DIGITALNA ARHIVA ŠUMARSKOG LISTA
prilagoðeno pretraživanje po punom tekstu



ŠUMARSKI LIST 7-8/1971 str. 61     <-- 61 -->        PDF

62.
Samse t I.: Terrain Classification of Forest Areas in the Greek Mountains.
Norwegian Forest Research Institute. Nr. 84, Bind XXII, 1967.
63.
S a n k t j o h a n s e r L.: Zur Frage der optimalen Wegedichte in Gebirgswaldungen.
Forstwiss. Cbl., 3, 1971.
64.
Schönaue r H.: Der Einfluss der Knickschlepperrückung auf das Forstwegenetz.
Allg. Forstzg, 2, 1970.
65.
Segebaden G., Strömnes R. a. Winer J.: Proposal for International
System of Terrain classification. XIV IUFRO-Kongress, München, 1967, Sect.
31—32.
66.
Splechtn a K.: Erfahrungen mit Knickschleppern in Gebirge. Allg. Forstztg,
2, 1970.
67.
Ugrenovi æ A.: Eksploatacija šuma, Zagreb, 1957.
68.
Vasile v V.: Po voprosite za ispolzuvane na traktorite v gorskoto stopanstvo.
Gorsko Stopanstvo, 11, 1967.
69.
Vyple l K.: Zur Arbeitsorganisation beim Knickschlepper-Einsatz. Allg. Forstztg,
2, 1970.
70.
Vör y J.: Prospects of logging methods. Metsäteho report, 215, Helsinki, 1963.
71.
W i n e r H. I.: Environmental factors and their effect on the productivity of tree-
length skidding. IUFRO, Munich 1967. Sect. 32.
Summary


AN ANALYSIS OF WORK OF FRAME-STEERED TRACTORS
IN TREE-LENGTH SKIDDING


The author deals with the problem of extraction of stems with the Kockum
KL860 frame-steered tractor.


Skidded were Beech and Oak stems, in fact, the lower parts of stems containing
logs. On the felling site was carried out a final cutting from which 198 cu. m.´ha. or
72 trees/ha. were removed. The average length of stems amounted to 11 m., and their
volume to 1.78 cu. m.; the tractor pulled on an average 2.11 stems totaling 3.75 cu. m.
in volume. The average skidding distance amounted to 194 m.


The loaded tractor had to move uphill. The average driving speed of the unloaded
tractor amounted to 2.15 km./hour, and of the loaded tractor to 0.848 km.´hour; no
skidding trails for the tractor were built on the felling site.


The tractor effective time increased with the skidding distance increasing, viz.
at 100 m.-distance it accounted for 64.7%, and at 500 m.-distance for 77.9% of total
working time.


The driving time of the loaded and unloaded tractor increased in percentages at
greater distances, as follows: at 100 m.-distance it increased to 37.0% and at 500 m.distance
to 67.7% of the total working time. This was caused by the low driving speed
of the tractor.


When skidding uphill — at slopes over 20% — the stems had to be winched too
so that the operating tractor was spending on an average 63.6% of time for net driving,
and 36.4% for winching.


For fastening logs chains were used. There was a correlation between the time
consumption for fastening and the diameters of stems, while at unfastening such a
correlation was not established. Stem loading and unloading time on an average
accounted for 34.5% of total working time.


The daily output of the tractor declined rapidly with the skidding distance increasing:
at 100 m.-distance under experimental conditions it amounted to 63.00 cu. m.,
while at 500 m.-distance to 23.25 cu. m. of timber.


For increasing the output it is necessary to undertake certain measures such as:
laying out tractor-skidding trails; introducing tree-length (whole stem) skidding; for
coupling stems chokers instead of chains should be used; applying directional felling
of trees.