Water-use efficiency of Australian tropical trees: mechanistic analysis at multiple scales. The proposed research will provide valuable information about the physiological functioning of trees in northern Australia. Experiments will elucidate mechanisms that can result in variation in water-use efficiency among different tree species. Such a mechanistic understanding will have multiple benefits: (1) results will be able to be incorporated into process-based models of carbon and water cycling ....Water-use efficiency of Australian tropical trees: mechanistic analysis at multiple scales. The proposed research will provide valuable information about the physiological functioning of trees in northern Australia. Experiments will elucidate mechanisms that can result in variation in water-use efficiency among different tree species. Such a mechanistic understanding will have multiple benefits: (1) results will be able to be incorporated into process-based models of carbon and water cycling in the north-Australian landscape; (2) they will provide valuable information for land managers interested in optimizing both plant biomass production and water resource management; and (3) they will provide a critical test of proxy methods for identifying high water-use efficiency in taxonomically diverse tree species.Read moreRead less
High temperature limits of leaf function. In arid and semi-arid central Australia, Acacia spp. dominate the over-storey, but this shifts to Eucalyptus and Corymbia spp. in more mesic coastal regions. Areas of central Australia are extremely hot, dry and sunny, and it is this combination of stresses that likely excludes Eucalyptus spp. from many landforms. There has been little research on high temperature tolerance of Acacia and Eucalyptus, despite the putative importance of this stress, in co ....High temperature limits of leaf function. In arid and semi-arid central Australia, Acacia spp. dominate the over-storey, but this shifts to Eucalyptus and Corymbia spp. in more mesic coastal regions. Areas of central Australia are extremely hot, dry and sunny, and it is this combination of stresses that likely excludes Eucalyptus spp. from many landforms. There has been little research on high temperature tolerance of Acacia and Eucalyptus, despite the putative importance of this stress, in combination with other stresses, in limiting species? distributions. Our program of collaborative research will examine the tolerance of Acacia and Eucalyptus to a combination of high temperatures, drought and high light.Read moreRead less
An ecophysiological analysis of key factors determining jarrah forest productivity on rehabilitated bauxite minesites. Following bauxite mining, soils are prepared for rehabilitation. After sowing or planting of the original species, a vegetation is established. Despite a successful first phase of rehabilitation, there is large variation between stands 5 to 10 years later. The aim of this project is to analyse the causes of this variation, especially variation in performance of jarrah (Eucalypt ....An ecophysiological analysis of key factors determining jarrah forest productivity on rehabilitated bauxite minesites. Following bauxite mining, soils are prepared for rehabilitation. After sowing or planting of the original species, a vegetation is established. Despite a successful first phase of rehabilitation, there is large variation between stands 5 to 10 years later. The aim of this project is to analyse the causes of this variation, especially variation in performance of jarrah (Eucalyptus marginata) between sites. Nutrient and water status of trees will be assessed, in a search for correlations with plant performance. Effects of fertilisation and irrigation on plant peformance will be investigated. The remarkably high phosphate-use efficiency of jarrah will also be analysed.Read moreRead less
Balancing Water Quality and Ecosystem Health with Water Yield -- Ecosystem Response to Thinning in Wungong Catchment. Reduced rainfall in past decades and future climate uncertainty have added a sense of urgency in Australia to search for new water resources to sustain a growing economy and population. A forest thinning trial is planned in the Wungong Catchment, Western Australia, to substantially increase water yield. Thinning is attractive as a low-cost option, and is potentially suitable for ....Balancing Water Quality and Ecosystem Health with Water Yield -- Ecosystem Response to Thinning in Wungong Catchment. Reduced rainfall in past decades and future climate uncertainty have added a sense of urgency in Australia to search for new water resources to sustain a growing economy and population. A forest thinning trial is planned in the Wungong Catchment, Western Australia, to substantially increase water yield. Thinning is attractive as a low-cost option, and is potentially suitable for other catchments. However the potential environmental and ecological impacts, which are major community concerns, must be investigated. This project will assess the levels of impact, associated ecosystem responses and the capacity of catchment ecosystems to sustain such management intervention.Read moreRead less
