School of Agriculture, Food and Ecosystem Sciences - Theses
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ItemSclerotinia minor in sunflowers : onset of disease and bioprotection with gliocladium virens( 1994)Sclerotinia stem rot (Sclerotinia minor) is a serious constraint to sunflower production in south-eastern Australia, where the lack of cultivars with adequate levels of resistance and the costs of chemical control make biocontrol an attractive option. Onset of disease in the field occurs at bud development. Field trials with the highly susceptible inbred line, PacF2582, confirmed the absence of disease during vegetative growth. A study of root development found a marked proliferation of lateral roots at GS 3.1-3.3 (early to mid-bud) in field-grown sunflowers and slightly earlier in glasshouse plants. Glasshouse studies demonstrated the susceptibility of vegetative stage plants to infection of lateral roots by one or 2 pre-germinated sclerotia. Onset of disease in soil inoculated to a high density with sclerotia was also delayed, generally until GS 1.5 (8 leaf), suggesting that occasional contact between roots and sclerotia is not sufficient for disease initiation. A model system was developed to examine the effects of surface microflora and exogenous nutrient on sclerotial germination. Field sclerotia, incubated on water agar disks, required surface sterilisation to relieve fungistatic dormancy. Root sap and exudates from sunflower lines stimulated germination of partially surface sterilised field sclerotia, as did root sap from non-host species. Germination rates were significantly higher with root nutrient from plants during vegetative growth than from plants at mid-bud stage. Exposure to root sap for more than 3 days was required for stimulation of germination in vitro. The germination response of soilconditioned culture sclerotia to nutrients was less consistent than that of field sclerotia. The results indicate that root nutrients have potential to stimulate germination during vegetative growth, but onset of disease awaits root proliferation at bud development. It was proposed that a threshold of root activity prolongs the exposure of sclerotia to root exudates, while overlapping rhizospheres may provide a critical concentration of nutrient for germination and mycelial development. An isolate of Gliocladium virens from disease-affected soil proved highly antagonistic to S. minor in culture. Seed treatment with G. virens suppressed disease induced by inoculation of lateral roots in pasteurised potting medium and in field soil. Significant disease control was also obtained by sowing seed into a plug of G. virens growing on V8-vermiculite or by pre-germination of seed with a culture of G. virens. Bioprotection by seed treatment with G. virens was evaluated at two field sites, and was effective in field microplots where disease incidence was less than 50%. Since G. virens, applied on seed, did not affect root growth and did not grow into the lateral root zone, it was concluded that seed treatment with G. virens creates a "cordon sanitaire" around the upper tap root, sufficient for bioprotection of inoculated plants in pots and field microplots. If seed priming techniques can be adapted to allow germination of G. virens on seed before sowing, it may be possible to enhance the cordon sanitaire and delay onset of disease in the field to obtain commercial yields.
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ItemA simulation study of nitrogen fertilizer management strategies for wheat crops in North-West Victoria( 1994)This study addresses the issue of nitrogen fertilizer application in wheat crops under variable climate in the dryland Mallee and Wimmera districts of north-west Victoria. A crop simulation model is used to determine the response of crops to various management strategies over a number of years, using generated weather data characteristic of the study area. In the first stage of the study, the performance of a weather generator is tested. for accurate representation of weather data at a range of sites so that it can then be used to provide daily weather data for input to crop models. A weather. generator which requires only monthly weather statistics as input was tested (SIMMETEO). It overpredicted the annual number of wet days and rainfall by less than 6% of annual rainfall, which would cause small errors in crop simulations results. Generated and observed mean monthly temperatures were not significantly different. Mean monthly solar radiation was underestimated by up to 2.8 MJm-2day-1. This was found to be mostly related to the prediction of solar radiation on wet days and a solution has been suggested for sites in southern Australia. A method for the estimation of mean, monthly solar radiation from latitude was successfully tested and this can be used to provide input data for the weather generator at sites where long-term data for solar radiation are not available. The weather generator was found suitable, for use with crop simulation models in the temperate wheat-producing areas of the Australian wheat belt, where it performed better than in the tropics. In the second stage of the study the performance of a crop simulation model was tested in north-west Victoria. The CERES-Wheat-N model was tested using data gathered from commercial crops with various nitrogen fertilizer treatments from two farms over two gears at Donald and Warracknabeal. Crop growth was overestimated early in the season, which also caused the overestimation of nitrogen uptake, especially in the fertilized treatments. Soil moisture was often underestimated towards the end of the season. Nevertheless, grain yields (range; 0.6-3.7 t ha-1) were better predicted (r2:0.79) than these crop growth components and reflected known crop responses to fertilizer application and rainfall variation. The CERES-Wheat-N model