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Although greenspaces in built-up areas (GSB) heavily contribute to human health and wellbeing in anthropized environments, large-scale data and information on GSB are still lacking. This study aims to estimate abundance, coverage and average size of GSB in Italy through the integration of inventory and cartographic data, even considering GSB patches smaller than 0.5 ha. GSB were classified according to their type (forested and non-forested), canopy cover and location with respect to population density (from thinly to densely populated areas). We refer to built-up areas instead urban, thus including, for example, road infrastructures, buildings and sparse settlements in rural areas, otherwise neglected. Results show that 43.5% of built-up areas in Italy is unsealed, of which more than 18% is covered by GSB, mainly dominated by forested ones. Results also reveal that the number of forested GSB, their coverage and average patch size decrease with the increase of the population density, while their canopy cover follows the opposite trend. Main findings demonstrate that the proposed approach provides reliable GSB estimates to better understand interactions between humans and nature along an urban-rural gradient, thus representing a valuable support towards the implementation of Nature-Based Solutions in urban planning.

Deadwood and microhabitats play a fundamental role in many forest ecosystem processes. Deadwood provides the substrate for a multitude of wood-dependent organisms, as well as a variety of microhabitats. Deadwood is a key factor in maintaining the ecosystem functionality and increasing the overall forest biodiversity. In Mediterranean forests, the relationship between stand-structure attributes and species-diversity indicators is still poorly investigated. In this study, we hypothesized that the abundance of saproxylic species was influenced by (i) the composition and amount of deadwood, and (ii) the heterogeneity in types and density of microhabitats. The investigation was carried out in a broadleaved mixed forest located in Central Apennine (Italy), in which silvicultural interventions were interrupted for several decades. The experimental area extends on approximately 240 ha; structural traits, deadwood and microhabitats were sampled on 50 plots of 530 m2. Saproxylic beetles were collected using window flight traps and emergence traps on decaying deadwood. We applied joint species distribution models (JSDM) to quantify the relationship between forest attributes and the abundance of saproxylic species, explicitly including their functional traits (e.g., trophic level). Results demonstrated that microhabitats, living biomass, basal area and coarse woody debris had a significant effect of saproxylic beetles belonging to different trophic categories. Considering the conservation status, only the stand basal area significantly affected the abundance of Near Threatened (NT) saproxylic beetles. This study highlighted the importance of integrating multiple biodiversity indicators to find sustainable solutions for conservation purposes, unlike many studies on conservation-oriented management strategies, more frequently focused on independent forest biodiversity indicators.

Maritime pine (Pinus pinaster) stands in Italy have recently been invaded by maritime pine bast scale (Matsucoccus feytaudi), resulting in widespread tree mortality. Clearcutting has been applied to progressively remove infected maritime pine, concurrent with planting of holm oak (Quercus ilex) seedlings. Establishment of holm oak regeneration has, however, been severely constrained by fallow deer (Dama dama) browsing pressure. We hypothesized that the ability of planted holm oak to grow above the browse line was closely correlated with protective cover provided by natural regeneration. This study was carried out in a coastal protected area in central Italy, where overall performance of planted holm oak was assessed under browsing pressure in relation to the relative distance of seedlings to surrounding vegetation. To interpret the results, four categories of holm oak were identified: (i) dead plants, (ii) sprouts from stump, (iii) repeatedly browsed plants without growth, and (iv) plants that were able to develop at least one tall shoot safe from browsing. The occurrence of the latter was positively related to increasing canopy cover and plant height of surrounding vegetation, especially maritime pine. Density, height, canopy cover, and crown radius of maritime pine, as well as its relative distance from holm oak all promoted the survival and growth of target plants. Complete protection around holm oak was not required for facilitation, but the presence of crown and branches occupying the space above the target plants was crucial. Maritime pine saplings primarily served as a mechanical barrier to browsing and thereby favored the development of holm oak shoots. Site-specific, long-term monitoring studies on competition from and facilitation by surrounding vegetation are required, before implementing under-planting strategies.

