 30 mL per 5 days and no water), and two seed-sowing methods (surface-sown vs buried beneath a 5-mm vermiculite layer) on eucalypt germination and early establishment were examined. Coating the seed with microbial inoculants as well as daily watering significantly increased germination. The interaction between sowing method nested within coating treatment and watering regime was significant. Soil moisture was essential for eucalypt germination and MycoApply® appeared to enhance water capture during the critical early post-germination phase when desiccation was most likely. When soil moisture was limited, seed burial beneath vermiculite was important because it increased seed-soil contact, providing better access to soil moisture, but only in seed coated with microbial inoculants. Seed-coating treatments did not benefit seedling growth (height) because soil moisture was not limiting.
The final study examined the effects of four weed-control treatments (scalping, glyphosate, sugar and glyphosate, and sawdust and glyphosate) on the recruitment of native grasses and weed suppression. Recruitment of native grass was significantly higher in scalped plots compared to other treatments. The most effective weed- control treatments were scalping and the combinations of sugar and sawdust with glyphosate. Scalping and carbon (sugar and sawdust) addition controlled weeds by depleting weed seed banks, and alleviating soil nutrient enrichment. In combination with glyphosate application, which removed above-ground biomass, these techniques were effective strategies for combatting competitive invasive weeds.
A summary of the main findings, study limitations and recommendations for future research were presented in the final chapter.

Over 50% of the alluvial plains of the Moree Shire are used for dryland and irrigated cropping, and most of the remaining land is grazed by livestock. The 'Dichanthium sericeum' (Queensland Bluegrass) and 'Astrebla' spp. (Mitchell Grass) tussock grasslands were once common on the fertile clay soils of the region, but have suffered large reductions in area through cultivation. These grassland communities are also poorly conserved and only occur within one reserve (Kirramingly Nature Reserve) in New South Wales. There has been little conservation-oriented research into these grasslands, and there is a need for research to determine the best management strategies to conserve their plant diversity.

Coolibah ('Eucalyptus coolabah' subsp. 'coolabah' Blakely & Jacobs) woodlands in the Darling Riverine Plains of New South Wales have been extensively cleared and modified since European occupation. Coolibah regenerated densely following floods in the 1970s and patches of dense regeneration are perceived to have negative effects on plant biodiversity although there is no documented evidence to support this notion. This thesis investigates aspects of the community and population dynamics of coolibah woodlands in order to investigate the potential negative effects of dense regeneration on plant biodiversity, and to assess the role of dense regeneration in the conservation of biodiversity and woodland persistence in the landscape. I found that patches of dense regeneration contained greater species richness and diversity of groundstorey plants compared to adjacent grasslands. When I compared alternative vegetation states - remnant woodlands, dense regeneration, derived grasslands and degraded derived grasslands - I found that groundstorey plant composition was not strongly associated with vegetation structure and that dense regeneration contained some woodland-associated groundstorey species that were uncommon in grassland states. Tree size distributions revealed that dense regeneration occurs where large trees are sparse, remnant woodlands appear to have regenerated episodically in the past and there is little ongoing recruitment within remnant woodlands. I investigated the ability of coolibah seedlings to establish in derived grasslands and found that tree seedling survival was affected more by seasonal conditions and herbivory than competition from grasses and that grasses actually facilitate seedling survival following germination. I propose that these results support a patch-dynamic model in which dense regeneration patches replace old-growth woodlands and contribute to the persistence of woodlands in the landscape. Further, these results suggest that dense regeneration occurs sporadically in response to rare climatic conditions, has no negative effects on plant diversity or composition and appears to be on a trajectory towards the remnant state.

This study examined whether the response of herbaceous vegetation to environmental disturbances such as mechanical soil disturbance and fertilization can be predicted from a knowledge of the component species' plant attributes. Some aspects of Grime's (1979) C-S-R model were also tested. The model proposed that the three permutations of low stress and low disturbance, low stress and high disturbance, and high stress and low disturbance are associated with competitive (C), ruderal (R) and stress-tolerant (S) plant strategies, respectively. A completely randomised block experiment with three factors, soil disturbance, fertilization and sowing, was established in an area of moderately grazed temperate grassland on the Northern Tablelands of New South Wales. The site was dominated by the tall, warm season perennial grasses, 'Aristida ramosa' and 'A. warburgii' and its yellow podzolic soil was deficient in phosphorus, nitrogen and sulphur. The study area experiences an annual average rainfall of 914 mm, an annual average maximum temperature of 20.3°C and an annual average minimum temperature of 7.3°C. There were three levels of soil disturbance (none, hand-hoed and rotary-hoed), two levels of fertilization (none and fertilized NPS) and two levels of sowing (none and sown). The sown treatment consisted of hand-sowing the propagules of seven exotic species into the plots. During the experimental period (August 1992 -February 1994), the sown treatment was applied once in August 1992, disturbance was applied annually in August, fertilizer was applied twice a year and the vegetation was sampled in spring (November) and summer (March/February) each year. ... In conclusion, the response of herbaceous vegetation to mechanical soil disturbance and fertilization could be predicted from a knowledge of the component species' plant attributes. Plant attributes relating to plant persistence, biomass partitioning (leaves vs reproduction vs storage), and use of resources (conservative versus liberal) were strongly related to fertilization and soil disturbance. Plant attributes can discriminate between habitats as well as, or better than, floristic data. On a community scale, the influence of historical factors on vegetation response was not removed by the plant attribute approach, although it was somewhat reduced. Thus, the relationships found using this approach were of intermediate generality and are applicable to sites with a similar fertilizer and disturbance history. The greatest support for the C-S-R model was found using the key (4 predictions upheld, 1 inconsistent and 2 rejected). Support for the model was also found by testing its underlying hypotheses (2 predictions upheld, 2 inconsistent and 2 rejected), while the ordination of vegetation samples by the mean Rmax and MI of its component species was unsuccessful (0 predictions upheld, 2 inconsistent and 3 rejected). The present study shows how vegetation models may be viewed as a starting point for research and refinement rather than something that must be either wholly accepted or rejected.

