DETERMINATION OF OPTIMAL SECONDARY FOREST ROAD NETWORK LAYOUT

Određivanje prostornog rasporeda sekundarnih šumskih prometnica predstavlja jedan od osnovnih parametara za određivanje optimalne otvorenosti odjela. Za što kvalitetniju izradu studije otvorenosti odjela, primijenjeni su moderni instrumenti, softveri i metode u postupku prikupljanja i analize terenskih i sastojinskih čimbenika, te analize postojeće sekundarne mreže. Ove analize su neophodne za pravilno i opravdano projektiranje novih i optimizaciju postojećih elemenata sekundarne prometne mreže u odjelu. Također, obrađena je problematika s tehničkog, ekološkog i ekonomskog gledišta privlačenja te funkcija sekundarne mreže u istom.Značajan segment rada predstavlja analiza kvantitativnih i kvalitativnih obilježja postojeće mreže u odjelu 94/1 G.J. "Šiša-Palež" Š.P.P. "Ključko". Analiza kvantitativnih obilježja rađena je na temelju prethodno snimljenih elemenata sekundarne mreže pomoću GPS uređaja i njihove obrade u GIS-u. Na ovaj se način planirala sekundarna mreža, te uz pomoć GIS alata i analiza došlo se do podataka na temelju kojih su izračunati parametri otvorenosti i kreirale se odgovarajuće tematske karte. Slijedom toga planirao se uzorak za procjenu kvalitativnih obilježja postojećih elemenata sekundarne mreže. Ove informacije imale su veliko značenje u fazi optimizacije postojeće mreže prometnica te izrade varijante I.In this paper different instruments and softwares for collecting and analysis of data influencing on planning of the socondary network of communications have been applied. By means of them data has been given which present actual picture of factors of terrain and factors of forest in the department. These factors are necessary to enable right solutions in the sense of selection of optimum technology of work in the phase of skidding and in the sense of designing and construction of optimum network of communication in the department. The existing secondary network of communication in characterized by very long tractor roads (19.492,17 m), high absolute openness (201,35 m/ha) and low ratio openness efficiency (calculated via number of trees) 28,86 %. The secondary network of roads designated as variant I is characterized by less length of roads in comparison with existing one (by 53 %), lower absolute openness, high relative openness (calculated via number of trees) which amounts to 95,55 % and significantly higher ratio of openness efficiency (calculated via number of trees) which amounts to 73,82 %.The qualitative indicators of the network of tractor roads estimated on the basis of examples serve as one of the foundations in occasion of the procedure of elimination of roads from existing network. Because of that from the existing network the inefficient roads have been eliminated which have also been characterized by higher percentage of damages. Besides that, on the basis of condition of skid road it is possible to make calculation of the costs of rehabilitation of tractor road after exploitation. The secondary network of communication of variant I has got lower total costs of labour in all phases (from skidding to rehabilitation) by 1.883,80 € or 9,23 % and lower unit costs of labour by 0,88 €/m3 or 9,19 %. The costs of rehabilitation of skid roads of variant I are much lower than for the existing network. In total amount direct costs of rehabilitation are lower by 6.493,41 € or 59 %. This difference in total costs of rehabilitation of tractor roads is the consequence of less length and higher percentage of undamaged skid roads of variant I.The selection of optimum technology of work in the phase of skidding of forest wooden products and establishment of optimum network of communication in the department are very important for forestry company which manages these forests and for the forest as the natural object and broader social community