Plantations & Health Research Group
Postgraduate, Honours and Industry project opportunities
The Plantations & Health group undertakes research into the growth and management of plantations for wood products and environmental services, and into the health and protection of plantations and (native) forests.
Projects may particularly be developed through associates in the Victorian hardwood (e.g. Midway Pty Ltd, Timbercorp Ltd) and softwood (e.g. Hancock Victorian Plantations Pty Limited) plantation industries, and in the Victorian departments of Primary Industries, and Sustainability and Environment.
Primary contacts and general research areas
Tom Baker
tgbaker@unimelb.edu.au
Plantation growth in relation to site factors (climate, soils), and growth responses to silvicultural treatment (cultivation, weeding, fertiliser, thinning, pruning).
Nick Collett
ncollett@unimelb.edu.au
Ecology and control of native and exotic insect pests, and effects of plantation establishment on insect biodiversity.
David Forrester
davidif@unimelb.edu.au
Nitrogen fixation, nutrient cycling, growth dynamics, competition and the construction of carbon and nitrogen budgets in monoculture and mixed species plantations.
Ian Smith
ismith@unimelb.edu.au
Pathogens affecting growth and survival of native forests, and eucalypts and pines growing in plantations and in nurseries.
Yue Wang
yuewang2@unimelb.edu.au
Quantifying the structures and dynamics of uneven-aged, mixed species forests; modelling long-term growth responses to silvicultural interventions of plantations.
Postgraduate project opportunities
Postgraduate scholarships (variously full or top-up stipends) are currently available in the following areas:
Plantation site and resource evaluation. Contact: Tom Baker
Areas for research include using current and emerging technologies to monitor and measure tree growth and environmental site variables important to plantation productivity, to quantify the effects of forest growth on water, soil nutrients and carbon through successive plantation rotations, and to capture this information into decision support tools for future management. The project will be undertaken within Research Program 1 Managing and Monitoring for Growth and Health in the CRC Forestry.
The effect of silviculture on wood properties in eucalypt plantations managed for high-value timber production. Contact: Tom Baker
This project will contribute new knowledge to underpin the development of hardwood plantations in Australia for timber production, particularly at the critical interface of silvicultural management, wood properties and processing/utilisation. Advances in processing technology for small logs and the imperative of economies of scale in mill size are causing a reconsideration of the optimum management regimes regarding stand density and tree/log size.
The project will focus on temperate species, and can draw on longer-term field experiments in Victoria, Tasmania and Western Australia. The focus species is Eucalyptus globulus, but where useful, comparisons with for example E. nitens or E. viminalis could be undertaken. Opportunities for research include (i) studies of the interacting effects of genetics, site-quality, thinning and fertiliser application on cell-level wood properties that are recognised as affecting sawing and drying performance, (ii) within-stand environmental and competition effects on tree crown shape/balance and consequently wood properties, and (iii) processing studies that evaluate the impact of genetics and silvicultural regimes on solid and engineered-wood product outcomes.
The project will be undertaken within Research Program 2 High Value Wood Resources in the CRC Forestry. Full APA(I)-equivalent stipend, and project-specific operating are provided. The project is also supported by industry participants through in-kind access to field experiments and data.
Growth and yield of trees integrated into farming landscapes in 400-600 mm rainfall zones. Contact: Tom Baker
Species of interest include Eucalyptus cladocalyx, E. occidentalis, and Corymbia maculata. Requires studies of soil strength and water holding capacity, and vertical and horizontal root growth in block- and belt/row-configured plantations in water-shedding and water-gaining landscape elements. Relevant to production (volume/biomass yield), carbon sequestration, and tree water use and catchment water balance questions. Empirical or process-based or hybrid modelling approaches might be taken. Supported by industry collaborators’ existing field trial base across New South Wales, South Australia, Victoria and Western Australia. The project will be undertaken within Research Program 3 New Woody Crop Systems in the CRC Future Farm Industries.
Tree genotype x site water relations in lower rainfall (400-600 mm) farm forestry species. Contact: Tom Baker
Requires provenance/family-level comparative studies of tree water relationships (use, efficiency, stress, competition) in species including Eucalyptus cladocalyx and Corymbia maculata. Relevant to production (volume/biomass yield), carbon sequestration, and tree water use and catchment water balance questions; and to tree improvement (selection/breeding). Supported by industry collaborators’ existing field trial base across a range of site climatic and edaphic conditions. … The project will be undertaken within Research Program 3 New Woody Crop Systems in the CRC Future Farm Industries.
The impact on insect biodiversity of plantation establishment. Contact: Nick Collett.
Interactions between remnant vegetation and plantations are poorly understood. Does a change in land use within a landscape have a positive, negative or neutral effect on insect biodiversity within the remnant vegetation surrounding or within a plantation itself? Does the age-class, size and proximity to native vegetation of a plantation determine the insect biodiversity found within the plantation? The project will be undertaken within Research Project 4.2 Biodiversity in the CRC Forestry.
Insect biodiversity and plantation health. Contact: Nick Collett.