Understanding, conserving and effectively managing forests is an important undertaking for managing and maintaining biodiversity, indeed globally around 65% of terrestrial taxa are supported by these ecosystems. In Australia, forest conservation is particularly important in terms of eucalypt-dominated forest, with 79% of forests in Australia dominated by eucalypts. However, the rapid and premature decline of leaf biomass in eucalypt trees, a process known collectively as 'dieback', has been observed in many eucalypt stands nationally, with the factors and processes determining mortality remaining poorly understood. Bell miner associated dieback is a particular type of dieback that has been associated with the presence of, and tri-trophic interactions among bell miners, 'Manorina melanophrys', a native, despotic honeyeater, an introduced plant lantana, 'Lantana camara', and arbivorous insects such as psyllids. Together, these three factors have been suggested to cause dieback throughout southeast Australian forests where these groups co-occur. To gain a greater understanding of this phenomenon, this thesis examines the impact of foliar herbicide application on subsequent lantana health, bell miner density and habitat selection, soil chemistry and overall canopy health.

The aim of my thesis is to document the cultural history and heritage of the ancient Australian canine, the dingo. An analysis of the complex symbiotic relationship between the dingo and human society for over 4,600 years reveals an animal uniquely positioned as both a human companion and top-order predator - fulfilling important ecosystem services across the Australian mainland, complementary to their role in traditional Aboriginal society. The thesis collates ethnographic, scientific and social representations of the dingo, and interrogates the legacy of 200 years of dingo control across the south-eastern third of the continent. I use a writing technique called a prosopography to explore areas of knowledge about dingoes, and the culture and heritage surrounding them. This involves recording human-animal encounters in the form of the stories of individual animals within a contextual history, revealing themes, patterns, inconsistencies and anomalies in dingo-human history. The listing of the species as endangered on the IUCN Red List (2004) and as a threatened species in the State of Victoria (2008) underscores the importance of critical analysis, revealing processes underlying the construction and dissemination of dingo knowledge that reinforce their cultural and physical marginalization. The study reveals a complex human-dingo history, and strives to present this information in a comprehensible format as a basis for discussion - allowing new insights into the unique history of the dingo's survival at the heart of traditional Aboriginal society and at the limits and borderlands of contemporary environmental management.

Previous studies have indicated that 'Eucalyptus radiata' Sieb. ex DC subsp. 'radiata' has the potential to produce a high quality medicinal oil commanding a premium price over other species in a niche market. This study has two aims: (1) to assess the potential gain in 'E. radiata' subsp. 'radiata' tree growth and essential oil traits achieved through selection and breeding; and (2) to determine the effect on economic viability of a farm-scale eucalyptus oil enterprise through utilising selected 'E. radiata' subsp. 'radiata' stock and varying a number of key production parameters. The work is based on a 38-month-old provenance/progeny trial of 32 open-pollinated families from four south-eastern NSW provenances, at Brogo in southern New South Wales. Tree growth and essential oil traits were assessed. Heritability and genetic correlation of traits were determined, and estimations of gain in the key traits of leaf oil concentration, tree basal area and 1,8-cineole content through selection were calculated. A breeding strategy was proposed.

Scattered paddock trees are keystone features in temperate grazing landscapes in Australia. These scattered trees provide a range of ecological functions, and the impact of these trees on the environment is large relative to the small area they individually occupy. However, our understanding of the influence of these trees on their immediate environment is limited. In this thesis, the effects of scattered mature Eucalyptus trees on both native and sown pasture systems are examined in the temperate landscapes of the Northern Tablelands of New South Wales, Australia. Specifically, the influence of scattered trees on soil fertility, litter distribution, the nutrient pools in litter, pasture production and nutrient status, as well as the root distribution of a mature tree and the influence of shade on pasture biomass, are observed. The coarse tree roots (≥10 mm) of a scattered tree decreased with increasing depth in the soil and distance from the tree, forming a broad inverted conical structure. Most roots were largely restricted to within 2 canopy radii of the tree, and 80% of coarse roots were found below 20 cm in the soil profile. This suggests that coarse tree roots and pasture roots are unlikely to compete for the same soil resources because they occur largely at separate depths in the soil profile.