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In the managed beech forests of Central Italy (Molise), the diversity of saproxylic species is potentially under threat by intensive management. To evaluate the impact of forestry on the biodiversity of these ecosystems, we analyzed the relationship between abundance of saproxylic beetles and (i) forest stand exposure and elevation, (ii) deadwood availability (coarse woody debris - CWD - and stumps), (iii) abundance of microhabitats. Four sampling sectors with different altitudes and exposure were identified in a 400-ha study area in the Appenine mountains. Fifteen circular plots (13 m radius) were established in each sector where deadwood and microhabitats were surveyed and saproxylic beetles sampled. We fitted joint species distribution models to quantify the relationship between forest attributes and saproxylic species’ abundance, including the interactions with their family and trophic category. Overall, 2334 specimens belonging to 64 species of saproxylic beetles were collected. Both abundance and species richness were higher in the sectors with high elevation (respectively, 55% and 44%) and South exposure (respectively, 28% and 44%). Average deadwood volumes were low (stumps: 7.6 m3 ha-1; CWD: 0.3 m3 ha-1; snags: 0.4 m3 ha-1), and insect galleries were the most abundant microhabitat (380 records over a total of 434). The most important variables affecting abundance were stump characteristics (model deviance = 81.2), elevation (deviance = 64.7), and CWD characteristics (deviance = 58.0). Our results show that topographical variables and forest structure jointly affect the abundance patterns of saproxylic beetle communities in managed beech forests. These ecological interactions imply that management has different impacts on the saproxylic communities in different topographic conditions. To acknowledge this complexity we advocate for a landscape-level forest management supporting the local beetle diversity maintaining a mosaic of semi-natural forest characteristics in different topographic contexts. The ecological value of the forest landscape will be further enhanced by the application of closer-to-nature management interventions based on deadwood retention, microhabitat creation and tree retention, in line with the guidelines of the new EU Forest Strategy for 2030.

The recognition of the key role of forests in contrasting the dramatic effects of climate change and biodiversity crisis is the pillar of many initiatives on a global, European, and national scale calling for afforestation campaigns. The Italian forest nursery sector is currently inadequate to meet the demand for tree seedlings for the national campaigns. Forest nursery production is characterized by regional or local companies that are remarkably different from each other in organization and efficiency. It is therefore urgent to develop a comprehensive restructuring of the entire sector to be able to respond to the specific needs of forestry projects in Italy and Europe. In this paper, we present a series of key principles and criteria aimed at guiding the renaissance of the sector. Strategic actions are proposed by integrating research, governance, public/private partnership, training, and communication. The strategic approach presented is based on a collaborative structure integrating various skills and responsibilities. The first step is an expert review of the Basic Materials (BM) included in the National Register thanks to the development of the genetic studies of forest stands and the inclusion of shrub and herbaceous species, essentials for ecosystem restoration projects counteracting the biodiversity crisis. A series of actions concerns the aspects of certification, voluntary or prescriptive, of the quality of BM, and the ultimate harmonization of national production to European standards. Particular importance needs to be devoted to the collection, evaluation, and conservation of seeds to develop innovative solutions both for the production of BM and for specific implementation phases of afforestation projects and ecosystem restoration. The governance phase might be implemented through the creation of interregional centers with the duty of collecting and conserving seeds, thus enhancing the existing experiences of outstanding regional and provincial tree nurseries with the support of the National Centers for the study and conservation of Forest Biodiversity. Furthermore, the promotion of partnerships between public and private companies and the creation of a shared and accessible national platform represent strategic actions of primary importance. A fundamental role is then assigned to the implementation of training programs and the construction of an open and incremental communication plan. Thanks to these actions it will be possible to place forest nurseries at the center of the relationships between tree planting and afforestation plans and programs, integrated forest design, implementation of new forests, and their adaptive management.