Can enhancement of biodiversity improve plantation health? This project will examine management options within plantations and surrounding remnant vegetation to improve biodiversity. An important element of this work would be examining in detail insect pest species within plantations and whether various management options improve levels of their natural enemy populations. The project will be undertaken within Research Project 4.2 Biodiversity in the CRC Forestry.
Honours and Industry project opportunities
Family-level variability in Eucalyptus globulus coppicing ability. Contact: Tom Baker.
In Eucalyptus globulus pulpwood plantations the coppice developing after harvest may be either managed for a second crop, or require removal/control where the site is replanted. Continual tree improvement through selection and breeding may have changed coppicing ability in deployed germplasm for this species. The study will utilize recently thinned E. globulus age 5 years family trials (c. 100 families) on contrasting sites in western Victoria and Gippsland. Conventional measurements of growth and vigour could be supported by physiological studies, with quantitative genetic analysis of heritability of observed traits.
Tree improvement for species for lower rainfall environments. Contact: Tom Baker.
Tree improvement for species suitable for plantations in lower rainfall areas (400- 600 mm MAR) such as Eucalyptus cladocalyx, E. tricarpa, E. sideroxylon, E. occidentalis, Corymbia maculata is relatively undeveloped. The study can access a range of family / provenance trials of these species established in Victoria under the auspices of the Australian Low Rainfall Tree Improvement Group. Conventional measurements of growth and stem form traits could be supported by physiological studies, with quantitative genetic analysis of sources of variation.
Tree- and stand-level biomass relationships for Eucalyptus globulus plantations. Contact: Tom Baker.
Tree- and stand-level biomass relationships/equations are required for a variety of purposes, ranging from bioenergy production, to estimation of carbon sequestration in plantations to calibration / validation of process-based growth models. The study will draw on a large body of Eucalyptus globulus data from individual studies for development of robust compatible biomass equations that are applicable across a range of sites.
Calibration of fertiliser responses in eucalypt plantations. Contact: Tom Baker.
The precision of predictions of fertiliser responses in eucalypt plantations can be improved by using plant tissue and/or soil nutrient analyses. The study will draw on a large body of rotation-length growth and response data coupled with foliar analysis, and climatic and edaphic data from field trials established across a range of site types throughout Victoria. Empirical and/or process-based response modelling approaches may be taken.
Tree growth in relation to salt accumulation in soils in irrigated plantations. Contact: Tom Baker.
Wastewater re-use into tree plantations in low rainfall areas has been of long-standing interest to promote growth and avoid disposal of nutrient-rich water to natural water bodies; and now most recently has a bioenergy emphasis. The study will draw on a large body of rotation-length growth and response data coupled with climatic and edaphic data, including profiles of soil salinity development with time, from irrigated field trials established in northern Victoria. Empirical and/or process-based response modelling approaches may be taken.
Biomass, litter and soil carbon changes following reforestation of agricultural grassland with Eucalyptus, Acacia and Pinus. Contact: Tom Baker.
The impact of reforestation on soils continues to be a contentious issue, particularly with respect to plantation monocultures and potential deleterious long-term impacts on soil quality and productivity. This project will utilize a 6 year-old field experiment planted in south-western Victoria providing for replicated comparison of Eucalyptus globulus, Acacia mearnsii and Pinus radiata. The work will require tree growth measurements together with application of existing (or newly developed) tree biomass allometric equations to estimate biomass, and litter and soil sampling and analysis.
Effects of fire retardant application on litter-dwelling Formicidae (ants) and Coleoptera (beetles) in heathland ecosystems of Victoria. Contact: Nick Collett.
Victoria has some of the most bushfire prone environments in Australia. To minimise fire damage there is a heavy reliance on intensive fire suppression activities including use of fire retardant chemicals. Previous studies have shown that while the application of fire retardant to heathland ecosystems has no lasting impact on litter invertebrate activity to ordinal and some sub-ordinal levels, the situation is less certain at lower taxonomic levels for Formicidae and Coleoptera where some slight variations in activity over time were observed. The project will examine these two groups to lower taxonomic levels to determine whether or not changes are expressed at family/species level in these two important indicator groups.
Comparison of different types of pitfall sampling methodologies. Contact: Nick Collett.
This study will examine the efficiency of traditional transect pitfall trap lines compared to circle design pitfall layout. Different insect orders would be examined, as well as whether accuracy of data is maintained using different pitfall traps in a design layout. The study will assist in designing future invertebrate experimental work.
Examination of the varying population patterns of Sirex around Victoria. Contact: Nick Collett.
A large amount of population data on Sirex and its parasitoids has been gathered over the past 10 years from different parts of the Victoria including Sirex nematode and parasitoid levels and their infectivity. An analysis of these data would lead to a more targeted and planned approach to Sirex control within Victoria.
Reducing tree water use by pruning (foliage removal). Contact: David Forrester.
Pruning of lower branches enables the production of knot free wood. However, pruning can remove more than half of the canopy leaf area and thus slow growth and reduce the amount of water used by the tree. This project would estimate water use by measuring rates of sap flow and the cross sectional area of conducting tissue (sapwood).
