Quercus Suber Forests Research Articles

The relationships between modern pollen rain assemblages and vegetation from Sougna Mountain (Rif Mountains-Northern Morocco)

This study discovers the distribution of vegetation in the Sougna Mountain and its modern pollen representation and investigates the relationships with environment and land use variables. A total of 31 moss polsters were collected between 138 and 1364 m above sea-level from wooded to open areas (e.g. cork oak forest, pine reforestation, and shrubland). At each sampling site land use and environment variables were collected. The vegetation in the Sougna Mountain is scattered in a mosaic along three vegetation belts which are displayed in distinct pollen assemblages dominated by the pollen equivalents of the vegetation types (Quercus suber forest, matorrals of Erica spp. and Cistus spp. and Pinus pinaster reforestation). The variation between the variables and pollen data was performed using CCA analysis. The anthropogenic variables such as grazing, and cultivation, contribute to discrimination of the degraded and grazed areas. High precipitation and altitude have a rather good correlation to wooded communities and consequently a good relation to the tree cover. Our results show that the pollen types of Poaceae, Cannabis, Plantago, Nicotiana, Asteraceae, and Urtica are related mostly to human practice and distinguish the disrupted communities. The presence of those taxa in the pollen diagram must be interpreted carefully. A high taxonomic resolution is recommended to prevent the overestimation of the abundance of some taxa. Our results contribute to the advancement of palynological reconstructions of past vegetation and land use in Sougna Mountain and generally in the Rif landscape.

Revising the role of belowground fungi in pentachlorophenol pollution management: insights from Tunisian cork oak forests

This summarizes the doctoral thesis “Belowground fungi are key sentinels in forest soils vulnerable to pentachlorophenol pollution: a mechanistic study in Quercus suber forests”. The PhD degree was awarded by ITQB NOVA in March 2018. It comprises a revision of the major issues, objectives, methodology and results, as well as a few possible recommendations for future work on bioremediation of halogenated aromatic pollutants. The working hypothesis of the thesis proposed that soils in Tunisian cork oak forests are likely contaminated with pentachlorophenol (PCP), a persistent organic pollutant (POP). This hypothesis is based on frequent reports of cork contamination with pentachloroanisole (PCA), which is likely formed through microbial conversion of PCP. Furthermore, PCP was considered a suitable model for investigating the role of soil mycobiota in pollution management due to its ability to travel long distances in the atmosphere, partition favourably into the soil layer, and moderate abiotic resistance, besides its life-threatening toxicity. Finally, fungi play a key role in colonizing soil in cork oak forests. These concepts have been applied in the "Preventive and remediation strategies for continuous elimination of polychlorinated phenols from forest soil" project (SfP-NATO 981674, 2006-2011). Overall the major findings of the study include the demonstration of the prevalence of PCP in the soils of Tunisian cork oak forests. Additionally, the study elucidated both the significance and impact of fungal activity in the mitigation and dispersion of PCP.

Quercus suber forest and Pinus plantations show different post-fire resilience in Mediterranean north-western Africa