With the publication of a Decree that has established a List of the Italian old-growth forests, we have analyzed, using text mining software, the state of the art of Italian research in this field. We have analyzed 188 ISI and 72 non-indexed papers or reports. The analysis has identified 165 locations of which more than 50% are on pure beech or mixed beech and silver fir stands. The analysis was focused mainly on structural characteristics and bio-indicators. The current knowledge represents reliable support for the establishment of an Italian network of old-growth forests and this green infrastructure offers important opportunities for research and collaboration between research, natural resource management, and local, regional, and state administrations.

The increasing demand for innovative forest management strategies to adapt to and mitigate climate change and benefit forest production, the so-called Climate-Smart Forestry, calls for a tool to monitor and evaluate their implementation and their effects on forest development over time. The pan-European set of criteria and indicators for sustainable forest management is considered one of the most important tools for assessing many aspects of forest management and sustainability. This study offers an analytical approach to selecting a subset of indicators to support the implementation of Climate-Smart Forestry. Based on a literature review and the analytical hierarchical approach, 10 indicators were selected to assess, in particular, mitigation and adaptation. These indicators were used to assess the state of the Climate- Smart Forestry trend in Europe from 1990 to 2015 using data from the reports on the State of Europe's Forests. Forest damage, tree species composition, and carbon stock were the most important indicators. Though the trend was overall positive with regard to adaptation and mitigation, its evaluation was partly hindered by the lack of data. We advocate for increased efforts to harmonize international reporting and for further integrating the goals of Climate-Smart Forestry into national- and European- level forest policy making. Key words: silviculture, adaptation, mitigation, forest inventory, forest damage. La demande croissante pour des strategies innovantes en amenagement forestier, dans le but d'attenuer les effets du changement climatique et de s'y adapter tout en ayant un effet positif sur la production des forets, ce qu'on appelle la foresterie intelligente face au climat, exige un outil pour le suivi et l'evaluation de la mise en reuvre de ces strategies et de leur effet sur le developpement de la foresterie dans le temps. L'ensemble paneuropeen de criteres et d'indicateurs pour un amenagement forestier durable est considere comme un des outils parmi les plus importants pour evaluer plusieurs aspects de l'amenagement forestier et sa durabilite. Cette etude offre une approche analytique pour choisir un sous-ensemble d'indicateurs destines a supporter la mise en reuvre de la foresterie intelligente face au climat. Sur la base d'une revue de litterature et d'une approche analytique hierarchique, 10 indicateurs ont ete selectionnes pour evaluer plus particulierement les mesures d'attenuation et d'adaptation. Ces indicateurs ont ete utilises pour evaluer l'etat de la tendance europeenne en matiere de foresterie intelligente face au climat de 1990 a 2015 a l'aide de donnees provenant de rapports sur l'etat des forets europeennes. Le dommage cause aux forets, la composition en especes arborescentes et le stock de carbone etaient les indicateurs les plus importants. Bien que la tendance ait ete dans l'ensemble positive en ce qui concerne l'adaptation et l'attenuation, son evaluation a ete en partie entravee par le manque de donnees. Nous recommandons d'augmenter les efforts visant a harmoniser sur une base internationale la presentation des rapports et d'integrer davantage les objectifs de la foresterie intelligente face au climat dans l'elaboration des politiques forestieres a l'echelle nationale et europeenne. [Traduit par la Redaction] Mots-cles: sylviculture, adaptation, attenuation, inventaire forestier, dommage cause aux forets., 1. Introduction Over the years, the anthropogenic impacts on natural resources due to the increased societal demand for ecosystem services have challenged the sustainable management of forests. Climate change has [...]

