Persian Oak Research Articles

Analysis of Persian Oak (Quercus Brantii Lindl)’s Spectral- Temporal Behaviour Under the Stresses of Water Deficiency and Dust Particles

Persian oak (Quercus Brantii Lindl) is the most abundant tree species in Zagros mountain range that is affected by western dust storms and harsh droughts in recent years. The lack of spectral-temporal information about these trees has caused limitations on the usage of remote sensing images to make a synoptic estimation of damages caused by dust storms and drought. The objective of this research is to analyse the spectral-temporal behaviour of Persian oak under the stress of water deficiency and dust storms. The aim is to improve the competitive abilities of experts on modelling the stress of water deficiency and dust storms on trees using remote sensing images. For the purpose of this experimental investigation, a greenhouse laboratory has been built. Analysis of the experiments was carried out using 54 two-year-old oak tree seedlings; Fieldspec-3-ADD; and wind tunnel at the greenhouse of the faculty of agriculture of the Tarbiat Modares University in 2016. Results show that the water stress could be modelled much better using geometrical indices extracted from continuum removed spectrum. Area and the depth were best indices. Water stress has been modelled better that dust stress.

Endophytic fungi isolated from healthy and declining Persian oak (Quercus brantii) in western Iran

Endophytic fungi isolated from healthy and declining Persian oak (Quercus brantii) in western Iran

Association analysis of tolerance to dieback phenomena and trunk form using ISSR markers in Quercus brantii

Oak decline is a complex syndrome in which several damaging agents interact and bring about a serious dieback in tree condition. Genetic diversity is a key factor for better adoption of natural populations to environmental stresses. The objective of this research was to identify the association of polymorphism patterns of different reproducible genomic Inter simple sequence repeats (ISSR markers) to level of dieback phenomena and also growth type in 18 different stands of Persian oak in central Zagros region. Totally, 180 trees were sampled and evaluated for growth type, tree diameter at breast height (DBH) and level of tree dieback. Genomic DNAs extracted of fresh leaves amplified using 15 multi-locus ISSR primers. The population structure determined using the Bayesian model-based clustering method implemented in STRUCTURE software by Monte Carlo Markov Chain (MCMC) method. Five distinct sub-populations (K=5) determined by the log likelihood of the data. Genome wide association study (GWAS) performed using the generalized linear model (GLM) and the mixed linear model (MLM) with Kinship matrix. Informative alleles recognized for level of tolerance to dieback and tree growth type traits. It was observed a significant co-segregation for phenotypic data and some of amplified fragments. Identification of these informative DNA markers can be utilized for pre-screening of high quality oak seedlings in early growth stages and better management in restoration of damaged stands.

Modelling climate change effects on Zagros forests in Iran using individual and ensemble forecasting approaches

It is believed that climate change will cause the extinction of many species in the near future. In this study, we assessed the impact of climate change on the climatic suitability of the Persian oak in Zagros forests in southwest Iran, by simulating their conditions under four climate change scenarios in the 2030s, 2050s, 2070s, and 2080s. Additionally, we evaluated the predictive performance of different modelling algorithms by projecting the geographic distribution of Persian oak, using a block cross-validation technique. According to the results, the Persian oak shows a stronger response to temperature, particularly the maximum temperature of the warmest month, rather than precipitation variables. This indicates that temperature has a powerful control over the geographic distribution of the Persian oak. Based on a comparison of the Persian oak’s current climatic suitability and future projections, regardless of the chosen climatic scenarios, there will be an upward shift in its climatic suitability. However, an upward shift under the pessimistic scenarios was greater than the optimistic ones. The results also indicate that an ensemble of all models had a higher accuracy than single models. Despite the agreement between current climate condition predictions (mean correlation of 0.94), the projection of different algorithms for future periods is highly variable (mean correlation of 0.71). Thus, the ensemble approach was used to reduce the uncertainty of modelling, favouring the consensus of all models for future projection.