requires further testing in dryland agriculture in Victoria but it can presently provide valuable information for the management of wheat crops. The performance of the model in this test is discussed in relation to other studies reported over a wider range of sites and environments. In the final stage of the study SIMMETEO and CERES-Wheat-N were.used.to examine the response of wheat crops in north-west Victoria to nitrogen fertilizer application under variable rainfall, associated with El Nino-Southern Oscillation (ENSO) and anti-ENSO episodes. These simulations were run for three sites in the Wimmera and Mallee, namely Donald, Horsham and Ouyen. Wheat production was simulated for a range of combinations of soil type, sowing date and fertilizer application over 50 years of generated weather data typical of overall, ENSO and anti-ENSO years. Simulated grain yields ranged from 0.2-3.8 t ha-1 at Ouyen, 0.3-3.8 t ha-1 at Donald and 2.3-3.8 t ha-1 at Horsham, without any applied fertilizer. The results for each combination were summarised, as exceedence probability curves for yield. These provide information about the probability of yield exceeding a certain level over the climatic range at the site. The results indicated that wheat variety Matong produced die highest yields when sown in May compared to June and July, given that frost damage at flowering is not considered. The highest yields occurred on the heavy clay soil at Horsham, followed by the grey-clay loam at Donald and the sandy loam at Ouyen. Crops on these soils also showed varied response to nitrogen application, mostly dependent on soil moisture during the season. Crop yields were higher in anti-ENSO years and lower in ENSO years, compared to overall years. Yield response to rainfall variability was marked on the sandy soil and the clay loam but not on the heavy, clay which had sufficient soil moisture to support crop growth, even in ENSO years. Applied nitrogen caused yield reductions in some ENSO years, sometimes seen as a cross-over of exceedence probability curves. The presentation of the simulation results as exceedence probability curves provides information to help decide how much nitrogen can be safely applied to achieve a particular yield with a specified risk of crop failure. Thus, wheat growers are able to identify a fertilizer management strategy that will give the most benefit in the long run, depending on the economics of production on individual farms and their attitude to risk. This study has demonstrated the potential value of using crop growth models and weather generators in crop management and has also contributed towards identifying areas in which research is required to improve the potential for the practical application of these simulation techniques.
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ItemEvaluating community involvement in revegetation( 1994)As community awareness of the effects of land degradation has increased, groups of volunteers have formed to return native vegetation to the Australian landscape. Community involvement in revegetation expands the economic, social and environmental impacts of such projects. The research reported in this thesis aims to develop an evaluative framework for assessing such impacts for community-based revegetation projects in central Victoria. From this general aim, a specific set of research objectives were developed. They were: 1) To gain an understanding of land degradation and describe the development of community involvement in revegetation from an historical perspective. 2) To define 'revegetation', 'community', and 'government support' as key terms of reference; and hence projects eligible for the study. 3) To briefly review literature describing the terms social impact, economic impact and environmental impact. 4) To review literature investigating techniques for evaluating these impacts, with specific reference to revegetation projects and projects involving volunteers. 5) To identify the types of groups and structures involved in community-based revegetation in metropolitan Melbourne and rural central Victoria. 6) To categorise and describe the broad impacts of these revegetation projects. 7) To select three groups for investigation on a case study basis. 8) Develop a set of criteria appropriate for the evaluation of community-based revegetation. 9) To evaluate the case study groups using these criteria and discuss the strengths and weaknesses of the framework. 10) Based on the research findings make general recommendations regarding the community-based revegetation movement. The review of the literature revealed decreases in agricultural productivity and moves by land managers to counter these losses with conservation measures. Revegetation was one such measure that had the greatest net social benefit when it was part of potentially sustainable land use system. Further investigation of the literature failed to reveal techniques specifically developed to evaluate the range of impacts associated with community-based revegetation projects in Australia. Baseline data were collected at 44 rural and 35 urban revegetation sites by personal interview. Multiple regression analysis was used to identify the factors which influenced plant survival. The major objective for revegetation of urban sites was improvement of amenity and scenic values. Planning of the revegetation projects generally was primitive and once established, some 70 per cent of sites relied on government. organisations for maintenance. Volunteers had contributed more hours than government officers to establish approximately 347,100 plants. The major factors influencing plant survival were season, planning, use of indigenous plants, plant protection and vandalism. The major objectives for rural revegetation were amelioration of salinity and erosion and creation of windbreaks. Planning of revegetation projects also was