Branch Research Articles

Circular Economy Approach for Sustainable Tree Litters Waste Management, study case in Universitas Diponegoro

Universitas Diponegoro, with an open forest area and planted vegetation of 30 – 40%, produced vast amounts of organic waste, especially tree litter. Piles of tree litter are everywhere if it is not properly managed. Universitas Diponegoro has taken a comprehensive approach to handling leaf and tree litter by converting it into economically valuable and beneficial products to meet the objectives of SDGs 12, which are focused on Responsible Consumption and Production. Through the Technical Implementation Unit for Occupational Safety, Health, and Environment (UPT K3L) Universitas Diponegoro has pyrolyzed tree branches to create liquid smoke and anaerobically converted leaf waste into compost. Later, the liquid smoke produced by pyrolysis and compost can achieve the consumer demand standard. In addition, from the policy approach, it is mandatory for every building to handle tree litter surrounds into compost using composting pits and composting bags. The circular economy idea has been incorporated into waste management at Universitas Diponegoro.

Pore-forming aegerolysin and MACPF proteins in extremotolerant or extremophilic fungi.

Aegerolysin proteins are involved in various interactions by recognising a molecular receptor in the target organism. The formation of pores in combination with larger, non-aegerolysin-like protein partners (such as membrane attack complex/perforin proteins [MACPFs]) is one of the possible responses in the presumed competitive exclusion of other organisms from the ecological niche. Bicomponent pairs are already observed at the gene level. Fungi growing under extreme conditions can be divided into ubiquitous and extremotolerant generalists which can compete with mesophilic species and rare, isolated extremophilic and extremotolerant specialists with narrow ecological amplitude that cannot compete. Under extreme conditions, there are fewer competitors, so fungal specialists generally produce less diverse and complicated profiles of specialised molecules. Since extremotolerant and extremophilic fungi have evolved in numerous branches of the fungal tree of life and aegerolysins are unevenly distributed across fungal genomes, we investigated whether aegerolysins, together with their partner proteins, contribute to the extreme survival ecology of generalists and specialists. We compiled a list of 109 thermo-, psihro-, acido-, alkali-, halo-, metallo- and polyextremo-tolerant/-philic fungal species. Several challenges were identified that affected the outcome: renaming fungal species, defining extremotolerant/extremophilic traits, identifying extremotolerant/extremophilic traits as metadata in databases and linking fungal isolates to fungal genomes. The yield of genomes coding aegerolysins or MACPFs appears to be lower in extremotolerant/extremophilic fungi compared to all fungal genomes. No candidates for pore-forming gene pairs were identified in the genomes of extremophilic fungi. Aegerolysin and MACPFs partner pairs were identified in only two of 69 species with sequenced genomes, namely in the ubiquitous metallotolerant generalists Aspergillus niger and A. foetidus. These results support the hypothesised role of these pore-forming proteins in competitive exclusion.

Enhancing sustainability and power generation from sewage‐driven air‐cathode microbial fuel cells through innovative anti‐biofouling spacer and biomass‐derived anode

AbstractBackgroundRecently, the concept of the membrane‐less microbial fuel cell (MFC) has gained traction to avoid the high internal resistance that is created upon utilizing conventional membranes. Nevertheless, an overlooked problem arises from the ingress of oxygen from the cathode side into the anolyte solution, fostering the formation of biofilms by aerobic microorganisms on the cathode surface. This biofilm layer poses a formidable impediment, leading to cell disconnection. Moreover, low surface area of conventional anodes is another important issue behind the low power density generation. In this research, a novel approach to circumvent biofilm formation and achieve stable and high‐power‐density output from MFCs by harnessing a commercial antibacterial spacer is introduced.ResultsAir‐cathode, sewage‐driven MFCs showed continuous power generation without the need for external microorganisms. Conversely, the absence of the innovative membrane resulted in a catastrophic power breakdown after 125 h of operation due to the formation of a dense biofilm layer on the cathode. Through the utilization of the proposed membrane strategy, stable power density output of 100 ± 8, 135 ± 11 and 142 ± 10 mW m−2 with carbon cloth, carbon paper and carbon felt anodes, respectively, was achieved. Moreover, a novel anode is introduced from graphitization of grape tree branches. The proposed anode could increase the generated power to 516 ± 17 mW m−2 from the sewage‐driven air‐cathode MFC, more than three times compared to the best conventional anode, carbon felt.ConclusionThis study provides significant solutions for sustainability, low‐performance and high‐cost problems of microbial fuel cells. © 2024 Society of Chemical Industry (SCI).

