engleski

Influence of Prescribed Method of Roundwood Scaling on Forwarder Efficiency

In timber trade in Croatian forestry, roundwood is usually dispatched by volume in accordance with the standard (EN 1309-2: 2006) and there is a loss of volume due to the prescribed ways of measurement: 1) length, 2) mean diameter, 3) deduction of bark and 4) the expression for estimating the volume of roundwood. Impact analysis of transported load (actual timber volume, timber mass, reduced volume due to the prescribed measuring) for Valmet 840.2 forwarder’s productivity in relation to the transportation distance was determined using a multi-criteria productivity forwarder model (Stankić et al. 2012). The study was based on five different loads of oak (Quercus robur L.) in a forwarder, which differed with respect to: 1) the type of loaded assortments (roundwood, firewood, mixed load), 2) the amount of loaded timber (full height of loading area, <2/3 height of loading area, <1/3 height of loading area of the vehicle). In addition to weighing (with the purpose of determining the mass of the load) measurement of timber within the load was also performed, measurements included: 1) measurement of length to centimeter accuracy, and 2) measurement of diameters on the thicker and thinner end and in the middle of logs. Actual (gross) volume of each log was calculated using Reicke – Newton's formula, and the net volume of timber was calculated in accordance with the standard (EN 1309-2: 2006). Differences in forwarder’s productivity, expressed in terms of timber gross volume and load mass are negligible (<1%) due to the effects of wood density 995.8 ± 2.5 kg/m3. Forwarder’s productivity expressed in terms of timber net volume ranged from 3.5% to 24.3% when compared to timber gross volume. The obtained results depend on the type and size of loaded assortments and quantity of loaded timber. Obviously, the transport of timber and trade of timber contain two different concepts, from the standpoint of timber volume or load volume, and with the different impact on the participants in the timber supply chain.

Prescribed measurement of roundwood; mass; volume; forwarder

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