Oak Types Research Articles

Comparison of Soil Organic Matter in Pure and Mixed Types of Oak in North Zagros (Case Study: Armardeh Baneh Forests)

Comparison of Soil Organic Matter in Pure and Mixed Types of Oak in North Zagros (Case Study: Armardeh Baneh Forests)

The Impact of the Deterioration on Wood by Chlorine: An Experimental Study.

The use of disinfection and cleaning chemicals in several municipal facilities, such as swimming pools and drinking water treatment plants, causes the degradation of various types of wood, which leads to failures in equipment and the corresponding need for maintenance. This degradation creates added costs for municipalities, as well as the closure of certain facilities due to curative or preventive maintenance and, in many cases, public health issues, due to the water being contaminated with deteriorating products. Through a thorough study of the degradation effect on the products, more resistant materials can be found which are able to withstand these adversities and increase the lifespan of wood in regular contact with chemical agents. This is achievable by the determination of the cost-effectiveness of the substitute material to replace these components with alternative ones, with properties that better resist the deterioration effects promoted by aggressive environments. No studies have been found so far strictly focused on this matter. The objective of this study is to evaluate the degradation presented by two types of wood, beech and oak, which are exposed to the action of chlorine in municipal facilities. This degradation varies according to the chlorine content and the materials' time of contact with the chemical agent, allowing the selection of new materials which will provide an extended lifetime of the components, reducing maintenance drastically, as well as costs for the facilities and the risk to public health. The performed experimental tests have shown that the oak wood has the best results regarding chlorine degradation resistance.

Rapid Ecological Integrity Assessment Metrics to Restore Wildlife Habitat and Biodiversity for Shortleaf Pine–Oak Ecosystems

Open woodlands dominated by shortleaf pine (Pinus echinata Mill.) and oak are historically an important component of the landscape across the southeastern United States. These ecosystems support numerous wildlife species, many of which have declined in recent years as the amount and condition of their habitat have declined. Land managers and private landowners need guidance on how to efficiently and accurately quantify the condition and wildlife habitat value of the pine stands that they manage. Here we provide a set of rapid assessment metrics, based on NatureServe’s ecological integrity assessment (EIA) method, to (a) identify exemplary tracts that provide the best habitat for key wildlife species, and (b) monitor restoration efforts to assess progress toward the improved quality of existing tracts. To ensure an ecologically appropriate scaling of metrics, we distinguished six types of shortleaf pine–oak woodland: A.—Interior Highlands shortleaf pine–oak (including A.1—shortleaf pine–oak forest and woodlands; A.2—shortleaf pine–bluestem woodlands); B—montane longleaf pine–shortleaf pine woodlands; C—southern Appalachian pine–oak woodlands; D—West Gulf coastal plain shortleaf pine–oak woodlands; and E—southeast coastal plain and Piedmont shortleaf pine–oak woodlands. We relied on a narrative conceptual model and peer review-based indicator selection to identify a core set of 15 stand-level metrics (two were optional). Individual assessment points (thresholds) and ratings (Excellent, Good, Fair, and Poor) were developed that were sensitive to the distinct attributes of each of the five shortleaf pine–oak and Appalachian pine–oak types. Values for the metrics can all be collected using rapid field methods, such as using basal area prisms and ocular (visual) estimates of cover. Protocols for the consistent application of these EIA methods are provided. A case study is presented from the Cherokee National Forest in Tennessee. These methods provide improved and rapid EIA metrics for all shortleaf pine–oak ecosystems in the southeastern US to help guide conservation-minded landowners in assessing the biodiversity and priority wildlife values of shortleaf pine–oak and southern Appalachian pine–oak ecosystems.

The Effect of Different Oak Products Used during Fermentation and Ageing on the Sensory Properties of a White Wine over Time.