Linking morphological and ecophysiological leaf traits to canopy dieback in Persian oak trees from central Zagros

Intraspecific variability in morphological and ecophysiological leaf traits might be theorized to be present in declining populations, since they seem to be exposed to stress and plasticity could be advantageous. Here we focused on declining Persian oaks (Quercus brantii Lindl. var. persica (Jaub and Spach) Zohary) in the Zagros Mountains of western Iran, representing the most important tree species of this region. We selected trees with contrasting crown dieback, from healthy to severely defoliated, to investigate the relationships between canopy dieback and leaf morphology, water content and pigments. We also measured esterase and peroxidase, as enzymatic antioxidants and indicators of contrasting genotypes. Trees showing moderate to severe defoliation showed higher leaf mass area (LMA), reduced relative water content (RWC), and lower stomatal density (SD). Increasing LMA indicates a more sclerophyllic structure, according to drier conditions. We did not find significant differences in leaf pigments (chlorophyll a and b, and carotenoids) among crown dieback classes, suggesting that Persian oak trees are able to maintain accurate photochemical efficiency, while reduced RWC and SD suggest hydraulic limitations. Our results do not provide a consistent pattern as regards enzymatic antioxidant defense in Persian oak. Morphological leaf traits would be important drivers of future adaptive evolution in Persian oak, leading to smaller and thicker leaves, which have fitness benefits in dry environments. Nonetheless, drought responses may be critically affecting carbon uptake, as photosynthetic compounds are less effectively used in leaves with higher sclerophylly.

The role of charcoal disease and wood borers on Quercus brantii Lindl. decline under different physiographical conditions

Oak decline is an expression describing death and drying up of oak trees. The present research evaluated the relationship between various geographical directions and altitude and some factors predisposing Persian oak (Quercus brantii Lindl.) decline, such as charcoal disease and oak wood boring insects in a 100 hectares area of the Shurabad forests in Lorestan Province of Iran. A 200 by 200 m sampling network was first designed on a regular-random (systematic) basis, and the trees were sampled from 1500-m2 circular plots. Information including hillside direction, altitude, infection site (on tree crown or on trunk), type of infection (charcoal disease or wood borers), crown vigor, and heights of the infection sites on the trees was recorded in each sample plot. Results indicated the significant relationships of infection type and severity with altitude, geographical direction, slope, and location of the sample plot at the significance level of 5%. Wood borers were the most common cause of infection. There was very little attack by charcoal disease in the study area. Most diseased trees were in the valley, in a northerly direction, at the 1101–1150 m elevation class and the 41–50% slope class. There were very few healthy trees in the study area, and most of them were on the ridges, in a southwesterly direction, at the 1151–1200 m altitude class and the 11–20% slope class.

Preparation and Evaluation of a Herbal Mouthwash Containing Oak Husk of Quercus brantii and Zataria multiflora

Background: Considering increasing antibiotic resistance and periodontal diseases incidence, the need of a safe, effective, and economical alternative mouthwash seems necessary. Combination of Persian oak husk of Quercus brantii (Jaft) with astringent and antibacterial properties of its tannins and Zataria multiflora leaves with anti-bacterial activity related to its essential oil seems to be more effective. Objectives: The aim of the present study was to prepare and evaluate a herbal mouthwash formulation containing the extract of Oak husk and essential oil of Zataria multiflora. Methods: The essential oil of Zataria multiflora leaves was obtained by hydro-distillation. Oak husk powder of Quercus brantii was extracted by infusion and then the extract was freeze-dried. Determination of tannin amount in the extract was performed by the Folin-Denis method. The essential oil analysis was performed by GC/MS. Formulations were prepared at five different concentrations of tannin (0.1%, 0.2%, 0.5%, 1%, and 2%) with 0.15% v/v of essential oil in the base of polyethylene glycol 400 and propylene glycol. The selected formulations were subjected to screening against Candida albicans, Lactobacillus acidophilus, Staphylococcus aureus, and Streptococcus mutans, using standard protocol of cell viability in comparison to the Persica mouthwash. Stability tests, such as tannin assay and pH, were done on days zero and forty-five after preparation of the formulations. Results and Conclusions: The best formulations with 0.2% and 0.5% of tannin, which were more stable and showed significantly more antibacterial effects than Persica mouthwash may be safe and effective for future clinical studies.

