DIGITALNA ARHIVA ŠUMARSKOG LISTA
prilagođeno pretraživanje po punom tekstu



ŠUMARSKI LIST 11-12/1978 str. 27     <-- 27 -->        PDF

SUMMARY


Relation between the time consumption and lower limit ot the primary
conversion of Fiv trees


The author deals with the problem of lower limit (of the diameter at the
small end of the stems) in the primary conversion of Fir trees. Usually the
stem and the top section of the trees up to the diameter of 7 cm outside bark
are converted.


In the time study the author applied the work sampling method, and the
sterns for this purpose were divided into the sections of 4 m in length. Only
the top sections could be shorter. B. h. d. of treated trees ranged betwen 35 and
75 cm.


It was established that the time consumption per 1 m3 of converted volume
at top sections for the barking was about twice, and for the trimming on the
average even seven times longer than at the other (lower) part of the stem.
Therefore, if the top sections are omited, the time consumption for the trimming
and barking of converted volume per tree shortens absolutely and relatively
in a higher degree than the omited wood volume.


Three variants of the primary conversion were treated: 1. The conversion
of stems up to the diameter of 7 cm outside bark at the small end; 2. The top
section of the 2 m average length were omited; 3. Two top sections of the 6,3 m
average length were omited.


All diminutions of the time consumption and of the wood volume, mentioned
further, represent the average value for all treated trees.


In the second variant the wood volume per tree, in relation to the first
variant, diminished by 1,2%; the time consumption for the trimming by 8,6%,
for the barking by 2,6B/a, and the both consumptions together by 5,2%. At the


3. variant the above mentioned diminutions amount up to 5,1%; 28,8%; 9,9´V»
and 17,8 % respectively.
Furthermore, the effective time which was divided into two parts and that:
the fixed (invariable) time and the variable time, was treated. To the fixed
time belong the following work operations: Walking from tree to tree, felling
and beard outting off. These work operations are fixed, because their time consumption
per tree is the same, irrespectively of the converted part of the stem.
The variable work operations are: trimming, barking, marking for cross-cutting
and cross-cutting. The time consumption per tree of the variable times varies
in individual variants, with regard to the converted length of the stem. Because
of the fixed component of time, the effective time diminished in the second
and third variant with the smaller intensity than the whole time consumption
of trimming and barking, which dominates in the variable time. The diminution
of the effective time per tree in the second variant amounts to 4,8 %, and in
third variant to 15,6%, with regard to the above mentioned diminution of converted
volume.


The diminution of the effective time per 1 m´! of converted volume in the


2. and 3. variant is a little smaller than per tree, because the fixed time increases
per 1 m3 of converted volume in the 2. and 3. variant, with regard to the diminution
of the converted volume, by which the time consumption is divided.
In the 2. variant, the lower limit of conversion amounts on an average to 15,6
cm, and in the 3. variant to 23,9 cm.
It was found that the time consumption of the trimming for a certain
round-wood section of the same diameter increases with the increasing diameter
of the stern, from which the section is derived. The increasing can be threefold.
The reason for it is that the round-wood of the same diameter of thicker stems
lies higher on the stem, in the more branchy part. The similar increasing of the
time consumption for the barking is not significant.


457