Search Results (16)

Evaluating wood’s natural durability is essential when establishing the level of protection that is required depending on the end use to extend its service life. Natural durability is defined as the intrinsic resistance of wood against the attack of destructive organisms. There are standardized methods for estimating a durability value. In Europe, the EN 350:2016 standard is responsible for establishing the basic guidelines, as well as the necessary tests to determine this value. This standard applies to commercial wood, both native and imported, and helps to improve and obtain better construction applications depending on the final use. This work aimed to study the natural durability of Quercus pyrenaica Wild. against Basidiomycetes (Coniophora puteana (Schumacher ex Fries) Karsten and Trametes versicolor (Linnaeus) Quélet) and termites (Reticulitermes grassei Clément). The standards applied were EN 113-2:2021 and EN 117:2023. The heartwood of the Quercus pyrenaica is highly durable against both xylophages basidiomycetes and subterranean termites. The sapwood is moderately durable against Coniophora puteana, slightly durable-not durable against Trametes versicolor, and moderately durable against termites. These results open the door for commercialization of this species, and it is expected to be included in EN 350:2016, where Q. pyrenaica is not included. Full article

Climate change poses a major threat to forests, impacting the distribution and viability of key species. Quercus pyrenaica Willd., a marcescent oak endemic to the Iberian Peninsula (Portugal and Spain) and southwestern France and a structural species in submediterranean forests, is particularly susceptible to shifts in temperature and precipitation patterns. Aiming to assess its potential loss of suitable area under future climate scenarios, we developed high-resolution spatial distribution models to project the future habitat suitability of Q. pyrenaica under two climate change scenarios (SSP3-7.0 and SSP5-8.5) for the periods 2070 and 2100. Our model, which has an excellent predictive performance (AUC of 0.971 and a TSS of 0.834), indicates a predominantly northward shift in the potential distribution of the species, accompanied by substantial habitat loss in southern and lowland regions. Long-term potential suitable area may shrink to 42% of that currently available. This, combined with the limited natural dispersal capacity of the species, highlights the urgency of targeted management and conservation strategies. These results offer critical insights to inform conservation strategies and forest management under ongoing climate change. Full article

Climate models forecast warmer winter conditions, which could lead to an earlier spring xylem phenology in trees. Localized stem heat experiments mimic this situation and have shown that stem warming leads to an earlier cambial resumption in evergreen conifers. However, there are still few comprehensive studies comparing the responses to stem heating in coexisting conifers and hardwoods, particularly in drought-prone regions where temperatures are rising. We addressed this issue by comparing the responses (xylem phenology, wood anatomy, growth, and sapwood concentrations of non-structural carbohydrates—NSCs) of two pines (the Eurosiberian Pinus sylvestris L., and the Mediterranean Pinus pinaster Ait.) and a ring-porous oak (Quercus pyrenaica Willd.) to stem heating. We used the Vaganov-Shashkin growth model (VS model) to simulate growth phenology considering several emission scenarios and warming rates. Stem heating in winter advanced cambial phenology in P. pinaster and Q. pyrenaica and enhanced radial growth of the three species 1–2 years after the treatment, but reduced the transversal lumen area of earlywood conduits. P. sylvestris showed a rapid and high growth enhancement, whereas the oak responded with a 1-year delay. Heated P. pinaster and Q. pyrenaica trees showed lower sapwood starch concentrations than non-heated trees. These results partially agree with projections of the VS model, which forecasts earlier growth onset, particularly in P. pinaster, as climate warms. Climate-growth correlations show that growth may be enhanced by warm conditions in late winter but also reduced if this is followed by dry-warm growing seasons. Therefore, forecasted advancements of xylem onset in spring in response to warmer winters may not necessarily translate into enhanced growth if warming reduces the hydraulic conductivity and growing seasons become drier. Full article

Oaks are characterized by high plasticity and intense interspecific gene flow due to natural hybridization. This generates a wide phenotypic spectrum, which creates taxonomic confusion within the genus. We compared the acorn traits across a temperature gradient in two types of Mediterranean Quercus (Quercus faginea Lam. and Q. pyrenaica Willd.) and their hybrids. Genetic groups were identified using amplified fragment length polymorphism (AFLPs) analysis. Acorns sampled from each of the three genetic groups were used for comparative purposes by means of 15 morphological characteristics. Eight of the traits showed discriminant value among the three groups. The acorn height tended to decrease with decreasing temperatures across the gradient, whereas the acorn width exhibited the opposite response. However, fruit traits allowed discrimination between the three groups, and the differences were consistent in the different zones. Both the number of acorns produced and the individual acorn size were larger for Q. pyrenaica. Hybrids showed intermediate traits between both parent species. Traditionally, the persistence of parental species in the absence of reproductive barriers has been explained by the lower fitness of the hybrids. Our results, however, do not reveal the presence of transgressive characteristics in the hybrids that could justify a lower competitive capacity. Full article