Change in biochemical parameters of Persian oak (Quercus brantii Lindl.) seedlings inoculated by pathogens of charcoal disease under water deficit conditions

Drought alone or in combination with charcoal disease pathogens led to modifications in some biochemical characteristics of Persian oak seedlings. Drought conditions enhances the effects of charcoal fungus with effects at biochemical level. Charcoal disease is one of the common diseases in oak forest of Zagros in western Iran that has increased in the recent years. The disease is associated with abiotic stress, especially drought, and contributes to the decline of Persian oak (Quercus brantii Lindl.), the major oak species in this forest association. Persian oak seedlings were exposed to a factorial combination of two irrigation levels and inoculation with either Biscogniauxia mediterranea or Obolarina persica (agents of charcoal disease). Proline, total soluble sugar and soluble protein contents in seedling foliage were increased in response to charcoal pathogen inoculation, especially when combined with water stress, while starch, chlorophyll a + b and carotenoid contents strongly declined. Pathogen inoculation stimulated malondialdehyde content, electrolyte leakage, and hydrogen peroxide and superoxide radical contents in oak leaves, and were increased by water stress. The combination of charcoal disease agents and water stress increased peroxidase and superoxide dismutase activity while, for catalase and ascorbate peroxidase activities, the interaction between the two factors of variability was not significantly increased. Ascorbate peroxidase activity was at maximum level in seedlings infected with O. persica independently of water stress. Glutathione reductase had the highest activity in inoculated seedlings under soil moisture stress while those under higher soil moisture levels, the enzyme was increased only when inoculated with O. persica. Contents of non-enzymatic antioxidants including ascorbic acid and glutathione increased in response to combined pathogen inoculation and water stress and was higher when seedlings were inoculated with O. persica than with B. mediterranea. Chitinase activity significantly increased because of pathogen inoculation. Furthermore, foliar phenylalanine ammonia lyase activity was higher under all treatment combinations, as compared to the controls. The effects of B. mediterranea or O. persica pathogens on foliar biochemical responses of Q. brantii seedlings were more severe under water-stress and it was more sensitive to B. mediterranea than O. persica.

First Report of Leaf Spot Caused byTruncatella angustataon Persian Oak (Quercus brantii) in Iran

First Report of Leaf Spot Caused by<i>Truncatella angustata</i>on Persian Oak (<i>Quercus brantii</i>) in Iran

Effect of drought stress on some growth, morphological, physiological, and biochemical parameters of two different populations of Quercus brantii

Abstract: In recent years, drought-induced tree mortality has occurred in the oak forests of the Zagros Mountains (western Iran). The impacts of climate change induced by drought stress have been most acutely experienced by two populations of Persian oaks (Quercus brantii Lindl) grown in the western provinces (Ilam and Lorestan) of the Zagros region. We surveyed growth, physiological, and biochemical responses of one-year-old Persian oak seedlings from Melasyah (Ilam) and Chegeni (Lorestan) provenances, which were subjected to three watering regimes (100%, 40%, and 20% of field capacity) in a greenhouse. The severe drought stress decreased the diameter and height growth, total biomass, net photosynthesis, gas exchange, xylem water potential, maximum Rubisco activity (Vcmax) as well as the maximum PSII photochemical efficiency of the oak seedlings in both populations, but the rate of decrease was greater in Chegeni seedlings as compared to Melasyah seedlings. Although proline and soluble sugar contents significantly increased in response to drought in both populations under stress, the rate of increase was higher in Melasyah seedlings as compared to Chegeni seedlings. In addition, the activities of peroxidase, superoxide dismutase, catalase, and ascorbic peroxidase as well as that of phenylalanine ammonia lyase were promoted in both populations under drought stress. However, the incremental rate was higher in the Melasyah population than in the Chegeni population. Under severe drought stress, the MDA content, electrolyte leakage, the content of hydrogen peroxide, and superoxide radical significantly increased in both the populations. The rate of increase, however, was higher in the Chegeni population. Under drought stress, the total phenol and flavonoid contents of Melasyah seedlings were higher than those of Chegeni seedlings. The results showed that Chegeni seedlings are more sensitive than Melasyah seedlings when exposed to a water limitation stress. Our findings suggest that the climate conditions of the Persian oak stands should be considered by nursery managers while creating establishment and restoration programs.