Tree-related microhabitats (hereafter TreMs) are structures occurring on trees, such as rot holes, cavities, large nests, mould, fruiting bodies and mycelia of decomposer fungi. TreMs have been widely recognized as important substrates and structures useful for biodiversity conservation in forest ecosystems, and they can be used as indicators for describing and monitoring forest naturalness. However, most studies on the occurrence of TreMs have been mainly done in forest ecosystems of Central Europe, while less research has been conducted in Mediterranean mountain forests. In this study, we investigated the diversity and abundance of 23 types of TreMs on living trees and on deadwood in seven Mediterranean mountains unmanaged forests located in the Apennines (Italy). The abundance of TreMs was evaluated by counting the number of TreMs per tree, while the diversity of TreMs was evaluated by means of the Shannon-Wiener index. We focused on the relationships between diversity and abundance of TreMs, and tree size (e.g., diameter, height, volume), and the time since the last harvest. Among the investigated stands, 2612 living trees, 457 standing dead trees and snags, and 1247 lying deadwood pieces were analysed. For living trees, a generalized linear mixed model was applied to test the effect of several variables on the abundance of TreMs per tree. Diameter at breast height (DBH) of tree stems influenced the abundance and diversity of TreMs. The time since the last harvest also significantly affected the probability that TreMs could be formed in a long-term perspective. The interaction of the predictors “DBH2” and “Years since the last harvest” generated a better model than the one in which the two variables were kept separate. Indeed, these two factors together would better represent the transition of a previously managed forest to a more natural state over time. This study might provide useful information to land managers committed to forestry practices towards sustainable management and biodiversity conservation, especially referring to survey and inventory of forests of high nature value.

Interactions between tree species determine the dynamics of forest communities. Spatial and temporal changes in resource availability, variation in species composition and spatial distribution of trees may alter competitive interactions between species and, therefore, affect tree growth and forest productivity. In this study, we analyzed the intra and inter-specific interactions between European beech (Fagus sylvatica L.) and silver fir (Abies alba Mill.) in southern Italy (Molise and Calabria regions), and how these interactions affect basal area increments in mixed-species and pure stands. Results showed that intra-specific interactions have a negative effect on the basal area increment, both in pure and mixed-species stands of Molise and Calabria. Basal area increment was higher influenced by intra-specific interactions in pure stands than in mixed-species stands. Silver fir in Molise showed higher basal area increment in mixed-species stand, probably in relation with stand structure and space occupation that resulted in less competition between individual trees. European beech showed high values of intra-specific interactions in pure stands, likely related to the low self-tolerance of this species and to the spatial arrangement of trees, due to canopy closure. The absence of inter-specific interactions in mixed-species stands could be explained by the sub-dominant position of European beech, which may have limited the benefit derived from niche separation and complementarity for silver fir.

Global changes push to set up strategies able to mitigate and adapt agricultural and forest crops to environmental variability, and the sustainable intensification of production processes under agricultural and forestry systems is one of the approaches mainly supported. In Italy biomass and biogas are the renewable energy sources that have shown the greatest potential for growth in recent years. In this context, during the XV National Congress held in Bolzano in February 2018, the Italian Association of Agricultural Scientific Societies has promoted an analysis about potential and limits of the sustainable intensification of agricultural and forestry systems for bioenergy production. This document reports the outcome, in the form of a commented discussion on the main evidences and proposals from technical-scientific and operational points of view.

In recent decades, the conservation of biodiversity has become one of the main areas under consideration in managing forests in an ecologically sustainable way. Forest management practices are primary drivers of diversity and may enhance or decrease forest biodiversity, according to the measures applied (thinning options). We have focused on three beech (Fagus sylvatica L.) forests across a latitudinal gradient in Italy, characterised by different structures resulting from dissimilar management. We tested the short-term effects of differently-based silvicultural intervention vs. stands where no silvicultural practices were applied on biodiversity indicators and related proxies: deadwood amounts, microhabitat density, floristic richness and life form abundance. In each study area, the occurrence of the above indicators and proxies was evaluated before and after the implementation of crop tree thinning (CTT) and thinning from below (LT) methods, comparing them with control areas where no interventions were performed. After two years, the management options resulted in different responses of the investigated parameters. The CTT increased deadwood amounts in comparison with the LT ones, while stumps increased significantly after the LT thinning. Microhabitats increased significantly where intervention was not undertaken. On the contrary, they remained unaltered after the LT treatments. CTT thinning created favourable conditions for the development of microhabitats and their proliferation in the long term. Two years after the application of the CTT thinning treatment, all forest stands demonstrated a significant increase in their floristic richness and herb layer cover. Significant differences were also found in both the frequency and cover of life forms in relation to silvicultural treatment. These findings provide a better understanding of short-term effects of silvicultural treatment useful for maintaining biodiversity in mountain beech forests.