In the African rim of the Western Mediterranean Basin, cork oak forests and pine plantations coexist. Under similar fire regimes, cork oak forest is more resilient in terms of habitat structure (canopy, understory, and complexity of vegetation strata) than pine plantation. By contrast, both woodland types show similar resilience in plant species composition. Resilience in habitat structure varies between the two woodland types because of the resprouting and seeding strategies of cork oak and pine species, respectively. These differences can be relevant for the conservation of biodiversity of forested ecosystems in a future scenario of increased fire frequency and scale in the Mediterranean basin. Wildfires have major impacts on ecosystems globally. In fire-prone regions, plant species have developed adaptive traits (resprouting and seeding) to survive and persist due to long evolutionary coexistence with fire. In the African rim of the Western Mediterranean Basin, cork oak forest and pine plantation are the most frequently burnt woodlands. Both species have different strategies to respond fire: cork oak is a resprouter while pines are mostly seeders. We have examined the hypothesis that pine plantations are less resilient in habitat structure (canopy, understory, diversity of vegetation strata) and plant composition than cork oak woodlands. The habitat structure and plant species composition were measured in 30 burnt and 30 unburnt 700-m transects at 12 burnt sites from north-western Africa, where the two forest types can coexist. Habitat structure and plant species composition were compared between burnt and unburnt transects from cork oak and pine plantation woodlands with generalized linear mixed models and general linear models. The results showed significant interaction effect of fire and forest type, since cork oak forest was more resilient to fire than was pine plantation in habitat structure. By contrast, both forest types were resilient to fire in the composition of the plant communities, i.e., plant composition prior to fire did not change afterwards. The higher structural resilience of cork oak forest compared to pine plantation is related to the resprouting and seeding strategies, respectively, of the dominant tree species. Differences in the responses to fire need to be considered in conservation planning for the maintenance of the Mediterranean biodiversity in a future scenario of changes in fire regime.

The use of large databases to characterize habitat types: the case of Quercus suber woodlands in Europe

The conservation of habitat types has been recognized to be of relevant importance for the conservation of biodiversity and is a major concern in the European Union. With the 92/43/EEC Habitats Directive, the European Commission targeted these habitat types, which conservation must be ensured by Member States. In this context, the Habitat type 9330 “Quercus suber forests” is intended to ensure the conservation of cork oak woodlands in Europe. To support the enhancement of nature conservation policies, in this study we provide a classification of cork oak woodlands in Europe using a large vegetation database. We identify four major groups with clear biogeographic differences and characterize them by lists of indicator species. We also provide distribution maps based on occurrence data and the modelled potential area of distribution as an additional tool for conservation. This study offers a contribution to the comparative description of the European Q. suber woodlands subtypes and to establish a protocol for habitat monitoring and assessment.

Plant-soil feedbacks in declining forests: implications for species coexistence.

Plant-soil feedbacks (PSFs) play a relevant role as drivers of species abundance, coexistence, and succession in plant communities. However, the potential contribution of PSFs to community dynamics in changing forest ecosystems affected by global change drivers is still largely unexplored. We measured the direction, strength and nature (biological vs. chemical) of PSFs experienced by coexisting tree species in two types of declining Quercus suber forests of southwestern Spain (open woodland vs. closed forest) invaded by the exotic soil pathogen Phytophthora cinnamomi. To test PSFs in a realistic community context, we focused not only on individual PSFs (i.e., comparing the growth of a tree species on conspecific vs. heterospecific soil) but also calculated net-pairwise PSFs by comparing performance of coexisting tree species on their own and each other's soils. We hypothesized that the decline and death of Q.suber would alter the direction and strength of individual and net-pairwise PSFs due to the associated changes in soil nutrients and microbial communities, with implications for recruitment dynamics and species coexistence. In support of our hypothesis, we found that the decline of Q.suber translated into substantial alterations of individual and net-pairwise PSFs, which shifted from mostly neutral to significantly positive or negative, depending on the forest type. In both cases however the identified PSFs benefited other species more than Q.suber (i.e., heterospecific positive PSF in the open woodland, conspecific negative PSF in the closed forest). Our results supported PSFs driven by changes in chemical soil properties (mainly phosphorus) and arbuscular mycorrhizal fungi, but not in pathogen abundance. Overall, our study suggests that PSFs might reinforce the loss of dominance of Q.suber in declining forests invaded by P.cinnamomi by promoting the relative performance of non-declining coexisting species. More generally, our results indicate an increase in the strength of net PSFs as natural forests become disturbed by global change drivers (e.g., invasive species), suggesting an increasingly important role of PSFs in forest community dynamics in the near future.

