Cork Oak Forests Research Articles

Oak protein profile alterations upon root colonization by an ectomycorrhizal fungus.

An increased knowledge on the real impacts of ectomycorrhizal symbiosis in forest species is needed to optimize forest sustainable productivity and thus to improve forest services and their capacity to act as carbon sinks. In this study, we investigated the response of an oak species to ectomycorrhizae formation using a proteomics approach complemented by biochemical analysis of carbohydrate levels. Comparative proteome analysis between mycorrhizal and nonmycorrhizal cork oak plants revealed no differences at the foliar level. However, the protein profile of 34 unique oak proteins was altered in the roots. Consistent with the results of the biochemical analysis, the proteome analysis of the mycorrhizal roots suggests a decreasing utilization of sucrose for the metabolic activity of mycorrhizal roots which is consistent with an increased allocation of carbohydrates from the plant to the fungus in order to sustain the symbiosis. In addition, a promotion of protein unfolding mechanisms, attenuation of defense reactions, increased nutrient mobilization from the plant-fungus interface (N and P), as well as cytoskeleton rearrangements and induction of plant cell wall loosening for fungal root accommodation in colonized roots are also suggested by the results. The suggested improvement in root capacity to take up nutrients accompanied by an increase of root biomass without apparent changes in aboveground biomass strongly re-enforces the potential of mycorrhizal inoculation to improve cork oak forest resistance capacity to cope with coming climate change.

Landscape dynamics in Mediterranean oak forests under global change: understanding the role of anthropogenic and environmental drivers across forest types

The Mediterranean region is projected to be extremely vulnerable to global change, which will affect the distribution of typical forest types such as native oak forests. However, our understanding of Mediterranean oak forest responses to future conditions is still very limited by the lack of knowledge on oak forest dynamics and species-specific responses to multiple drivers. We compared the long-term (1966-2006) forest persistence and land cover change among evergreen (cork oak and holm oak) and deciduous oak forests and evaluated the importance of anthropogenic and environmental drivers on observed changes for Portugal. We used National Forest Inventories to quantify the changes in oak forests and explored the drivers of change using multinomial logistic regression analysis and an information theoretical approach. We found distinct trends among oak forest types, reflecting the differences in oak economic value, protection status and management schemes: cork oak forests were the most persistent (62%), changing mostly to pines and eucalypt; holm oak forests were less persistent (53.2%), changing mostly to agriculture; and deciduous oak forests were the least persistent (45.7%), changing mostly to shrublands. Drivers of change had distinct importance across oak forest types, but drivers from anthropogenic origin (wildfires, population density, and land accessibility) were always among the most important. Climatic extremes were also important predictors of oak forest changes, namely extreme temperatures for evergreen oak forests and deficit of precipitation for deciduous oak forests. Our results indicate that under increasing human pressure and forecasted climate change, evergreen oak forests will continue declining and deciduous oak forests will be replaced by forests dominated by more xeric species. In the long run, multiple disturbances may change competitive dominance from oak forests to pyrophytic shrublands. A better understanding of forest dynamics and the inclusion of anthropogenic drivers on models of vegetation change will improve predicting the future of Mediterranean oak forests.

Endemic and Emerging Pathogens Threatening Cork Oak Trees: Management Options for Conserving a Unique Forest Ecosystem.

Cork oak (Quercus suber) forests are economically and culturally intertwined with the inhabitants of the Mediterranean basin and characterize its rural landscape. These forests cover over two million hectares in the western Mediterranean basin and sustain a rich biodiversity of endemisms as well as representing an important source of income derived from cork production. Currently cork oak forests are threatened by several factors including human-mediated disturbances such as poor or inappropriate management practices, adverse environmental conditions (irregular water regime with prolonged drought periods), and attacks of pathogens and pests. All these adverse factors can interact, causing a complex disease commonly known as "oak decline." Despite the numerous investigations carried out so far, decline continues to be the main pathological problem of cork oak forests because of its complex etiology and the resulting difficulties in defining suitable control strategies. An overview of the literature indicates that several pathogenic fungi and oomycota can play a primary role in the etiology of this syndrome. Therefore, the aim of this review is to analyze the recent advances achieved regarding the bio-ecology of the endemic and emerging pathogens that threaten cork oak trees with particular emphasis on the species more directly involved in oak decline. Moreover, the effect of climate change on the host-pathogen interactions, a task fundamental for making useful decisions and managing cork oak forests properly, is considered.

