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Evaluation of lifespan values of six tree taxa in city streets
25-27.Views:329The aim of this study was to evaluate lifespan values of trees in tree-row system in the streets of Debrecen in two years (2009 and 2017). Six selected taxa (Pyrus calleryana, Acer tataricum, Sorbus intermedia, Magnolia kobus, Acer platanoides and Crataegus x lavalleei) were estimated for the following lifespan parameters: i) trunk diameter (cm), ii) tree crown size (m), iii) trunk status (in 0-5 grades), iv) tree crown status (in 0-5 grades), and v) estimated tree viability (in 0-5 grades). Our results showed that the largest were achieved for Pyrus calleryana and the lowest for Acer tataricum. The largest tree crown diameters were achieved for Acer platanoides and the lowest Magnolia kobus. The best trunk statuses by 2017 were achieved for Pyrus calleryana and the worst Crataegus x lavalleei. The best tree crown statuses by 2017 were achieved for Pyrus calleryana and the worst for Acer tataricum. The best estimated tree viability status was achieved for two taxa (Pyrus calleryana and Acer platanoides). Overall tree values were 2.73 times higher in 2017 compared to 2009. In summary, this study demonstrated the role of appropriate choice of tree taxa for a tree-row system under city street conditions.
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Sunburn assessment: A critical appraisal of methods and techniques for characterizing the damage to apple fruit
7-14.Views:396Many methods and techniques have been introduced for measuring alterations in the fruit and in its surrounding environment related to sunburn incidence. The research objectives, fruit materials and the environment to be evaluated dictate the methods to follow. These procedures are either non-destructive and involve techniques that allow us to track the course of sunburn development and related environmental parameters, or destructive and involve the removal of fruit from the tree for field/laboratory measurements. Techniques employed can be used for pre-symptomatic monitoring (before symptoms become visible) or characterizing the symptoms already present. The principles behind the measurements and their usefulness for sunburn assessments are discussed and critically evaluated in this review paper. Descriptions and evaluations of the methods and techniques were made in the following groups: 1. Thermal measurements; 2. Visual assessments; 3. Fruit quality measurements; 4. Measurements of physiological and biochemical alterations; and 5. Practical evaluation of sunburn damage. Thermal measurements involve methods tracking the ambient temperature and fruit surface temperature, and their relation to sunburn formation. Visual assessments cover all measuring techniques (skin color, chlorophyll fluorescence, radiation reflection, electron microscopy) that are able to detect changes on/in the fruit skin related to sunburn formation. Fruit quality measurements are used to point out differences in qualities (soluble solids, firmness, titratable acidity, and water content) between unaffected and sunburned areas of the fruit. The measurements of physiological and biochemical alterations (gas exchange, pigment analysis, enzyme activity, gene expression) give us a better insight to the mechanism of sunburn formation. Practical evaluations involve many procedures that are used by scientists to characterize the susceptibility of cultivars, evaluate protection technology, etc. For this purpose, the following methods are in use: expressing the percentage of the total fruit surface area affected by sunburn or the percentage of the total number of fruits damaged on the tree, or even a scale based on the severity of the symptoms occurred. All assessing methods and techniques described here have their pros and cons as well as their specific applicability, therefore any of these cannot be favored to use exclusively for assessing sunburn incidence. The combination of these techniques will be the best choice to meet a given research objective perfectly.
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The tests of effectiveness of Frostbuster under excessive weather conditions in an apricot plantation
87-91.Views:317Frostbuster is a new system, engine and technology, developed to protect fruit plantations from the frost damage. In order to raise domestic experiences and measurements, experimental approach has been initiated to prove the utility of the system under excessively low temperature in the plantation of the Siófoki Gyümölcstermesztési Zrt (Fruit Growing Co. Siófok). The first opportunity ensued in the night of February 23-24, 2011, when the temperature sank to 12°C below zero. The question was to see whether we could prevent the drop of temperature by the frostbuster technique. The margin of an anticyclone staying on East Europe secured a stable condition to make tests. The only difference from the imaginable conditions of dangerous frosts was the heat keeping capacity of trees was weak, much inferior than compared with trees in full boom. As a consequence, the tree rows represented much lower heat-capacity and cooled down much quicker than blooming trees in springtime, i.e. their temperature was more variable. The other difference was, compared with an episode in spring that the hard frost lasted much longer than usually in spring. For testing the system, those conditions had even more advantage. Six meteorological stations helped us in measurement. Data-collectors were timed to 1 minute distances and the bulk of data proved to be beneficial for testing the Frostbuster. The results prove that the system is adequate to keep the temperature continuously higher than the surrounding field under excessively low temperatures. Further measurements are still needed to find the optimal solutions fitting to the growing site and its microclimate. Results presented offer a basis of further proofs.