To study simultaneous biotic and abiotic stress effects on monoterpene mediated defence response, four-year-old seedlings of two clones of Picea abies (c386: “relatively resistant” c386; c171: “relatively susceptible” clone 171) were inoculated with an isolate of rot fungus Heterobasidion parviporum and simultaneously subjected to a drought stress recovery cycle. Fungal growth into the wood was generally higher in well-watered (W) than in drought-stressed (D) plants. As predawn water potential decreased, gas exchange and maximal photochemical efficiency of PSII also declined. Water potential and chlorophyll fluorescence showed differences between clones in D plants, c386 being more tolerant than c171, while stomatal conductance and net photosynthesis differed between clones in W plants; c171 showing higher values than c386. A recovery of physiological functions was observed after re-watering. The clones showed different constitutive monoterpene profiles. The infection generally caused some extensive compositional changes in the relative contents of several monoterpenes and their enantiomers; also, sterile infection (wounded only samples) affected the relative proportions of monoterpenes, although to a lesser extent than reactions elicited by the fungus. The trend in monoterpene response to disease treatments was the same in D and W plants of both clones. In particular, higher proportion of δ-3-carene was found constitutively in c386 in comparison with c171; besides, infection with H. parviporum increased the relative contents of δ-3-carene in all the samples, even if proportions of this monoterpene in wounded plus inoculated tissues of c386 were significantly higher than cortical tissues from non-inoculated branches only in W seedlings 44 days after treatment. Although drought stress decreased the total absolute contents of monoterpenes, total monoterpene concentrations significantly increased in response to infection by H. parviporum.

Forested patches play an important ecological role in urbanized landscapes. Nevertheless, in particular conditions, trees can paradoxically worsen air quality through the emission of Biogenic Volatile Organic Compounds (BVOCs) (i.e., isoprenoids), which participate to the reactions forming O 3 together with anthropogenic VOCs and nitrogen oxides (NO X ). Given the continuous increase in urban population, there is the necessity of providing urban managers with sustainability indices in urban areas related to these subtle pollutants. Our study aims to give an overview of reference cities or typology of urban areas suitable for expanding the research on future BVOC-O 3 dynamics. Such “reference” cities represent a sort of study target in order to better model and forecast the future behaviours of BVOC emissions and O 3 pollution. Contexts have been selected on both a regional and global scale in both warmer and colder environments, considering future climate scenarios and gradients from more natural conditions. Urban Heat Island and Urban Cold Island effects were also discussed as representative models for anticipating the impact of climatic change on urban trees. Finally, other factors, such as UV rays, Secondary Organic Aerosols wind transportation and the surrounding biome were considered as interactive drivers of the change.

There is a growing need for understanding the timing of wood formation in relation to the dynamics of bud phenology at wide geographical scale. This study analysed the relationships between long-term chronologies of xylem growth and the timing of plant phenology detected by Normalized Difference Vegetation Index (NDVI) in five permanent stands across the latitudinal distribution of black spruce [ Picea mariana (Mill.) BPS] in the boreal forest of Quebec, Canada. Xylogenesis was studied weekly from April to October for thirteen years (2002–2014) on anatomical sections derived by wood microcores. The timing of the growing season detected by remote sensing was extracted from MODerate resolution Imaging Spectroradiometer (MODIS) 250 m 16-days NDVI data. The NDVI time-series were fitted using a double-logistic curve. Phenological chronologies from remote sensing and xylem phenology showed a latitudinal trend. The models correlating the data inferred from satellite sensors and the spring observations of xylem phenology were significant ( p