Demografia i conservació de <em>Simethis mattiazzi (Liliaceae)</em>, espècie d’interès per a la flora vascular de Catalunya

Aportamos nuevos datos corológicos, demográficos, fenológicos, fitosociológicos, ecológicos y de gestión ambiental sobre Simethis mattiazzi en Cataluña, una planta vascular amenazada en la región mediterránea. En la comarca de la Selva hemos localizado 27 rodales, cuyos recuentos nos dan una estimación de 176.052 individuos (22 rodales). El área de ocupación es de 43.594 m2 y se distribuyen en 10 cuadrados UTM de 1 km de lado. Simethis es una especie característica de la asociación Lavandulo stoechadis-Ericetum scopariae y se puede encontrar presente en tres hábitats diferentes (32k Brezales de Erica scoparia, 45b Bosques de Quercus suber con sotobosque de matorral acidófilo y 45i Bosques mixtos de Q. suber y Pinus spp.), prefiriendo claramente el 32k. Aun así, produce más flores por individuo en los ambientes que le son menos favorables (45b y 45i). Por lo que parece, el factor predominante de su distribución en Europa y África es el clima, el cual siempre tiene que ser atlántico o submediterráneo con tendencia oceánica. Asimismo, damos propuestas para su conservación y confirmamos el estatus actual UICN de «En Peligro» (EN) de Simethis en Cataluña. [ca] Aportem noves dades corològiques, demogràfiques, fenològiques, fitosociològiques, ecològiques i de gestió ambiental sobre Simethis mattiazzi a Catalunya, una planta vascular amenaçada a la regió mediterrània. A la comarca de la Selva hem localitzat 27 rodals, els recomptes dels quals ens donen una estimació de 176.052 individus (22 rodals). L’àrea d’ocupació és de 43.594 m2 i es distribueix en 10 quadrats UTM d’1 km de costat. Simethis és una espècie característica de l’associació Lavandulo stoechadis-Ericetum scopariae i es pot trobar present en tres hàbitats distints (32k Bruguerars d’Erica scoparia, 45b Boscos de Quercus suber amb sotabosc de brolla acidòfila i 45i Boscos mixtos de Q. suber i Pinus spp.), tenint una clara preferència pel 32k. Malgrat això, produeix més flors per individu en els ambients que li resulten menys favorables (45b i 45i). D’altra banda, pel que sembla, el factor predominant de la seva distribució a Europa i Àfrica és el clima, el qual sempre ha de ser atlàntic o submediterrani de tendència oceànica. Així mateix, donem propostes de conservació i confirmem l’estatus actual UICN de «En Perill» (EN) de Simethis a Catalunya.

Wood exploitation and food supply at the border of the Roman Empire: the case of the vicus of Thamusida – Sidi Ali ben Ahmed (Morocco)

This paper presents the results of inter-disciplinary work drawing on archaeobotanical and archaeometric studies to trace the agroforestry landscape and the supply economy at the vicus of Thamusida in north-west Morocco at the border of the Roman Empire. The available data indicate the self-sufficiency of the settlement in both forestry and agricultural products throughout the period investigated from the end of the 1st century BC to the beginning of the 4th century AD. Charcoal data testify to the presence of a Quercus suber forest in the close surroundings of the site and its exploitation for a variety of forestry products such as timber, fuelwood, cork, and probably also leaves and acorns to feed livestock. The overwhelming presence of Q. suber in the archaeological layer investigated clearly indicates that this forest was under human influence prior to Roman occupation and was already partially degraded. Charred seed and fruit remains suggest that the diet of both troops and civilians was mainly based on locally grown products and that all the inhabitants of the site had access to good cereals such as barley, naked wheats and pulses with large seeds such as horse bean and pea; quality fruits, such as olive and grape, were also produced locally for fresh consumption. Organic residue analyses of the contents of ceramic vessels and plastered vats allowed archaeobotanical data to be complemented, thereby shedding light on some of the imports at Thamusida. Despite the remote location of this settlement, imported goods such as oil and wine were transported here in amphorae from different parts of the Empire.