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Effects of crop load on tree water use in apple (Malus x domestica Borkh.)
29-31.Views:131Sap flow rate measurements were carried out during two consecutive ('on' and 'off') years in an apple orchard cv. 'Florina' M.26 to analyse the effects of various crop load on tree water use. Sap flow rate was measured by thermal dissipation method in trunks of nine trees from June to the harvest. Crop load was between 0.2-9.0 fruits • cm -2 of trunk cross section area (equal to 0.5-35.0 fruits•m-2 of leaf area), trunk diameter varied between 4.7-8.7 cm.
Total leaf area was estimated by leaf counting or using shoot girth and leaf area relationship. In both years, fruit growth rate was determined by measuring diameter of 280 marked fruits with 7 days frequency. Fruit volume calculated as a function of fruit diameter based on a previously determined relationship.
Total leaf area of trees ranged from 4.4 to 19.5 m2 and it was closely related to trunk cross section area. At high crop load the fruit growth rate peaked in August with 0.51.tree-l.day-1 and the leaf area specific total fruit volume reached 61 m2 before the harvest.
There was a linear relationship between total leaf area and daily water use, while the leaf area specific water use was influenced by crop load rate. The relationship was described by piecewise linear regression with the breakpoint at crop load rate of 12 fruits•m2 of leaf area. At low crop load the slope of the fitted regression line was less than at high crop load rate.
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Mass and displacement relationships of tree shakers
36-40.Views:116The degree of mechanically harvested fruit removal by shakers is determined by the displacement pattern, the frequency and the amplitude of shaker mechanism attached to the tree trunk. The displacement pattern is derived from the structural setup of the vibration mechanism, the frequency can easily be adjusted by the rev/min (rpm) of the rotating masses. More problems are arising in determining the dynamics of the tree-shaker system. Among others the amplitude of the attachment point and its components, the effective masses reduced to the attachment point.
Recent work gives some new insight into the tree-shaker dynamics including new calculation methods to determine the displacement components and the effective masses reduced to the attachment point. A fully new approach is given to include the vibrating soil mass into the total effective mass. The assumptions are supported and verified by laboratory and field measurements.
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Evaluation of fruit tree waterstress condition and transpiration with heat fl ux sensors
leaf area index, evapotranspiration, water stressViews:252In this study the transpiration properties and response to heat stress of Granny Smith and Jonagold apple species were measured. The examinations were set at an orchard near to Debrecen. The chosen trees were two years old, without fruits, in 20l container, placed in the mixture of mulch matrix, wood chips and sawdust and grown at the same climatic conditions. One of the most important goals was to determine the leaf area of the trees which is a basic data for transpiration modeling. Leaf area was larger (signifi cance level p<0.05) in the upper part of the canopy to achieve larger photosynthetic surface. Jonagold species with less leaf number (–18% compared to Granny Smith) reached almost the same canopy area, than Granny Smith, due to larger leaf area of Jonagold. Another aim was to measure the transpiration rate of the apple trees. The transpiration measurements were carried out by sap fl ow meter. Only a small transpiration difference can be found between species. During the investigation time there were wet and cool as well as dry and extremely hot periods. In the case of dry and extreme hot periods the transpiration is decreased, which causes decrease in transpiration and enhanced the water stress of trees.
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Evaluation of fruit tree transpiration with heat flux sensor
11-13.Views:202One of the biggest professional challenges of the following years is to develop the water resource management for apple trees. In order to know the water consumption of plants, some traditional and modern methods could useful. In our research the sap flow measurement of the plants were carried out. We have analyzed the transpiration properties of the trees in the investigation period. In order to compare the transpiration of the trees, the leaf areas were scanned and evaluated. Beside these measurements, soil water properties were determined by tensiometers, thus it makes possible to observe the soil-plant-atmosphere system.