This work establishes the relationship between climate, bioclimate, and forest ecosystems and highlights the need to teach these topics in educational institutions. It was found that such knowledge is not currently taught in universities, leading to scarce or non-existent teacher training in these areas. However, the teaching of bioclimatic aspects over a three-year period as a basis for land use planning, has shown highly positive results. The objective is to propose the teaching of bioclimatology to future managers and teachers in order to obtain a balanced environmental development. The analysis of bioclimatic diagrams makes it possible to stipulate the duration of the water reserve in the soil. This is essential for agricultural and forestry management. The edaphic factor and the bioclimatic ombrotclimatic (Io) and thermoclimatic (It/Itc) indexes condition the types of forests and crops that can exist in a territory, with the particularity that the ombrotype is conditioned by the edaphic factor, which allows a decrease in the ombrothermal index, expressed by the ombroedaphoboxerophilic index (Ioex). The humid ombrotypes condition the presence of Abies pinsapo, Quercus pyrenaica, Q. broteroi, and Q. suber, and the dry ones Q. rotundifolia and Olea sylvestris. Full article

Infectious keratoconjunctivitis (IKC) is an eye disease caused by Mycoplasma conjunctivae that affects domestic and wild caprines, including Iberian ibex (Capra pyrenaica), a medium-sized mountain ungulate. However, its role in IKC dynamics in multi-host communities has been poorly studied. This study assessed M. conjunctivae in Iberian ibex and seasonally sympatric domestic small ruminants in the Natural Space of Sierra Nevada (NSSN), a mountain habitat in southern Spain. From 2015 to 2017, eye swabs were collected from 147 ibexes (46 subadults, 101 adults) and 169 adult domestic small ruminants (101 sheep, 68 goats). Mycoplasma conjunctivae was investigated through real-time qPCR and statistically assessed according to species, sex, age category, year, period, and area. The lppS gene of M. conjunctivae was sequenced and phylogenetically analysed. Mycoplasma conjunctivae was endemic and asymptomatic in the host community of the NSSN. Three genetic clusters were shared by ibex and livestock, and one was identified only in sheep, although each host species could maintain the infection independently. Naïve subadults maintained endemic infection in Iberian ibex, with an epizootic outbreak in 2017 when the infection spread to adults. Wild ungulates are epidemiologically key in maintaining and spreading IKC and other shared diseases among spatially segregated livestock flocks. Full article

Despite being rich in starch, over half of acorn production is undervalued. High hydrostatic pressure was used to modify the properties of Q. pyrenaica (0.1 and 460 MPa for 20 min) and Q. robur (0.1 and 333 MPa for 17.4 min) acorn starches to obtain high-valued ingredients. Pressure significantly altered the span distribution and heterogeneity of the acorn starch granules depending on the species, but their morphology was unaffected. Pressurization increased the amylose/amylopectin ratio and damaged starch contents, but the effect was more prominent in Q. pyrenaica than in Q. robur. However, the polymorphism, relative crystallinity, gelatinization temperatures, and enthalpies were preserved. The pressure effect on the starch properties depended on the property and species. The solubility, swelling power, and acorn gels’ resistance towards deformation for both species decreased after pressurization. For Q. pyrenaica starch, the in vitro digestibility increased, but the pseudoplastic behavior decreased after pressurization. No differences were seen for Q. robur. Regarding the commercial starch, acorn starches had lower gelatinization temperatures and enthalpies, lower in vitro digestibility, lower resistance towards deformation, superior pseudoplastic behavior, and overall higher solubility and swelling power until 80 °C. This encourages the usage of acorn starches as a new food ingredient. Full article

The interest of winemakers to find new woods that can give their wines a special personality and the need for cooperage wood have led to the use of other woods than traditional oak. The aroma of wines is undoubtedly one of the quality factors most valued by consumers. Volatile compounds from wood are transferred to wines during ageing. The type and quantity of aromas in wood depend on several factors, with the species, origin and cooperage treatments, particularly toasting, being very important. The transfer of volatile compounds to the wine depends not only on the wood but also on the wine itself and the type of ageing. This review therefore aims to recapitulate the volatile composition of alternative oenological woods at different cooperage stages and to compare them with traditional woods. It also summarises studies on the effect of wine aromas during ageing both in barrels and with fragments of alternative woods. In summary, it is observed that both woods and wines aged with alternative species of the Quercus genus present the same volatile compounds as traditional ones, but differ quantitatively; however, non-Quercus woods also differ qualitatively. Full article