The sensorial evaluation of Chenin blanc wine produced with different types of oak wood treatments over time has not been investigated before. The main aim of this study was to assess the sensory profile, using a trained panel, of a South African Chenin blanc wine fermented and matured in old barrels, three types of new oak barrels, two types of oak staves as well as a stainless steel tank over time, which has not been done before. Results indicate mainly separation between the stainless-steel tank/old barrel treatments from the stave and new barrel treatments, with separation between the latter two treatments also being found. More fruity descriptors were used in the stainless-steel tank and old barrel treatments, with oak-related descriptors being used in the stave and new barrel treatments. Separation between among the new barrel and stave treatments were also noted, which was still reflected during bottle maturation. These results indicate that winemakers need to take cognizance of the sensorial differences induced by barrel and stave maturation in white wines and how these evolve over time.

Biomass and carbon stocks in three types of Persian oak (Quercus brantii var. persica) of Zagros forests in a semi-arid area, Iran

Persian oak (Quercus brantii var. persica) is a dominant tree species of Zagros forests in a semi-arid area, western Iran. However, the capacity of biomass and carbon stocks of these forests is not well studied. We selected three types of oak, i.e., seed-originated oak, coppice oak and mixed (seed-originated and coppice) oak of Zagros forests in Dalab valley, Ilam Province, Iran to survey the capacity of biomass and carbon stocks in 2018. Thirty plots with an area of 1000 m2 were systematically and randomly assigned to each type of oak. Quantitative characteristics of trees, such as diameter at breast height (DBH), height, crown diameter and the number of sprouts in each plot were measured. Then, aboveground biomass (AGB), belowground biomass (BGB), aboveground carbon stock (AGCS) and belowground carbon stock (BGCS) of each tree in plots were calculated using allometric equations. The litterfall biomass (LFB) and litterfall carbon stock (LFCS) were measured in a quadrat with 1 m×1 m in each plot. One-way analysis of variance and Duncan’s test were performed to detect the differences in biomass and carbon stocks among three types of oak. Results showed that AGB, BGB and BGCS were significantly different among three types of oak. The highest values of AGB, AGCS, BGB and BGCS in seed-originated oak were 76,043.25, 14,725.55, 36,737.79 and 7362.77 kg/hm2, respectively. Also, the highest values of LFB and LFCS in seed-originated oak were 3298.33 and 1520.48 kg/hm2, respectively, which were significantly higher than those of the other two types of oak. The results imply the significant role of seed-originated oak for the regeneration of Zagros forests. Further conservation strategy of seed-originated oak is an important step in the sustainable management of Zagros forests in Iran.

Volatile and phenolic profiles of traditional Romanian apple brandy after rapid ageing with different wood chips

The aim of this work was to find differences in the volatile and phenolic profiles of the traditional Romanian apple brandy pălinca aged with various species of wood chips. Seven types of wood species, two types of oak (Quercus petraea and Quercus robur), plus sweet chestnut, mulberry, walnut, fir and cherry, were considered. The majority of volatile compounds characterizing the aroma profile of pălinca were esters, particularly ethyl esters, with ethyl isobutyrate, ethyl isovalerate, ethyl caproate, ethyl octanoate and ethyl decanoate as the most abundant. The most important source of catechin was cherry wood. Rutin and juglone were solubilised only in walnut wood aged brandy. Vanillin, increased significantly in chestnut aged apple brandy. Given the cost and difficulty in handling wooden barrels, and as an alternative being able to select from a range of specific wooden chips, this work could potentially guide actors in beverage industry to less expensive alternatives.

Use of Alternative Wood for the Ageing of Brandy de Jerez.

The use of alternative types of wood has arisen for the aging of the Brandy de Jerez, on a pilot plant level. In particular, besides the use of American oak, two more types of oak have been studied, French oak and Spanish oak, allowed by the Technical File for the ID Brandy de Jerez, and chestnut, which, though it is not officially allowed, is a type of wood which had been traditionally used in the area for the aging of wines and distillates. All of them have been studied with different toasting levels: Intense toasting and medium toasting. The study of the total phenolic composition (TPI), chromatic characteristics, organic acids, and sensory analysis have proven that chestnut leads to distillates with a higher amount of phenolic compounds and coloring intensity than oak. This behavior is the opposite as regards the toasting of the wood. Among the different types of oak, Spanish oak produces aged distillates with a higher phenolic composition and a higher color intensity. Regarding tasting, the best-assessed samples were those aged with chestnut, French oak, and American oak, and the assessors preferred those who had used a medium toasting level to those with an intense level.