Soil Bradyrhizobium population response to invasion of a natural Quercus suber forest by the introduced nitrogen-fixing tree Acacia mearnsii in El Kala National Park, Algeria

We analyzed the diversity and identity of the rhizobial populations nodulating an invasive Australian legume tree Acacia mearnsii in a natural Quercus suber forest in the El Kala National Park, Algeria. Soils from three different forest plots corresponding to non invaded original Q. suber stand, partially invaded by A. mearnsii, and totally invaded (monodominant) A. mearnsii stand were used to trap nodulating bacteria with the same tree species. Symbiotic nitrogen-fixing bacteria were isolated from root nodules and characterized by sequencing of the internal transcribed spacer region, then submitted to phylogenetic analyses. A total of 67 isolates was obtained, representing the 3 different forest plots, all renodulating A. mearnsii in monoxenic conditions. Phylogenetic analyses showed that all isolates belong to different Bradyrhizobium lineages, according to each of the three locations with little intermixing between forest plots. These results illustrate the adaptation of nodulating Bradyrhizobium populations to the new soil conditions induced by invasion. This symbiotic adaptability is presumed to be a key factor of the invasive character of this tree species.

Breeding ecology of the Atlas Pied Flycatcher Ficedula speculigera in an old oak Quercus suber forest in northeastern Algeria

Capsule Low clutch size (CS) in the Atlas Pied Flycatcher breeding in evergreen Mediterranean forest was compensated for by relatively high overall reproductive success.Aims To describe the breeding ecology of the Atlas Pied Flycatcher Ficedula speculigera in detail for the first time, in an old oak Quercus suber forest.Methods A total of 102 nests were monitored during 2010–2012. Breeding phenology, population density, clutch and brood sizes, egg biometrics, breeding losses and breeding success were accurately determined.Results The species arrived in the breeding area in late April. Population density was very high with 4.87 (±1.02) pairs/ha. Mean egg laying date (LD) was 19 May and CS averaged 4.92 eggs. Hatching and fledging success were 88.7% and 83.5%, respectively. The number of fledged young averaged 3.8 (±1.66) and decreased with LD (4.2 ± 1.45 chicks fledged per nest at the start of the season versus 2.8 ± 1.56 at the end).Conclusion Lower CS compared to Ficedula hypoleuca populations was compensated by relatively high fledging success, thereby ensuring overall reproductive success of this species. Moreover, the Atlas Pied Flycatchers seem to benefit from the lower seasonality in their food in the evergreen habitat.

Geochemical approach to assessing human impacts in Cork Oak forest soils of the MED region

Cork oak forests in the MED region are of critical social and ecological value and under stress from both environmental change and variation in management practice. This study, as part of a NATO Science for Peace project (SfP 981674), evaluated geochemical methods to assess potentially toxic element (PTE) input to field sites from Quercus suber forests in Tabarka (Tunisia) and an experimental control forest managed by ARGIS-Sardega (Italy). Surface and subsurface soil samples were collected from environmentally comparable sites in the two regions. Sites were identified with varied stand and shrub density and characterised for basic soil properties and multi element content. The data were evaluated using principle component analysis (PCA) and soil enrichment factors (SEF). Soils showed chemical variability associated with differences in parent material and the effects of biomass density. Contributions from events such as fire damage, as well as biomass, sea salt and geogenic sources can be identified, and evaluation is enhanced using a combination of assessment methods. Ultimately despite concerns for the regulation of forest activities in the study area, little direct anthropogenic impact was on soil quality.

