Quercus Castaneifolia Research Articles

Soil fauna communities and microbial activities response to litter and soil properties under degraded and restored forests of Hyrcania

Reforestation has long been the best practice to restore degraded forests due to human interventions. In this paper we investigated the effect of forest degradation (DNF) along with reforestation using 4 endemic species (Alnus subcordata, ASP; Acer velutinum, AVP; Cupressus sempervirens, CSP; Quercus castaneifolia Mey, QCP) on forest’s soil chemical and biological indicators compared to a close-to-virgin natural forest (VNF). For this study, a total of 24 physico-chemical and 25 biological and microbial indicators were measured in soils of all 6 forest stands along with the litter properties. Results showed that the lowest soil quality was observed under DNF, CSP, and QCP which was the result of forest cover degradation in DNF and low litter quality, especially low pH and high C:N, in CSP and QCP. Soil fauna communities were significantly affected by tree species. We found two times higher density of earthworms in VNF compared to ASP, but in DNF the density was 5 times lower than VNF. We found no epigeic earthworms in QCP, CSP and DNF and no endogeic earthworms in DNF. Acarina and Collembola density was high in VNF and ASP, but they showed significant differences (VNF>ASP), and their density sharply decreased in other stands, especially in CSP (3 times lower than VNF) and DNF (8 to 10 times lower than VNF). Nematode density was statistically equal in VNF, ASP, and AVP, but significantly lower in other stands. Protozoa, bacteria and fungi densities were significantly higher in VNF and ASP (VNF>ASP) compared to each other and other forest stands. Basal respiration, substrate induced respiration, microbial biomass N and P, and carbon availability index was also higher in VNF and ASP compared to other stands. Although VNF has the best condition because of old forest cover and high diversity, ASP soil showed significant improvements, demonstrating the importance of litter quality in soil restoration. Restoration effectiveness ranking of the four tested species on soil improvement are therefore ASP>AVP>QCP>CSP. The significant improvement of soil quality under ASP compared to other reforestated stands, only after 3 decades, emphasizes the importance of tree species selection and litter quality on soil chemical and biological restoration.

Classification of plant communities in the Caspian Hyrcanian English yew (Taxus baccata L.) forests using environmental factors: testing the modified TWINSPAN method

The purpose of this research is to evaluate the quality of the modified and classical TWINSPAN classification based on the environmental factors to identify the plant communities of Taxus baccata L. forests of Golestan Province. Fifty 400-m2 plots were systematically selected along an elevation gradient in the Taxus baccata forests. In each plot, soil was sampled using a composite sample taken to a depth of 20 cm. All vascular species were recorded on each plot according to the Braun-Blanquet’s method. In total, 56 plant species belonging to 48 genera and 34 families were recorded in spring 2018. The comparison of the results of modified and classical TWINSPAN showed that the modified TWINSPAN did not change the classification logic, but introduced more flexibility in the hierarchy of the division. It was also found that the compliance rate of the results provided by the classical TWINSPAN method was lower than the modified method. Using modified TWINSPAN, Detrended correspondence analysis (DCA), and Redundancy analysis (RDA), we determined four floristic groups in the Taxus baccata habitat. The first (Carpinus betulus) and second (Taxus baccata) groups were located at low altitudes and soil contents in silt and clay were higher than in the other groups. In contrast, the third (Quercus castaneifolia) and the fourth (Juniperus communis) groups were located next to each other at higher altitudes and southwestern aspects, on steeper slopes and soils exhibited a high pH and a high sand content. We found close relationships between the distribution of vegetation groups of Taxus baccata habitat with edaphic and physiographic factors using RDA method. To conclude, the modified TWINSPAN offers a more efficient and flexible method to identify vegetation communities. This is a first step to implement future management and ecological restoration measures in habitats of high ecological value such as yew forests.

Quantitative growth and Soil Characteristics of Pure and Mixed Stands of Quercus castaneifolia (in Sorkhdary Forest Management Plan in Golestan Province)

Quantitative growth and Soil Characteristics of Pure and Mixed Stands of Quercus castaneifolia (in Sorkhdary Forest Management Plan in Golestan Province)

Effects of plant species on soil quality in natural and planted areas of a forest park in northern Iran.