Experimental Estimation of Fire Characteristics and Heat Release Rate for Jordanian Natural Wood by Means of Oxygen Consumption

Natural wood is one of the main sources of interior finishing of buildings, such as offices, kitchens, and furnishings that are widely used in Jordan. Inevitable hazards of wood fires have encouraged scientists and researchers for further investigations and tests in order to improve fire-resistance and to provide efficient protection from fire. Wood types of Beech, Oak, Pine, and Hickory were selected and tested since they represent the 40% of the total natural wood used in Jordan. Dual calorimeter approach under ISO 5660-1:2002, as a fire-testing device, is utilized to measure, experimentally, the thermal properties of wood samples during flaming combustion. The tested samples have been exposed horizontally in order to incident heat fluxes of 50 kW/m2. Time to ignition, heat release rate, burning rate or mass loss rate, effective heat of combustion, total heat release and concentration of carbon monoxide production have been measured. Moreover, the effect of paint has also been investigated as a fire retardant for the safety of furniture. The results show that treating wood with fire retardant materials affects the flaming behavior and significantly reduces the heat release rate and other ignition parameters during a period of 360 seconds. The average value of heat release rate for Beech types is 142.71 kW/m2. The reduction in heat release rate reaches a value of 18.43% for Pine wood types.

Assessing the suitability of recovering shrub biowaste involved in wildland fires in the South of Europe through torrefaction mobile units

Several types of shrubs and oak inducing high wildland fire risk in the South of Europe were evaluated for their potential valorization through torrefaction. Biomasses were firstly characterized in terms of macromolecular and elemental composition. Lab-scale TGA-GC/MS torrefaction experiments allowed the in-depth study of the solid mass transformation and the production profile of 23 volatile species (200 to 300 °C at 3 °C·min−1 and 300 °C for 30 min). The proportion of the torrefied products (solid, CO, CO2, water and volatile species) was evaluated through mass balance in a lab-scale furnace under typical torrefaction conditions (300 °C, 40 min). The results show a similar characterization and behavior in torrefaction for oak and shrublands, and slightly different characteristics for fern. However, fern may grow separately from shrublands and is considered to present a low fire risk. This suggests that the in-situ direct valorization of these biomasses through torrefaction mobile units seems promising. However, other properties, such as density, flowability and grindability need to be studied to confirm the feasibility of the process. Regarding torrefaction products, a higher carbon content and an interesting increase in heating value were measured for the torrefied solid, which makes it suitable for energetic valorization, among other uses. The composition of permanent gases was evaluated and found in agreement with previous studies. Finally, the volatile species released were studied in function of the torrefaction temperature, in view of their possible valorization as green chemicals.

Assessment of Phenolic Content, Antioxidant Activity, Colour and Sensory Attributes of Wood Aged “Tsipouro”

This study aimed at investigating the benefits of immersing oak sticks in the Greek pomace brandy named tsipouro, regarding its total phenolic content, antiradical-antioxidant activity, colour parameters and sensory profile. In order to induce rapid aging of tsipouro, alternative experimental conditions were applied. Results revealed that the phenolic migration from the wood to the tsipouro significantly increased both with temperature increase during aging as well as with the oak sticks /tsipouro ratio (w/v). The impact of oak wood diversity was also tested, by selecting different types of French oak (Quercus robur) and French and American oak mix (Quercus robur- Quercus alba) sticks. Results exhibited a significant effect of wood stick type on total phenolic content, antioxidant and antiradical activity, colour values and sensory attributes, especially on overall acceptance. High positive correlation among total phenolic content, antiradical and antioxidant activity and overall acceptance was found for all the extracts studied. Wood aging promoted the migration of phenolic compounds from the wood into the tsipouro, which, apart from the organoleptic characteristics, could possess health beneficial effects.