Estimate of biomass and carbon pools in disturbed and undisturbed oak forests in Tunisia

Aim of the study. To estimate biomass and carbon accumulation in a young and disturbed forest (regenerated after a tornado) and an aged cork oak forest (undisturbed forest) as well as its distribution among the different pools (tree, litter and soil).Area of study. The north west of TunisiaMaterial and methods. Carbon stocks were evaluated in the above and belowground cork oak trees, the litter and the 150 cm of the soil. Tree biomass was estimated in both young and aged forests using allometric biomass equations developed for wood stem, cork stem, wood branch, cork branch, leaves, roots and total tree biomass based on combinations of diameter at breast height, total height and crown length as independent variables.Main results. Total tree biomass in forests was 240.58 Mg ha-1 in the young forest and 411.30 Mg ha-1 in the aged forest with a low root/shoot ratio (0.41 for young forest and 0.31 for aged forest). Total stored carbon was 419.46 Mg C ha-1 in the young forest and 658.09 Mg C ha-1 in the aged forest. Carbon stock (Mg C ha-1) was estimated to be113.61(27.08%) and 194.08 (29.49%) in trees, 3.55 (0.85%) and 5.73 (0.87%) in litter and 302.30 (72.07%) and 458.27 (69.64%) in soil in the young and aged forests, respectively.Research highlights. Aged undisturbed forest had the largest tree biomass but a lower potential for accumulation of carbon in the future; in contrast, young disturbed forest had both higher growth and carbon storage potential.Keywords: Tree biomass; disturbance; allometry; cork oak forests; soil organic carbon stock.

Distribution and abundance of hole-nesting birds in Mediterranean forests: impact of past management patterns on habitat preference

This study explores the relative abundance of hole-nesting birds in fourMediterranean forest types, each of which has undergone different patterns of forest management. Nine species were sampled in 24 study plots, to compare cork oak forest, turkey oak forest, holm oak forest and pine plantation. The abundance of hole-nesters was greater in cork oak forest and turkey oak forest. Three species were most frequently detected: Great Tit (Parusmajor), Blue Tit (Cyanistes caeruleus) and Nuthatch (Sitta europaea). Bird abundancewas significantly lower in holmoak forest, particularly in the cases of Great Spotted Woodpecker (Dendrocopos major), Green Woodpecker (Picus viridis), Nuthatch and Short-toed Treecreeper (Certhia brachydactyla). TheGreat SpottedWoodpecker showed a positive correlation with the abundance of three secondary cavity nesters: Nuthatch, Short-toed Treecreeper and Starling; in contrast, Green Woodpecker showed a negative correlation with Starling. Habitat structure varied significantly among forest types, especially themean andmaximumtree height, these being lower in holmoak forest. The Great SpottedWoodpecker proved to be a good indicator of less disturbed woodlands. In fact, maximum tree height turned out to be a significant and positive explanatory variable for woodpecker abundance.We consider that intensive coppicing and timbermanagement in holm oak forest during the 20th century widely affected trees’ age-profile, with consequences for their suitability forwoodpeckers and other hole-nesting birds. Tomonitor the response of hole-nesting birds to forest management in terms of abundance, we propose the use of the great spotted woodpecker as an indicator species.

Defense pattern of Chinese cork oak across latitudinal gradients: influences of ontogeny, herbivory, climate and soil nutrients.