Modelling fuel succession in Mediterranean cork oak forests along a 70-year chronosequence

Mechanical removal of understory vegetation is increasingly used in Euro-Mediterranean forests to reduce fire hazard, but little is known about the long-term patterns of fuel change after management. We used a 70-year post-management chronosequence to investigate fuel succession in cork oak Quercus suber forests. Mean shrub height, crown volume, total standing biomass, and biomass of leaves, and coarse and fine materials, increased rapidly during the first 10years after management, but then converged slowly to a plateau that was not reached within the chronosequence. A high vertical continuity of fuels from the ground level to the tree canopy (0–2m) was reached in about 10–20years, but peak understory cluttering occurred only at 50–70years. Fine materials accumulated primarily at lower strata (<1m) throughout the chronosequence, whereas leaves and coarse materials accumulated first at lower strata, and then progressively occupied the upper strata (>1.5m). Results suggest that recurrent fuel management may promote highly flammable pioneer shrublands, whereas lack of management promotes late-successional vegetation with high risk of intense wildfires. Solving this conundrum requires careful planning of the spatial and temporal distribution of treatments to reduce the risk of fire spread at the landscape scale.

Long‐term responses of Mediterranean birds to forest fuel management

Summary1. Mechanical management of forest fuels is increasingly used in the Euro‐Mediterranean region in response to the abandonment of traditional agroforestry and the concurrent increase in fire hazard. Although fuel management may have positive side effects for biodiversity, its long‐term impacts remain largely unknown.2. We used a 70‐year post‐management chronosequence to investigate the influence of time since fuel management and management frequency on bird assemblages in cork oak Quercus suber forests.3. Fuel management strongly affected bird species richness, abundances and assemblage composition, with rapid changes often occurring during the first 10–20 years, followed in the next decades by a slow convergence to pre‐management levels.4. In winter, overall species richness and abundance, and that of frugivores and shrub foragers, were negatively affected by recent and recurrent management, only recovering in stands unmanaged for &gt;50 years. In spring, insectivore abundance and the richness and abundance of shrub foragers declined immediately following management, increased to a maximum about 20 years later, and declined thereafter. Breeding granivores and ground foragers were the only groups that benefitted from fuel management. There were no overall effects on species of conservation concern, although a few species with unfavourable status benefitted from fuel management.5. Synthesis and applications. Our study confirmed that mechanical fuel management has positive effects on some early‐successional bird species of conservation concern, although its effects were limited. These benefits should be compared with the strong negative impacts on key bird species such as wintering frugivores, which play a pivotal role in ecosystems by promoting seed dispersal. To reconcile the positive and negative aspects, fuel management should be used to create heterogeneous mosaics of forest patches encompassing a range of sizes (10–100 ha) and successional stages of understorey vegetation, including stands undisturbed for &gt;50 years. This management strategy will likely maintain conditions for a wide range of species with contrasting ecological requirements while also reducing fire hazard.

Cork oak (Quercus suber L.) forest decline in Tunisia: A linkage between physiological adaptation and stress

In the past, several decades, the decline of Quercus suber forests has been observed over wide areas of the Mediterranean basin. Mediterranean-climate sclerophyllous trees are known to typically possess anatomical and morphological structures in their leaves, or other vegetative organs, which provide high resistance to desiccation induced damage during substantial water stress. Long-term exposure of cork oaks to water-deficit and a shaded environment might also alter the morphology, anatomy and physiology of the plant. Even though cork oaks are able to acclimate in response to changes in their abiotic environment, such as drought regime and shading, many studies have suggested that the cork oak forest decline phenomenon in Tunisia seems to be strongly associated to changes in tree physiology. Key words: Adaptation, decline, physiology, Quercus suber, stress.

Can net photosynthesis and water relations provide a clue on the forest decline of Quercus suber in North Tunisia

Net photosynthesis, sap flow density (SFD) and water use efficiency (WUE) were measured in a Quercus suber forest in north Tunisia in an attempt to explain the forest decline. In general, sap flow was positively related to light intensity and water loss, indicating that high light intensities can increase the SFD up to the saturation point in the cork oak. CO2 assimilation of cork oak in this region was light intensity-dependent. Cork oak showed a general increase in photosynthetic rates with increasing light intensity up to the light saturation point. Increased radiation probably increased the photosynthesis and growth above ground in this area, whereas the below-ground soil had insufficient moisture for uptake through the roots because the high light intensity and temperature induced high evapotranspiration. Key words : Decline, evaportranspiration, light intensity, Quercus suber, sap flow density, water use efficiency.