Reforestation may help protect the health of endangered forest ecosystems. To implement this action, it is important to evaluate the effects of the planted species on soil quality. Previous studies have demonstrated that soil properties are closely driven by the effects of plant roots and plant remains (quantity and quality) reaching the soil surface. However, little research is available about the effects of plant species on soil quality of reforested sites compared to natural forest ecosystems. This study evaluates the changes in the main soil properties between two 30-40year-old stand types in forest areas of northern Iran: i) two stands, each one comprising a natural species (Parrotia persica or Pinus taeda); and ii) two stands, each one with planted trees (Quercus castaneifolia or Alnus glutinosa). Compared to reforested sites, the soils with natural trees showed higher root weight density (+43%), pH (+17%), and organic carbon (+64%). These differences led to higher nutrient contents, microbial respiration, aggregate stability, and water retention in soils with natural trees, as confirmed by the correlation analysis. A principal component analysis provided a meaningful combined factor (the first principal component) that showed a clear discrimination in soil quality and fertility among natural and reforested species. The calculation of a soil quality index confirms that planted species may lead to an overall lower quality of soils with planted species compared to natural forest. Since the lower soil quality of planted forests can be also the result of unsuitable management practices, this study suggest that forest operations in reforested areas should be avoided, since this could lead to negative effects on soil quality and contribute to an increase in the risk of soil degradation.

The evaluation of soil detachment capacity induced by vegetal species based on the comparison between natural and planted forests

Planted forests and management operation method can potentially alter the soil properties as a consequence of changes in the characteristics of tree and plant species. However, the effects of planted forest species with different root systems on the soil detachment capacity (Dc) have not well been quantified. This study investigates the effects of plantation practice on the soil detachment capacity of soil with six vegetal species (Quercus castaneifolia, Alnus glutinosa, and Zelkova carpinifolia, as planted forest species) and Carpinus betulus, Parrotia persica, and Pinus taeda (as natural forest species) based on a comparison between natural and planted forests in forestland of the Saqalaksar Park (Northern Iran). To this aim, the soil detachment capacity on samples collected under trees of the studied species was measured in an experimental flume at five slopes (0.26, 0.35, 0.46, 0.57 and 0.69 m m−1) and flow rates (0.037, 0.086, 0.185, 0.285 and 0.376 L m−1 s−1). Moreover, simple prediction equations are suggested to evaluate the soil detachment capacity and rill erodibility (Kr) for studied species. The soils of natural forestland showed the lower soil detachment capacity compared to soils of the planted forestland, due to the different influence of plant root systems. Moreover, the inappropriate management practices in planted forestland could have worsened the soil properties and thus increased the soil detachment rate. The unit stream power was better predictor of Dc compared to other hydraulic parameters in both natural and planted forestlands. The rill erodibility of soils was higher in planted forestland than in natural forestland. According to the results, the natural forestland is able to show higher resistance against soil erosion in comparison with the planted forestland. These findings indicate that for sustainable management of forest ecosystems, the maintenance of natural vegetal species can be an effective practice to reduce the soil erosion.

Evaluating the effects of forest tree species on rill detachment capacity in a semi-arid environment