Knowledge of latitudinal patterns in plant defense and herbivory is crucial for understanding the mechanisms that govern ecosystem functioning and for predicting their responses to climate change. Using a widely distributed species in East Asia, Quercus variabilis, we aim to reveal defense patterns of trees with respect to ontogeny along latitudinal gradients. Six leaf chemical (total phenolics and total condensed tannin concentrations) and physical (cellulose, hemicellulose, lignin and dry mass concentration) defensive traits as well as leaf herbivory (% leaf area loss) were investigated in natural Chinese cork oak (Q. variabilis) forests across two ontogenetic stages (juvenile and mature trees) along a ~14°-latitudinal gradient. Our results showed that juveniles had higher herbivory values and a higher concentration of leaf chemical defense substances compared with mature trees across the latitudinal gradient. In addition, chemical defense and herbivory in both ontogenetic stages decreased with increasing latitude, which supports the latitudinal herbivory-defense hypothesis and optimal defense theory. The identified trade-offs between chemical and physical defense were primarily determined by environmental variation associated with the latitudinal gradient, with the climatic factors (annual precipitation, minimum temperature of the coldest month) largely contributing to the latitudinal defense pattern in both juvenile and mature oak trees.

Evaluation Exhaustive De La Diversité Des Plantes Aromatiques Et Médicinales De La Péninsule Tingitane (Maroc)

Aromatic and Medicinal Plants (AMP) represent a large part of biodiversity. However, in the absence of a detailed record of this diversity, research and AMP development projects are generally limited to a small portion of ethnobotanical heritage. To guide prospection, exploitation and conservation studies of the existing potential, a comprehensive evaluation of the natural diversity of AMP is required. The western Rif region in northern Morocco, which area represents less than 1% of national territory, is home to about 50% of the Moroccan floristic richness (2053 species and infraspecific taxa). This heritage includes 630 taxa from which only 23 are currently exploited and merely 57% are recognized by ethno-botanists. Among these assets, a list is drawn up containing 106 taxa with a special conservation status (very rare or rare taxa, and / or endemic and / or threatened) and some of which are widely exploited. From a phytosociological point of view and based on an available database of 449 floristic samples, natural forest stands and matorrals contain about 27% of all MAP of the study area. These AMP organize almost half the floristic composition of sclerophyllous forests (oleaster, kermes oak and cork oak forest) and about a third of the richness of each of the other groups analyzed (thermophilic formations, pure fir, limestone mountains forest, calcifuges deciduous, maritime pine, matorrals). Mountain groups are the richest in exclusive, endemic, rare and endangered AMP.

Impact of pine invasion on the taxonomic and phylogenetic diversity of a relict Mediterranean forest ecosystem

Invasion by non-native tree species is a major driver of reduction and fragmentation of forest ecosystems, also altering biodiversity components. However, the effects of this process on the phylogenetic structure and diversity of Mediterranean woodlands are still unknown. Accordingly, we used cork oak (Quercus suber) stands invaded by self-sowing populations of maritime pine locally introduced ca. 70years ago as a model system to assess the impact on the taxonomic and phylogenetic diversity of the native seed plant community. We performed vegetation sampling of the two forest types in sites of central Italy with similar conditions. Taxonomic diversity was negatively affected by the pine at three levels (gamma, alpha, beta). Indicator species were significantly less numerous than in cork oak stands, and did not include two growth-forms such as herbs and vines. Phylogenetic diversity metrics were inferred from an evolutionary tree of seed plants based on a ITS-5.8S nuclear DNA dataset including original sequences from local plant material. Phylogenetic diversity (PD) was positively related to species and genus richness, showing a marked decrease in the pine stands. Seven major clades (orders) of angiosperm dicots were only represented in the cork oak community. Both the NRI and NTI indices showed a significant reduction of phylogenetic evenness in the pine forest. Here, the proportional increase of related taxa with acid-tolerance specialization suggests that soil acidification is a major driver for a “habitat filtering” effect causing the exclusion of several understorey species and genera of cork oak forests. Progressive thinning of the pine stands is advocated to avoid further acidification and promote the re-conversion to oak woodlands by natural regeneration. This will ultimately favor the recovery of the associated plant diversity and the restoration of a vanishing forest ecosystem of the ancient Mediterranean landscape.