Control of mercury and methylmercury in contaminated sediments using biochars: A long-term microcosm study

The effectiveness of activated carbon and four types of biochar, switchgrass (300 °C and 600 °C), poultry manure (600 °C), and oak (∼700 °C) with respect to mercury (Hg) and methylmercury (MeHg) control was assessed in microcosm experiments carried out for 524 d. Early in the study (<30 d), minimal differences in concentrations of <0.45-μm filtered total Hg (THg) in control and 5% biochar-amended systems were observed. At later stages, THg concentrations in the amended systems decreased to 8–80% of concentrations in the sediment controls. Aqueous concentrations of MeHg were generally lower in the amended systems than in the controls, with an initial peak in MeHg concentration corresponding to the onset of iron and sulfate reduction (∼40 d) and a second peak to methanogenic conditions (∼400 d). Pyrosequencing analyses indicate the microbial communities initially associated with fermenters and later shifted to iron-reducing bacteria (FeRB), sulfate-reducing bacteria (SRB), and methanogens. These analyses also indicate the existence of 12 organisms associated with Hg methylation in all systems. Community shifts were correlated with changes in the concentrations of carbon sources (dissolved organic carbon (DOC) and organic acids) and electron acceptors (NO3−, Fe, and SO42−). Co-blending of biochars with Hg-contaminated sediment can be an alternative remediation method for controlling the release of Hg and MeHg, but the potential for Hg methylation under some conditions requires consideration.

Studies of Phenological Forms of Pedunculate Oak

We review the specificity of early and late phenological types of pedunculate oak differing in the spring flushing of leaves, namely, its occurrence in topographical elements, soil conditions and hydrology, responses to weather, and vulnerability to unfavorable factors. We show that phenological forms differ in a set of morphological and physiological indicators, growth energy, and peculiarities of the wood. We focus on the importance of the phenological specificity of planting materials when organizing oak plantations with regard to ongoing climatic changes and the ubiquitous decline of oak forests. The late form of oak is more preferable in most cases, because it is more resistant to spring frosts and insect damage, as well as the fact that it has higher quality wood in solid-volume trunks.

Habitat connectivity affects specialist species richness more than generalists in veteran trees

Intensified human land use continues to increase habitat loss and fragmentation, and leads to a homogenization of biodiversity. Specialized species with narrow niches seem to be declining more rapidly than generalist species. Veteran trees offer an excellent model system for testing the responses of habitat specialists vs. generalists in a changing environment, as they host a rich fauna of associated insects, with different degrees of strict habitat affinity.In this study, we use an extensive dataset of more than 22 000 wood-living beetles collected from 62 veteran oaks across Southern Norway, combined with a full-cover map predicting the occurrence of similar oaks in the surrounding landscape. We calculate three different connectivity measures, at eight different scales up to 25kmradius, and compare the response to patch size and patch connectivity for the specialist beetles in the veteran oak community, with that of the remaining beetle species in the community. We investigate these responses in oaks in two different surroundings; forests and parks. Our overall aim is to test whether habitat specialists and generalists respond differently to habitat patch connectivity, and if so, if differences in species traits or close surroundings can explain the response.We found that the specialists showed a positive response to habitat amount on a small scale (0.5km), and this effect of small-scale connectivity was the only common factor explaining a high species richness of specialists in all models, independent of park or forest surroundings. For generalists, there was no or only a weak response to connectivity, and only at the largest scale (25km) tested.The differences in response to habitat connectivity between specialists and generalists in veteran oaks can partly be explained by differences in traits, as the specialists were found to have larger body sizes, and feed on larger and more decayed dead wood material. These are all traits that have been related to increased sensitivity to forest fragmentation in earlier studies. The size and vitality of the oak, as well as the openness around it, also influenced the species richness, with different patterns between specialists and generalists and between the two types of oak surroundings.We conclude that increasing biotic homogenization is likely to take place with further fragmentation and loss of veteran trees, and specialist species will be the major group affected.

Rapid Induction of Ageing Character in Brandy Products – Part III. Influence of Toasting

As part of a broader study that investigated techniques for the rapid induction of the needed ageing character in brandy products, the effect of oak wood toasting on quality and chemical composition of oak wood extracts and matured and unmatured pot-still brandy, is reported on. Extracts, prepared from oak chips supplied by a South African cooper, and from commercially obtained oak, and representing different oak types and levels of toasting (i.e. untoasted, light, medium and heavy), were added to 70% (v/v) unmatured pot-still brandy and stored for eight months in glass containers (Schott bottles) at room temperature, or in the case of controls, below 0°C. Matured and unmatured (control) pot-still brandy samples were analysed for wood-derived congeners by means of HPLC and GC. Toasted, as opposed to untoasted oak, gave acceptable extracts, the best overall quality pot-still brandies and generally higher concentrations of volatile (GC-determined) and less volatile (HPLC-determined) wood-derived congeners. Toasting provoked an important separation as indicated by discriminant analysis.