The conservation of biological diversity is one of the main goals for managing forests in an ecologically sustainable way. Presence and abundance of microhabitats, such as tree cavities or bark pockets, can be conveniently used as indicators to evaluate the effectiveness of sustainable forest management measures. In Mediterranean forest ecosystems, the relationships between stand-structure attributes and species-diversity indicators are still poorly studied. We described the structural attributes, deadwood characteristics and microhabitat occurrence in a silver fir forest of Central Apennines (Italy), which has not been submitted to silvicultural interventions for several decades. We assessed linkages between these characteristics and the abundance, distribution and diversity of saproxylic beetle fauna. A systematic aligned sampling method was conduced on 240 ha, examining 50 plots of 530 m 2 each. Saproxylic beetles were sampled using window flight traps and emergence traps in relation to abundance and species richness at the plot level, but also on decaying deadwood. The heterogeneity in types and frequencies of microhabitats, and the link between structural attributes associated with stand complexity and saproxylic species, were also analysed. With the aim of describing the complex saproxylic ecological network, beetle species were classified according to the type of interactions with wood and other insects fauna, but also in relation to the trophic guilds. Linear regressions were conducted for highlighting metric variability and relationships between parameters, while geostatistical analyses were used to describe the spatial variability of structural features and the spatial pattern of beetle distributions. Results of linear regression and geostatistical analysis showed how the saproxylic beetle community is influenced by the amount, type and stage of decay of deadwood, but also by the forest structural complexity and the occurrence of microhabitats. Gap dynamics and natural disturbances had effects on deadwood amounts and microhabitat abundance, which was significantly higher than in managed and structurally simplified forest stands. Most of the entomological variables (namely, Families, Species, Total individuals, Saproxylic individuals, Staphylinidae, Elateridae, Nothodes parvulus, Curculionidae, Ernoporus fagi, Phyllobius emery ) were clumped, highlighting the existence of aggregation areas in the sampled forest. In several cases the insect distribution was linked to the spatial pattern of forest attributes, particularly deadwood components.

Deadwood is known to significantly contribute to global terrestrial carbon stocks and carbon cycling, but its decay dynamics are still not thoroughly understood. Although the chemistry of deadwood has been studied as a function of decay stage in temperate to subalpine environments, it has generally not been related to time. We therefore studied the decay (mass of deadwood, cellulose and lignin) of equal-sized blocks of Picea abies wood in soil-mesocosms over two years in the Italian Alps. The 8 sites selected were along an altitudinal sequence, reflecting different climate zones. In addition, the effect of exposure (north- and south-facing slopes) was taken into account. The decay dynamics of the mass of deadwood, cellulose and lignin were related to soil parameters (pH, soil texture, moisture, temperature) and climatic data. The decay rate constants of Picea abies deadwood were low (on average between 0.039 and 0.040y(-1)) and of lignin close to zero (or not detectable), while cellulose reacted much faster with average decay rate constants between 0.110 and 0.117y(-1). Our field experiments showed that local scale factors, such as soil parameters and topographic properties, influenced the decay process: higher soil moisture and clay content along with a lower pH seemed to accelerate wood decay. Interestingly, air temperature negatively correlated with decay rates or positively with the amount of wood components on south-facing sites. It exerted its influence rather on moisture availability, i.e. the lower the temperature the higher the moisture availability. Topographic features were also relevant with generally slower decay processes on south-facing sites than on north-facing sites owing to the drier conditions, the higher pH and the lower weathering state of the soils (less clay minerals). This study highlights the importance of a multifactorial consideration of edaphic parameters to unravel the complex dynamics of initial wood decay.

Beetle communities are excellent indicators to monitor biodiversity in forest environments. The most common indicators monitored for assessing the effectiveness of the sustainable forest management measures are deadwood amount, forest structure, and microhabitat traits. In Mediterranean mountain forests, however, the relationships between stand-level attributes and species diversity indicators have been still poorly studied. We have investigated the patterns of species diversity of beetle communities in relation to stand structural traits in two unmanaged forests located in central Apennines (Italy). The two forest stands are characterized by different tree species composition and management history. The experimental area extends over approximately 300 ha, within which 50 circular plots of 530 m2 were sampled for each studied forest. Coleoptera were collected using window flight traps and emergence traps on decaying deadwood. We evaluated i) the differences in species diversity (richness, Shannon diversity and Simpson diversity) between the two forests and ii) the beetle Shannon diversity and composition in relation to selected forest variables, with a particular focus on saproxylic species. Principal Component Analysis followed by rarefaction analysis were applied to examine differences in species diversity. Within each forest stand, a Boosted Regression Tree model and a Non-Metric Multidimensional Scaling were performed to relate the species Shannon diversity and community assemblages to the forest structural attributes. Results revealed how these forest structural attributes have a fundamental role in influencing the diversity of Coleoptera and their assemblages. Forest vertical heterogeneity, snag volume and tree dominance were the most important variables for saproxylic assemblages in these Mediterranean mountain forests, while the amount of coarse woody debris positively affected the overall beetle diversity and that of saproxylic species. At stand level, differences in species diversity were mainly driven by tree composition, probably indicating that food resources, determined by tree species, are of primary importance in determining species assemblages and beetle diversity in these forests; while at plot level, we found that the variables, which drove species composition and beetle diversity, varied between the two forests. This study provides the basis for the integration of independent biodiversity indicators in sustainable solutions for the conservation of unmanaged forests in Mediterranean mountain systems.