Carbon storage in degraded cork oak (Quercus suber) forests on flat lowlands in Morocco

The present study aims to quantify the carbon stored in a degraded cork oak (Quercus suber L.) ecosystem in the north west of Morocco, in view of potential management implications. To this end, carbon stocks were evaluated in the first 100 cm of the soil, the cork oak trees, and the understorey species (both above- and belowground). Results show that the total carbon stocks in the cork oak ecosystem ranges from 65 to 237 Mg ha-1 with a mean value of 121 Mg ha-1. The first 100 cm of the soil (including the forest floor) represents the largest carbon pool (~51% of the total organic carbon) of the ecosystem. Tree biomass (above- and belowground tissues of cork oak) represents the second largest pool (47%), whereas the contribution of the understorey is less than 2%. Within the first 100 cm of the soil, over 87% of all the soil organic carbon is situated in the first 40 cm of the soil depth. The amount of carbon stored here ranges from 30 to 110 Mg ha-1and these organic carbon stocks vary considerably with the stand basal area of the cork oak (R2 = 0.82). In practice, the carbon stocks of the different pools considered are strongly correlated with the stand density of the cork oak stands. In the semi-arid forest ecosystems of our study, management prescriptions aiming at increasing the standing biomass of the cork oak should thus considerably contribute, both directly through tree biomass and indirectly through increased soil organic matter, to efficient carbon sequestration.

Cork oak pests: a review of insect damage and management

Cork oak decline is widespread in all its distribution range and seems to be triggered mainly by both mismanagement and unfavorable climatic factors. As a result, cork oak forests become susceptible to pest attack, which accelerates the onset of decline. Pest management strategies for this valuable and highly biodiverse ecosystem are examined in this review, taking into account the main insect pests and how their impact on cork oak forests is affected by climate change. While monitoring pests may provide the tools to predict the transition from endemic to epidemic insect populations, forestry practices (sanitary felling), biological control, and trapping are some of the most promising measures in protecting cork oak forests. Over the last decades, cork oak (Quercus suber L.) decline has affected millions of trees throughout its distribution range. Cork oak is a typically Mediterranean species remarkably relevant for the biodiversity and landscape conservation of vast evergreen oak forests. Cork oak is also well known and highly valued for cork production. Climatic changes, management practices, and biotic factors, particularly plant pathogens and insect pests, play a decisive role in tree death and market devaluation of cork. Here, we review the major insect pests possibly involved in cork oak decline, while discussing pest management strategies. A survey of the current literature was performed to identify major insect pests affecting cork oak trees, as well as to establish the most promising pest management strategies under climate change. Many authors seem to agree that the decline is triggered by both anthropogenic and abiotic factors, such as the mismanagement of cork oak forests and unfavorable climate (high temperatures and droughts). Consequently, trees become susceptible to pests and pathogens, which accelerate the onset of decline. Since a further increase in temperatures and droughts is expected, developing adequate management strategies to adapt cork oak trees to climate change, while simultaneously preventing and reducing insect pest attacks, is of foremost importance in the effort to conserve these unique and highly diverse ecosystems.

Factors determining the occurrence of Pleurodeles poireti (Caudata: Salamandridae) on Edough Peninsula, northeastern Algeria

Pleurodeles poireti is one of the lesser-known amphibians in the Mediterranean region. This species is strictly endemic to the Edough Peninsula in northeastern Algeria. Here we investigated the factors that determine the presence of P. poireti, by affecting its selection of both aquatic and terrestrial habitats. Aquatic habitats were characterised according to their morphology and the physicochemical parameters of the water. We also examined the topographical and substrate features, plant cover and climatic conditions at the occurrence sites. Our surveys indicated that P. poireti is widely-distributed on the Edough Peninsula. Pleurodeles poireti predominantly breeds in moderate to large water bodies densely covered with emergent vegetation. The water parameters are less influential in its selection of breeding sites, except dissolved oxygen and turbidity, which are usually high at the occupied sites. At the broad spatial scale, P. poireti is positively associated with lowlands in cultivated landscapes. However, the species has a relatively broad niche in the region, and also occurs in cork oak forests. The species tolerates some level of human alteration of the landscape, but some populations close to villages could disappear in response to the combined effects of habitat destruction and the presence of alien fish.