Remobilization is an important mechanism of resource conservation in plants. However, our understanding of whether the responses of resource remobilization to global warming differ between deciduous and evergreen trees remains unclear. We assessed resource remobilization from leaves to 1-year-old shoots in a deciduous (Betula ermanii) and an evergreen (Quercus aquifolioides) species along elevational gradients (i.e., temperature gradient) at the end of growing season. We aimed to test the hypotheses that the reallocation rate increased with increasing elevation and that more resources were reallocated from leaves to storage tissues in deciduous species than in evergreen species. We analyzed the concentrations of non-structural carbohydrates (NSC), nitrogen (N) and phosphorus (P), and compared the differences in remobilization efficiency of NSC, N, and P between leaves and shoots within each species and between the two species along the elevational gradients. Due to the different strategies of evergreen and deciduous species in nutrients use, the deciduous species had higher N and P remobilization rate, but lower remobilization rate of sugars, starch, and NSC than the evergreen species at the end of growing season. The remobilization rate of NSC, N, and P was significantly higher in trees at their upper limits compared to lower elevations. Our results suggest that trees reallocate resources from leaves to storage tissues before leaf senescence or at the end of growing season, to increase the resource use efficiency and to adapt to the harsh alpine environments. These results contribute to better understanding of the alpine treeline phenomenon in a changing world.

Deadwood is a substantial component of forests playing a central role in many ecosystem processes. It provides habitats for a multitude of wood-dependent organisms, maintaining the ecosystem health and reducing the effect of natural disturbances. Deadwood is recognized as an indicator of local species diversity and contributes to the global carbon pools and nutrient cycles. Despite its importance, how saproxylic communities respond to deadwood dynamics across multiple spatial and temporal scales is still not clear. With the present review, we aim to summarize the effects of deadwood characteristics on the diversity and composition of saproxylic insects and fungi, with focus on European forests. We also discuss the influence of other biotic and abiotic components that indirectly affect these communities by altering wood continuity and variety. Niche differentiation is the main ecological driver of saproxylic organisms, as the presence of multiple microhabitats supports differently specialized taxa. The assemblage and richness of these saproxylic communities within forest ecosystems can be considered as indicators of climate-smart forestry trajectories. This aspect deserves to be regarded as a major target in sustainable forest management plans, especially in mountain areas, where the conservation of threatened species and the promotion of biodiverse forests are considered a priority.

The Decree on Climate 2019 represents an innovative and concrete framework for applying the international recommendations aimed at preventing and mitigating the effects of climate change. It focuses, in addition to many environment-related aspects, on the old-growth forests, recognizing them as forest ecosystems of high environmental value, defining their main ecological traits. According to this legislation, the extent of these forests in Italy is important, since many forest ecosystems have been left unmanaged from more than 60 years. Even if these stands are not always characterized by high level of naturalness, they are currently evolving towards more complex structures, due to the absence of human-related disturbance. Old-growth forests are unique ecosystems with a high structural complexity and peculiarities that are absent in managed forests. They are also an essential point of reference for sustainable forest management and environmental monitoring, in terms of conservation of biological diversity and ecological processes. For these reasons, they represent a unique benchmark for developing silvicultural models that incorporate knowledge of structural complexity (vertical and spatial) and developmental processes, duration of development and particularly the role of disturbances in creating structural legacies that become key elements of the post-disturbance stands. These forests, as the new Decrete underlines, must be protected, preserved and monitored in a long-term perspective, in order to safeguard their biodiversity, avoiding the structural simplification, which often characterizes the managed forests.

Forest fires in 2017: a useful lesson. Forest fires, together with the decline of silviculture practice, are one of the most important natural disturbances affecting Mediterranean forests. The year 2017 is shaping up to be a record breaking fire season all around Southern Europe and especially in Italy for the sheer amount of hectares burned. Here we discuss about the importance of forest fire management, highlighting the role of prescribed burning and mechanical treatment (e.g., manual removal, thinning) in reducing the risk of high-intensity wildfires. We report on the successful applications of those fire management techniques on the pinewoods of Vesuvio National Park and Castel Fusano Natural Reserve. The information compiled in the present article aims to demonstrate the potential relevance and impact of forest resources management for fire hazard reduction and shows the necessity of strong interaction among not only the scientific community, but also forest managers, decision makers and the civic responsibility of society at large.