Nouvelles contributions à l’histoire tardiglaciaire et holocène de la végétation en Algérie : analyses polliniques de deux profils sédimentaires du complexe humide d’El-Kala

The study of two pollen sequences from El-Kala marshes allowed the reconstruction of the regional vegetation history supported by eight radiocarbon dates. Pollen assemblages from Bourdim site were dominated by local input of Alnus and Salix, while regional vegetation was characterized by scattered Quercus suber forests with a well-developed Erica arborea matorral. While the vegetation dynamics recorded at Bourdim is recent (Late Holocene), the majority of the pollen diagram from Garaat El-Ouez is contemporaneous to the Late Pleniglacial and is characterized by open woodlands with Pinus, Poaceae and several heliophilous herbs. The significant values of Cedrus pollen identified in this period indicate that the region of El-Kala most probably played the role of a refugium for this tree.

Effects of silvicultural treatments on forest biodiversity indicators in the Mediterranean

Biodiversity maintenance is a key management objective and a requisite for sustainable forestry. Research efforts on the effects of forest management on biological diversity are therefore increasingly needed, particularly in regions such as the Mediterranean that have been comparatively less studied in this respect. We analysed the effects of different regeneration and stand improvement treatments on six forest biodiversity indicators (snags, mature trees, shrub abundance, shrub species richness, tree species richness and tree species diversity) in the Mediterranean region of Catalonia (NE Spain) by analysing a set of 9808 plots from the Third Spanish National Forest Inventory comprising both managed and unmanaged stands. Managed stands had significantly fewer large-diameter trees (with the exception of Quercus suber forests) and snags than unmanaged ones. While clearcutting decreased tree species richness, stands with selection cutting had higher shrub and tree species richness and tree species diversity, which is consistent with the intermediate disturbance hypothesis, which states that diversity is highest at intermediate disturbance levels. Stand improvement treatments increased the number of large-diameter trees, tree species richness and diversity (cleaning and thinning), and shrub species richness (pruning), while no significant negative effect was found for any of the other indicators. Our results suggest that preventing silvicultural disturbances may not be the best solution for conserving and enhancing biodiversity in the Mediterranean forests of Catalonia, where many stands have high tree density that impedes the establishment of a variety of plant species and the transition to more developed stages. Selection cutting may be an appropriate and sustainable regeneration treatment for Mediterranean forests in this respect, but their practical implementation should avoid the systematic harvesting of the highest quality and largest trees, which is still common in many private forests in Catalonia.

Oak regeneration in heterogeneous landscapes: The case of fragmented Quercus suber forests in the eastern Iberian Peninsula

Quercus suber recruitment is quantified at local (in different vegetation types) and landscape level in three marginal populations (sites) ranging in size from 70 to 7000 ha and located in the eastern Iberian Peninsula (Spain). We hypothesised that: (1) recruitment of marginal Q. suber populations in eastern Iberia should be higher than in the core area of distribution, western Iberia, (2) within our study area, there should be a trend in the regeneration from north (the largest forest patch) to south (the smallest patch), and (3) within a site, recruitment should not be randomly distributed, but rather some vegetation types should show higher recruitment than other vegetation types. To test these hypotheses, a total of 61 plots measuring 12.5 m × 12.5 m were established on seven vegetation types in five previously selected 3 km × 3 km quadrats. On each plot all Quercus plants shorter than 3 m were labelled and tracked between 2003 and 2005. Results support the first and third hypotheses but not the second one. Q. suber recruitment densities ranged from 0 to 7200 plants per hectare. The complete regeneration process (from recruitment to growth) occurred on old fields; well-established seedling banks were abundant under forest canopies; recruitment in shrublands was practically null. To better understand Q. suber recruitment, both landscape configuration and interactions with other Quercus species should be considered.

