Search

In thinning operations in Mediterranean beech forests, pack animals are often used when topographic conditions do not allow for the use of mechanisation to perform logging operations. Otherwise, mechanised extraction is the primary choice. In an effort to reduce soil disturbance caused by mechanised ground-based logging, the forest authorities who guard protected areas have been mandating animal logging at all logging sites in recent years. Since no comparative scientific trials of soil disturbance of these two extraction systems have ever been conducted in the target setting, there is no scientific evidence to sustain this approach. On this basis, we chose two study areas where the forest authorities mandated animal logging. Each study area consists of three sub-compartments, one unharvested, one harvested by animals, and one harvested by tractor in the same year (2021). We examined soil compaction, soil organic matter, and soil microarthropod biodiversity in animal skid trails, tractor skid trails, soil unaffected by extraction methods, and unharvested control sites in each study areas. We used linear mixed-effects models, indicating the study area as random intercept, to investigate the effect of the experimental treatments on the target soil features, and to check the relationship among soil physico-chemical parameters and soil microarthropod biodiversity. We discovered that only the animal and tractor skid trails showed signs of disturbance in terms of soil compaction and organic matter loss. Additionally, there was a significant decline in the biodiversity of soil microarthropods in both the skid trail types, with values of the QBS-ar index which were practically halved in comparison to the control area. We did not find any significant difference in the values in the tractor and animal skid trails for any of the examined soil characteristics. Low soil microarthropod biodiversity was found to be correlated with high soil compaction in terms of penetration resistance and low soil organic matter levels, according to linear mixed-effects models. Despite our preliminary findings, we made it clear that the short wood system by a tractor fitted with forwarding bins is unquestionably a very soil-disturbing extraction system, that ought to be avoided when conducting logging operations in protected areas. However, pack animals are not a suitable solution to reduce soil disturbance. Other extraction systems such as chute, small-scale cable yarders, as well as combination of animals and machine avoiding extensive traffic on the forest soil, are better solutions to the fundamental issue of low-impact logging in protected areas. • Forest authorities have been requiring pack animals logging in protected areas. • We compared soil disturbance after animal and small-scale mechanised logging. • We found a strong disturbance in both the animal and tractor skid trails. • No difference was found between the two types of skid trails. • Pack animals are not recommended as low-impact extraction system in protected areas. [ABSTRACT FROM AUTHOR]

Despite the high ecological value of Mediterranean beech forests, very little is known about the implications of forest operations on soil microarthropod biodiversity and litter decomposition rate. There is also no information concerning the amount of time needed for disturbed forest soil to recover and return to the pre-harvesting conditions. Silvicultural treatments are scheduled about every ten to fifteen years, without taking into account the amount of time necessary for recovery. The purpose of this study was to determine this information. The study started by selecting three study sites located along the Italian Apennine, each including a chronosequence of three forest parcels: one harvested in 2021, one harvested in 2012, and a control parcel which had not been harvested within the last forty years. In the harvested parcels we investigated skid trails which are classified as disturbed, and soil not affected by the passage of a machine which is classified as undisturbed. Thus in each study area there were five experimental treatments including the control area. The soil physico-chemical properties were assessed for each treatment. These included bulk density, penetration resistance, shear resistance, organic matter content, and soil microarthropod biodiversity which was assessed by the QBS-ar index (Soil Biological Quality based on microarthropods, a qualitative index measuring the quality of soil according to the biodiversity of the microarthropod community). We further established a litter decomposition experiment, using teabags as reference material, to check the differences among treatments in litter decomposition rates. We used linear mixed-effects models to investigate the effects of the experimental treatment on the physico-chemical and biological features, and relationships among QBS-ar index and soil physico-chemical features. We analysed the effects of the experimental treatment on the litter decomposition rate using generalised linear-mixed effects models. A significant effect caused by machine passage was found in the recently harvested parcels on soil penetration resistance (∼+70 % comparing to the control), shear resistance (∼+35 %), and QBS-ar index (-25 %). Effects of machine passage on soil bulk density and organic matter content were not significant. All the investigated variables in the skid trails returned to values similar to those recorded in the control after ten years. We did not find effects of any soil physico-chemical features on QBS-ar index. Finally, no effect of the experimental treatment was found on the litter decomposition rate, suggesting that a stronger magnitude of soil disturbance is needed to affect this complex biogeochemical process. Although the initial impact was highly significant, it was found that a 10-year period is sufficient for recovering the investigated soil features in the upper soil layer. This was observed in Mediterranean beech forests when forest operations were done with low-weight machines and a limited number of machine passes on the skid trails. Thus, it can be concluded that planning another operation 10–15 years after the previous thinning, as is currently done, remains in line with the time needed for the forest soil to recover. • We assessed the effects of logging on soil physico-chemical and biological features. • We found a significant increase of soil penetration resistance and shear resistance in the skid trails. • We found a significant decrease in soil microarthropod biodiversity in the skid trails. • We did not find any alteration of soil organic matter or litter decomposition rate. • A 10-year period was enough to restore all the altered soil features in the skid trails. [ABSTRACT FROM AUTHOR]