primitive. Rural group members had established almost 233,700 plants at group planting sites and 1,163,200 plants by individual plantings. Respondents believed lack of moisture, vermin, weed competition, insect and waterlogging had contributed to plant loss. The groups were categorised on the basis of their organisational structures. Three groups were selected for case study analysis, using Bennett and Nelson's (1975) evaluative model for community development as a framework. Performance indicators were drawn from the preliminary survey and recent evaluations of ParkCare and LandCare. Castle Creek Catchment LandCare group members were farmers who had joined the group because they were interested in better land management. Many respondents preferred to plant individually on their own farms, with availability of time as their major constraint. The group had planted approximately 25,000 trees and shrubs with 70 per cent survival rate. The combined value of volunteer and government labour, government grants and the cost of materials gave a estimate of $353,900 spent on revegetation. The ratio of Castle Creek Catchment LandCare group inputs to government inputs was 2:1. The cost per tree was calculated to be $20, the major component of which was labour costs. The second group, Sunbury LandCare group, was located on the urban fringe. As most members were hobby farmers there was division between those interested in public land and those whose priority was to revegetate their own properties. The group had established approximately 29,400 plants with 71 per cent plant survival. The value of contributions to revegetation was $236,000, with a ratio of 3:1 for volunteer inputs to government inputs. The cost per tree was estimated to be $11. At Greenlink Box Hill, an urban group, all members understood and agreed with group objectives. The group leaders were experts in the field of indigenous revegetation, so the standard of revegetation was high. The ratio of volunteer inputs to government inputs was 9:1. The group had established in the vicinity of 60,000 trees, shrubs, grasses, herbs and forbs. The cost per plant was $10. From the case studies, it was concluded that group success required a clear set of objectives which reflected member interests. Government support through grants and staff support was significant for all three groups. Officers working with the groups required technical and liaison skills. The standard of revegetation projects was linked to the constraints upon individuals and within the groups. Time, money and knowledge all influenced the level of planning, site preparation and maintenance. It appeared that the aims of shelter creation and improvement of landscape aesthetics were achievable through community-based revegetation. However, lack of monitoring of land degradation processes made it impossible to speculate upon the extent to which more complex processes such as erosion were affected. The underlying distinction between rural and urban revegetation was that most rural projects were on private land, whereas urban revegetation took place on public land. Lack of planning and explicit arrangements for follow-up maintenance, management and protection raise questions about the extent to which project objectives will be achieved in the long term. It is suggested that some of these shortcomings could be alleviated through a change in funding arrangements.
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ItemSoil physical and chemical properties under Casuarina cunninghamiana Miq. (river sheoak) shade trees in northern Victoria( 1994)Casuarina cunninghamiana Miq. (river sheoak) is an Australian native tree with a natural distribution throughout eastern Australia. It is one of the three Australian casuarinas being widely grown in many countries as an exotic multipurpose tree. This thesis reports on a study of soil physical and chemical properties under C. cunninghamiana shade trees in northern Victoria. The study aimed to assess whether the presence of the trees had any effect on soil properties (bulk density, organic matter and chemical properties) by comparing soil under the canopy with soil under the adjacent open pasture. The study was conducted at the Department of Agriculture Rutherglen research station which has a mean annual rainfall of 590 mm and moderately to strongly acid Rutherglen loam soil. The study involves two main treatments: under the tree canopy and under open pasture. The treatments were replicated in each quarter of the sample plot containing nine sample trees. Soil samples were collected only once for soil bulk density, organic matter and chemical properties. The results showed that the presence of C. cunninghamiana shade trees did not improve soil bulk density, organic matter content and chemical properties of the surface soil (0-15 cm depth) under the canopy. Soil bulk density and organic matter content under the canopy were not significantly different (1.12 g cm-3 and 4.44% respectively) compared with open pasture (1.19 g cm-3 and 4.07% respectively). Soil pH and total nitrogen were significantly less (pH 4.20 and 0.08% respectively) under the canopy compared with under the open pasture (pH 4.48 and 0.01% respectively). Available phosphorus and exchangeable potassium levels under the canopy (2.09 ?g/g and 4.22 cmol kg-1 respectively) were not significantly different compared with open pasture (0.773 .Lglg and 4.88 cmol kg- I respectively). The lack of improvement in soil bulk density and nutrients under the canopy is probably due to the inherent acidity of the soil. This may make conditions unsuitable for litter breakdown and nitrogen fixation. Low rainfall and seasonal flooding of the study site may also be influencing these soil properties. The results demonstrate that the potential of C. cunninghamiana to improve soil properties may be variable depending on the site conditions.