Growth of a mixed species plantation of Blackwood and Douglas fir. Contact: David Forrester; Mark Stewart (marks@unimelb.edu.au)
The interactions that occur between different species in mixtures can lead to significant improvements in growth rates, tree form and wood quality, particularly when one of those species is capable of fixing nitrogen (such as Blackwood). This project will examine the growth and interactions in a mixture of Douglas fir and Blackwood. This could involve measurements of growth (diameter, heights, volume), and the resources for which trees compete, such as light, water and nutrients.
Designing a silvicultural regime for Poplar plantations. Contact: David Forrester
Several decades ago a couple of poplar trials were established to examine the effect of spacing on tree growth. These stands have now reached maturity and provide an ideal data set to examine the growth dynamics and competitive processes of this stand. This could involve relating tree growth to the competition it experiences from its neighbours. Measurements of crown size and leaf area may also be useful.
Regeneration and growth of native forests. Contact: David Forrester; Simon Murphy (scmurphy@unimelb.edu.au)
Due to the differing shade tolerance of natural vegetation, species regeneration is influenced by the size of gaps in forested areas. For example, eucalypts require larger sized gaps for seedlings and saplings to develop, while wattles and other understorey species are more favoured by shading. Ideal gap sizes vary depending on the shade tolerance of the species. Young trees growing on gap edges, next to adult trees, will be shaded and hence grow more slowly or even die. This effect is often ignored when estimating species composition and growth rates of regenerating patches of native forests, but a high proportion of young trees can be affected by this competition, particularly if the gaps are small. This study will relate the growth and frequency of young eucalypts and understorey species to their distance from the gap edge in order to better understand ‘edge effect’ and the partitioning of productivity. Study sites will focus mainly on mountain ash forests near Tanjil Bren, in the Central Highlands, but could include mixed species forests at Cabbage Tree Creek, in East Gippsland.
Canopy efficiency of eucalypts growing in mixtures with nitrogen fixing acacia trees. Contact: David Forrester
Mixed species plantations of Eucalyptus with a nitrogen fixing species such as Acacia can be significantly more productive than Eucalyptus monocultures. This results from increased nutrient availability via nitrogen fixation and accelerated rates of nutrient cycling, and reduced competition for light. However, these factors only explain part of the growth response, there appears to be another factor that is also responsible, which is likely also to be linked to increases in canopy efficiency. This has not been examined in mixtures and would be the focus of the proposed project. This could involve gas exchange measurements of maximum rates of photosynthesis, electron transport, carboxylation efficiency and dark respiration. Additional data quantifying leaf nutrition and canopy shape and size would also be collected. This knowledge will provide information required for the growth modelling of mixed species plantations and would fill a knowledge gap currently existing in mixtures research.
The influence of competition on tree form in eucalypt plantations. Contact: David Forrester
The value of wood from trees is related to growth rates, wood quality and tree form. Many studies examine the effect of thinning, pruning or mixing species together on growth but few examine the influence of these treatments on tree form. The proposed study aims to examine the effect of neighbourhood competition on the form of individual trees by calculating competition indices and relating this to a trees size, branching habit and height to diameter ratio. This technique could be applied to several Eucalyptus plantations that have a range of thinning or pruning treatments or to mixed species plantations containing Eucalypts with Acacia mearnsii or Acacia melanoxylon. The results will be used to design planting patterns that will facilitate the development of well formed trees.
Forest, plantation, and amenity tree health. Contact: Ian Smith.
Topics include:
• Evaluation of stream baiting techniques for Phytophthora spp.
• Examination of aspects of insect and fungal biodiversity in the Forest Gallery of the Museum of Victoria in Melbourne.
• Evaluation of insecticides against Essigella californica on Pinus radiata .
• Mundulla Yellows, a disease/disorder of Eucalyptus and other native species.
• Evaluation of fungicides against Armillaria species that cause significant tree and shrub losses in native forests and home gardens.
• Development of a bioassay for determining pathogenicity of Fusarium oxysporum to Canary Island Date Palms.
Modelling stem form response to thinning in eucalypt plantations. Contact: Yue Wang.
Tree stem taper models have been commonly used in many computer-based decision support systems in forestry (forest yield models or simulators) to estimate various wood products (e.g. pulpwood, sawlogs, veneer logs). Traditionally, stem taper has been modeled as a generic, species-specific mathematical relationship between the relative underbark stem diameter and relative height along the stem of trees. Such generic taper models cannot account for the variation of stem form in different forest stands, particularly plantations with intensive silvicutural interventions (e.g. thinning, pruning). This study aims to: (1) investigate different biometric modelling approaches for improving the predictive ability of taper models in responses to thinning of eucalypt plantations, and (2) to explore error structures of taper models under different modelling approaches. The project may require taking field measurements on stem tapers of sample trees, and associated tree or stand characteristics from eucalypt plantations with known silvicutural treatment histories.
Contact Dr. Yue Wang, yuewang2@unimelb.edu.au
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