engleski

Terrain Roughness Evaluation for Timber Extraction by Cable Skidder

This paper gives analysis of ground obstacles in one Management unit of selective forests in hilly-pre-mountainous part of Croatia, Zalesina, as one part of terrain description and classification required for planning forestry operations. In the area of high karst, terrain roughness is defined in terms of slope, its various direction forms and ground obstacles as soil condition is of minor importance for vehicle mobility due to highly skeletoid soil composition. Available data (pedological maps, official management plans) in Croatia regarding ground obstacles (stoniness/rockiness while other obstacles are left unmentioned) is still given in terms of share per area and as such does not really differentiate areas unsuitable for various forestry vehicles. According to literature guidelines, ground obstacles were recorded on 319 sampling plots, each of size 10 × 10 m and with 100 m of distance. Height and frequency of ground obstacles were measured on each sample plot and according to frequency were divided into four groups: 1) isolated, 2) infrequent, 3) moderately frequent and 4) frequent ; as well as in four height classes: 1) H20 (10-30 cm), 2) H40 (31-50 cm), 3) H60 (51-70 cm) and 4) H80 (> 71 cm). Based on share analysis of ground obstacle groups, manoeuvrability angles and clearance radiuses of skidder which describe its mobility characteristics, three new terrain roughness categories were defined: 1) skidding timber across ground obstacles is possible (20.14% of MU area), 2) skidding timber while by-passing ground obstacles is possible (24.54% of MU area) and 3) construction of skid roads is necessary (54.16% of MU area).

ground obstacles, terrain trafficability, skidder, terrain roughness

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