School of Agriculture, Food and Ecosystem Sciences - Theses
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ItemQuality, management and value to landholders of remnant vegetation in the box-ironbark region of Victoria( 1999)Since European settlement of Australia, forest cover has been reduced from 10 to 5 % of the continent, woodland cover from 23 to 15 %, and in Victoria, forests and woodlands have been reduced from 75 to 33 % of the state's area. The Box-Ironbark ecosystem is a major vegetation type, stretching from Wodonga to Stawell, and was the centre of activity in the Victorian gold rush of the 1850s. Mining and agriculture have led to the clearance of 75 % of the original 1 Mha of the Box-Ironbark in northern Victoria. Of the 250,000 ha remaining, 15 % is located on private land, and 85 % on public land. The private land remnants are often smaller, isolated, and affected by surrounding land use. A recent Department of Natural Resources and Environment report identified that some of the best examples of some habitat types can be found on private land. This research seeks to attain an understanding of the values and concerns of landholders with respect to their remnant vegetation, and to understand the quantity and quality of remnants on private land, so as to better manage remnants in the future. A mail survey was sent to 552 landholders, receiving a 70 % response rate. The survey requested information regarding habitat quantity and quality, values and concerns about remnant vegetation, landholders contact with agencies, and demographics. In order to assess remnant quality, nine components of habitat quality which landholders could easily identify and grade for abundance were chosen to give an integrated numerical rating of habitat quality. The mail survey found that some 65 % of landholders managed Box-Ironbark remnants, and these approximated 4 % of the total private land. Results indicate that 50 % of the Box- Ironbark remnants had been impacted by grazing or other disturbance, 10 % of this severely, with approximately 20-50 % of Box-Ironbark remnants of moderate to high quality. The size of the remnant had the largest impact on habitat quality, with larger remnants generally being of higher quality. With regard to landholder values and concerns, results demonstrate that landholders hold mainly utilitarian values for their remnant vegetation, such as erosion control and water table protection. However, habitat and wildlife values were also held, especially among landholders with smaller properties and those with a higher level of education. One third of landholders believe remnant vegetation lifts production on their properties. Weeds, pests, and fire were the main concerns of landholders regarding Box-Ironbark remnants. Three quarters of landholders would not consider clearing any of their remnant vegetation, and 92 % would not consider clearing all or a large part of their remnant. Landholders on larger properties clearly value funding for on-ground works more than demonstrations and provision of technical advice, and this was also demonstrated in that they value the Land Protection Incentive Scheme and Landcare as the most useful programs. Those on smaller properties value the provision of technical advise more, and Land For Wildlife is the most highly regarded program. Other programs were relatively unknown to landholders. Findings demonstrate that landholders can be divided into two general groups according to property size. Those with larger properties would benefit from incentives as the remnant vegetation may be an economic hindrance. Education on the benefits that remnant vegetation can provide the property would also be worthwhile. Landholders with smaller properties are less concerned with productivity, and utilise the remnant for recreation and lifestyle. This group would benefit more from a program of education on best management of remnant vegetation.
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ItemControl of thinning operations for maximum production( 1998)Thinning of plantations is a recognised practice for concentrating growth onto selected trees while providing an intermediate return from the thinnings. A great deal of work has been done on methods for estimating optimum time and weight of thinning for the particular stand. However, the selection of individual trees to be thinned in the forest has relaxed in recent years to make thinning more flexible, reduce costs and to better facilitate mechanised harvesting. Some plantations are now being thinned by the harvesting machine operator selecting the trees to be thinned while harvesting. A series of field trials were undertaken in Pinus radiata plantation at Rennick, Victoria, to compare conventional tree marked thinning with operator selected thinning (OST) where the harvesting machine operator selected trees while harvesting. The results indicate good control of tree selection by the operators: thinning to the same density and diameter distribution as the tree marked treatment while removing all required defect trees. Operator tree selection did not affect harvesting productivity, however, it improved log processing time in a second thinning by an experienced tree selecting operator, it also improved falling and work cycle time (approach tree, fall and process) in first thinning on a high site quality. Thinning trials at an operational level, about 6 ha, tested operator selection thinning to two different sets of guidelines: a diameter limit; and spacing requirements for residual trees. These OST thinning operations were no worse than the conventional tree marked thinning and resulted in less residual tree damage and more trees harvested per hour in second thinning. A simple economic analysis, based on data from the field trials, showed each operator selection thinning to be similar to the conventional tree marked thinning for revenue from thinnings and PNV of the rotation taken through to final harvest by a computer model. Of the trials, first thinning on high site quality by a relatively inexperienced operator selecting trees was the least favourable for stand production.