Rapid Induction of Ageing Character in Brandy Products. Ageing and General Overview

Ageing is one of the most important and most costly factors determining the quality of distilled beverages. As part of a broader study that investigated techniques for the rapid induction of a desirable ageing character in brandy products, the effect of maturation for eight months at room temperature and below 0°C in glass bottles, and the relationship/correlation between treatment, chemical composition or wood-derived congener concentrations and pot-still brandy sensory quality, are reported on. Extracts representing different oak types (American or French), levels of toasting, suppliers (i.e. cooper or commercial), types of medium (ethanol or water), concentration types (open or reduced pressure) and concentration levels (by 45, 65 or 85%) were added to pot-still spirit and stored for eight months in glass containers. Matured and unmatured (control) pot-still brandy samples were analysed for wood-derived compounds by means of HPLC and GC. The different treatments brought about chemical changes with a noticeable impact on the acceptability of oak extracts and the overall quality of pot-still brandies. Through application and selection of the correct oak type and treatment combinations, it therefore was possible to rapidly produce good quality brandies without the use of expensive oak barrels. Maturation in glass bottles had a lesser impact on further improvement of the final product, not the same as the reported improvement from ageing in wooden barrels. The production of good quality brandies and the rapid induction of the ageing character through certain treatment combinations, with little need for further maturation, therefore was achieved in glass. The complexity of brandies aged in glass rather than wooden barrels might be different, since ageing in wooden barrels brings about all the characteristics, complexities and flavours that characteristically evolve over time under the more oxidative conditions in wooden barrels. Future research should focus on a combination of both technologies, using certain oak treatment combinations together with traditional barrel maturation for the improvement and rapid induction of the ageing character in brandy products.

Wild Boar Impact to the Natural Regeneration of Oak and Acorn Importance in its Diet

In this study, the impact of wild boar on the natural regeneration of oak and importance of acorns in the wild boar diet were surveyed. The data were collected near Moravian Krumlov (Czech Republic) in three types of oak stands differing in the canopy density: fully-stocked stand (1), open-canopy stand (2) and the forest stand in a conversion to the coppice forest (3). Within each stand 150 m long lines were set out. Seed traps to collect acorn harvest and control plots were installed on these lines. The plots were inspected at weekly intervals. After the end of acorn fall the average amount of fallen acorns was evaluated. The quantity of metabolizable energy in acorns was assessed and daily survival dose of energy for average weight of wild boar was counted. In spring 2014 the number of seedlings was counted at the same plots. Production of acorns per hectare and basic energy needs for one individual wild boar per day were evaluated for each chosen stand type. The found seedling density amounted to 29,600, 32,000 and 14,000 ind./ha in the first, second and third stand under study, respectively. Wild boar is a major consumer of acorns. In the studied area the production of acorns sufficiently supplied the local wild boar population during winter. Necessary amount of acorns remained for the natural regeneration.

Honey shows potent inhibitory activity against the bovine testes hyaluronidase

The purpose of this study was to investigate the anti-hyaluronidase activities of honeys from different botanical origins honeys in order to determine their anti-inflammatory properties. The total phenolic contents, total flavonoids and total tannin levels of six types of honey, chestnut, oak, heather, pine, buckwheat and mixed blossom, were determined. Concentration-related inhibition values were tested turbidimetrically on bovine testis hyaluronidase (BTHase) as IC50 (mg/mL). All honeys exhibited various concentration-dependent degrees of inhibition against BTHase. Inhibition values varied significantly depending on honeys’ levels of phenolic contents, flavonoid and tannin. The honeys with the highest anti-hyaluronidase activity were oak, chestnut and heather. In conclusion, polyphenol-rich honeys have high anti-hyaluronidase activity, and these honeys have high protective and complementary potential against hyaluronidase-induced anti-inflammatory failures.

