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Znanstveno-stručno i staleško glasilo
Hrvatskoga šumarskoga društva
Journal of Forestry Society of Croatia
      Prvi puta izašao 1877. godine i neprekidno izlazi do današnjeg dana
   ISSN No.: 0373-1332              UDC 630* https://doi.org/10.31298/sl
upute autorima
WEB EDITION
ARHIVA ČASOPISA


HRČAK


 
ORIGINAL SCIENTIFIC PAPERS
     
Pernar, N., Vukelić, J., Bakšić, D., Baričević, D. UDK 630* 114.4 + 188
An Insight Into Genesis and Properties of Soil in the Riparian Region of North-Eastern Baranja     pdf     HR     EN 223
Krpan, A. P. B., Poršinsky, T. UDK 630* 363
Efficiency of Mechanical Felling and Processing in Soft and Hardwood broadleaved stands – Part 2: Efficiency of harvesters in the culture of soft broadleaf trees     pdf     HR     EN 233
Summary: This paper shows the results of research of machine felling and processing carried out by Timberjack 1270B Harvester in a 23-year old willow culture. The volume of the mean felling tree was 0.5 m3, and diameter at breast height 25 cm. The felling density was 633 trees/ha. Thick undergrowth layer is made of bird cherry, black elder, common dogwood and glossy buckthorn. The harvester’s operation was monitored for 6 working days (54.11 h), and during that time 1825 trees were felled and 949.1 m3 of roundwood was processed.The mean diameter of technical roundwood is 29 cm, the length is 4.5 m and the volume 0.30 m3. The mean diameter of pulpwood is 17 cm, the mean length is 4 m and the mean volume 0.11 m3. The computer system Timberjack 3000 was calibrated before the operation started. The preset minimum sizes were entered (diameter at the thinner end with bark and length) of first class saw logs (27 cm, 2.5 m), second class saw logs (22 cm, 2.5 m) and pulpwood (7 cm, 4 m). The results confirmed that the dimensions of the processed assortments do not vary from the preset values.
Delay times of 52.7 % and effective time of 47.3 % of the total recorded time were established by time study. With such a time ratio, the harvester achieved an efficiency of 17.5 m3/h or 34 trees/h, consuming a total of 3.42 min/m3. The average consumption of effective time is 1.62 min/m3. Felling and processing account for 66.1 %, hydraulic crane idling for 17.8 %, undergrowth cleaning for 12.8 %, and harvester moving at the felling site for 3.3% of effective time. Allowance time was 30.9 % of effective time.
The values of standard time and harvester productivity have been investigated by regression analysis and fitted by exponential curve with a very strong correlation. In doing so, it has been established that 84 % of productivity and standard time variability can be explained by the influence of the trees diameter at breast height.

Key words: machine felling; Timberjack 1270B; clear cut of willow culture; efficiency
Zečić, Ž., Krpan, A. P. B., Poršinsky, T., Šušnjar, M. UDK 630* 375
Efficiency of tractors 8090 and 9078 in shelterwood fellings of stands in Požega mountains     pdf     HR     EN 245
Pilaš, I., Potočić, N. UDK 630* 561 + 116
Depedence of intraseasonal variations of tree stem diameter changes, electrical resistanee of cambial zone and groundwater in common oak stand (Q. robur L.)     pdf     HR     EN 255
Popijač, M., Seletković, I., Volner, M., Lovrenčić, I., Barišić, D., Kezić, N. UDK 630* 160 + 161
Dynamics of 137Cs and 40K Movement in Silver fir Trees on Sljeme Mountain     pdf     HR     EN 269
Posavec, S. UDK 630* 652
Specificy of Bussines Analyses Entities in Managing with Forest and Forest Land     pdf     HR     EN 279
Štorga, D. UDK 630* 582 + 525
Application of GIS in Stand Extraction According to Dendrometric Parameters     pdf     HR     EN 287

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