Land abandonment is a major global change driver in the Mediterranean region, where anthropic activity has played an important role in shaping landscape configuration. Understanding the woodland expansion towards abandoned croplands is critical to develop effective management strategies. In this study, we analyze the colonization pattern of abandoned croplands by Quercus pyrenaica in the Sierra Nevada mountain range (southern Spain). We aimed to assess differences among populations within the rear edge of the Q. pyrenaica distribution. For this purpose, we characterized (i) the colonization pattern of Q. pyrenaica, (ii) the structure of the seed source (surrounding forests), and (iii) the abundance of the main seed disperser (Eurasian jay, Garrulus glandarius). The study was conducted in five abandoned croplands located in two representative populations of Q. pyrenaica located on contrasting slopes. Vegetation plots within three habitat types (mature forest, edge-forest and abandoned cropland) were established to compute the abundance of oak juveniles. The abundance of European jay was determined using data of bird censuses (covering 7 years). Our results indicate that a natural recolonization of abandoned croplands by Q. pyrenaica is occurring in the rear edge of the distribution of this oak species. Oak juvenile abundance varied between study sites. Neither the surrounding-forest structure nor the abundance of jays varied significantly between study sites. The differences in the recolonization patterns seem to be related to differences in the previous- and post-abandonment management. Full article

Specific functional traits such as shade tolerance or leaf habits can enhance root growth dynamics and structure of planted seedlings in the understory of planted forests. We assessed how low and moderate light levels (17 and 33% of full sunlight, mimicking after-thinning stocking) affect the root growth dynamics and structure of four late successional trees, three deciduous (Acer monspessulanum L., Quercus pyrenaica Willd and Sorbus torminalis (L.) Crantz) and one evergreen (Quercus ilex L.) species. Rooting depth, dynamics and structure were mainly explained by species functional differences. Roots of deciduous trees elongated faster and deeper and were larger than the roots of the evergreen Q. ilex. Among deciduous trees, S. torminalis had the lowest root growth. Specific leaf area and nutrient concentration were positively related to root growth, highlighting the importance of traits related to the plant economic spectrum, as determinants of species root growth differences. Moderate light level slightly enhanced root growth and decreased the specific leaf area (SLA). Species differences in water potential under drought were positively related to rooting depth, evidencing the importance of its role in overcoming drought stress during seedling establishment. These findings can guide the selection of late successional, shade tolerant tree species for underplanting thinned Mediterranean plantations and provide insights into their ecology. Full article

Research Highlights: The regeneration of Quercus species is usually very difficult in many oak woodlands transformed by livestock farming. Some studies have reported that shrubs can facilitate regeneration. However, the strength of interaction may vary depending on, among other factors, the shrub species and the stress tolerance of the oak species. Moreover, further studies are necessary to clarify the relative importance of the two facilitation mechanisms in the same community. Background and Objectives: Cytisus multiflorus (L’Her.) Sweet is a predominant shrub species in the Mediterranean grazed open-oak-woodlands found in the central west of the Iberian Peninsula (bioclimatic limit) and is present with Quercus pyrenaica Willd and Quercus ilex subsp. ballota Samp trees. Thus, we assessed the effect of these native shrubs and acorn size, and the effect of excluding large herbivores, on the seedling emergence of two contrasting co-occurring Quercus species under a bioclimatic limit. Materials and Methods: A manipulative field experiment was carried out considering four treatments as a combination of shrubs (shrub/no-shrub) and fence (fenced/open) factors. A total of twenty plots, five replicates for each treatment were available. In each plot, 20 acorns were sown: 10 acorns (5 small and 5 large) for each Quercus species. Acorn emergence was recorded during the first four years following the sowing. Results: Seedling emergence took place mostly in the spring of the first year after sowing. The presence of shrub was the main significant factor and incremented the emergence of both Q. ilex and Q. pyrenaica. The effect of the fence depended on the Quercus species considered, improving only the emergence of Q. pyrenaica. A negative effect with the small acorns was detected but only for Q. pyrenaica. In all treatments, Q. ilex emerged more than Q. pyrenaica. Conclusions: C. multiflorus had a clear facilitative effect on the seedling emergence of Q. ilex and Q. pyrenaica, which was much greater than the physical effect that acorn size and excluding large herbivores had. As such, this native shrub may have a key role in oak regeneration in Mediterranean grazed areas. Furthermore, in these areas of contact between marcescent and sclerophyllous Quercus species, Q. ilex currently emerges more than Q. pyrenaica. This could be indicative of a shift towards more xeric climatic conditions, which could lead to a change in the dominant tree species in the future. However, this change could be modulated by the effects of native shrub and large herbivores. Full article

