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Log bunching with winches is still popular in small scale forest operations, and where machine traffic is confined to widely spaced designated trails. Like all tree handling methods, winching has a potential to incur residual stand damage, especially when harvested trees need to be moved around a dense residual stand. Snatch blocks are special pulleys designed for changing the pulling direction, in order to maneuver the winch load around obstacles. This study was aimed at determining the effect of using a snatch block on stand damage and work productivity. Using a snatch block allowed reducing by one quarter the frequency of wounded trees, which dropped from 50% to 36%. The snatch block was especially effective in preventing damage to dominant trees. No significant difference was recorded for wound size and wound severity. Survival of advance regeneration was significantly higher when using a snatch block. When no block was used, almost half of the saplings were lost. In contrast, only one sapling out of four was lost when using a snatch block. Using a snatch block did not cause any significant change of work productivity. Lower incidence of hang-up delays and faster pulling fully offset the time required to rig the snatch block. The study did not include ergonomics, and could not indicate how operator workload was affected by adding the weight of a snatch block to that of the cable and chain rigging. © 2012 Elsevier B.V.

The main aims of this study were to determine the productivity, profitability and energy balance (output/input) of mechanized harvesting applied to a eucalyptus plantation in central Italy. The study area was located in Rome, at an altitude of 35 m a.s.l., on a flat, even site (average slope gradient 3%). The stand was a eucalypt coppice (Eucalyptus camaldulensis Dehnh.) harvested for the first time in 2000. The planting pattern was square with 3 m among stumps (1111 trees ha–1). By 2009, insect (Phorachantha semipunctata) attacks had reduced stump density to 592 stumps ha–1. The work system applied was theWhole Tree System(WTS) and the final assortement chips for energy.Machine rateswere calculated using coefficients and mathematical formulas extracted from themain methodologies proposed by different authors. Energy balance was estimated with the Gross Energy Requirements (GER) method. In these plantations, mechanized harvesting seems most appropriate: this is demonstrated by the high productivity recorded (PSH15 6.5 td.w. h–1 worker–1) and by the favorable energy balance (output/input 23.8, 95.8% system efficiency). However harvesting cost is still high (44.30 € tf.w. –1) and can only be reduced through careful operational planning.

Damage to residual stand after partial harvesting or thinning may lead to serious economic losses in terms of both timber quality at the final harvest, and tree growth reduction. Logging damages and their effect on tree growth were studied in a long term experiment on Corsican pine in central Italy. Damage frequency, agent (felling, skidding), position (root damage, stem base, between 0.3 and 1 m a.g.l., >1 m a.g.l.) and severity (light, severe) and tree growth were measured after selective thinning from below and at 10 years after the treatment. In detail, we aimed at: monitoring mechanical damages to trees at the end of thinning and after 10 years; and assessing stand stability, growing stock, ring width and basal area at 10 years after the thinning. The thinning removed about 20% of volume, 38% of trees and 26% of basal area. The basal area decreased from 56 m 2 ha −1 to 42 m 2 ha −1 but after 10 years it increased again to 56 m 2 ha −1 . Immediately after thinning, 13.6% of the standing trees was damaged, out of these 36.17% showed severe injuries. Damages to standing trees were mainly due to skidding. Ten years after thinning, the percentage of damaged trees was about 17%, out of which 86.67% showed severe wounds. An increase of damaged trees and of trees with severe wounds was observed suggesting that a deeper knowledge on long-term effect of logging damages is needed. This study did not highlight any effect of logging damage on tree growth. In fact, no difference in ring width was recorded between damaged and undamaged trees.

We set out to determine the particle-size distribution, the fiber, the bark and the leaves content, the heating value, the CNH and the ash content of a wide sample of wood chips, collected from 10 forestry and 10 agroforestry production sources. This sampling focused on two main production types: forestry (Full Tree System—FTS—and logging residues—LR) and agroforestry(Short Rotation Coppice—SRC). For the forestry production wood chips from coniferous and broadleaf species were considered. For the agroforestry production wood chips from poplar plantations were examined (different clones with two different harvesting intervals). Overall, we collected 400 samples. Particle size distribution was determined with an automatic screening device on 200 samples. The higher heating value was determined on 200 subsamples using an adiabatic bomb calorimeter. The CNH and the ash content was ascertained on another 200 subsamples. FTS and SRC (with three year old sprouts) offered the best quality, with high fiber content (71%–80%), favorable particle-size distribution and good energetic parameters. On the contrary, both logging residues and SRC (with two year old sprouts) presented a high bark content (18%–27%) and occasionally a mediocre particle-size distribution, being often too rich in fines (6%–12%), but the energetic parameters are in the normal range.&nbsp