Characterization of cocoa (Theobroma cacao L.) wood branches as a potential resource for paper production

For sustainable use of lignocellulosic resources, pruned tree branches of cocoa, one of the major evergreen tropical tree crops with significant economic importance worldwide, were investigated as a potential source of kraft pulp. This study determined the chemical composition, fiber dimensions, kraft pulp, and paper properties of the cocoa tree (Theobroma cacao L.) branches compared to the deciduous trees traditionally used in the paper industry. A handsheet of cocoa pulp showed promising results with narrow fiber length distribution, high paper density, and high mechanical strength. The yield of kraft pulp made from cocoa branches wood was lower. The tensile and burst indices of cocoa pulp handsheet were 2 and 2.5 times higher than that of hardwood traditionally used in the paper industry. These results suggest a potential use of cocoa (Theobroma cacao L.) tree branch wood for pulp production using the kraft process.

Tool–Branch Interaction Mechanism of Impact-Pruning Process Based on Finite Element Method

This study addresses the necessity for a more profound comprehension of the mechanical behavior and fracture mechanisms of tree branches during impact pruning. The methodologies of the research are to develop a failure model of impact-cutting mechanics and a tool–branch interaction model using the finite element method (FEM). The validation of the model was conducted through the measurement of cutting forces and cross-sectional morphology in the field. A comparative analysis between experimental and simulation data revealed an average relative error below 15% for cutting force and below 10% for the cross-sectional ratio, thereby confirming the accuracy of the model. The findings indicate the presence of plastic deformation within the cutting zone, with elastic deformation prevailing in the surrounding region. As the branch approaches the yield point, the phenomenon of plastic deformation intensifies, resulting in a notable increase in internal energy demands, particularly in larger branches. The optimal pruning diameter was identified as 15 mm. An increase in cutting velocity raises the peak cutting force by 460.9 N per m/s, while a 1° increase in the blade wedge angle adds 34.9 N. A reduction in normal stress by increasing the tool back angle improves energy efficiency. This study provides insights to optimize pruning practices, enhancing efficiency and precision.

Complicated thermo-chemical heterogeneity of the mantle transition zone beneath the Philippine Sea Plate revealed by SS precursors investigation

The Philippine Sea Plate (PSP), a region renowned for its intricate history of multi-stage subduction and back-arc extension, encounters difficulties in elucidating its deep seismic structure, primarily due to the sparse distribution of seismic stations. This study uses over 44,086 traces of SS precursors collected from >1,000 seismic stations over 10–20 years period, to image the mantle transition zone (MTZ) beneath the PSP. With the curvelet denoising technique, we provide high-resolution maps of the depths of the 410 km (D410) and 660 km (D660) discontinuities and the thickness of the MTZ. Notably, we demonstrate a 10–35 km MTZ thickening extending from the West Philippine Basin to the Shikoku Basin, which may be associated with the thermal effect and dehydration of stagnated slabs in the MTZ. Furthermore, the reflection gap and multiple reflectors were both observed in D410 and D660 beneath the Mariana Trench, which suggests that the vertically subducted Pacific plate transports substantial water and non-olivine components into the MTZ in this area. Additionally, a ∼10–25 km MTZ thinning with an abnormally shallow D660 has been observed beneath the Parece Vela Basin and Caroline Plate in the southern PSP, suggesting the potential existence of thermal upwelling from a secondary plume, which may be possibly the tree branch of the Caroline mantle plume in MTZ. Our results provide new seismological constraints on present and past mantle dynamics in and around the PSP.