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ItemFinishing prime lambs using pulse stubbles, and pulse and cereal grains in the Wimmera region of Victoria( 1998)Three trials were conducted as part of this study. The first trial evaluated faba bean and chick pea stubble as feed source for the finishing of lambs. The second trial evaluated the use of barley and field peas in feed lot rations for lambs, and the final trial evaluated narbon beans and vetch as substitute grains for field peas in feed lot rations for lambs. In the first experiment one hundred and twenty six Poll Dorset x (Border Leicester x Merino) mixed sex lambs with a mean liveweight of 40.0 kg � 0.3 kg were grazed on faba bean (FB) or chick pea (CP) stubble at a stocking rate of 6.5/ha and received a supplement of 300 g/hd/day of barley (+B) or were unsupplemented (-B). There was no significant difference (P>0.05) in average daily gain (ADG) over the duration of the trial between lambs grazing faba bean and chick pea stubble, supplemented with barley or unsupplemented. Lambs supplemented with barley tended (P- 4.06) to have a lower ADG in the first fortnightly period, and had significantly lower (P<0.05) ADG in the second period. This result is supported by the observation of supplemented lambs not grazing the stubble but waiting to be fed the barley supplement. This result was reversed in the third period when supplemented lambs tended (P~.06) to have a higher ADG, and in the final period when the ADG was significantly higher (P<0.05) than the unsupplemented lambs. There was a significant correlation (P<0.01 for faba bean stubble and P<0.05 for chick pea stubble) between ADG of unsupplemented lambs and the quantity of grain residue in the stubble. In the second experiment eighty Border Leicester x Merino mixed sex lambs with a mean liveweight of 27.3 kg � 0.2 kg were fed barley (B) or barley + field peas (B+FP) (60:40) either daily at 800 g/hd/day or ad libitum for 56 days following a 14 day introductory period. Hay was provided ad libitum. There was no significant difference (P>0.05) in ADG between lambs fed the treatment rations. Lambs fed B+FP were significantly different to lambs fed barley in the following: higher carcass weight (P<0.05); fatter (P<0.05); higher dressing percentage (P<0.01); higher estimated carcass weight gain (P<0.05) and lower dry matter intake to estimated carcass weight gain ratio (P<0.05). There was no significant difference (P>0.05) in any of the measured characteristics between lambs fed restricted or lambs fed ad libitum. In the third experiment twenty four Poll Dorset x (Border Leicester x Merino) lambs with a mean liveweight of 28.8 kg � 0.45 kg were individually penned and fed ad libitum a ration of narbon beans (NB), vetch (V) or field peas (FP) mixed with wheat and formulated to 16% crude protein. Milled hay was provided separately ad libitum. There was no significant difference (P>0.05) in growth rate, carcass weight, dressing percentage, feed intake, or dry matter intake to liveweight gain ratio between lambs fed the three rations. The growth rate and feed intake of lambs fed FP was more consistent than lambs fed NB or V. Scouring was observed in lambs fed V. There was highly significant (P<0.001) separation and selection of wheat in the NB and FP based rations. Further research needs to be carried out to evaluate meat quality of lambs fed narbon beans and vetch, in particular to determine if there is any effect on flavour of the meat. The use of pulse stubbles, combined with lot feeding can form a feeding system to enable lambs to be finished in the autumn-winter period in the Wimmera region. The growth rate of lambs grazing pulse stubbles is dependent on the quantity of grain residue on the ground. The growth rate can be maintained as grain level declines by the introduction of a barley supplement. Lot feeding can be used to finish lambs when pulse stubbles have been grazed out. A combination of a cereal grain and a pulse grain formulated to 16% crude protein can be fed ad libitum. Hay can be provided separately ad libitum, or a more controlled intake of hay can be achieved by feeding a calculated amount daily.
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