Current issue: 58(5)
Articles containing the keyword 'maasto'
Category : Article
As a subproblem in the joint Nordic Terrain-Machine Project the requirements set by forest road construction on the terrain classifications were studied during the summer 1973 in ten operations, in which either a bulldozer or an excavator method was used.
The most important terrain factors of the ground factors affecting the construction time of the road base were the so-called depth index and the moisture content of the soil, and in addition to these the amount of stumps as a ground roughness factor. These variables explained, however, only a rather minor part of the wide variation in the construction output of the practical operations.
The PDF includes a summary in English.
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Haarlaa,
E-mail:
rh@mm.unknown
The study deals with the trampling tolerance of forest vegetation in a Myrtillus type closed forest of Norway spruce (Picea abies (L.) H. Karst.), based on the effects of simulated trampling on the coverage and biomass on the field and between layers of the vegetation. The reliability of the results from the simulated trampling was tested by comparing them with those obtained from real trampling.
According to the results, the trampling tolerance of the bottom layers is greater than that of the field layer. The trampling tolerance of different species varies, so that grasses and dwarf shrubs have a higher tolerance capacity than herbs. Even light trampling of short duration caused noticeable changes in the coverage and biomass of the ground vegetation. Despite certain deficiencies, the simulated trampling gave parallel results of those obtained for real trampling.
The PDF includes a summary in English.
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Kellomäki,
E-mail:
sk@mm.unknown
The mobility of logging tractors was tested in the winter 1969 on difficult snow conditions to gather information for planning of logging operations and for logging machinery design. The tractors tested were Clark Ranger 666, Timberjack C, Valmet Terra, Ford Brunett 5000, Fiskars 510, BM-Volvo SM 660, BM Volvo SM 661, Ford Country 6, MF-Robur I and BM-Boxer T-350.
According to the results, there is a preference of tracked vehicles in difficult snow conditions compared to wheeled tractors. Ford Country with long and bearing full-tracks proved to have the best mobility. On downhill grades it was found significant differences between three-quarter-track-tractors and skidders, although the performance on level ground and uphill grades was relatively similar. The tracked vehicles can easier move on the packed snow layer and reach a higher speed.
The driving speed does not increase significantly until the density of snow has entirely changed through getting wet. Wet top layer of snow affects positively on driving, because it increases packing of the snow. Increasing density of the snow improves especially the mobility of broad-tired wheeled tractors. To be able to predict the driving speed of a tractor in winter working conditions one must know the depth of the snow layer and the density of the snow and the grade of the slope. In addition, the passages on the same route and the packing of the snow must be regarded.
The PDF includes a summary in English.
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Silvennoinen,
E-mail:
us@mm.unknown
- Haarlaa, E-mail: rh@mm.unknown
The purpose of this study was to explain whether it is possible to affect, in practical working site conditions, by means of logging waste on the strip road, the depth of the track which is formed in terrain transportation and the injuries of the growing stand. Five 20 m long investigation areas with logging waste and five similar areas without logging waste were arranged on one strip road at Teisko logging site in Southern Finland. The logging waste layer was mainly Norway spruce and 10–15 cm thick. A KL–836 B forwarder was used. The type of soil was loam.
The logging waste affected the depth of the track only by decreasing the wear of humus layer. Even decreasing effect of logging waste on the injuries in the growing stand was minor. At Kitee working site in Eastern Finland strip roads were studied. The type of soil was thick, rather mouldered peat. The thickness of logging waste was 3–4 times greater than in Teisko, mainly spruce. A Volvo Nalle SM 460 forwarder was used. The effect of the logging waste on the depth of the tracks was clearly to be noticed. On basis of the appearance of the tracks one could assume that the difference was due to different wear of the humus, and not so much due to the quantity of logging waste that improves the carrying capacity of terrain.
In some extent logging waste was also found to affect the amount and quality of tree injuries. In practical working conditions, the importance might be small, since in the experiments an unrealistically great amount of logging waste was used.
The PDF includes a summary in English.
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Kärkkäinen,
E-mail:
mk@mm.unknown
The article is a report from the meeting of the Section 32 of the IUFRO in Canada on September 15.–25. 1964, which three Finnish forestry experts participated. The theme of the meeting was classification of forest terrain.
The PDF includes a summary in English.
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Makkonen,
E-mail:
om@mm.unknown
Category : Article
The aim of the investigation was to obtain by snow and soil frost observations sufficient material for determination of regional springtime snow and soil frost values, because the water equivalent of snow and the frost depth affect runoff. The present paper elaborates a method by which the observations along a survey line can be corrected to be valid for a basin. Along the line 50 measurement points were arranged at specific intervals. Snow depth was recorded at each point, and snow density and frost depth at every fifth point. The terrain was studied along the line and the terrain of the survey points were classified in eight classes depending on the vegetation. The classes ranged from cultivated lands and open bogs to wooded areas according to volume of the growing stock and tree species composition.
The mean snow depth was 51.9 cm and mean snow density 0.235 g/m2. Water equivalent of snow in class 4 terrain (forest with small growing stock) was 30% higher than in class 8 (forest with high growing stock). An ample stand increases evaporation in wintertime. The difference can be partly caused by the different accumulation of snow in the different types of stands.
Soil type was not found to have any distinct influence on the frost depth in the present material. On cultivated lands the soil frost clearly penetrates to greater depth than in the forest. The growing stock of wooded areas influences the snow depth
The PDF includes a summary in English.
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Mustonen,
E-mail:
sm@mm.unknown
The possibilities of using microwave techniques in detecting the trafficability of peatlands is discussed. Three microwave methods were tested. 1) A FM-CW radar using 1.0–1.8 GHz frequency was used to measure the frost thickness of peat layer. It was possible to follow the variations in snow and frost layer thickness. Total reflected power might indicate the wetness class of the peatland, which is also a trafficability factor. 2) A short-pulse radar with 100 MHz frequency was tested in summer condition. Good profiling of peat layers was obtained, giving basic information for trafficability analysis. 3) A mapping of brightness of temperature of peatlands in summer conditions using a 790 MHz radiometer. The measured brightness temperature was correlated with vegetation cover, thus giving some information of trafficability.
The PDF includes a summary in English.
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Saarilahti,
E-mail:
ms@mm.unknown
