DIGITALNA ARHIVA ŠUMARSKOG LISTA
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ŠUMARSKI LIST 13/2005 str. 89 <-- 89 --> PDF |
P. Horek, P. Mauer, L. Novak: LARIX FOREST CABLEWAYS - IMPLEMENT OF THE NATURE OR1KNTED ... Šumarski list SUPLHMENT (2005), 78-89 regeneration period. The present rotation period being 130 years, the first advance growths emerge as early as at the stand age of 90 years. Therefore, it is necessary that conditions are created for the rise of self-seedings and subsequent shelterwood felling already at implementing the last tending measure. The to-be regenerated stands are to be divided by approximately 100 - 120 m by inserting cableway routes, i.e. strip clear-fellings whose width would be 4 to 5 m. There is a principle to be observed at the measure implementation that the entire strip width is not cut before the proper cableway timber skidding takes place but it is only the narrowest slit possible to enable the operation of an about 3 m wide cableway which is going to be widened to the required width of the strip felling by Polansky only after the entire logging operation was accomplished. This is how trees along the line can be removed, which were possibly scratched while serving as fenders at skidding. Then the felled strip-cut becomes a starting point for the natural regeneration which shifts under the parent stand from below. The logging is made in the context with shelterwood felling the intensity of which is decreasing from the cableway line edge into the stand inside. This shelterwood treatment is made along the both sides of the cableway route and results in the removal of mainly large-diameter trees with ill-shaped stems or crowns from the main stand level up to the distance of 20 - 30 m from cableway reach. Qualitative individuals with perfect crowns and good growing characteristics are left in the stand for seed. By selecting the ill-shaped large-diameter trees, we release main-level and sub-dominant trees of smaller diameters, which respond to the release with increased light increment on qualitative mass. Research results indicate that the increment can fully compensate production losses often recorded at the selection of large-diameter trees. The consistent and timely selection of large-diameter individuals together with the reduced rotation period help to prevent the development of false heart which can result in great economic losses. At logging, we principally save the sub-dominant trees which influence the stand microclimate for the sound development of advance growths. After the stand has been gradually felled and ensured, there are other fellings inserted into the original system of strip fellings, which gradually results in complete rgeneration of the whole stand. The described system of beech stand management is a good example of qualitative increment management and there is a number of these examples in the stands of TFE Krtiny, which can document correctness of the above described method. As to the technical aspects of cableway skidding employed at the above mentioned silvicultural procedures, it is the LARIX forest cableways which have been exclusively used at the TFE Krtiny over the last 9 years, whose technical parameters and suitability correspond the shelterwood system in individual selection fellings. The following technical solutions of the LARIX type cableways facilitate the application of mild timber skidding methods in the conditions shelterwood system in individual selection fellings. 3. TECHNICAL CHARACTERISTICS OF LARIX FOREST LARIX cableways produce the Czech firm Training Forest Enterprise at Krtiny. The characteristic and parameters of modern cableways LARIX and also carriages are mentioned below. LARIX 550 and LARIX 3T The LARIX 550 and 3T cableways are designed as trailed implements on agricultural tractor where the tower and winches of the cableway are carried on the rear three-point linkage, and another part drums with running lines are carried on the front three-point linkage. This means that the cableway´s weight is evenly distributed onto the two axles, which makes the tractor with the cableway mobile also in the difficult terrain. The LARIX 550 and 3T is equipped with 5 cables: skyline, running line, hoist line, slack- pulling line and straw line. The system with endless line make possible that load during transport does not to be braked and there is CABLEWAYS very simple to direct the carriage with or without the load, targeted automation of in hauling or out hauling carriage is in standard equipment. Cableways are radio-controlled right from the forest. LARIX Hydro Hydrostatic driven cable systems LARIX Hydro are designed for timber transport, uphill as well as downhill. The cable system is built either on a truck with stationary motor (LARIX Hydro A) or on the special trailer to a bigger agricultural tractor with minimum engine power about 100 kW (LARIX Hydro P). Between mainline and haulback line drum is an interlock system with recuperation of braking power what enables target automatic with storage commands and programmed speed change of carriage with or without the load. The set-up time is very short. Independence of remote control - at landing place cable remote control, at logging place radio control. Technical parameters are as follow: |