Changes in tree growth and insect distribution are projected due to climate warming. The expected effects of climate change on forest disturbance (e.g., insect outbreak) regime call for a better insight into the growth responses of trees to varying environmental conditions over geographical regions in eastern North America. In this study, the effects of a latitudinal thermal gradient and spruce budworm (SBW) outbreaks on the tree growth of black spruce (Picea mariana Mill.) were investigated along a 400 km transect from 48 degrees N to 51 degrees N across the continuous boreal forest in Quebec, Canada. Time series data were analyzed to synchronize climatic factors (temperature and precipitation trends), insect dynamics (SBW population frequency) and tree growth (ring-width chronology). Radial growth resulted as being synchronized with climate patterns, highlighting a positive effect of maximum temperatures on tree growth, especially in the northernmost site. Increasing temperatures and precipitation had a more positive effect on tree growth during epidemic periods, whereas the detrimental effects of SBW outbreaks on tree growth were observed with climate patterns characterized by lowered temperature. The lag between time series, synchrony and/or frequency of synchrony between tree growth and SBW outbreak were considered in order to link the growth of host trees and the dynamics of insect populations. The proposed analytical approach defined damage severity on tree growth in relation to population dynamics and climate fluctuations at the northern distribution limit of the insect. Overall, a decline in tree growth was observed in these boreal forests, due to SBW outbreaks acting in combination with other stress factors.

Diurnal and seasonal trends of leaf photosynthesis (A), stomatal conductance to water (gs) and water potential (Ψl), whole-plant transpiration and tree canopy spectral reflectance indices were evaluated in rainfed and well-watered (control) mature olive (Olea europaea L., cv. Leccino) trees. The objective was to evaluate whether photochemical reflectance index (PRI), water index (WI) and normalized difference vegetation index (NDVI) could be used for detecting plant functioning in response to seasonal drought. The measurements were made from March to November, repeated every four weeks during the drought period of the growing season. Rainfed trees were subjected to prolonged water deficit with soil water content ranging between ∼30% and 50% than that of control. Consequently, there were significant differences in the diurnal trend of Ψl, A, gs and sap flux density between treatments. Under severe drought, Ψl ranged between ∼−4.5 MPa (predawn) and ∼−6.4 MPa (midday), A ranged between maximum morning values of ∼6 μmol m−2 s−1 and minimum late afternoon values of 2.5 μmol m−2 s−1, gs was lower than ∼0.03 mol m−2 s−1 for most of the daily courses, whereas stem sap flux density reached maximum peaks of 2.1 g m−2 s−1 in rainfed plants. The diurnal trends of all these parameters fully recovered to the control level after autumn rains. PRI, NDVI, and WI of olive tree canopy assessed significantly the effects of drought on rainfed trees and their subsequent recovery. PRI resulted better correlated with A (r2 = 0.587) than with the other measured parameters, pooling together values measured during the whole growing season. In contrast, NDVI showed a stronger relationship with Ψl (r2 = 0.668) and gs (r2 = 0.547) than with A (r2 = 0.435) and whole-plant transpiration (r2 = 0.416). WI scaled linearly as gs and Ψl increased (r2 = 0.597 and r2 = 0.576, respectively) and, even more interestingly, a good correlation was found between WI and whole-plant transpiration (r2 = 0.668) and between WI and A (r2 = 0.640). Overall PRI and WI ranked better than NDVI for tracking photosynthesis, whereas WI was the most accurate predictive index of plant water status and whole-plant transpiration. This study, which is the first to our knowledge that combines diurnal and seasonal trends of leaf gas-exchange, whole-plant transpiration and reflectance indices, clearly shows that PRI and WI measured at the tree canopy can be used for fast, nonintrusive detection of water stress.