The beneficial effects of plant roots in decreasing soil detachment in forest ecosystems exposed to rill erosion are well known. However, these effects vary largely between different plant species. There has been lots of research into the relationship between root-soil systems and rill erodibility with a particular focus on grass species. Conversely, fewer studies are available for tree species, especially in forests of semi-arid or arid environments. Greater knowledge is therefore needed to identify the most effective tree species against rill erosion in these ecosystems, where water availability is the limiting factor for vegetation growth and afforestation is often the only solution to control erosion. To fill this gap, this study evaluates the rill detachment capacity of soils with four tree species (Parrotia persica, Carpinus betulus, Quercus castaneifolia, and Pinus taeda) in a semi-arid forest ecosystem in Northern Iran. These species are typical of these forests, but they also grow in other environmental contexts. The rill detachment was simulated in a laboratory flume at five slope gradients (1% to 5%) and five flow rates (0.22 to 0.69 L m−1 s−1) on soil samples with each of the tree species. The specific goal of the study was to evaluate which tree species with its specific root characteristics is most effective at reducing the rill detachment capacity. Moreover, simple prediction models are proposed to evaluate if it is possible to estimate the rill detachment capacity and rill erodibility (Kr) from the unit stream power for the investigated tree species. The soils with Parrotia persica and Carpinus betulus showed the lowest and the highest rill detachment capacity, respectively. The greater root system biomass of Parrotia persica could have played a binding effect on the soil, thus improving its aggregate stability thanks to the action of plant's root system. Based on these results, Parrotia persica is able to provide a higher soil protection capacity against erosion compared to the other tree species. A logarithmic function was accurate in predicting the rill detachment capacity from the unit stream power at water flow rates over 0.0025 m s−1. By a regression between the rill detachment capacity and the shear stress of the soil, rill erodibility and critical shear stress of soils were estimated for the four tree species; the rill erodibility and critical shear stress are important input parameters for physically-based erosion models. Overall, the results of this study can support land planners in the choice of tree species most indicated for soil conservation as well as in the extensive application of erosion prediction models.

Development of individual tree growth and yield model across multiple contrasting species using nonparametric and parametric methods in the Hyrcanian forests of northern Iran

The Hyrcanian forests of Iran contain many species-rich communities that can only be maintained through an understanding of the renewal and development of these forests. Located in the Jojadeh section of the Farim forest in northern Iran, individual tree growth of five distinct species [(Oriental beech (Fagus orientalis Lipsky), chestnut-leaved oak (Quercus castaneifolia Coss. ex J.Gay), Persian maple (Acer velutinum Boiss.), common hornbeam (Carpinus betulus L.) and Caucasian alder (Alnus subcordata C.A.Mey.)] were measured on 313 permanent sample plots (0.1 ha) over a 10-year period (2003–2013). In this analysis, various tree-level predictions were investigated using the available data with application of parametric models and two artificial neural networks [i.e., the multilayer perceptron (MLP) and radial basis function (RBF) networks]. Individual tree diameter growth models showed a robust negative relationship with basal area in larger trees, which was relatively consistent across species. A total height model indicated that the examined species did not differ for a given set of covariates. In the survival model, the survival probability of Oriental beech was lower than the other species, while the ingrowth model revealed sapling density of all species increased with greater basal area. The artificial neural network based on the MLP was superior for all models and predicted more accurately than the RBF. Furthermore, the models based on the MLP were also superior to the parametric individual tree models developed using mixed-effect regression. The use of these developed models in forest planning and management is imperative, particularly for uneven-aged stands, but assessment of long-term projection behavior across the contrasting statistical approaches used is warranted despite the general superiority of the nonparametric models.

Effects of Four Afforestation Stands on Some Physical, Chemical and Biological Properties of Soil in Northern Iran

Selected species for afforestation have different effects on soil quality in addition to differences in their growth. The aim of current study was to investigate the effects of afforestation with four tree species, including chestnut-leaved oak, loblolly pine, black alder and Persian maple on the soil properties in the northwest of Iran. For this purpose, eight sample plots of 400 m 2 were conducted in the study area and diameter and total height of the trees were measured. Then, eight soil samples were taken from a depth of 0 to 30 cm of each stand and transferred to the soil laboratory to be investigated some physical, chemical and biological properties of the soil. Hence, a total number of 16 different soil parameters of the four stands were measured and compared using ANOVA. Besides, the correlation between different soil properties and their relationship with tree species was analyzed, using principal components analysis (PCA). The results showed that among the studied stands, the loblolly pine had a higher mean diameter, mean height, basal area and volume. Regarding soil properties, alder stand possessed the highest porosity and the lowest bulk density. The pine stand, however, was estimated to possess the highest value of basal respiration, substrate induced respirations, microbial carbon biomass, organic carbon, total nitrogen, C/N ration, absorbable potassium and the lowest pH value. Finally, the maple stand possessed the highest amount of absorbable phosphorus. Based on the results of this study, pine species due to its high diameter growth and positive effects on most soil properties is recommended for afforestation in Hyrcanian region and similar habitats in west Asia.

