volume: 41, issue: 1
Forwarding can be divided into separate work elements. These are affected by several factors: forwarding distance, load volume, and types of assortments harvested. For a detailed planning of thinning, productivity models should include these factors. This study analysed the time consumption of forwarder thinning operations in five pine plantations in the north-east of Argentina, determining how the log size and log concentration affect each work element. Time-and-motion studies were carried out, recording the activities with digital video cameras, and tracking the forwarder movements with global navigation satellite system (GNSS) receivers. Different linear mixed models were fitted to estimate the time consumption of each work element in relation to different predictive factors. When driving on the road, the forwarders had an average speed of 71.6 m min-1 empty and 75.7 m min-1 loaded. When driving in the stand, the average speed was 56.9 m min-1 empty and 52.2 m min-1 loaded. These speeds did not correlate with the forwarder size or load volume. For the loading and unloading elements, the linear mixed model explained 56% and 49% of the variability considering only the fixed effect of the logs size and the load volume. For driving while loading, the total volume loaded, and the log concentration of the assortment loaded explained 50% of the time consumption variability, with 17% being explained by random effects. The general time and productivity model developed can be applied to support accurate decisions in the process of thinning planning.
volume: 45, issue:
The aim of the study was to provide a comprehensive overview of global long-distance road transportation of industrial roundwood. The study focused on the maximum gross vehicle weight (GVW) limits allowed with different timber truck configurations, typical payloads in timber trucking, the road transportation share of the total industrial roundwood long-distance transportation volume, and the average long-distance transportation distances and costs of industrial roundwood. The study was carried out as a questionnaire survey. The questionnaire was sent to timber transportation logistics experts and research scientists in the 30 countries with the largest industrial roundwood removals in Europe, as well as selected major forestry countries in the world (Argentina, Australia, Brazil, Canada, Chile, China, Japan, New Zealand, South Africa, Türkiye, the United States of America and Uruguay) in February 2022, and closed in May 2022. A total of 31 countries took part in the survey. The survey illustrated that timber trucking was the main long-distance transportation method of industrial roundwood in almost every country surveyed. Road transportation averaged 89% of the total industrial roundwood long-distance transportation volume. Timber truck configurations of 4 to 9 axles with GVW limits of around 30 tonnes to over 70 tonnes were most commonly used. The results indicated that higher GVW limits allowed significantly higher payloads in timber trucking, with the lowest payloads at less than 25 tonnes, and the highest payloads more than 45 tonnes. The average road transportation distance with industrial roundwood was 128 km, and the average long-distance transportation cost in timber trucking was €11.1 per tonne of timber transported. In the entire survey material, there was a direct relationship between transportation distance and transportation costs and an inverse relationship between maximum GVW limits and transportation costs. Consequently, in order to reduce transportation costs, it is essential to maximise payloads (within legal limits) and minimise haul distances. Several measures to increase cost- and energy-efficiency, and to reduce greenhouse gas emissions in road transportation logistics, are discussed in the paper. On the basis of the survey, it is recommended that up-to-date statistical data and novel research studies on the long-distance transportation of industrial roundwood be conducted in some countries in the future.