Application of Date Palm Tree Branch-Based Activated Carbon for Aqueous Toxicity Reduction

The Kingdom of Saudi Arabia (KSA) has millions of date palm trees for commercial scale date-fruit production. The respective industry also generates agricultural waste including date palm tree branches. This rich bio-resource can be used for several beneficial applications. The present study therefore investigated the application of granular activated carbon (GAC) produced using date palm tree branches to successfully remove phenol, p-cresol, and copper from synthetic wastewater. The respective adsorption equilibrium results fitted well to the Langmuir-type adsorption isotherm. Furthermore, the pH-dependent adsorption results both for phenol and p-cresol appeared to follow an anionic-type adsorption behavior (i.e., decreasing adsorption with an increase in aqueous phase equilibrium pH). However, the pH-dependent adsorption finding for copper showed a cationic-type adsorption behavior. These adsorption trends were explained employing the pH-dependent speciation of the respective pollutants. In general, findings from the present work indicate that a high-specific-surface-area (SSABET) GAC material from the date palm tree branches can be successfully employed for aqueous phase pollution control.

Repeated shifts out of tropical climates preceded by whole genome duplication.

While flowering plants have diversified in virtually every terrestrial clime, climate constrains the distribution of individual lineages. Overcoming climatic constraints may be associated with diverse evolutionary phenomena including whole genome duplication (WGD), gene-tree conflict, and life-history changes. Climatic shifts may also have facilitated increases in flowering plant diversification rates. We investigate climatic shifts in the flowering plant order Ericales, which consists of c. 14 000 species with diverse climatic tolerances. We estimate phylogenetic trees from transcriptomic data, 64 chloroplast loci, and Angiosperms353 nuclear loci that, respectively, incorporate 147, 4508, and 2870 Ericales species. We use these phylogenetic trees to analyse how climatic shifts are associated with WGD, gene-tree conflict, life-history, and diversification rates. Early branches in the phylogenetic trees are extremely short, and have high levels of gene-tree conflict and at least one WGD. On lineages descended from these early branches, there is a significant association between climatic shifts (primarily out of tropical climates), further WGDs, and life-history. Extremely short early branches, and their associated gene-tree conflict and WGDs, appear to underpin the explosive origin of numerous species rich Ericales clades. The evolution of diverse climatic tolerances in these species rich clades is tightly associated with WGD and life-history.

Visual Servoing for Aerial Vegetation Sampling Systems

This research describes a vision-based control strategy that employs deep learning for an aerial manipulation system developed for vegetation sampling in remote, dangerous environments. Vegetation sampling in such places presents considerable technical challenges such as equipment failures and exposure to hazardous elements. Controlling aerial manipulation in unstructured areas such as forests remains a significant challenge because of uncertainty, complex dynamics, and the possibility of collisions. To overcome these issues, we offer a new image-based visual servoing (IBVS) method that uses knowledge distillation to provide robust, accurate, and adaptive control of the aerial vegetation sampler. A convolutional neural network (CNN) from a previous study is used to detect the grasp point, giving critical feedback for the visual servoing process. The suggested method improves the precision of visual servoing for sampling by using a learning-based approach to grip point selection and camera calibration error handling. Simulation results indicate the system can track and sample tree branches with minimum error, demonstrating that it has the potential to improve the safety and efficiency of aerial vegetation sampling.

Sleet damage to branches and crowns of street camphor trees (Cinnamomum camphora) in a central China mega-city: damage statistics, modelling, and implications

IntroductionExtreme weather becomes increasingly frequent and severe under climate change, causing unexpected damage to trees. Among them, sleet damage is particularly harmful to evergreen trees in subtropical area. Camphor trees (Cinnamomum camphora), as dominant street trees in central China, are prone to sleet damage, resulting in loss of valuable ecosystem functions.MethodsBy measuring tree size characteristics of 118 camphor trees before and after a record-breaking sleet event in Wuhan, a mega-city in central China, we built allometric equations between size and volume of broken branches and used the random forest regression to model sleet damage to camphor trees.ResultsWe identified that larger trees with intermediate bole height suffered more than smaller trees with tall bole height from the sleet event. We estimated the volume of broken branches of a camphor tree with DBH at 35.0 cm as 106.4 dm3, equivalent to 55.3 kg biomass loss, from the sleet event.DiscussionWe suggest that pruning the branches instead of topping the main stems of small camphor trees would reduce the sleet hazard. To mitigate the negative impacts of climate change, regular pruning should be practiced on street camphor trees to protect them from future heavy sleet events.