Changes in soil chemistry and element uptake by Oak seedlings after application of soil amendment

ABSTRACT The purpose of this study is to investigate the effect of cellulosic wastes and nanoscale zero-valent iron (nZVI) on the soil properties and the nutrient uptake by Quercus castaneifolia C.A.Mey seedlings. The seedlings were planted in pots (unpolluted soil) and cadmium (Cd) was added to the pots in three concentrations (10, 20, 30 mg.kg−1). Cellulosic wastes were mixed with the soil (at the same time as the planting) in four levels (W: 0, 10, 20, 30 g.100g−1 soil). The reduction method was used to prepare nZVI, then the nanoparticles were injected into the polluted pots in four levels (N: 0, 1, 2, and 3 mg.kg−1). The lowest concentration of Cd in leaves, stems and roots and for all the contamination levels was observed in N3. All the cellulosic wastes and N3 significantly increased the soil pH at all the levels of contamination. An increasing trend of the soil carbon (C) content was observed by adding the cellulosic wastes. The highest pH and C content were observed in W3. The lowest bioavailable Cd contents for all the contamination levels was observed in N3. According to the results, nZVI and cellulosic wastes could help the plants establishing in heavy metal-polluted lands.

SEASONAL CHANGE OF CHLOROPHYLL CONTENT (SPAD VALUE) IN SOME TREE AND SHRUB SPECIES

Chlorophyll, which is of vital importance for living things, is the main active ingredient of photosynthesis, and the amount of chlorophyll in the plant can show very sensitive responses to various environmental factors, especially site conditions and plant species. In this study, it was aimed to determine the change of chlorophyll content (SPAD value) at the beginning (20 May) and the end (15 October) of growth period in some native and exotic tree and shrub species in Kanuni campus of Karadeniz Technical University and to reveal the differences between the species. Within the scope of the study, measurements were made on a total of 20 species including five native (Quercus hartwissiana Steven, Fagus orientalis Lipsky, Ulmus minör Mill., Liquidambar orientalis Mill., Quercus pubescens Willd.) and seven exotic (Eucalyptus camadulensis Dehnh., Ginkgo biloba L., Quercus castaneifolia C.A.Mey., Cinnamomum camphora (L.) Sieb., Acer negundo L., Quercus rubra L., Aesculus hippocastanum L.) tree species and seven native (Cercis siliquastrum L., Laurus nobilis L., Osmanthus decorus (Boiss.&Balansa) Kasapligil, Laurocerasus officinalis M.Roem., Ostrya carpinifolia Scop., Corylus avellana L., Arbutus unedo L.) and one exotic (Weigela coraensis Thunb.) shrub species. Chlorophyll content was determined with four replications by portable chlorophyll meter (Minolta SPAD-502, Osaka, Japan) which indirectly measures the amount of chlorophyll in the leaf. The data obtained were subjected to Wilcoxon test, variance analysis (one-way ANOVA) and Duncan’s test by using SPSS 23.0 statistical program. As a result of the study, it was determined that there are statistically significant differences (p

Antibacterial and fungicidal activities of ethanol extracts of 38 species of plants