The relevance of the environmental pollution by heavy metals warrants the necessity to develop and assess more efficient plant-based technologies. This study was conducted to evaluate a quick screening approach in order to investigate the cadmium (Cd) and copper (Cu) phytoextraction potential of Quercus pubescens in a micro-propagation system. Increasing concentrations of Cd (0, 5, 50, and 250 µM) and Cu (0, 5, 50, 250 and 500 µM) were separately applied to evaluate the effect of metals on their absorption and accumulation in downy oak plants. At high concentrations, Cd and Cu significantly reduced the dry biomass of shoots and roots and the plant tolerance index. Cd was toxic at increasing concentrations, inducing higher reduction of shoot dry mass than roots, whereas Cu increased dry mass at 5 µM. This study represents the first attempt to assess Cd and Cu uptake in Q. pubescens under in vitro conditions. The in vitro screening potential is meanly related to the following purposes: (i) proper selection of plant materials resilient to excess metals in the growth substrate; (ii) efficient removal of metals by the selected tree species; (iii) minor interference with the growth of plants accumulating metals in their tissues; (iv) rapid provision of plant materials for tree breeding programs.

Old-growth forests are key elements of ecosystem diversity and conservation strategies, providing niche differentiation and trophic pathways that produce structural and compositional heterogeneity. In these forests, deadwood is particularly important for saproxylic and mycorrhizal fungi, sustaining forest productivity and environmental services. In this study, the saproxylic fungal diversity in Mediterranean mountain forests, characterized by different management histories and forest types (holm oak and beech), was analyzed. The relationships between saproxylic fungal biodiversity and structural attributes were considered in three forest stands of the Apennines (Italy). In addition, descriptive environmental parameters and forest traits were related to prevailing fungal communities, in order to analyze the species composition and distribution patterns of saproxylic fungi resulting from the ordination processes. The study sites were selected on the basis of their late-serial stage of development. Species frequency was analyzed through multivariate techniques to test the relationships between fungi, structural attributes and environmental variables. A Detrended Correspondence Analysis (DCA) was used to investigate the response of the overall fungal community structure to environmental gradients. Living tree volume, altitude, vegetation type, and the frequency of species with ephemeral sporocarp lifespan played a crucial role in diversifying species distribution patterns. Deadwood volume and decay classes were related to taxonomic and trophic community diversity. However, differences between the considered climatic regions exerted a major role on the occurrence of fungi with ephemeral sporocarps more than deadwood abundance, utilized primarily as fructification substrate.