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ItemAn evaluation of fuel-reduction burning in the dry sclerophyll Wombat State Forest( 1994)Each year, between one and three per cent of the total forested area in Victoria is fuel-reduced as a part of the Department of Conservation and Natural Resources' program to implement its overall fire protection policy. The dry sclerophyll Wombat State Forest has been fuel-reduced since the 1960's, - a practise considered important because of its susceptibility to fire and its highly flammable plant community. This thesis presents the results of an evaluation of fuel-reduction burning in the Wombat State Forest, commencing with a review of forest conditions, principles of fuel-reduction burning, fire behaviour and fire effects. This is followed by observations and measurements in the field to document current practices of fuel-reduction burning, to select an appropriate fire-behaviour prediction model, to identify time-intervals between successive burns and to evaluate the effects of fuel-reduction burning on forest trees. Historical data of wildfires were used to evaluate the effectiveness of fuel-reduction burning in limiting the number, area and losses from wildfires. "Multi-criteria analysis" was then applied to select priority areas for fuel-reduction burning. The fuel-reduction burning program which is conducted 'every year during autumn and spring requires detailed planning and preparation, because it can only be carried out under certain prescriptions for weather, fuel and fire behaviour. Depending on the extent and conditions of each area, either ground or aerial ignition is applied. Large areas ignited from the air often result in variations of fire behaviour and intensity that leave many un-burnt patches within the broad areas of burnt forest. In order to predict fire-behaviour, comparisons were made between the Control Burning Meter, the McArthur Fire Danger Meter and the Fire Behaviour Tables for Western Australia (the Red Book). From a study of small trial plots, it was shown that the fire behaviour model incorporated in the Control Burning Meter for messmate-gum or silvertop forest type provided quite realistic predictions of low-intensity prescribed fires compared with predictions based on the McArthur Forest Fire Danger Meter and the Fire Behaviour Tables for Western Australia. Since its inception, fuel-reduction burning in the Wombat State Forest has decreased the quantity of litter and twigs, but it has had no significant effect on the quantity of humus and coarse fuels. This reduction of flammable fuels has reduced the potential for major fires and the study showed that a fuel-reduction burning cycle of less than five years is required to restrict the build up of fine fuels to acceptable levels. With regard to the impact of fuel-reduction burning, it was shown that it causes scorches on most trees, and that there is a significant relationship between scorch-height and tree diameter for the two dominant species, messmate (Eucalyptus obliqua L'Herit) and peppermint (E. radiata Sieb. ex. DC.). However, because of their different bark types, average scorch height was higher for messmate. Due to the considerable variation in the severity of fire seasons, hence in the frequency and severity of fire, no significant differences were detected in the number of wildfires and the extent of areas burnt, before and after the application of fuel-reduction burning in the Wombat State Forest. However, analysis of the historical fire data led to the conclusion that fuel-reduction burning has achieved its objective of limiting the severity of wildfires. Most of the wildfires occurred on areas that either had never been fuel-reduced or that had been fuel-reduced for more than five years. The costs of fuel-reduction burning have been relatively modest in comparison with the potential losses. Therefore, when properly planned and implemented, fuel-reduction burning is a valuable management tool for protecting forests and wider community values. This study has also provided a general idea on the applicability of "multi-criteria analysis" for identifying priority areas for fuel-reduction burning in the Wombat State Forest, with priority areas being selected on the basis of level of fire hazard (fuel, weather and topographical conditions) and values of particular sites (significant values, timber quality, distance from the nearest township and extent of the area). The result was a ranking of areas according to their priorities for burning.