Galenic preparations are broadly used against microorganisms pathogenic to humans, thought their poteintial in this aspect is not studied completely. In our in vitro experiment we studied the influence of alcohol tinctures from 38 species of plants on 15 species of bacteria and one species of fungus. Zones of growth inhibition of colonies measuring over 8 mm were observed during the use of ethanol extracts of Maclura pomifera against eight species of microorganisms (Escherichia сoli, Proteus mirabilis, Serratia marcescens, Yersinia enterocolitica, Salmonella typhimurium, Rhodococcus equi, Campylobacter jejuni and Corynebacterium xerosis), Ginkgo biloba – against eight species (Enterococcus faecalis, S. marcescens, Y. enterocolitica, Klebsiella pneumoniae, Listeria іnnocua, L. monocytogenes, Р. аeruginosa and C. jejuni), Genista tinctoria – against seven species (E. coli, Enterobacter aerogenes, Proteus mirabilis, K. pneumoniae, S. typhimurium, Р. аeruginosa and Rh. equi), Phellodendron amurense – against seven species (E. faecalis, S. marcescens, S. typhimurium, Rh. equi, C. jejunі, C. xerosis and Candida albicans), Berberis vulgaris – against seven species (P. mirabilis, S. marcescens, K. pneumoniae, S. typhimurium, C. jejuni, Р. аeruginosa and C. xerosis), Vitex negundo – against six species (E. faecalis, E. coli, P. mirabilis, K. pneumoniae, S. typhimurium and Rh. equi), Koelreuteria paniculata – against six species (E. faecalis, P. mirabilis, S. marcescens, S. typhimurium, C. jejunі and E. coli), Magnolia kobus – against six species (E. faecalis, E. coli, P. mirabilis, S. marcescens, S. typhimurium, C. jejunі and C. xerosis), Liriodendron tulipifera – against six species (K. pneumoniae, Listeria іnnocua, Р. аeruginosa, C. jejuni, Rh. equi and C. albicans), Clematis flammula – against six species (E. faecalis, P. mirabilis, L. monocytogenes, Р. аeruginosa, C. jejuni and C. xerosis), Wisteria sinensis – against five species (E. coli, S. typhimurium, L. monocytogenes, Rh. equi and C. albicans), Chimonanthus praecox – against five species (E. faecalis, S. marcescens, L. monocytogenes, C. jejuni and Rh. equi), Colchicum autumnale – against five species (S. marcescens, K. pneumoniae, L. ivanovi, L. monocytogenes and Р. аeruginosa). As a result of the study, these plants were found to be the most promising for further study of in vivo antibacterial activity. In the search of antibacterial and antifungal activities, the following plants were observed to be less promising: Ailanthus altissima, Aristolochia manshuriensis, Artemisia absinthium, Callicarpa bodinieri, Campsis radicans, Catalpa duclouxii, Celastrus scandens, Dictamnus alba, Eucommia ulmoides, Geranium sanguineum, Laburnum anagyroides, Nepeta racemosa, Parthenocissus tricuspidata, Polygonatum multiflorum, Prunus dulcis, P. laurocerasus, Ptelea trifoliata, Pteridium aquilinum, Quercus castaneifolia, Q. petraea iberica, Salvia officinalis, Securigera varia, Styphnolobium japonicum, Tamarix elongata and Vitex agnus-castus.

Quantitative assessment of forest ecosystem stress caused by cement plant pollution using in situ measurements and Sentinel-2 satellite data in a part of the UNESCO World Heritage Site

Anthropogenic industrial dust decreases productivity and slows down the growth of plants. Quantifying the effects of industrial dust on vegetation and determining the distance over which factories scatter dust are of paramount importance for biodiversity conservation and sustaining ecosystem services. This study aims at quantifying the effect of dust emitted by the Neka cement plant (NCP), Mazandaran province, northern Iran, on the surrounding Hyrcanian forests based on an analysis of the Leaf Area Index (LAI) retrieved from Sentinel-2 imagery. An Inductively Coupled Plasma Mass Spectrometer (ICP-MS) was used to quantify the concentrations of cadmium (Cd), chromium (Cr), copper (Cu), lead (Pb), calcium (Ca), magnesium (Mg), sodium (Na), silicon (Si) and zinc (Zn) in leaves of the dominant Chestnut-leaved Oak (Quercus castaneifolia). A feed-forward neural network algorithm and field measurements were used to retrieve the leaf area index (LAI) from Sentinel-2 data with a RMSE of 0.42 (m2/m2). MODIS-NDVI and EVI time series spanning 17 years (2000 to 2017) were analysed to ensure the independence of the variation in the condition of the vegetation from drought or other environmental factors. The results indicate that Sentinel-2 data can be used to map degradation due to pollution from the cement plant and quantify the effect of the dust spatially. Dust from the cement plant (dust source) was carried approximately 4700 meters in the direction of the prevailing wind. A significant correlation of 0.849 was recorded between LAI and distance from the NCP. It is concluded that dust from the NCP had adverse ecological effects on the neighbouring forest ecosystems recently designated a UNESCO World Heritage Site.

