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1
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Wpływ pory roku na uszkodzenia drzewostanów olchowych podczas trzebieży wczesnej

100%
Grzywinski W., Turowski R., Naskrent B.
Sylwan
|
2020
|
tom 164
|
nr 05
The paper presents the comparison of the influence of the season (winter and summer) on the level of damage to trees remaining after the timber harvest during early thinning in young alder stands. The study was carried out in black alder stands aged 38 and 40 years located in north−eastern Poland (Płaska Forest District). Chainsaw logging was performed in the cut−to−length harvest system, while timber was extracted using an agricultural tractor with a trailer with manual timber loading and unloading. The number and share of damaged trees and stand damage rates were estimated in a particular season of the year. Logging resulted in the damage of 8.3% to residual trees. Almost twice as many trees were damaged in summer as in winter (p=0.001). Significantly higher share of trees in 3rd, 4th, and 5th damage classes was found. Only the damage of timber fibers (6th class) did not differ significantly between analyzed seasons. The stand weighted damage rate (W) ranged in winter from 0.12 to 0.38, and in summer between 0.12 and 0.80. In turn, the value of weighted coefficient of damaged trees in the remaining stand amounted to 10.24−60.15 in winter, and 19.07−119.64 in summer. Both W (p<0.01) and WDI (p<0.05) indices were twice higher in the summer than in the winter period.
2
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Zrywka drewna średniowymiarowego w drzewostanach trzebieżowych przy użyciu ciągnika rolniczego z przyczepą nasiębierną

100%
Naskrent B., Polowy K., Grzywinski W., Sobczak A.
Sylwan
|
2019
|
tom 163
|
nr 02
The amount of timber extracted from Polish forests is expected to increase in near future. The most common equipment for timber extraction is an agricultural tractor with a trailer equipped with a hydraulic crane. The research was carried out in the Wymiarki Forest District (Regional Directorate of the State Forests in Zielona Góra) in the third (TP1) and fourth age class (TP2) in Scots pine stands, during extraction of timber from thinning. Extraction was carried out using BELARUS MTZ 1221.2 agricultural tractor with PALMS 120 forest trailer equipped with PALMS 700 hydraulic crane. The scope of the study was to conduct time studies of extraction process and to estimate the extraction productivity as well as time and fuel consumption. Working time was measured by stopwatch, while the forwarding distance was determined with measuring wheel. The exact number of logs in each load was established. Average volume of each log and each load was calculated. The dominant work time category was effective working time 74.78% (TP1) and 73.60% (TP2), while the prevailing work task was loading 56.82% (TP1) and 58.99% (TP2). In older stands, the extraction productivity was higher than in younger ones reaching 11.28 and 9.62 m³/h, respectively. Statistical analysis proved that extraction distance significantly affect productivity and time consumption. With increasing extraction distance productivity decreases and time consumption increases. Fuel consumption was exactly the same in younger and older stands (0.52 l/m³).
3

Eye-tracking w badaniach operatorów maszyn leśnych

100%
Naskrent B., Grzywinski W., Polowy K.
Przegląd Leśniczy
|
2018
|
tom 28
|
nr 05
4
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Struktura roczna i rzeczywisty czas pracy na stanowiskach leśniczego i podleśniczego

88%
Grzywinski W., Tomczak A., Jelonek T., Burzynska-Jedrzejczak G., Naskrent B.
Sylwan
|
2019
|
tom 163
|
nr 05
The aim of the study was to recognize the annual worktime structure and the actual number of working hours at the forester and deputy forester workstations in the State Forests. The research was carried out on the sample group of 462 workers in all regional directorates of the State Forests in 62 forest districts and 242 forest ranges. The study group consisted of 21 (4.5%) forest foresters from one−man forest districts (L1), 222 (48.1%) foresters and 219 deputy foresters (47.4%) from two−men forest ranges (L2 and PDL respectively). Altogether 17 groups of activities were distinguished. The workers were studied in spring, summer, autumn, and winter. Every time the research was conducted during one full week (Monday−Sunday). In case of two−men forest districts, both workers were studied simultaneously. The measurement of timework was carried out with the specially designed mobile application LP1 operating in Android system. The duration of particular activities at L1 and L2 workstations was similar. The office work constituted most of their worktime: 109.7 minutes (22.9%) for L1 and 111.5 min (23.3%) for L2. Transportation took 80.2 and 84.8 min (17.7 and 17.6%), whereas wood sale required 69.7 and 62.8 min (14.5 and 13.1%) for L1 and L2 work stations respectively. At PDL workstation passages took 84.7 min (17.6%), wood quality inspection and registration – 65.4 min (13.6%), and office work – 60 min (12.5%). The tasks comprising preparation, harvesting and sale of raw timber took 34.9% of L1 worktime, 32.5% in case of L2 and 41.6% for PDL’s worktime. All employees devoted the least of their worktime to tasks connected with fire precautions, nature conservation, and environmental education (tab. 1). The overrunning of normative worktime was recorded at all studied workstations. The mean daily worktime for PDL amounted to 8.17 hrs, whereas for L1 and L2 it was 8.47 and 8.52 hrs respectively. Except extra working hours during the working week, the overtime during the days−off was recorded too. Most of time spent on work in such situations was recorded for L1 (1.69 hrs on average per week), while the least (0.97 hrs) for L2 workstation.
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