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A survey of cable logging contracts was conducted in 5 of the 8 Alpine countries, namely: France, Germany, Italy, Slovenia and Switzerland. The goals of the survey were to set a general reference for cable logging rates, to identify eventual differences between countries and to determine the effect of technical work parameters (i.e. piece size, removal per hectare, line length) on actual contract rates. With a total sample size of 566 units, the mean removal and rate were 165 m3 ha-1 and 42.9 EUR m-3, respectively. Both removal per hectare and contract logging rates varied considerably and the study found significant differences between countries. Switzerland stood out from the group with the highest removal (345 m3 ha-1), but also the highest contract rate (79.5 EUR m-3). Removal per hectare was lowest in Italy with just 58.3 m3 ha-1, and logging rate lowest in Slovenia at 29.3 EUR m-3. Logging rates were highly correlated with the average labour rate of each country. Technical factors such as tree size, line length and tract size explained about 40% of the variability in logging rates. Therefore, 60% of the variability is explained by other technical factors not included in our data and by non-technical factors, such as local market dynamics.

Chipping is an essential element in the energy supply chain and mobile chippers are very popular because they can work directly in the forest or at the roadside landing. Due to space constrain, drum chippers are dominating forest biomass operations. Drum chipper are less efficient then disc chipper but they are also less sensitive to feedstock quality. Drum chippers come in two main design types: closed drum with full-length knives and open drum with staggered narrow knives. The goal of this study was to analyse the specific effect of these design types on productivity, fuel consumption and product quality, using different raw material types. For this purpose, two commercial chipper models with almost identical characteristic were selected to represent the alternative drum designs. Both machines were fed with two different feedstock types: chestnut logs and chestnut branches. The study included 12 repetitions per combination of drum design, feedstock type and knife condition (new or worn out) for a total of 2 x 2 x 2 x 12 = 96 repetitions. Both chippers were attached to the same instrumented tractor, and all product obtained from each chipping bout was blown into big bags and weighed with a load cell attached to a forklift. The study showed that the closed drum design was better suited to handle branch material, compared to the open drum design, especially when knives were dull. Under these conditions, productivity was higher, fuel consumption lower and chip quality better for the closed drum design. No significant differences between the two designs were found when processing logs or when the knives were new. In general, the performance of both designs was significantly affected by feedstock type and knife wear.

The Authors set out to determine the particle-size distribution, the fiber and bark content, and the heating value of a wide sample of wood chips, collected from 60 commercial biomass terminals active in Northern Italy. This sample was meant to represent a cross-section of the Italian fuel chip market, and focused on four main feedstock types: sawmill residues, logging residues, small trees and short rotation coppice (SRC). Overall, the Authors collected 300 samples, each weighing approximately 1 kg. Particle-size distribution was determined with an automatic screening device on 210 samples, according to European Standard CEN/TS 15149-1. All samples were also manually separated into the following main components: fiber, bark, twigs, leaves, dust and other. The higher heating value (HHV) was determined on 56 one-gram subsamples using an adiabatic bomb calorimeter. Sawmill residues and small trees offered the best quality, with high fiber content (85-90%) and favorable particle-size distribution. On the contrary, both logging residues and SRC presented a high bark content (>= 20%) and occasionally a mediocre particle-size distribution, being often too rich in fines (>= 10%). These problems were especially serious with fuel derived from 1-year old SRC sprouts. There is a need for reducing the supply cost of small trees, and improving the quality of SRC biomass.