Monitoring the decline of Persian oak in Iran using remote sensing – Case study of Basht forest

Oak forest decline is a complex problem that it has started for a long time ago in the world. This problem is widelyspread because of lacking of efficient and reliable facilitiesfor monitoring these forests. In this research, the pattern of spatial-temporal distribution and decline of Iranian Oak stands in the Bashtforest wasmonitored using remote sensing. The area of study is located in the provinces of Kohgilouyeh and Boyer Ahmad in Iran. After selecting the study area,forest visitswere carried out and samples of dead trees were collected. Based ontheoak crown declineattack, the forest wasdivided into four categories: low (crown dieback 20-0 percent), medium (between 40-20% of crown dieback), high (between 60-40%) and severe (more than 60% crown dieback). The geographical locations of the harvested trees wererecorded using global positioning system (GPS). In order to determine the most appropriate vegetation index, root mean square error (RMSE) for 12 vegetation indiceswere calculated from Landsat 8 images. The results of this study provedthat ratio vegetation index (RVI) indicator with the lowest RMSE wasanappropriatetoolfor assessing the status of the Iranian Oak forests. Finally,in order to study temporal changes of the Oak forests,dieback canopy variance and RVI for 6 years(1987, 2000, 2003, 2009, 2013 and 2014) were computed from different Landsat images. The computed indices indicatedthat crown freshness witnessedsignificantand continuous decrease.

Rapid and economical protocols for genomic and metagenomic DNA extraction from oak (Quercus brantii Lindl.)

Two new efficient, fast and low-cost metagenomic DNA extraction methods were developed for different Persian oak tissues (leaf, stem, root, and rhizospheric) and soil samples. The new “omics” studies on the genus Quercus are of importance to help finding efficient strategies for overcoming environmental challenges, and to do this, presence of efficient DNA extraction protocols for different Quercus species are very critical. The objective of the present study was to develop new efficient methods for extraction of metagenomic DNA (mDNA) from of Persian oak (Quercus brantii Lindl.) tissues. The efficiency of two newly developed mDNA extraction methods, including indirect SDS-based (ISB or concentrate method) and one spin column-based method (SCB) were compared to that of two classical direct methods, including CTAB-based and SDS-based methods, and two commercial mDNA extraction kits. The maximum average yield of mDNA for all samples (leaf, stem, root, bulk, and rhizospheric soils) was obtained by SCB (258 ng/μl) and ISB (189 ng/μl) methods, respectively. Successful PCR amplification for 16SrRNA and ITS sequence was consistently observed for ISB, SCB, and kit-extracted mDNAs, which confirmed the high purity of mDNA extracted by these methods. The new methods showed more than 96% quantitative PCR efficiency, and partial restriction digestion and metagenomic library construction confirmed the high efficiency of the newly developed methods. It could be concluded that two new protocols enhanced efficiency (yield, purity, and cost) of mDNA extraction from different tissues of Persian oak.

Site factors and stand conditions associated with Persian oak decline in Zagros mountain forests

Aim of study: Drought and stand structure are major and interconnected drivers of forest dynamics. Water shortage and tree-to-tree competition may interact under the current climate change scenario, increasing tree mortality. In this study, we aimed to investigate climate trends, site and stand structure effects on tree mortality, with the main hypothesis that drought-induced mortality is higher as competition increases.Area of study: Persian oak forests from Zagros Range, western Iran.Material and Methods: We split the study area into 20 topographical units (TUs), based on aspect, slope and elevation. In each TU, three 0.1 ha plots were established to quantify site and stand characteristics, namely the diameter of all trees and shrubs, stand density and basal area, canopy dieback and mortality. In addition, soil profiles were analyzed to obtain physical and chemical soil properties. Six transects 100 m length were established per TU to measure tree-to-tree competition for alive and dead trees.Main Results: The highest mortality rates and crown dieback were found at higher elevations and southern and western aspects. Our findings confirm increasing rates of tree mortality in stands with higher tree density and shallow soils. As regard links between climate change and forest decline, our results suggest that changing forest structure may have a significant impact on dust emission.Research highlights: Despite severe dry years occurred recently the study area, they are not significantly different than those recorded in the past. Stand structure appears as a modulating factor of climate change effects, linked to competition-related tree vulnerability to drought.