A modelling strategy is proposed to obtain spatially explicit estimates of net carbon accumulation in Italian beech forests. This approach is based on the use of a biogeochemical model, BIOME-BGC, which is capable of simulating all main processes of ecosystems in quasi-equilibrium conditions. The model predictions are then corrected for actual forest biomass (growing stock volume) and stand age. The method is applied to predict the current annual increment (CAI) of 30 beech forest stands in Molise, Central Italy, which have been sampled during several measurement campaigns. A preliminary test is conducted to assess the model's ability to reproduce the interannual production variations of these stands. Trials are then carried out driving the modelling strategy with both growing stock measurements collected in the field and a recently produced growing stock map. The final CAI estimates are validated through comparison with conventionally collected dendrochronological measurements. The results obtained indicate that the modelling approach is capable of reproducing interannual variations of net primary production and estimating the ground CAIs with an acceptable accuracy and when driven by the mapped growing stock. Additionally, the CAI estimates are not affected by the silvicultural system and development stage of the observed stands. Key words: biogeochemical model, carbon accumulation, current annual increment, dendrochronology, spatial estimates. On propose une strategie de modelisation pour obtenir des estimations spatialement explicites de l'accumulation nette de carbone dans les forets italiennes de hetre. Cette approche est fondee sur l'utilisation d'un modele biogeochimique, BIOME-BGC, qui est capable de simuler tous les processus importants des ecosystemes dans des conditions de quasi-equilibre. Les predictions du modele sont ensuite corrigees pour la quantite reelle de biomasse forestiere (volume du materiel sur pied) et l'age du peuplement. Cette methode est appliquee pour predire l'accroissement annuel courant (AAC) de 30 peuplements de hetre a Molise (centre de l'Italie) qui ont ete echantillonnes lors de plusieurs campagnes de mesure. Un test preliminaire est effectue pour evaluer la capacite du modele a reproduire les variations interannuelles de production de ces peuplements. Des essais sont ensuite realises en utilisant la strategie de modelisation avec les mesures du materiel sur pied collectees sur le terrain et une carte recente du materiel sur pied. Les estimations finales de l'ACC sont validees en les comparant aux mesures dendrochronologiques collectees de facon conventionnelle. Les resultats ainsi obtenus indiquent que l'approche de modelisation est capable de reproduire les variations interannuelles de la production primaire nette et d'estimer les AAC au sol, avec une exactitude acceptable, meme lorsqu'elle est utilisee avec le materiel sur pied cartographie. De plus, les estimations de l'AAC ne sont pas influencees par le systeme sylvicole ou par le stade de developpement des peuplements que nous avons observes. [Traduit par la Redaction] Mots-cles : modele biogeochimique, accumulation du carbone, accroissement annuel courant, dendrochronologie, estimations spatiales., Introduction The continuous increase of greenhouse gas emissions from land use change and fossil fuel combustion is contributing to the warming of the Earth (Intergovernmental Panel on Climate Change (IPCC) [...]

Liliana Dell’Osso,1 Marianna Abelli,1 Stefano Pini,1 Marina Carlini,1 Barbara Carpita,1 Elisabetta Macchi,2 Federica Gorrasi,2 Francesco Mengali,1 Rosalba Tognetti,2 Gabriele Massimetti1 1Department of Clinical and Experimental Medicine, Section of Psychiatry, 2Prorectorate to Students Affairs and Right to Education, University of Pisa, Pisa, Italy Abstract: Social anxiety disorder is a common condition often associated with severe impairment in educational career. The aim of this paper was to evaluate prevalence rates and correlates of mild, moderate, and severe forms of social anxiety spectrum in a large sample of university students. Overall, 717 university students were assessed with the Social Anxiety Spectrum Self-Report questionnaire. Using two cut-off scores, 61.4% of subjects were classified as low scorers, 10% as medium scorers, and 28.6% as high scorers. Both high and medium scorers reported fears related to social situations. Interpersonal sensitivity and specific phobias were more common among women with low scores. Childhood/adolescence social anxiety features were more common among males with medium scores. Behavioral inhibition was more common among males with high scores. Functional impairment was severe among high scorers and, to a lesser extent, among medium scorers. Social anxiety spectrum is largely represented among university students. Future studies should investigate whether sufferers of social phobia underachieve or end their professional objectives prematurely. Keywords: social anxiety spectrum, behavioral inhibition, gender, subthreshold, self-rating, DSM-5

Recent work of our research group demonstrated the applicability of a calibrated bio-geochemical model, BIOME-BGC, for estimating current annual increments (CAIs) of Mediterranean forests. In the current case, the model is applied to assess the gross primary production (GPP) of nine beech forest sites in Italy using a previously produced data set of meteorological data descriptive of a ten-year period (1999-2008). The obtained GPP estimates are integrated with relevant autotrophic respirations and allocations to derive forest net primary production (NPP) averages for the same forests. The simulations are performed assuming different levels of ecosystem disequilibrium, i.e. progressively taking into account the effects of specific site history in terms of woody biomass removal and stand aging.The NPP estimates, converted into CAIs by means of specific coefficients, are validated through comparison with data derived from tree growth measurements. Results indicate that the modelling of quasi-equilibrium conditions tends to produce overestimated CAI values, particularly for not fully stocked, old stands. The inclusion of information on existing biomass introduces a partial improvement, while optimal results are obtained when information on ecosystem development phase is considered. The implications of using different NPP estimation methods are finally discussed in the perspective of assessing the forest carbon budget on a national basis.