Post-release habitat utilisation by Francolinus bicalcaratus ayesha, a critically endangered subspecies endemic to Morocco: implications for optimising future release programmes

SummaryCharacterising the habitat use of released captive-bred birds is required to help optimise future avian reintroduction programmes. The critically endangered Double-spurred Francolin Francolinus bicalcaratus ayesha is endemic to north-west Morocco, where it inhabits forests of cork oak Quercus suber. To improve the viability of this threatened population, 300 captive-bred francolins were released into a game reserve, and post-release monitoring was conducted. This study aimed to identify habitat variables determining the habitat selection of the Double-spurred Francolin. Auditory detection was used during transect surveys of calling males to locate birds and their habitat occupation. Comparison of occupied and random plots showed that this bird is found mostly in flat topography with high cover of shrubs and dense cork oak trees, and close to the release site and water points. Conservation of Double-spurred Francolin depends on the choice of the release point within the cork oak forest, which should be in proximity to suitable cover of cork oak trees, shrubs and water points. Such choices would allow a rapid adaptation to prevailing conditions within release sites. Further multi-scale studies are needed to improve our understanding of the effects of ecological factors on the processes of habitat selection by this endemic subspecies.

Warm and Fertile Sub-Humid Conditions Enhance Litterfall to Sustain High Soil Respiration Fluxes in a Mediterranean Cork Oak Forest

Soil respiration is a major component of the global carbon budget and Mediterranean ecosystems have usually been studied in locations with shallow soils, mild temperatures, and a prolonged dry season. This study investigates seasonal soil respiration rates and underlying mechanisms under wetter, warmer, and more fertile conditions in a Mediterranean cork oak forest of Northern Tunisia (Africa), acknowledged as one of the most productive forests in the Mediterranean basin. We applied a soil respiration model based on soil temperature and relative water content and investigated how ecosystem functioning under these favorable conditions affected soil carbon storage through carbon inputs to the soil litter. Annual soil respiration rates varied between 1774 gC m−2 year−1 and 2227 gC m−2 year−1, which is on the highest range of observations under Mediterranean climate conditions. We attributed this high soil carbon flux as a response to favorable temperatures and soil water content, but this could be sustained only by a small carbon allocation to roots (root/shoot ratio = 0.31–0.41) leading to a large allocation to leaves with a multiannual leaf production, enhanced annual twig elongation (11.5–28.5 cm) with a reduced leaf life span (<1 year) maintaining a low LAI (1.68–1.88) and generating a high litterfall (386–636 gC m−2 year−1). Thus, the favorable climatic and edaphic conditions experienced by these Mediterranean cork oak forests drove high soil respiration fluxes which balanced the high carbon assimilation leading to a relatively small overall contribution (10.96–14.79 kgC m−2) to soil carbon storage.

Production and Qualitative Analysis of Triterpenoids and Steroids of Ganoderma Species Harvested from Cork Oak Forest of North-Eastern Algeria

