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• Evaluation of tree measurements after the reconstruction of tree-row system in five narrow streets of Debrecen

  217-222

  Anikó André Zsiláné

  László Zsila

  Imre Holb

  Views:

  350

  Viable urban environment is largely dependent on the size, condition and distribution of urban green spaces within and around cities. Treerows in streets are one of the most essential elements of urban green spaces. The aim of this study was to evaluate tree taxa compositions and lifespan values of trees in tree-row system with special reference to five narrow streets (Garai, Jókai, Tanító, Csokonai and Zsák) of Debrecen. Tree numbers, tree taxa and the origin of tree taxa were determined in two years (2009 and 2017). As a next step, six selected taxa (Pyrus calleryana 'Chanticleer', Acer tataricum, Sorbus intermedia 'Browseri', Magnolia kobus, Acer platanoides 'Olmsted', and Crataegus x lavalleei 'Carrierei') were further 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), v) estimated tree viability (in 0–5 grades), and vi) tree value in Ft. Our results showed that the numbers of tree taxa were 9 and 11 in 2009 and 2017 as well as an overall 279 and 282 trees were evaluated in 2009 and in 2017, respectively. More than 60% of the trees were native or similar to native taxa. The largest and the lowest trunk diameters were achieved for Pyrus calleryana 'Chanticleer' and for Acer tataricum, respectively. The largest and the lowest tree crown diameters were achieved for Acer platanoides ’Olmsted’ and for Magnolia kobus, respectively. The best and the worst trunk statuses by 2017 were achieved for Pyrus calleryana 'Chanticleer' and for Crataegus x lavalleei, respectively. The best and the worst tree crown statuses by 2017 were achieved for Pyrus calleryana 'Chanticleer' and for Acer tataricum, respectively. The best estimated tree viability status was achieved for Pyrus calleryana 'Chanticleer' and for Acer platanoides. Overall tree values were 2.73 times higher in 2017 compared to 2009. In conclusion, this study clearly demonstrated the importance of appropriate choice of tree taxa for an establishment of tree-row system in narrow street conditions.

• Host plant preference of Metcalfa pruinosa (Say, 1830) (Hemiptera: Flatidae) in the north of Hungary

  84-95

  András Bozsik

  Views:

  528

  Citrus flatid planthopper, a native insect to North America had for a long time a scarce economic importance there. However, being polyphagous made little damage on citrus trees and some ornamentals. In 1979 it was introduced to Italy where it established and spread quickly. It is now an invasive alien species continually spreading in South and Central Europe causing considerable damage in fruit crops and various ornamentals. Present study shows the results of a series of observations carried out from 2011 to 2015 at a number of habitats in north of Hungary. The pest could be found at each habitat but the hedge, the tree row, the gardens and the orchard/vineyard were the most infested. Frequency and population density of Metcalfa pruinosa were considerable on Asteraceae, Cannabaceae, Fabaceae, Juglandaceae, Lamiaceae, Rosaceae and Sapindaceae. Typical vegetation could be functionally classified as ornamental plants, trees/shrubs, fruit plants, weeds and feral plants. Feral plants – some of them also invasive alien species – were found at each habitat. Plant species native to America were among them the most populated. As the hedgerows were neglected, and most gardens, orchards and vineyards abandoned, these are excellent conditions for the quick and long-lasting establishment of the pest as well as they may be reservoirs to infest cultivated fruit crops and ornamentals. The hedgerow was situated along a railway line. The length of similar hedges can be merely in Pest county several hundred km, which means M. pruinosa has plenty of opportunity for spreading along the railway and infest agricultural and ornamental cultures. On the surveyed alfalfa and maize fields, accidentally very few nymphs and adults were observed. Although, the population density of M. pruinosa was considerable on many hostplants, economic damage or yield losses could not be detected. Economic or significant damage was observed only on roses, raspberries and stinging nettle. This later is cultivated in Germany and Finland. The applied horticultural oil was efficient.