Poplars and willows (and other fast growing tree species) form an important component of agroforestry systems, providing a wide range of ecosystem services and products. The workshop held in Capracotta (6th and 7th June 2012) has communicated the latest research on poplars and willows in the field of environmental restoration conducted in Italy, providing a condensed overview on their basic response to pollutants and use in environmental monitoring, highlighting future challenges of phytotechnology issues. In the frame of the project MIUR-PRIN 2008 “Molecular, physiological, and agronomic analyses for selecting and managing Salicacee in phytoremediation”, 17 talks were delivered to an audience of more than 50 researchers. Prominence was given to stress biology and the importance of poplar and willow breeding in meeting the needs of ecological restoration. The aim of this review is provide a timely account of the questions related to phytotechnology in shaping the multifunctional tree, particularly with regard to tree responses to environmental pollution. While the question is scientifically challenging, progress may be achieved by exposing the different environmental restoration models and underlying guiding principles to tests against experimental data and each other. Research and development should focus simultaneously on maximizing the yield of multipurpose tree plantations, while preserving or restoring ecosystem services of close-to-nature willow-poplar stands (e.g., riparian forests). We hope that this review will stimulate further studies in this interesting area of tree biology.

Heavy metals provoke environmental pollution with potentially toxic effects on human and plants systems. Recently, investigations are conducted on plants that may play a relevant role on pollutants absorption or stabilization, focusing on fast growing tree species in agronomic conditions; little is known on the effects of contaminants on tree species colonizing abandoned fields to be used in restoration ecology. The effects of Cd on photosynthetic performance and metal accumulation were investigated in Quercus pubescens Willd. seedlings grown in pots containing a mixture of sand, clay, turf and Cd-treatments (0, 25 and 75 mg kg-1 dry soil). The studied photosynthetic parameters (Asat= net phytosynthesis; Rday= day respiration; Γcomp= CO2 compensation point; Vcmax= maximum carboxylation rate; Jmax = electron transport rate; TPU = triose phosphate use; Ci/Ca = ratio of intercellular (Ci) to ambient (Ca) [CO2] (Ci/Ca); Jmax/Vcmax = ratio; (gsmax) = maximum stomatal conductance; (lg) = stomatal conductance estimated relative to the photosynthetic rate; (Fv/Fm) = maximum quantum yield of PSII photochemistry; (ΔF/F’m) = effective photochemical efficiency) varied progressively with increasing Cd concentration in the soil, highlighting a negative impact on photosynthetic potential and PSII functioning. Approximately 10% of added Cd was found to be extractable from the substrate, at the maximum concentration applied, with about 12 and 0.75 as bioaccumulation and translocation factors, respectively. Analogously, Cd accumulated up to 34, 30 and 46 mg kg−1 in leaves, stem and roots, respectively. While it is not possible to extrapolate from the present study with seedlings to effects on mature pine trees, there are clear implications for regeneration in soils contaminated with heavy metals, which may lead to ecosystem deterioration.

A screening in hydroponics was carried out to assess the potential of Cd uptake and metal accumulation in roots of 4 poplar and 2 willow clones. Rooted cuttings were exposed for 3 weeks to 50 μM Cd sulphate in a growth chamber. Salicaceae clones were discriminated in their potential to absorb and distribute Cd in root tissues considering the interaction between metal and macronutrients. SEM-EDXMA was useful to investigate structural modifications and to identify in situ concentration and distribution of elements in roots, establishing indirect correlations between accumulation and localization of the metal. Overall, observations suggested differential patterns between species and clones in accumulating Cd within the root profile. In conclusion, Cd accumulation in root levels would hardly be a useful indicator of the ability of plants to translocate metal, independently from other parameters, while Cd location in the root cross-section levels could suggest clone-specific control mechanism to mineral uptake.