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ItemFactors influencing the success of direct seeding in three regions of Victoria( 1994)During March 1993, 130 direct seeding sites were studied in Gippsland, Corangamite and the Wimmera to try and determine the major factors influencing seedling establishment by direct seeding techniques. Thirty one variables believed to influence establishment were considered. A series of backwards regression procedures were used to identify statistically significant variables. Rainfall patterns during, and after seeding were unusual in all districts. Spring rainfall was between 20 and 100 per cent above the average, except on the Gippsland Plains were the majority of sites received 20.7 per cent below the spring average. During the summer months all areas studied received between 42 and 161 per cent above the average. These rainfall patterns influenced all aspects of the direct seeding projects. As rainfall increased prior to sowing, seedling numbers generally decreased, apparently due to the effects of waterlogging. This was evident on the Basalt and Gippsland Plains and in the Wimmera. The opposite occurred in the higher rainfall areas, and it is suspected that rainfall alone could not account for this trend and that other, unknown factors, possibly soil conditions and temperature may have been involved. On the Gippsland Plains, sites sown early with adequate moisture performed better than sites sown later, when moisture stress was believed to have reduced seedling numbers. For all other areas, seedling numbers increased as the sowing date was delayed, the exact reason is unknown, but later sowing dates generally coincided with higher soil temperatures, less rain and suspected higher evaporation rates and therefore fewer cases of waterlogging. It was concluded that the climate had an over-riding influence on all direct seeding projects. This effect was also influenced by the soil texture. Sites sown on sandy soils in the Wimmera performed well (1.28 seedlings per metre), but not on the Gippsland Plains (0.4 seedlings per metre) where soil moisture was believed to be a limiting factor. Generally, sites sown on loam and clay loam soils were associated with a high number of seedlings (an average of 1.23 seedling per metre). Heavier soils performed poorly (an average of 0.45 seedlings per metre). Other important factors highlighted by the study were: - Waterlogging was believed to be highly detrimental for establishment. This was most evident in the Wimmera, where waterlogged sites were associated with a twelve fold decline in seedling numbers (1.41 to 0.12 seedlings per metre on waterlogged sites). Waterlogging predominantly occurred on clay soils; - Cracking soils showed a similar trend. Sites on cracking soils had approximately half the number of seedlings than sites on non-cracking soils, (0.55 and 1.20 seedlings per metre respectively). This effect was again greatest in the Wimmera, but also evident on the Gippsland Plains. The above average rainfall on the Basalt Plains may have allowed the seedlings to develop a strong root system before the soils dried and cracked, and was not a factor in this area. - Weed cover at the time of sowing was suspected of favourably altering the micro-climate of the seed/seedling. Sites where a cover of weeds was present at the time of sowing had approximately three times as many seedlings present than sites were no weeds were present at the time of sowing (1.47 and 0.59 seedlings per metre respectively). The exact state of the weed cover or how the micro-climate was altered is unknown, except that a herbicide had been applied to the weeds prior to sowing. - Redlegged earth mite were present on 61.5 per cent of the sites studied, and these sites had 90.8 per cent fewer seedlings than sites where redlegged earth mite was not reported. The influence of this pest was particularly evident in the Hills region. It is suspected that irreversible damage had been done to the seedlings soon after emergence and that the majority of farmers failed to recognise this. Treatment for the pest was thought to have been applied too late, except on the Gippsland Plains. - Two and three pre-sowing applications of herbicide significantly increased seedling numbers apparently due to longer and more effective weed control than one or no herbicide applications prior to sowing. The use of residual herbicides did not influence seedling numbers, but it is suspected that the climatic patterns influenced this; and - The history of the paddock was important in influencing seedling establishment. The exact reason is unknown, but the fact that seedlings will establish readily on site previously grazed, with a history of fertiliser application may be important. Unimproved and cropping land did not perform so well and it is suspected that neglect, poor soil structure and chemical contamination of the soil are possible reasons for this. This study largely supports the work of other researchers in this area, but also highlights other important considerations often neglected.