Leaf Phenology Drives Spatio-Temporal Patterns of Throughfall under a Single Quercus castaneifolia C.A.Mey.

Throughfall (TF) makes up the majority of understory rainfall and thereby plays an important role in controlling the amount of water reaching the forest floor. TF under a single Quercus castaneifolia (C.A.Mey, chestnut-leaved oak) tree in Northern Iran was measured during the leafed and leafless periods. TF quantity under the Q. castaneifolia canopy made up 69.3% and 88.0% of gross rainfall during leafed and leafless periods, respectively. Phenoseason influenced TF distribution patterns as TF temporal patterns during the leafed period were slightly more stable than during the leafless periods. The minimum number of TF collectors needed to yield a representative mean TF with accepted errors of 10% at 95% confidence level was twenty-six and twelve TF collectors for leafed and leafless periods, respectively. We conclude that phenoseasonality significantly affects TF spatiotemporal variability and presented the required number of collectors necessary for sampling TF under an individual Q. castaneifolia tree.

The Potential Effectiveness of Biochar Application to Reduce Soil Cd Bioavailability and Encourage Oak Seedling Growth

Today, it is very important to protect plants in soils contaminated with metals. We investigated the behavior of cadmium during the establishment of oak seedlings (Quercus castaneifolia C.A. Mey.) under biochar influence. This study was conducted in pots with loamy soil. Cadmium was added to soil at 0, 10, 30, and 50 mg per kg of soil, indicated by Control, Cd10, Cd30 and Cd50. Biochar was produced at 500–550 °C from rice husk and added at 1, 3, and 5% (wt/wt) levels, indicated by B1, B3, B5, and mixed with soil at planting in three replications. Generally, increasing biochar rates had significant effects on seedling height, diameter, and biomass. This coincided with Cd immobilization in the contaminated soil which reflects a decrease in Cd concentrations in the plant bioavailability of Cd. The tolerance index increased significantly, by 40.9%, 56%, and 60.6% in B1, B3, and B5 with Cd50, respectively, compared to polluted soil. The percent of Cd removal efficiency for Cd50 was 21%, 47%, and 67% in B1, B2, and B5, respectively. Our study highlights that biochar can reduce Cd bioavailability and improve the growth of oak seedlings in contaminated soil.

Effect of artificial inhomogeneity of density and drilling on dynamic properties developed by poplar block species (Populus nigra) jointed with oak wood (Quercus castaneifolia) beams

Inhomogeneities in wood and wood products are evident. Sometimes these inhomogeneities are combined with other inhomogeneities such as drilling. Each can have different effects on dynamic properties, and these footprints can cause hidden defects in wood and wood products. In this research, the effects of artificial inhomogeneity of density and drilling diameters (1 mm, 3 mm, 5 mm, and 10 mm) on dynamic properties of the beams produced from oak wood jointed with poplar blocks (one at the end and the other at the central part of the beam) were investigated. Free vibration on a free-free beam test was subjected for the evaluations. The results indicated that factors such as dynamic modulus of elasticity, acoustic coefficients, and damping capacity, were affected by both inhomogeneity and drillings. The acoustical converting efficiency showed the exact location of inhomogeneity. It also showed the level of drilling diameter.

Projection of Climate Change Impacts on Potential Distribution of Chestnut-leaved oak (Quercus castaneifolia C.A.M.) Using Ensemble Modeling in the Hyrcanian Forests of Iran

Projection of Climate Change Impacts on Potential Distribution of Chestnut-leaved oak (Quercus castaneifolia C.A.M.) Using Ensemble Modeling in the Hyrcanian Forests of Iran

Comparison of Quantitative, Qualitative and Soil of Chestnut-leaved Oak and Loblolly Pine plantations of Shen-Rood Watershed No: 25 of Guilan Province