Submerged fermentation of higher fungi Ganoderma is increasingly, studied for its potential advantages particularly, improving the production biomass and bioactive metabolites. The present study mainly focuses on the qualitative assessment of triterpenoids and steroids in chloroform extracts of harvested mycelia from submerged cultures of three different strains of Ganoderma sp. by using a low cost complex medium. For the screening of these bioactive substances we employed a High Performance Liquid Chromatography (HPLC) system based on a gradient of acetonitrile acidified with formic acid, coupled to a Quadrupole Time-of-Flight Mass Spectrometer (QToF-MS) for a tentative determination of Ganoderic Acids (GA) and sterols. The LC-QToF-MS approach was successfully, used in the qualitative analysis of bioactive metabolites. The results show a considerable diversity of produced metabolites in the three samples and indicate the presence of putative target components, such as; GAA, GAH, GA theta, GA beta, GAK, GAE, GAC2, GAR, GAX and ergosterol. The comparison of the compounds according to their retention time and QToF-MS spectra reveals nine shared metabolites produced by the three different strains of Ganoderma sp., GAAm1, GAY, GAS, GAT-Q and GAT.

Understanding fungal functional biodiversity during the mitigation of environmentally dispersed pentachlorophenol in cork oak forest soils.

Pentachlorophenol (PCP) is globally dispersed and contamination of soil with this biocide adversely affects its functional biodiversity, particularly of fungi - key colonizers. Their functional role as a community is poorly understood, although a few pathways have been already elucidated in pure cultures. This constitutes here our main challenge - elucidate how fungi influence the pollutant mitigation processes in forest soils. Circumstantial evidence exists that cork oak forests in N. W. Tunisia - economically critical managed forests are likely to be contaminated with PCP, but the scientific evidence has previously been lacking. Our data illustrate significant forest contamination through the detection of undefined active sources of PCP. By solving the taxonomic diversity and the PCP-derived metabolomes of both the cultivable fungi and the fungal community, we demonstrate here that most strains (predominantly penicillia) participate in the pollutant biotic degradation. They form an array of degradation intermediates and by-products, including several hydroquinone, resorcinol and catechol derivatives, either chlorinated or not. The degradation pathway of the fungal community includes uncharacterized derivatives, e.g. tetrachloroguaiacol isomers. Our study highlights fungi key role in the mineralization and short lifetime of PCP in forest soils and provide novel tools to monitor its degradation in other fungi dominated food webs.

Biomass, Carbon and Nutrient Storage in a 30-Year-Old Chinese Cork Oak (Quercus Variabilis) Forest on the South Slope of the Qinling Mountains, China

Chinese cork oak (Quercus variabilis) forests are protected on a large-scale under the Natural Forest Protection (NFP) program in China to improve the ecological environment. However, information about carbon (C) storage to increase C sequestration and sustainable management is lacking. Biomass, C, nitrogen (N) and phosphorus (P) storage of trees, shrubs, herb, litter and soil (0–100 cm) were determined from destructive tree sampling and plot level investigation in approximately 30-year old Chinese cork oak forests on the south slope of the Qinling Mountains. There was no significant difference in tree components’ biomass estimation, with the exception of roots, among the available allometric equations developed from this study site and other previous study sites. Leaves had the highest C, N and P concentrations among tree components and stems were the major compartments for tree biomass, C, N and P storage. In contrast to finding no difference in N concentrations along the whole soil profile, higher C and P concentrations were observed in the upper 0–10 cm of soil than in the deeper soil layers. The ecosystem C, N, and P storage was 163.76, 18.54 and 2.50 t ha−1, respectively. Soil (0–100 cm) contained the largest amount of C, N and P storage, accounting for 61.76%, 92.78% and 99.72% of the total ecosystem, followed by 36.14%, 6.03% and 0.23% for trees, and 2.10%, 1.19% and 0.03% for shrubs, herbs and litter, respectively. The equations accurately estimate ecosystem biomass, and the knowledge of the distribution of C, N and P storage will contribute to increased C sequestration and sustainable management of Chinese cork oak forests under the NFP program.