Managing variable retention harvesting to maintain forest biodiversity—effects of forest influence and successional stage on recolonisation. The project will provide the ecological evidence that will allow forest harvesting practices to be designed to sustain the full range of biodiversity in managed forest systems. It therefore will provide the basis for sustainable forest management, with extensive economic implications. It will specifically test the biodiversity implications of the new and in ....Managing variable retention harvesting to maintain forest biodiversity—effects of forest influence and successional stage on recolonisation. The project will provide the ecological evidence that will allow forest harvesting practices to be designed to sustain the full range of biodiversity in managed forest systems. It therefore will provide the basis for sustainable forest management, with extensive economic implications. It will specifically test the biodiversity implications of the new and increasingly important variable retention methods of forest harvesting, and provide the basis for optimising these methods. In addition, the large database of DNA barcodes for forest beetles developed as a by-product by this project will provide a basis for less expensive and more accurate biodiversity assessments in sustainable management of forest systems in general.Read moreRead less
Increasing sandalwood (Santalum spicatum) recruitment in regional Western Australia through mammal conservation. The highly prized sandalwood is the basis of an industry that employs over 100 people and generates $12 million export income annually in regional WA. Natural recruitment of sandalwood is poor. This project will build on research, conducted by Murdoch University and the Forest Products Commission, that indicates natural recruitment of the tree is greatly enhance in the presence of nat ....Increasing sandalwood (Santalum spicatum) recruitment in regional Western Australia through mammal conservation. The highly prized sandalwood is the basis of an industry that employs over 100 people and generates $12 million export income annually in regional WA. Natural recruitment of sandalwood is poor. This project will build on research, conducted by Murdoch University and the Forest Products Commission, that indicates natural recruitment of the tree is greatly enhance in the presence of native rat-kangaroos who cache the seeds. This project will train an APA(I) postgraduate through an industry based project that will evaluate increased recruitment of sandalwood by native mammal caching. Many of these mammals are Conservation Dependent or Threatened with extinction.Read moreRead less
Understanding plant uptake of organic and inorganic nitrogen for optimal fertiliser application in forestry. Nitrogen (N) in soils occurs in both organic and inorganic forms. Plants can take up inorganic N - nitrate and ammonium - but, on average, these account for only 5% of the soluble N in soils. Recent evidence suggests that plants may be able to tap into some of the 95% of N that occurs in organic forms. We will investigate the importance of organic N uptake for two plantation Eucalyptus sp ....Understanding plant uptake of organic and inorganic nitrogen for optimal fertiliser application in forestry. Nitrogen (N) in soils occurs in both organic and inorganic forms. Plants can take up inorganic N - nitrate and ammonium - but, on average, these account for only 5% of the soluble N in soils. Recent evidence suggests that plants may be able to tap into some of the 95% of N that occurs in organic forms. We will investigate the importance of organic N uptake for two plantation Eucalyptus species by tracing the uptake of different N forms by bacteria, fungi and eucalypts. This information will redefine what is meant by 'available N' and will guide the development of a new test for soil N status.Read moreRead less
Plant : fungal symbioses in Australian forests - new perspectives using laser microdissection. Ericaceae are important components of the Australian flora in many habitats, including forests and fragile alpine regions that are significant to Australia's cultural and natural heritage, and several species are considered threatened. This project addresses the fundamental question of whether networks of symbiotic fungal mycelia act as below-ground bridges between Ericaceae plants and tree roots. If d ....Plant : fungal symbioses in Australian forests - new perspectives using laser microdissection. Ericaceae are important components of the Australian flora in many habitats, including forests and fragile alpine regions that are significant to Australia's cultural and natural heritage, and several species are considered threatened. This project addresses the fundamental question of whether networks of symbiotic fungal mycelia act as below-ground bridges between Ericaceae plants and tree roots. If demonstrated, this would alter current views of carbon and nutrient cycling in Australian forests and provide the basis for better informed decisions for the sustainable management of Australian forest resources. This is particularly important in the context of carbon sequestration and future climate change.Read moreRead less
Economics of carbon, nitrogen and water use in Acacia and Eucalyptus. Australia's flora is dominated by plants with sclerophyllous foliage, that is hard leaves that are tolerant of nutrient and/or water stress. Either nutrient and/or water stress are suggested as driving the evolution of sclerophylly and distribution of extant species. Mechanisms of tolerance to drought and nutrient stress differ, and these differences are reflected in patterns of nitrogen and carbon allocation and economics o ....Economics of carbon, nitrogen and water use in Acacia and Eucalyptus. Australia's flora is dominated by plants with sclerophyllous foliage, that is hard leaves that are tolerant of nutrient and/or water stress. Either nutrient and/or water stress are suggested as driving the evolution of sclerophylly and distribution of extant species. Mechanisms of tolerance to drought and nutrient stress differ, and these differences are reflected in patterns of nitrogen and carbon allocation and economics of nitrogen and water use in photosynthesis. The present study will use these differences in economics to distinguish between water- and nutrient-driven adaptations in a range of Acacia and Eucalyptus species from mesic to arid environments.Read moreRead less