Comparison of Quantitative, Qualitative and Soil of Chestnut-leaved Oak and Loblolly Pine plantations of Shen-Rood Watershed No: 25 of Guilan Province

Effects of dietary oak (Quercus castaneifolia) leaf extract on growth, antioxidant, and immune characteristics and responses to crowding stress in common carp (Cyprinus carpio)

The aim of the present study was to assess the effects of dietary oak (Quercus castaneifolia) leaf extract supplementation on growth performance, antioxidant, immune and stress responses in common carp (Cyprinus carpio). Ethanolic extract of the oak leaf were prepared and tested for in vitro radical scavenging and antibacterial properties. The results showed that the extract has radical scavenging property below that of butylated hydroxytoluene (BHT) at 12.5–75 μg mL−1, but there was no significant difference between the two materials at 100 and 200 μg mL−1. Moreover, the extract had bactericidal effects against Aeromonas hydrophila, which was near 5-fold lower than tetracycline. Then, the extract was added to the fish diet at 0 (CTL), 0.5 (0.5E), 1 (1E) and 2 (2E) g kg−1 diet. The fish were fed with aforementioned diets for 60 days before subjecting to a 6-h crowding stress. The results showed that the extract had no significant effects on the fish growth performance (P > .05). Dietary extract supplementation (1E and 2E) significantly increased plasma superoxide dismutase (P = .003), catalase (P = .015), glutathione peroxidase (P < .001), reduced glutathione (P < .001), lysozyme (P < .001), complement (P = .001), and bactericidal activity (P = .020) and decreased malondialdehyde (P < .001) levels. Dietary oak leaf extract supplementation had no significant effects on basal cortisol and glucose levels, but significantly (P < .001) mitigated post-stress levels of these parameters, compared to the CTL fish. In conclusion, oak leaf extract stimulates antioxidant and immune system of common carp, without affecting the fish growth performance. Moreover, the extract was partially beneficial to reduce stress in the fish. Dietary levels of 1–2 g kg−1 oak leaf extract are recommended for common carp feed formulation.

Impact of forest degradation and reforestation with Alnus and Quercus species on soil quality and function in northern Iran

Abstract Forest degradation causes soil carbon losses and affects soil C and N cycling. However, it is not clear how reforestation of degraded areas with different species affects soil and ecosystem restoration, particularly in northern Iran. The aim of this study was to evaluate the effect of forest degradation and reforestation with two contrasting species: Alnus and Quercus as N2-fixing and non N2-fixing tree species, respectively, on soil quality and function after 30 years in the northern Iran region. We selected four forest stands: Carpinus betulus-Parrotia persica natural forest (NF), Alnus subcordata (AP) and Quercus castaneifolia (QP) plantations as rehabilitated areas, and a degraded natural forest (DNF). We examined the main litter and soil chemical properties and soil C and N microbial fractions. Litter and soil physico-chemical properties and microbial activity differed among land covers. As expected, deforestation caused a decrease in most soil C and N fractions as well as in soil microbial activity with an increase in metabolic quotient-qCO2. The plantation with Quercus spp. improved substrate induced respiration, as well as microbial biomass carbon and dissolved organic carbon compared to the Alnus plantation, whereas mineral N was similar in the natural site and the Alnus plantation. Although forest plantations had not reached the same values of microbial activity as the natural forest soils, soil C and N fractions were similar to the natural site after 30 years. The findings of this study support the importance of preserving natural forests for soil conservation. In addition, employing of N2 fixing trees such as Alnus spp. or, Quercus spp., suitable native broadleaved species, is proposed for the rehabilitation of degraded natural forests. Although both forest plantations led to soil recovery after 30 years, Quercus plantations were more efficient in restoring microbial communities than Alnus plantations indicating that litter quantity is more important than litter quality for soil recovery.

Исследование параметров флуоресценции хлорофилла и флуктуирующей асимметрии листьев древесного растения – Quercus castanefolia С. А. Меу. в условиях города Баку, Азербайджан

Исследование параметров флуоресценции хлорофилла и флуктуирующей асимметрии листьев древесного растения – Quercus castanefolia С. А. Меу. в условиях города Баку, Азербайджан