Deficit irrigation at the nursery stage induces drought acclimation through the establishment of avoiding mechanisms and hardening processes. In this experiment, we hypothesized that water deficit would affect wood hydraulic conductivity and mechanical properties with effects on the leaf water potentials of two ornamental species, Photinia x fraseri var. Red Robin and Viburnum opulus L. The experiment was conducted in a nursery (Pistoia, Italy) during summer 2011. Individuals were arranged in three plots under three watering regimes. The control plot (C) received an amount of water replacing that lost via evapotranspiration, while two plots were maintained under severe water deficit (SWD =33% C) and moderate water deficit (MWD = 66% C). Water deficits reduced stem diameter in both species without changing wood density (D). Concerning mechanical properties, stiffness (E) and strength (YS) of Photinia resulted higher in Photinia than in Viburnum, which did not show differences between treatments in either E or YS, whereas in Photinia, E was lower in SWD (P

Stem radius variations result from the fluctuation of environmental factors, mostly temperature trend and water availability, in turn affecting plant water balance, and plant growth. High-resolution analysis of stem radius variation provides insights into the temporal patterns in radial growth and water balance, and their relationship with environmental variables. To test the causal effects of temporal climate fluctuation on stem radius variation, a mathematical procedure was applied to normalize and synchronize radial fluctuations and environmental parameters, whose baseline is largely unexplored. Stem radius variations were continuously monitored during two consecutive years in four saplings field-grown olive tree cultivars (Canino, Cipressino, Leccino, Maurino) in an experimental farm in central Italy, between November 2004 and October 2006, using automatic high-resolution point dendrometers. A derivative analysis approach applied on point dendrometer records was conveniently used to describe stem radius variation and to distinguish the timing of transition from the dormant winter state to the active growth stage and till the slow expansion phase. Stem diameter patterns showed intense shrinkage events suddenly after air temperature drop below 0 °C during winter. The onset of radial growth was delimited by the occurrence of rehydration (beginning of transpiration cycles) and increase of air temperature (end of cold cycles). The course of the growing season was described by patterns of air temperature, reference evapotranspiration, cumulative degree-days, vapour pressure deficit and soil moisture deficit, and correlated to patterns in stem radius cycles. Three phases of stem radius variation were evidenced through the seasonal course: induction signal, growth period, and slow expansion. This approach provides new and objective insights on shrinkage–swelling phenomena in Mediterranean environments, related to dehydration and hydration cycles, which are difficult to detect with empirical treatment of stem radius variation records. The ability to switch quickly between dormancy to growth would enable the olive tree to restart physiological processes and to cope with erratic climatic conditions of the Mediterranean region.

Poplar ( Populus ), the model system in tree research, is a fast-growing and high biomass plant which is promising for energy, paper and pulp production, and for growth in soils contaminated with metals. Contamination of soils and water with heavy metals has become a widespread problem; environmental pollution by excess zinc (Zn), one of the more important contaminants, occurs frequently and yet the responses of Populus to high Zn concentrations are still not clearly understood. We investigated the effects of Zn on the functional and structural parameters in the Populus × euramericana clone I-214 by Zn localization in frozen-hydrated leaves and roots by cryo-scanning electron microscopy (cryo-SEM)/energy-dispersive X-ray microanalysis (EDXMA). The experiment was conducted on cuttings grown in nutrient solutions with an increasing Zn concentration gradient (0.001–10 mM). Biomass partitioning and Zn uptake were affected by the metal treatments, showing organ- and tissue-dependent responses. In particular, Zn accumulated in old leaves and moved from shoot to root as the Zn concentration in the growth medium increased. At the highest treatment concentration (10 mM), Zn was preferentially localized in photosynthetic tissues of shoots, and in epidermis and cortex tissues of roots. Gas exchange and chlorophyll measurements showed impairments in leaf biochemistry rather than in stomatal function. Modifications in foliage area, stomatal density and leaf layer thickness were investigated to reduce and/or compensate the negative effects of excess Zn on CO 2 assimilation. To counteract Zn toxicity, clone I-214 adopted different defense/tolerance mechanisms involving complex structural, physiological and biochemical processes, attributed to both Zn excluders and accumulators. This study demonstrates the advantages of combining cryo-SEM/EDXMA, gas exchange and chemical analyses for studying metal localization and structural as well as physiological responses in plants.

