Ecophysiological limitations that affect water and carbon balance within large tree canopies: a comparative investigation. Supply of water to forest canopies is a major control of hydrological, atmospheric and biotic processes that impinge on groundwater stability, catchment yield, the fate of pollutants and plant productivity. Fundamental aspects of water transport and distribution within plant tissues remain obscured by conflicting experimental data and conflicting theoretical models that des ....Ecophysiological limitations that affect water and carbon balance within large tree canopies: a comparative investigation. Supply of water to forest canopies is a major control of hydrological, atmospheric and biotic processes that impinge on groundwater stability, catchment yield, the fate of pollutants and plant productivity. Fundamental aspects of water transport and distribution within plant tissues remain obscured by conflicting experimental data and conflicting theoretical models that describe physiological functioning.
Potential hydraulic constraints to the exchange of water and carbon between leaf and atmosphere require investigation before accurate models and informed decisions can be made with respect to the role of forests in biosphere-atmosphere processes. I will use large trees to investigate physiological and morphological determinants of hydraulic function and consider relationships between tree size, water requirements and water supply.
This project will foster comparative analyses of hydraulic functioning in large angiosperm and conifer species to elucidate universal principles that relate form to function and explain relationships between trees and their environment.
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Tree water use and amelioration of dryland salinity. Dryland salinity is a huge problem for large areas of Australia. One proposal for ameliorating dryland salinity is to plant trees in upslope sites in the landscape. Such planted forests reduce movement of water through the landscape, thereby reducing mobilisation and discharge of stored salts downslope onto agricultural and sensitive riparian areas. This project will investigate tree water use in a native forest, compare it with a planted fo ....Tree water use and amelioration of dryland salinity. Dryland salinity is a huge problem for large areas of Australia. One proposal for ameliorating dryland salinity is to plant trees in upslope sites in the landscape. Such planted forests reduce movement of water through the landscape, thereby reducing mobilisation and discharge of stored salts downslope onto agricultural and sensitive riparian areas. This project will investigate tree water use in a native forest, compare it with a planted forest in the same location and investigate fundamental relationships among climate, tree size, canopy area and water use. The outcome of this project is a deep mechanistic understanding of the efficacy of trees for salinity abatement.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
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
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
Mechanisms linking site water status and net primary productivity. Australia is the driest of all inhabited continents and also has the lowest primary productivity. This project will determine the mechanisms linking these observations. Through development of a detailed mechanistic understanding of how site water balance determines site productivity and application of this understanding in a state-of-the-art model, we shall improve forest and water resource management and our understanding of the ....Mechanisms linking site water status and net primary productivity. Australia is the driest of all inhabited continents and also has the lowest primary productivity. This project will determine the mechanisms linking these observations. Through development of a detailed mechanistic understanding of how site water balance determines site productivity and application of this understanding in a state-of-the-art model, we shall improve forest and water resource management and our understanding of the unique ecology of Australia.Read moreRead less
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