Regeneration of a marginal Quercus suber forest in the eastern Iberian Peninsula

AbstractQuestion: Small and marginal forest populations are a focus of attention because of their high biodiversity value as well as the risk of population decline and loss. In this context, we ask to what extent a small, marginal Quercus suber (Cork oak) population located in the eastern Iberian Peninsula (Valencia, Spain) has the capacity for self‐regeneration and what are the factors that determine its recruitment variability.Location: Quercus suber forest in Pinet (Valencia, Spain).Methods: We performed a spatially explicit sampling both of the recruitment and of the potential parameters that could account for the recruitment variability. Using regression techniques we model the recruitment occurrence and abundance, and then we test to what extent the model obtained is still constrained by the spatial dependence.Results: Quercus suber recruitment density ranges from 0 to 18.66 individuals/25m2 (mean = 1.46, SD = 2.8), with a very skewed distribution. Recruitment is similar under Q. suber forests and under Pinus forests, but it is almost absent under shrublands. Thus the parameters that explain most of the recruitment variability in local vegetation types are: the presence and cover of shrubs (negative relationship with recruitment), the basal area of Q. suber and Pinus and the amount of bare soil (all positively related to recruitment). These parameters are strongly related to the ecological processes driving recruitment (i.e. dispersal and predation) and they remove most of the spatial dependence of recruitment. Most recruiters, however, are small, forming a seedling bank rather than growing to successfully colonize new habitats.Conclusion: The results suggest that although recruitment densities are not very high, they do not limit potential regeneration in the Pinet Q. suber forest. However, successful regeneration is not observed. If we aim to increase the Pinet Q. suber population size, land management measures need to provide appropriate conditions for both seedling establishment in shrublands (e.g. shrub clearing) and seedling growth in woodlands (e.g. Pinus logging).

Regeneration of a marginal Quercus suber forest in the eastern Iberian Peninsula

Abstract Question: Small and marginal forest populations are a focus of attention because of their high biodiversity value as well as the risk of population decline and loss. In this context, we ask to what extent a small, marginal Quercus suber (Cork oak) population located in the eastern Iberian Peninsula (Valencia, Spain) has the capacity for self-regeneration and what are the factors that determine its recruitment variability. Location: Quercus suber forest in Pinet (Valencia, Spain). Methods: We performed a spatially explicit sampling both of the recruitment and of the potential parameters that could account for the recruitment variability. Using regression techniques we model the recruitment occurrence and abundance, and then we test to what extent the model obtained is still constrained by the spatial dependence. Results: Quercus suber recruitment density ranges from 0 to 18.66 individuals/25m2 (mean = 1.46, SD = 2.8), with a very skewed distribution. Recruitment is similar under Q. suber forests a...

The relationship between Cerambyx spp. damage and subsequent Biscogniauxia mediterranum infection on Quercus suber forests

In this paper we shall show the first data on the level of Cerambyx spp. beetle damage and the subsequent Biscogniauxia mediterranum (De Not) Kunze fungus infection in the Extremadura region (southwestern Spain). Our results indicate a strong correlation between damage, caused by bad cork removal and pruning practices (injuries that cannot heal and permit the attack of insects), and holes made by beetles ( r = 0.86). The relationship between holes and subsequent Biscogniauxia infection was r = 0.91. Different regression models have been proposed in order to find mathematical equations applied to forest health monitoring of wide areas. Additionally, we show the evolution in infection after 14 years in the four different areas. The results indicate an increase in damage by Cerambyx and Biscogniauxia infection after this period. Significant differences were found when comparing the four areas suggesting that local factors can be affecting these pests. Finally, we discuss the possible influence of different sociological, economic and agricultural factors on the management and conservation of Quercus suber forests in southwestern Spain and we propose possible solutions to integrate biological conservation and economic benefits of a sustainable cork industry associated with these Mediterranean forests.