Animal logging is one of the most ancient wood extraction methods and it is still applied in different parts of the world, including industrialised countries. Animal logging is often imagined as a low-impact method and sometimes, or rather often, it is recommended as a best-management practice. However, the literature findings depict a more complex scenario, and the goal of the present review is to shed light on the topic of environmental sustainability of logging operations performed by animals. Usually, animal logging causes less pollutant emissions and less damage to the residual stand in comparison to ground-based mechanised extraction methods. However, when applied in commercial forestry interventions such as coppicing, animal logging showed levels of soil compaction in line with those of ground-based machinery like tractors, skidders and forwarders. Specifically developed trials revealed that in the animal skid trails a strong disturbance to the soil microarthropod community occurred. Furthermore, the soil features in the animal trails seemed to get worse over time after logging, thus suggesting the possible presence of strong localised erosion along these trails. Despite the strong need to further investigate this topic, concerning the ecological aspects of forest soil which were generally neglected by the literature, the use of animal logging can be recommended in the case of small-scale forestry with wooden material sparsely located throughout the logging site. In the case of commercial logging on steep slopes instead it is recommended to replace animal logging with cable-based extraction systems. • Logging operations by the use of animals are still very common. • Animal logging causes lower emission and less damage to the residual trees than machinery. • Animal logging can cause disturbance to soil physicochemical and biological features. • Animal logging is recommended for isolated pockets of timber to be harvested. • Cable systems should be preferred to animal logging on steep slopes. [ABSTRACT FROM AUTHOR]

• Skidding and forwarding are the two options for ground-based forest operations. • Among practitioners, skidding is generally considered more impactful than forwarding. • Skidding in actually more impactful regarding the damages to residual stand. • Forwarding causes stronger soil compaction than skidding. • Application of Best Management Practices is fundamental to limit the impacts of both skidding and forwarding. The disturbance that ground-based extraction operations can imply on the forests ecosystem is an issue which demands more attention. Skidding and forwarding are the two most common ground-based extraction systems. While skidding implies to partially or fully dragging the logs on the ground, in forwarding, timber is transported on a deck thus avoiding direct contact with the soil. Generally, skidding is considered to be more impactful than forwarding in relation to the amount of disturbance on forest soil and residual stand. However, the framework depicted in current literature is not so strict. While skidding actually implies a higher level of damage to residual stand, the situation concerning disturbance to forest soil is much more complex. The dissimilarities in the results from various studies on this topic have shown the level of complexity. The lack of research investigating the consequences of the two extraction systems on the overall forest ecosystem is evident. Only a few studies were focused for example on the implications on biodiversity. However, the beneficial effects of best management practices, such as the application of snatch blocks during winching or positioning brush mats on the skid trails/strip roads to reduce soil compaction, have been clearly demonstrated. [ABSTRACT FROM AUTHOR]

In recent decades, the use of heavy machinery in forest management has significantly increased, causing the compaction of forest soils and potentially affecting seedling survival and establishment. We thus investigated the effects of soil compaction on soil physical parameters, microarthropod biodiversity, soil respiration, as well as growth and physiology of Pedunculated Oak ( Quercus robur ) seedlings in an experimental field in central Italy (coarse loamy soil). Two levels of soil compaction were simulated, i.e. 10 tractor passes vs. 25 tractor passes. The larger number of tractor passes increased soil bulk density (+27%) and penetration resistance (+46%), while porosity declined (−11%). Compaction decreased the qualitative biodiversity of soil microarthropods (−13%), the number of growth flushes (−22%) and of leaves (−22%), shoot biomass (−26%), the shoot/root ratio (−10%), the main root length (−24%) and the longest first-order later root length in the top 10 cm of soil (−31%). The decreased growth of seedlings in the soil compaction treatment was accompanied by lower photosynthetic rate (−34%) and leaf nitrogen content (−27%). We concluded that limited access and acquisition of nutrients and water due to the shorter length of main root likely played a key role for growth and physiological responses to soil compaction in Q. robur seedlings. [ABSTRACT FROM AUTHOR]

• This study assessed the environmental recovery dynamics in relation to coppicing activities. • Tree species composition of regeneration was not impacted by silvicultural treatment and slightly by harvesting system. • Soil features were only marginally impacted by coppicing but were strongly impacted by harvesting operations. • The more environmental-friendly harvesting system was Tree lengths System. • The recovery from coppicing impacts was almost complete 36 months after harvesting. Coppice is considered the oldest form of sustainable forest management in the Mediterranean area. Generally, it produces rapidly woody biomass and environmental benefits. This research was implemented through an experimental design based on two steps: analyzing the impact of silvicultural treatment (coppice with standards) and logging on forest soil and tree regeneration. It included the soil and regeneration recovery capacity of forests managed as coppice related to different logging systems and treatments applied over a six-year period. The findings demonstrated that tree species regeneration composition was not affected by silvicultural treatment and only slightly by harvesting system. Instead, the physical, chemical and biological soil features were only marginally affected by the silvicultural treatment applied, but strongly impacted by harvesting operations, with clear differences between the systems. The least damaging harvesting system was TLS (Tree Length System) followed by FTS (Full Tree System) and SWS (Short Wood System) that showed a more intense impact. This trend started only six months after harvesting and continued for more than 36 months post-harvesting in a lesser dynamic. The recovery of coppicing was almost complete 36 months after harvesting, without substantial differences between logging systems. Recovery from logging showed a clear positive trend, but 52 months after harvesting only the TLS area had completely recovered. For FTS and SWS, recovery occurred but was very weak. [ABSTRACT FROM AUTHOR]