DIGITALNA ARHIVA ŠUMARSKOG LISTA
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| ŠUMARSKI LIST 5-6/1970 str. 25 <-- 25 --> PDF |
TIME EXPENDITURE IN REDDENING TREES OF AUSTRIAN PINE AND FACTORS INFLUENCING THIS EXPENDITURE Summary The author deals with the problem of work and time expenditure when redde ning Austrian Pine trees by means of French method of resin-tapping. Investigations were carried out on the territory of the SR Bosnia-Herzegovina. In the time study was applied the method of time observation according to its duration. Measured were the times of all work elements and delays during an 8-hour working day. In the article are dealt with the time expenditures for the basic work element, i. e. reddening of trees. The trees are tapped and accordingly reddened from root swelling up to 4,1 m. above ground. In data processing the method of statistical analysis was applied. The results of the investigation may be summed up as follows: 1. The thickness of bark at any one place along the stem increases with the stem diameter increasing. This relates to the non-reddened bark layer, the layer which remains after reddening, as well as to the one removed by reddening. 2. The time expenditure for cutting one face at a definite height on the tree depends on the bark thickness. As the bark thickness increases in proportion to the stem diameter, so increases also the time required for cutting one face according to the stem diameter, which was proved by computing the significance of differences of arithmetical means concerning the time expenditures. The dispersion of time expenditures in reddening of trees is further caused by the inclination of the slope and the branches occurring on the faces. The differences between the arithmetical means of time expenditures in faces cut on trees from the lower side of the slope and those from the upper side are significant. The same occurs in face with branches and those without branches. 3. When computing the significance of differences of arithmetical means concerning the time expenditures on a flat or gentle terrain and on a steep terrain, it was shown that those differences are significant. From which it was concluded that the time expenditure for reddening depends also on the slope of the terrain. 4. With the help of a regression analysis it was established that there existed a correlation between the times spent for reddening trees on the one hand, and the heights of gutters above ground and slopes on the other. This relation was computed by means of the following regression equation: z´ = 147,255 — 80,3102 . x + 41,529496 . x2 —5,2843861 . x3 + 0,44546763 . y; r = 0,949 + 0,001665; through this analysis a close correlation between the time expenditure and the height of the gutter above ground and the inclination of the slope was proved. 5. A regression analysis proved that up the trees in all diameter classes the bark thickness decreases. 6. The time expenditure for reddening up the trees is not proportional to the bark thickness. With the height of the face above ground increasing the thickness of the bark decreases, while the time consumption increases. 7. The smallest time expenditure on all the slopes is at the 4,1 m.-heigt of the gutter above ground. The time expenditure under most unfavourable conditions is greater than under the most favourable conditions by 70,2°/o. Within the same slope the highest time expenditure differs from the smallest one owing to the varied heights of the gutter above ground by 45,4%>. At the same height of the gutter above ground the highest time expenditure differs from the smallest one by 24,4´"/» at most, owing to the varying slopes of the terrain. Thus a greater height of the gutter above ground influences in a more negative way the efficiency than does the increase of the inclination of the terrain. |