Unravelling spatiotemporal tree-ring signals in Mediterranean oaks: a variance-covariance modelling approach of carbon and oxygen isotope ratios.

Identifying how physiological responses are structured across environmental gradients is critical to understanding in what manner ecological factors determine tree performance. Here, we investigated the spatiotemporal patterns of signal strength of carbon isotope discrimination (Δ(13)C) and oxygen isotope composition (δ(18)O) for three deciduous oaks (Quercus faginea (Lam.), Q. humilis Mill. and Q. petraea (Matt.) Liebl.) and one evergreen oak (Q. ilex L.) co-occurring in Mediterranean forests along an aridity gradient. We hypothesized that contrasting strategies in response to drought would lead to differential climate sensitivities between functional groups. Such differential sensitivities could result in a contrasting imprint on stable isotopes, depending on whether the spatial or temporal organization of tree-ring signals was analysed. To test these hypotheses, we proposed a mixed modelling framework to group isotopic records into potentially homogeneous subsets according to taxonomic or geographical criteria. To this end, carbon and oxygen isotopes were modelled through different variance-covariance structures for the variability among years (at the temporal level) or sites (at the spatial level). Signal-strength parameters were estimated from the outcome of selected models. We found striking differences between deciduous and evergreen oaks in the organization of their temporal and spatial signals. Therefore, the relationships with climate were examined independently for each functional group. While Q. ilex exhibited a large spatial dependence of isotopic signals on the temperature regime, deciduous oaks showed a greater dependence on precipitation, confirming their higher susceptibility to drought. Such contrasting responses to drought among oak types were also observed at the temporal level (interannual variability), with stronger associations with growing-season water availability in deciduous oaks. Thus, our results indicate that Mediterranean deciduous and evergreen oaks constitute two clearly differentiated functional groups in terms of their carbon and water economies, despite co-existing in a wide range of environments. In contrast, deciduous oaks form a rather homogeneous group in terms of climate sensitivity.

Criteria to discriminate between wines aged in oak barrels and macerated with oak fragments

Wine aging in barrels is carried out to increase stability and achieve more complex aromas. In the last few years, however, the practice of macerating wine with small fragments of toasted oak (chips) has become increasingly common. This conveys similar tastes, aromas, and wooden notes to the wine as those obtained with traditional barrel aging, but much faster and at a fraction of the cost. Without proper regulation, this could lead to fraud if wine macerated with chips is offered as barrel aged wine.In the present study, 75 volatile compounds have been determined by applying gas chromatography–mass spectrometry (MS) and flame ionization detection (FID). It has been found that compounds directly related to the wood have greater discriminative power for telling apart wines aged in barrels from those macerated with oak fragments, but no single compound permits flawless classification. Therefore, we have studied the effect of the addition of oak fragments of different origins, different oak types, different formats and subjected to different toasting processes on a set of 231 samples from 6 Spanish Denominations of Origin wines (DOs), and compared them to those same wines aged in oak barrels. In light of the results, we have developed a set of criteria which allows distinguishing with high degree of accuracy between wines which have been aged in barrels and those macerated with oak fragments. The application of these criteria to different wines allows correct classification in over 90% of cases.

Controlled studies on aerosol formation during biomass pyrolysis in a flat flame reactor

A methane–air flat flame reactor was designed to study the initial stages of combustion through flash pyrolysis of biomass and factors contributing to particulate emissions were examined. Six different types of biomass, Prosopis juliflora, cotton stalk, poplar, applewood, oak, and cherry wood were pyrolysed in a methane–air flat flame at various moisture contents. Particulate matter formed was characterized through measuring mass, and particle number size distributions. The moisture content of biomass feed stock was varied from 0% to 20%, while the particle feed sizes were maintained at 105μm or below, to limit heat transfer effects in the particle. Thermo-gravimetric analysis was also conducted on the biomass to obtain mass fraction data (% volatiles, moisture content) along with kinetic data. Results indicated that the presence of moisture causes a delay in devolatilization thus decreasing the overall efficiency in combustion. The results from this study can be used to optimize biomass combustion for use as fuel in household settings to minimize negative impacts due to poor air quality.