© iForest -Biogeosciences and Forestry IntroductionIn the last decades forest management has shifted the focus from wood production to the provision of multiple environmental services and biodiversity conservation. Following this trend the conversion of forest plantations into naturally regenerating and more diverse and complex systems has become one of the aims of the sustainable forest management, often trying to revert a process which had instead transformed vast areas of natural forests into plantations across Europe since the XIX century (Johann 2006, Bolte et al. 2007.Silver fir (Abies alba Mill.) has frequently received attention from foresters and researchers, partly because there has been a long tradition of forest management in central and southeast Europe in areas where the natural share of fir is significant (e.g., Kramer 1992, Brändli 1996, but mainly because of fir's economic, environmental and social significance. Signs of decline in fir presence have also been investigated (e.g., Elling et al. 2009, Ficko et al. 2011). Recently, Volarik & Hedl (2013 suggested that periods of both decline and expansion have underpinned silver fir dynamics. While natural mixed beech-fir forests were largely converted to spruce plantations in central European mountains and in many Alpine areas (Johann 2007, Volarik & Hedl 2013, in the Apennine Mountains (Italy) fir -naturally present in beech dominated mixed hardwood forests -was generally disfavoured by forest exploitation and has become relatively rare (Nocentini 2009). Today silver fir is an important species of five Natura 2000 habitats in the Apennines, three being priority habitats (*): 9130: Asperulo-Fagetum beech forests; 9210*: Apennine beech forests with Taxus and Ilex; 9220*: Apennine beech forests with Abies alba and beech forests with Abies nebrodensis; 9410: Acidophilous Picea forests of the montane to alpine levels (Vaccinio-Piceetea); 9510*: Southern Apennine Abies alba.Fir had often been preserved in small areas around monasteries, such as Vallombrosa and Camaldoli (Tuscan Apennines) where fir cultivation has been documented at least from the XVI century (Senni 1955, Gabbrielli 2003. Since late XVIII century fir planting started in various forests in the Tuscan Apennines, and this trend continued until the middle of the XX century. Most fir plantations are on State property and until the 1970s they were managed following the traditional model based on area regulation methods with clear cutting and 100 year rotation age (Vazzano et al. 2011.In the 1970s and 1980s pure fir stands in the Apennines started showing symptoms which recalled fir decline and dieback observed in central Europe (Larsen 1986, Kandler & Innes 1995, raising some concern about the future of this species. Together with these symptoms, Heterobasidion annosum (later identified as H. abietinum -Niemela & Korhonen 1998) also caused some damage, consisting mainly in the death of individual or small groups of trees (Farina et al. 1990, Barzanti & Capretti 1996, Capretti 1998.At the end ...

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Si esamina un caso di rinnovazione artificiale di abete bianco impiantata a piccolissimi gruppi a seguito di un taglio

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© iForest -Biogeosciences and Forestry IntroductionUnderstanding ecosystem responses to disturbance at different scales is fundamental to develop sound strategies for forest management and nature conservation (Kremen 2005). To this end, biomonitoring -i.e., the analysis of the reactive components of ecosystems in response to environmental changes to assess deviations from the normal situation (Spellerberg 1991, Nimis et al. 2002 -and ecological indicators can be used to quantify the magnitude of stress, the degree of exposure or the ecological response to stresses (Dale & Beyeler 2001), thereby providing a simple and efficient method to assess the composition, structure and function of complex ecological systems (Karr 1991).Fire is one of the most important disturbances in many natural and semi-natural ecosystems worldwide (Granström 2001), including the Mediterranean Region (Pausas 2004). Fire also has an ecological role in influencing ecosystem biodiversity and guaranteeing the conservation of a variety of habitats (Hadjibiros 2001, Moreira et al. 2001, Blondel et al. 2010) and changing landscapes (Gillson 2009). The soil biota is one of the first soil components to respond to fire exposure, as fire alters the species composition and decreases the zoocenotic density (Bezkorovainaya et al. 2007).Fire may have direct or indirect effects on soil fauna. One of the principal direct impacts on the edaphic microarthropod community is the exposure of forest fauna to high temperatures, which can cause alterations in species composition and decrease the abundance of some taxonomic groups (Sgardelis et al. 1995, DeBano et al. 1998, Bezkorovainaya et al. 2007). Contrastingly, some authors claimed that the direct effects of fire on most soil vertebrates are minimal (Ream 1981, Neary et al. 1999). Indirect fire impacts include changes in habitat and food availability for these organisms. After a fire, alterations of hydrothermal conditions, litter mass and pH have an impact on animal survival, particularly the stenoecious species which suffer high temperatures as well as light and moisture extremes, with subsequent habitat loss (Roloff et al. 2005, Bezkorovainaya et al. 2007). While some changes of the edaphic community can be irrelevant in the short-term after fire, the subsequent postfire, aboveground succession can determine changes in soil fauna, affecting the age and trophic structure of soil animals (Bezkorovainaya et al. 2007).Edaphic microarthropods play an important role in regulating the rate of decomposition (Wallwork 1983, Seastedt 1984 and nutrient cycling (Heneghan & Bolger 1998) through interactions with the microbial and fungal communities (Seastedt 1984, Seastedt & Crossley 1984, Lussenhop 1992, and they also contribute to soil structure and humus formation (Wallwork 1983, Norton 1985, Striganova 2000. For all these reasons, the preservation of soil biodiversity should be considered an integral component of forest management practices (Marshall 2000). Therefore, understanding the reaction of a forest to fir...