Mixed Gangliocytoma-Pituitary Adenoma: Incidental Discovery During Eye Injury Evaluation: A Case Study

Abstract Introduction/Objective Mixed gangliocytoma-adenoma is exceedingly rare, representing less than 0.5% of sellar tumors. We present a unique case of mixed gangliocytoma-pituitary adenoma incidentally diagnosed during the evaluation of traumatic eye injury. We aim to clarify the diagnostic process using real clinical data, stressing how such cases might be missed without careful histopathological examination Methods/Case Report A 32-year-old male presented for elective transsphenoidal resection (TSR) due to a suspected growth hormone (GH) secreting pituitary tumor. Surprisingly, the adenoma was discovered incidentally during an eye injury evaluation. Referred from an ophthalmology clinic, initial concerns were a possible blood clot or foreign body in the left eye, following a forceful encounter with a tree branch Results (if a Case Study enter NA) Imaging incidentally identified a 2 cm pituitary mass. Further evaluation showed elevated levels of insulin-like growth factor 1 (IGF1) at 1162 ng/ml and GH at 10.2 ng/ml. Remarkably, the patient had not observed signs of acromegaly, until photographic comparison between past and present appearances was made. TSR of the pituitary mass was done. Microscopic examination revealed monomorphic cells with round nuclei with the typical speckled chromatin pattern of neuroendocrine cells with cytoplasm ranging from chromophobic to eosinophilic, consistent with pituitary adenoma. An additional unexpected finding was the presence of large gangliocytic cells (large neurons), dispersed throughout the tumor as single or clustered cells. In some regions, distinct patches of fine neuropil stroma were associated with the clustered ganglion cells. IHC staining with synaptophysin and neurofilament highlighted the gangliocytic component. CAM 5.2 IHC stain showed perinuclear dot-like expression in the adenoma cells, GH IHC showed patchy expression, and prolactin IHC was expressed in scattered cells. Ki67 index was ~ 2%. There was no evidence of necrosis nor mitosis. The coexistence of sellar gangliocytoma with pituitary adenoma, as observed in this case, represents a rare entity known as mixed gangliocytoma-pituitary adenoma Conclusion The adenomatous component of mixed gangliocytoma-pituitary adenoma often secrete GH, leading to its classification as pituitary somatotroph adenoma. This poses a diagnostic challenge due to the lack of specific symptoms or unique brain imaging features, necessitating thorough histological evaluation for precise diagnosis and to ensure the gangliocytoma component is not overlooked

Robust optogenetic inhibition with red-light-sensitive anion-conducting channelrhodopsins

Channelrhodopsins (ChRs) are light-gated ion channels widely used to optically activate or silence selected electrogenic cells, such as individual brain neurons. Here, we describe identifying and characterizing a set of anion-conducting ChRs (ACRs) from diverse taxa and representing various branches of the ChR phylogenetic tree. The Mantoniella squamata ACR (MsACR1) showed high sensitivity to yellow-green light (λmax at 555 nm) and was further engineered for optogenetic applications. A single amino-acid substitution that mimicked red-light-sensitive rhodopsins like Chrimson shifted the photosensitivity 20 nm toward red light and accelerated photocurrent kinetics. Hence, it was named red and accelerated ACR, raACR. Both wild-type and mutant are capable optical silencers at low light intensities in mouse neurons in vitro and in vivo, while raACR offers a higher temporal resolution.