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ItemAnalysis of growth and yield in uneven-aged, mixed species eucalypts at Mt. Cole State Forest( 1994)Continuous forest inventory (CFI) is an effective method for studying forest changes over time; it provides growth and yield information which forest planners and managers can use for planning and managing forests to meet long-term sustained yield. This thesis reports results from a 30 year series of successive CFI measurement at Mt. Cole State Forest in west-central Victoria, commencing in 1963. With an area of 12,352 ha, Mt. Cole State Forest consists of three sub areas; the northern and southern Blocks totalling 11,250 ha, and the Mt. Lonarch Block comprised of 1,102 ha. Permanent sample plots (CFI plots) were first established in the Mt. Cole Blocks in 1963 and these have been measured on seven occasions, including the most recent 1994 assessment. During this period, various changes to the inventory data-base have occurred, which have impacted on the analysis and interpretation of the data. Since 1983 the forest area of the Mt. Cole Blocks have been classified according to land use and management zoning, resulting in a reduction of the net productive area available for sawlog production to 2,758 ha. This area has also been stratified into four homogenous areas (strata) and the number of CFI plots has been reduced from an initial 114 to 66 plots. In the latest (1994) remeasurement, the 66 permanent sample plots for the four strata of the Northern and Southern Mt. Cole Blocks were rechecked and the data has been analysed to determine current growth and yield, and to estimate future volume growth and an available cut for the forest. The above analyses show that the structure and yield of the forest have changed from time to time, with a trend towards decreasing levels of available growing stock over time. The current (1994) growing stock levels of the Mt. Cole Blocks are approximately 80,676 m2�27% (P=0.95) or 28.6�3.7 m2 /ha for basal area, and 237,684 m3�36% (P=0.95) or 83.7�13.9 m3/ha for 'sawlog plus potential sawlog volume'. The current available sawlog volume is approximately 177,672 m3�44% (P=0.95) or 63.5�12.5 m3/ha. Additional analyses of periodic and annual growth rates of the growing stock for each stratum and the whole forest (Mt. Cole Blocks) show that the average diameter increment (underbark) of the forest is approximately 0.51�0.03 cm/yr; the net annual increment including ingrowth (Gn+i) of the growing stock in the Mt. Cole Blocks is approximately 0.63�0.11 m2 /ha/yr for basal area, 2.16�0.75 m3 /ha/yr for sawlog, and 1.78�0.68 m3/ha/yr for sawlog plus potential sawlog. The net annual changes in growing stock levels (Gd) are approximately 0.11�0.29 m2 /ha/yr for basal area, -0.15�1.52 m3 /ha/yr for sawlog, and -0.65�1.52 m3/ha/yr for sawlog plus potential sawlog. Models for predicting the current and future growing stock levels were developed using multiple regression based on the three parameters of initial basal area (BO), initial volume (Yo), and the interval of time between successive measurements (t ). Regulating forests to obtain long-term sustained yields requires a continuous flow of information on growth and yield and the development of comprehensive management strategies based on this information. In this study, such growth and yield information have been used to determine an annual available cut for the Mt. Cole Blocks of approximately 5,364�1,854 m3/yr.
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ItemA comparison of the efficiency of three models to estimate water yield changes after forested catchment conversion( 1994)This study used Cropper Creek (located southwest of Myrtleford, Victoria, Australia) data to compare the efficiency of a statistically based "black box" model derived from an antecedent precipitation index (API) model, a pseudophysical model (SFB), and a paired catchment regression model in predicting the effects of catchment land use change at times when data from the neighbouring catchment are not available, and to analyse whether the pseudophysical model can be used to estimate changes in the internal hydrology of the treated catchment due to the land use change. Each of the models was viewed as a representative of a different philosophic approach. The three models were calibrated using the pre-treatment record. A recession factor of 0.882 and threshold value of 0.1 mm of the antecedent precipitation index were found to satisfactorily estimate hydrograph response at the Clem Creek catchment during the calibration period. The parameters of SFB model (S = 200 mm, F = 80 mm/day, and B = 0.01 ) during the calibration period were obtained by the exhaustive gridding method in parameter space. The input of the paired catchment regression model included only streamflow of Ella Creek. The calibration paired catchment regression model was found to reliably estimate Clem Creek water yield during the calibration period. The paired catchment regression model gave a satisfactory representation of the hydrograph at Clem Creek during pre-treatment and post-treatment periods. The API and SFB models failed to estimate water yield during the calibration period and to predict water yield changes after forested catchment conversion. This failure is probably due to limitations of the conceptualisation of the process. Variations of seasonal and monthly streamflow, and low flow (December - May) were analysed during the study period. The water yield of Clem Creek increased after the treatment. Relative increases in streamflow of Clem Creek were greater in winter and spring than summer and autumn. Annual average increased streamflow was 51.3 megalitres for the paired catchment regression model after the treatment. Low flow changed after the treatment, but it was insignificant for the three models.
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