Understanding the ecology of populations located in the rear edge of their distribution is key to assessing the response of the species to changing environmental conditions. Here, we focus on rear-edge populations of Quercus pyrenaica in Sierra Nevada (southern Iberian Peninsula) to analyze their ecological and floristic diversity. We perform multivariate analyses using high-resolution environmental information and forest inventories to determine how environmental variables differ among oak populations, and to identify population groups based on environmental and floristic composition. We find that water availability is a key variable in explaining the distribution of Q. pyrenaica and the floristic diversity of their accompanying communities within its rear edge. Three cluster of oak populations were identified based on environmental variables. We found differences among these clusters regarding plant diversity, but not for forest attributes. A remarkable match between the populations clustering derived from analysis of environmental variables and the ordination of the populations according to species composition was found. The diversity of ecological behaviors for Q. pyrenaica populations in this rear edge are consistent with the high genetic diversity shown by populations of this oak in the Sierra Nevada. The identification of differences between oak populations within the rear-edge with respect to environmental variables can aid with planning the forest management and restoration actions, particularly considering the importance of some environmental factors in key ecological aspects. Full article

Natural forests are considered a reservoir of great biological diversity constituting one of the most important ecosystems in Europe. Quercus study is essential to assess ecological conservation of forests, and also of economic importance for different industries. In addition, oak pollen can cause high sensitization rates of respiratory allergies in pollen-allergy sufferers. This study sought to know the pollen production of six oak species in the transitional area between the Eurosiberian and Mediterranean Bioclimatic Regions, and to assess the impact of climate change on airborne oak pollen concentrations. The study was conducted in Ourense (NW Spain) over the 1993–2019 period. A Lanzoni VPPS 2000 volumetric trap monitored airborne pollen. A pollen production study was carried out in ten trees randomly selected in several Quercus forest around the Ourense city. Oak pollen represented around 14% of annual total pollen registered in the atmosphere of Ourense, showing an increasing trend during the last decade. Pollen production of the six studied oak species follow the proportions 1:1:2:5:90:276 for Q. ilex, Q. faginea, Q. rubra, Q. suber, Q. pyrenaica, and Q. robur respectively. We detected a significant trend to the increase of the annual maximum temperature, whereas a decrease of the maximum and mean temperatures during three previous months to oak flowering. This could be related with the detected trend to a delay of the oak Main Pollen Season onset of 0.47 days per year. We also found significant trends to an increase of the annual pollen integral of 7.9% pollen grains per year, and the pollen peak concentration of 7.5% pollen grains per year. Quercus airborne pollen monitoring as well as the knowledge of the reproductive behavior of the main oak species, bring us an important support tool offering a promising bio-indicator to detect ecological variations induced by climate change. Full article

Wood is one of the most highly valued materials in enology since the chemical composition and sensorial properties of wine change significantly when in contact with it. The need for wood in cooperage and the concern of enologists in their search for new materials to endow their wines with a special personality has generated interest in the use of other Quercus genus materials different from the traditional ones (Q. petraea, Q. robur and Q. alba) and even other wood genera. Thereby, species from same genera such as Q. pyrenaica Willd., Q. faginea Lam., Q. humboldtti Bonpl., Q. oocarpa Liebm., Q. stellata Wangenh, Q. frainetto Ten., Q. lyrata Walt., Q. bicolor Willd. and other genera such as Castanea sativa Mill. (chestnut), Robinia pseudoacacia L. (false acacia), Prunus avium L. and P. cereaus L. (cherry), Fraxinus excelsior L. (European ash) and F. americana L. (American ash) have been studied with the aim of discovering whether they could be a new reservoir of wood for cooperage. This review aims to summarize the characterization of tannin and low molecular weight phenol compositions of these alternative woods for enology in their different cooperage stages and compare them to traditional oak woods, as both are essential to proposing their use in cooperage for aging wine. Full article

Persistence of native forests is a global concern. We aimed at unveiling the main factors affecting tree recruitment in Portuguese native forests, modelling sapling data collected during the 5th Portuguese Forest Inventory, for five main Quercus taxa. Zero-inflated count data models allowed us to examine simultaneously (i) the absence of tree recruitment and (ii) the density of tree recruitment. Using Akaike weights, we obtained importance values for 15 relevant explanatory variables. Results showed that seed availability and climatic variables were determinant to understand regional absence of regeneration for all taxa. Seed availability was also an important driver of sapling density, except for Quercus suber. Other variables impacted on regeneration density: grazing hindered Q. suber regeneration; regeneration of Q. rotundifolia and Q. suber was lower in flat areas; recurrent fire hampered the regeneration of Q. robur and Q. pyrenaica; Q. broteroi and Q. pyrenaica showed depressed regeneration in regions where forest plantations abound, while Q. robur and Q. suber seemed selectively protected. We conclude that caution is warranted when analysing pooled data for Quercus spp. regeneration, as different variables affected Quercus taxa differently. Finally, we suggest dedicated management actions to enhance the establishment of new native forests. Full article