We investigated the effect of high copper (Cu) concentrations on poplar woody cuttings (Populus × euramericana) clone Adda in order to estimate the degree of metal tolerance. Metal accumulation was also investigated to determine where and to what extent Cu is stored within the plant. Plant responses to Cu were determined comparing biomass growth and photosynthetic potential measured at concentrations of 0.4 (control), 20, 100, 500 and 1000M of Cu supplied with Hoagland’s solution in an aerated hydroponic system. Results obtained in this study show that increasing levels of Cu resulted in a general reduction of plant growth at concentrations equal or higher than 100M. At these concentrations of Cu, reductions of chlorophyll contents and photosynthetic parameters were also observed. The metal was mainly accumulated in the root system at all Cu levels. Since no significant differences were noticed in growth and photosynthesis between control plants and those treated with 20M of Cu, we conclude that Adda clone was able to tolerate quite high concentration of Cu and we propose it as a good candidate for screening Cu tolerance in the field. © 2007 Elsevier B.V. All rights reserved.

In this study, the effects of non-hazardous levels of heavy metal (Zn, Cu, Cr and Cd)-enriched organic waste on biomass partitioning and heavy metal accumulation in plant organs in July and October were determined for two poplar clones (Populus deltoides × maximowiczii—clone Eridano and P. × euramericana—clone I-214) commonly used in Italian poplar plantations. Soil amended with the industrial organic waste did not exert any toxic effects on plants. Leaf, stem, root and woody cutting biomasses of treated plants were significantly greater than in the controls in both clones, except for stem biomass at the beginning of October. Leaf area of Eridano and I-124 treated plants was significantly higher than that of control plants, both in July and October, while specific leaf area (SLA) did not show any significant changes due to treatment. Shoot (SMR) and root mass ratios (RMR) were not significantly affected by the treatment in July, while in October plants grown in treated soil showed significant differences in stem and root biomass allocation with respect to controls. Among the four heavy metals (Zn, Cu, Cr and Cd) contained in the industrial organic waste, only Zn, Cu and Cr concentrations in plants differed consistently between clones or soil treatments, while Cd levels were always below the detection limits. Both phytoextraction and phytostabilisation strategies were observed in the two clones studied. The results suggested that only non-hazardous industrial biosolid levels might be environmentally sustainable for poplar plantations. © 2004 Elsevier B.V. All rights reserved.

The current work deals with the use in a Mediterranean environment of a simulation model of forest ecosystem processes which was originally created for temperate areas (FOREST-BGC). The model was calibrated and applied on two deciduous forest stands in Tuscany (Central Italy) by using conventional and remote sensing data as inputs. First, information on the two stands needed to initialise the model was derived from different sources, while meteorological data were extrapolated from a nearby station by an existing procedure (MT-Clim). Temporal profiles of leaf area index (LAI) were then derived both from direct ground measurement and from the processing of NOAA-AVHRR NDVI data. The model was calibrated using stand transpiration values obtained for 1997 by a sap flow method. Next, its performances were tested against the same transpiration values measured in 1998. The results obtained indicate that FOREST-BGC is capable of simulating water fluxes of Mediterranean forests when suitable LAI profiles are considered. Moreover, the derivation of these profiles from NDVI data can improve the model performance probably due to an enhanced consideration of the effects of the typical Mediterranean summer water stress. These results support the final objective of the work, which is the development of a procedure capable of integrating conventional and remote sensing data to operationally simulate water and carbon fluxes on a regional scale.