Oak trees decline; a sign of climate variability impacts in the west of Iran

The Persian oak, Quercus brantii, trees in the Zagros region of Western Iran have been in decline since 2000. The decline is assumed to be highly connected with changes in meteorological parameters. Our objectives were to quantify the long-term trends in meteorological parameters and reference evapotranspiration (ET0) in the Zagros region and estimate ecohydrological parameters highly affected by climate variability and related to rainfall interception (I) process (i.e., canopy storage capacity (S), the ratio of mean evaporation rate from the wet canopy to the mean rainfall intensity (E/R), and the free throughfall coefficient (p)). Long-term (1961-2010) changes in air temperature (T), precipitation (P), and wind speed (WS) were obtained from six synoptic meteorological stations located in the region. Throughfall (TF) was measured using the sixteen rain gauges randomly located underneath the crown of the five individual trees. P was measured using rain gauges fixed in an open space nearby to the oak trees .I was computed as the difference between P and TF. From 2000 to 2010, meteorological parameters and ET0 changed slightly; T, WS, and ET0 increased (+0.6 ˚C, +0.4 m.s-1, +0.25 mm.day-1, respectively), while P decreased (-60 mm).When climate patterns between 1961-2010 were analyzed for 6 synoptic weather stations, P significantly decreased significantly at one station, whereas T significantly increased at two stations and significantly decreased at another. I was estimated to be 40% and 25% within in-leaf and leaf-less periods, respectively. During the in-leaf period, the mean values of S, E/R, and p were roughly estimated to be 1 mm, 0.22, and 0.23, respectively. Our results indicate that the Zagros region is getting warmer and oak trees will indisputably experience reduction in the available water because of increased evaporative loss.

Novel Design, Preparation, Characterization and Antimicrobial Activity of Silver Nanoparticles during Oak Acorns Bark Retrograde

Abstract In search for a probable local solution for Qarasu River problems and based on our prescience about metal ion chelating/reducing ability of tannins which are found in large amount in oak acorns bark, Quercus brantii (Persian oak) acorns bark extract was exploited as reducing/capping agent in silver nanoparticles synthesis. Synthesis was carried out as a single-step method at room temperature, and without consuming any external energy by using these renewable barks. The crystallinity, size and shape of the nanoparticles were characterized by X-ray diffraction and scanning electron microscopy (SEM) respectively. The involvement of phenolic compounds in metal ion reduction was supported by UV-Visible and infrared spectroscopies and by acidity and conductivity measurements. The SEM-based particle size distribution analysis and antimicrobial susceptibility test of oak acorns bark-extract-mediated silver nanoparticles against bacterial effluent were pointed out to the critical proportion of silver salt to the capping/reducing agent. It seems that the bactericidal action depends on the extent to which accumulation of silver nanoparticle (Ag-Np) in bacterial cell surface alters the silver nanoparticle colloidal stability in broth medium.

Investigation on Root Distribution Pattern of Persian Oak and Hawthorn Species in Order to use in Bioengineering Models (Case Study: Boloran Forests, Kohdasht)

Investigation on Root Distribution Pattern of Persian Oak and Hawthorn Species in Order to use in Bioengineering Models (Case Study: Boloran Forests, Kohdasht)

Establishment of oak seedlings in historically disturbed sites: Regeneration success as a function of stand structure and soil characteristics

The establishment and development of oak (Quercus spp.) seedlings are frequently impaired by site heterogeneity resulting from historical anthropogenic disturbances in Mediterranean basin woodlands. In particular, the alteration of forest structure and soil biotic and abiotic components can compromise the natural regeneration of Persian oak (Quercus brantii Lindl.) in western Iran. This study aimed to investigate how soil properties, soil mesofauna diversity and stand structural indices differ between well and poorly regenerated areas. We sampled 105 plots in an oak woodland subjected to past disturbances but protected from human activities for the last 20 years. These 100-m2 plots were distributed into two groups: i) poorly regenerated plots (PRP) with only 0 or 1 newly established oak seedling, and ii) well regenerated plots (WRP) with ≥3 seedlings. In each plot, we characterized the forest structure using three structural indices, and determined the soil properties and mesofauna diversity. Structural indices were higher in WRP than in PRP for height (0.83 and 0.23), diameter differentiation (0.74 and 0.36) and species mixture (0.90 and 0.21). Also, richness and diversity of soil mesofauna were lower in PRP than in WRP.A canonical correspondence analysis (CCA) ordination clearly separated WRP, which were characterized by a clumped spatial distribution of mature oak trees on fertile soils, from PRP that exhibited a uniform spatial distribution of trees established on soils with a higher sand content (63 and 59%) and a higher bulk density (1.7 and 1.3).The uniform spatial distribution of trees, which was less favourable to oak seedling establishment, was inherited from intensive past human disturbances. To favour oak regeneration, we recommend applying management actions in cooperation with land-users, in particular the conservation of small patches of tree clumps to act as islands of fertility and seed sources.