Extinction debt of a common shrub in a fragmented landscape

Fil: Gonzalez Varo, Juan P.. Consejo Superior de Investigaciones Cientificas. Estacion Biologica de Donana; Espana

Production and trade analysis in the Iberian cork sector: Economic characterization of a forest industry

Cork oak forest grows endemically in the coastal regions of the western Mediterranean basin, particularly in the Iberian Peninsula. The cork agro-forestry systems play a key role in ecological processes, and the outer bark, or cork, can be extracted sustainability without damaging the tree or affecting biodiversity. Because of the properties of the cork, an important forestry and industrial structure has been developed around its most valuable goods. This paper describes the current global trade patterns in the Iberian Peninsula, where Portugal and Spain are world leaders. Although these countries bring most of their cork trade flows together with the rest of the world, there are clear differences between these sectors. The aim of this study was to identify these differences and to characterize each analysed sector from an economic perspective. The primary difference between the sectors lies in the characteristics of their supply chain and their capacity to generate wealth from raw cork. Portugal primarily produces and processes raw cork into products with high added value. Spain bases its cork sector on raw material and half-manufactured cork, and it is not able to use the full potential that cork provides. Catalonia is an exception because it is the global leader in the champagne stopper market. To encourage the development of the entire cork sector, every link in the supply chain should be strengthened through the establishment of companies and the generation of employment, and therefore the development of rural areas. Moreover, this industry must establish its own development strategies for the future, thereby increasing its investment in R&D and innovation in relation to the opportunities identified as follows: the potential for diversification beyond the wine market, the improvement potential for forest management and the enhancement of sustainability and eco-efficiency in every link of the cork supply chain.

Cork: Sustainability and New Applications

Cork is a strategic material used in multiple applications and its use has accompanied mankind since the days of Ancient Egypt. The cork oak forests are extremely well adapted to the semi-arid regions of south- ern Europe and northern Africa (west- ern Mediterranean). These forests help to prevent the advance of desertification, improve water penetration into the soil and hydrological regulation, promote soil conservation, and being the perfect habi- tat for many animal and vegetables species. Consequently, these forests promote biodi- versity (Pereira, 2007; Gil, 2011, 2014). the extraction. During the tree lifetime in operation, an average cork oak produces about four times more cork bark than the cork tree would produce if it were not sub- ject to stripping. The sum of the various layers of cork produced and harvested is greater than the single layer of cork pro- duced if there was no extraction during the life of a tree (Gil, 1998, 2011). Related to environmental aspects of the transformation of the cork raw mater- ial, it can be mentioned the production of expanded cork agglomerate. The man- ufacture of this cork product only uses superheated steam, using generators fueled with cork waste, not introducing any other products not exclusively cork, and giving up agglomeration based on resins of the cork itself. So, this is a completely nat- ural and ecological product. In addition, in the processing of this and other cork products an important residue is produced, cork powder. This powder is commonly burned to produce steam and/or power used in the factories themselves, given the high energy content of this material. Also, all other industrial cork wastes are reused or valorized in another way (Gil, 1998). So, there is really no wasted cork.

Defining soil quality by different soil bio-indexes: the Castelporziano reserved area experience

From 1995 to the present time, the Working Group “Soil”, led by the “Consiglio per la Ricerca e la sperimentazione in Agricoltura—Centro di ricerca per lo studio delle Relazioni tra Pianta e Suolo”, has promoted and performed the continual monitoring of the soil quality in the reserved area of Castelporziano, with the aim to identify specific indicators able to describe the biological fertility of forest and agricultural soils. Particularly, quantitative and qualitative investigations were performed on the soil organic matter to assess the relationships between changes in activity, composition and biodiversity of soil microbial biomass and the turnover of organic matter, by comparing pairs of sites that, while insisting on the same soil substrate, were managed in different ways for long time. This review summarizes the results obtained in about 10 years of monitoring of different soil sites in Castelporziano, which were representative of a wide variety of environments such as sandy dunes, retro-dune wetlands zones, Mediterranean high and low pseudo-steppe, Mediterranean lowland mixed forests, cork oak forests, pine forests, meadows for grazing wild boars, anthropic environments. In this sense, the Castelporziano experience, as a kind of “research gym”, can be taken as primary reference for the Mediterranean ecosystems in their entirety.