1907967274

Wydajność i koszt pozyskania drewna w trzebieżach późnych 93

zł/m³). Larger cost occurred for the short wood method when harvester and forwarder were applied (35.71 zł/m³ — with 20 m distance between operational strip roads). In the remaining processes the cost was distinctly larger (45.46-59.12 zł/m³, depending on the distance between operational strip roads. Decreasing of the distance between operational strip roads to about 20 m caused 5-15% of cost reduction depending on technological process. Basing on the above results the following conclusions were drawn:

1.    The formula elaborated and applied in this work allows to calculate and to compare technical unit costs of wood harvesting for different technological processes.

2.    Technological processes and distances between operational strip roads influence the differentiation ofwork efficiency and costs ofwood harvesting in the late thinning of pine stands.

3.    Taking into account the technical unit cost and also damage to tree and soil (based on the literaturę), occurring during wood harvesting in late thinning of pine stands, the short wood method with chain saw and forwarder should be recommended. Reasonable distance between operational strip roads should be about 30 m.

4.    Applying the short wood method of harvesting with one grip harvester and forwarder becomes effective in late thinning of pine stands if the mean volume of cut trees exceeds 0.15 m³. At present, it is necessary to apply distance between operational strip roads about 20 m.

5.    It is also rational to use method of the whole stem combined with felling and delimbing with chain saw as well as extraction with horse when its distance does not exceed 100 m. Taking into account the possibility of using short wood method in the next circulation period the strip roads should be planned c.a. every 30 m. It is also possible to use strip roads marked every 60 m, but the cost and damage to trees would be larger.

Transl. T. O.

PIŚMIENNICTWO

ARViDSON A. 1995: National status report for Sweden. Harvesting Early Thinnings Cost Effective-ly: the Present and the Futurę. A report from the Concerted Action. Danish Forest and Lands-cape Institute: 361-365.

BORT U., MAHLER G., PFEIL Chr. 1993: Mechanisierte Holzemte. Wechselwirkungen von Er-chlieBungsdichte, Pflegliechkeit und Betriebserfolg. Forsttechnische Informationen, 11: 121-124.

BOUVAREL L. 1995: National status report for France. Harvesting Early Thinnings Cost Effectively: the Present and the Futurę. A report from the Concerted Action. Danish Forest and Landscape Institute: 303-308.

Dale O. 1995: National status report forNorway. “Harvesting Early Tinnings Cost Effectively: the Present and the Futurę”. A report from the Concerted Action. Danish Forest and Landscape Institute: 350-352.

FoRBRIG A. 1994: Riickegassenabstande ein heiBes Eisen. Forsttechnische Informationen, 6: 57-59.

FORBRIG A., DUMMEI. K., GEHRJNGER M. 1996: Die Verfahren der Fachexkursion bei der 12. KWF-Tagung 1996. Durchforstung mit Kranvollemter bei 40 m Ruckegassenabstand. AFZ-Der Wald, 8: 451^154.

FRÓDING A: 1992. Bestandsskador vid gallring (Thinning damage to coniferous stand in Sweden). Sveriges Lantbruksuniversitet. Garpenberg.