Morphological and Molecular Differentiation in Populations of Persian Oak (Quercus Brantii Lindl.) in Southwestern Iran

PERSIAN oak (Quercus brantii Lindl.) is a common woody species in the Zagros forests of Iran. The current study evaluates the variation among the Q. brantii populations in the southwestern forests of Iran using amplified fragment length polymorphism (AFLP) and leaf morphology. A total of 135 trees were sampled from 27 populations representing nine regions in the provinces of Khuzestan (GOL, EMA, BAB, MOG, ALG), Chaharmahal and Bakhtiari (MON), Lorestan (KHA), Kohgiluyeh and Boyer-Ahmad (DIS) and Fars (BAA). Twelve morphological leaf traits were analyzed using PCA and Ward’s clustering methods. The results of ANOVA showed significant differences between populations, but the PCA graph and clustering analysis could not separate the populations on the basis of leaf characteristics. An analysis of molecular variance indicated that most genetic variation was contained within populations (95%); differences between populations accounted for only 1% and 4% was attributed to variation between regions. The five regions of Khuzestan have similar genetic structures. This was observed for the regions in Fars, Lorestan and Chaharmahal and Bakhtiari. Region DIS of Kohgiluyeh and Boyer-Ahmad had a separate genetic structure. The Dendrogram of Quercus brantii populations based on AFLP marker and Cluster analysis of populations using Ward’s method based on morphological data don’t confirm each other and in both, populations mix together. The current study revealed the some morphological and molecular differences in some populations of Persian oak in Iran. Population genetic information can provide critical insights into range expansion and evolutionary potential to adapt to environmental changes.

Morphological and molecular characterisation of Discotylenchus lorestanensis sp. n. (Nematoda: Tylenchidae) from Iran

Discotylenchus lorestanensis sp. n., recovered from soil near Persian oak (Quercus brantii Lindl.) from the Lorestan province of Iran, is described and illustrated based on morphological and molecular characters. The new species is characterized by females with a body length of 449–566 μm, a = 28.3–39.5) b = 5.2–5.8, c = 6.2–8.1, c' = 5.8–9.2, V = 63.3–71.1%, stylet 8–9 μm, spermatheca lobed and offset, filled with rounded sperm, post-vulval uterine sac (PUS) 4.8–6.5 μm, tail length 66–78 μm, not filiform, tapering to a rounded tip; and males with spicules 13–16 μm long. The new species has unique molecular sequences of SSU and the D2–D3 region of LSU expansion segments, Discotylenchus lorestanensis sp. n., separated from all known species of the Tylenchidae. We also provide an updated dichotomous key to the genus Discotylenchus.

Assessment of root-shoot ratio biomass and carbon storage of Quercus brantii Lindl. in the central Zagros forests of Iran

Assessment of carbon storage build-up in tree stems is a difficult task due to the lack of information on their carbon sequestration potential and allocation in different components. Similarly, high cost and complex methodology for accurate belowground biomass estimation make it in particular problematic. To this end, 18 Persian oak (Quercus brantii Lindley) trees from two growth forms in western Iran were destructively sampled to develop biomass and carbon mass prediction. Sampling covered a range of ages (40–145-year-old), sizes (DBH 7–38 cm) and mean crown diameter (1.9–8.55 m). We examined biomass proportion and carbon sequestration quantity at individual tree and growth form levels, which were: coppice and high forest. One-way ANOVA was used to test the significant differences in carbon concentration, biomass and carbon pools between the components of the two growth forms. Results showed that there was a difference in average biomass and carbon sequestration of trees from the two growth forms. The biomass distribution pattern was similar in the two growth forms. Amounts of stored biomass in trunk, stump, branch, twig and foliage were 24.79, 6.01, 63.82, 2.53 and 2.93% of aboveground components for high forest and 16.4, 10.12, 65.83, 4.23 and 3.46% for corresponding coppice trees. The average biomass of the root-shoot ratio in high-forest and coppice trees was determined 0.72 and 0.88, respectively. A general decline in these proportions was detected as the size of trees increased. We recommend a root-shoot ratio of 0.80 to be adopted for Persian oak.