Robust optogenetic inhibition with red-light-sensitive anion-conducting channelrhodopsins.

Channelrhodopsins (ChRs) are light-gated ion channels widely used to optically activate or silence selected electrogenic cells, such as individual brain neurons. Here, we describe identifying and characterizing a set of anion-conducting ChRs (ACRs) from diverse taxa and representing various branches of the ChR phylogenetic tree. The Mantoniella squamata ACR (MsACR1) showed high sensitivity to yellow-green light (λmax at 555 nm) and was further engineered for optogenetic applications. A single amino-acid substitution that mimicked red-light-sensitive rhodopsins like Chrimson shifted the photosensitivity 20 nm toward red light and accelerated photocurrent kinetics. Hence, it was named red and accelerated ACR, raACR. Both wild-type and mutant are capable optical silencers at low light intensities in mouse neurons in vitro and in vivo, while raACR offers a higher temporal resolution.

Adaptations and metabolic evolution of myzozoan protists across diverse lifestyles and environments.

SUMMARYMyzozoans encompass apicomplexans and dinoflagellates that manifest diverse lifestyles in highly varied environments. They show enormous propensity to employ different metabolic programs and exploit different nutrient resources and niches, and yet, they share much core biology that underlies this evolutionary success and impact. This review discusses apicomplexan parasites of medical significance and the traits and properties they share with non-pathogenic myzozoans. These include the versatility of myzozoan plastids, which scale from fully photosynthetic organelles to the site of very select key metabolic pathways. Pivotal evolutionary innovations, such as the apical complex, have allowed myzozoans to shift from predatory to parasitic and other symbiotic lifestyles multiple times in both apicomplexan and dinoflagellate branches of the myzozoan evolutionary tree. Such traits, along with shared mechanisms for nutrient acquisition, appear to underpin the prosperity of myzozoans in their varied habitats. Understanding the mechanisms of these shared traits has the potential to spawn new strategic interventions against medically and veterinary relevant parasites within this grouping.

Structural and physiological implications of witches' broom infection in Xylopia aromatica (Annonaceae) trees

AbstractWitches' brooms are abnormal branches that can affect various tree species in the Brazilian savanna, such as Xylopia aromatica. This disease leads to biomass loss and alters growth patterns. This study investigated the anatomical and physiological impacts of witches' broom on X. aromatica, hypothesizing that the disease induces changes in both infected and noninfected branches of the same tree. Measurements included leaf area, chlorophyll content and photosystem II (PSII) functionality in control and infected plants, as well as branch types (control, uninfected and infected branches for infected plants). Water potential was assessed at predawn and midday, and stem samples were analysed for anatomical and vessel element analysis. Witches' broom disease manifests as short brown stems and small yellowish‐green leaves. While infected and uninfected plants showed no significant differences in leaf area and leaf dry biomass, infected branches had reduced leaf number, area and weight. Chlorophyll content and PSII efficiency were significantly reduced in infected branches, indicating photosynthetic disruption. Water potential was lower at predawn in infected plants but normalized by midday, suggesting an adaptive response. Anatomical changes in infected branches included alterations in vessel elements and parenchymatic rays. Overall, X. aromatica displays localized changes due to witches' broom, which aids in water stress adaptation. Despite these findings, long‐term studies are needed to evaluate the impacts on biomass reduction and reproductive investment in Brazilian savanna areas, crucial for understanding the ecological impact and developing survival strategies for affected plants.

Synthesis and antifungal activities of small molecule arylthiazolamine derivatives.

Developing new fungicides to compensate for the deficiencies of existing fungicides resistance in phytopathogenic fungi is a research hotspot in the field of pesticides. Aiming to discover novel template small molecules with excellent antifungal activity, thirty-eight arylthiazolamine derivatives were synthesized through bromination, cyclization, halogenation, and acylation reactions. The synthesized compounds were screened for antifungal activity against ten typical fungal pathogens, and some halogenated arylthiazolamines and amides exhibited excellent broad-spectrum antifungal activity, especially compounds 4m (3.96-47.76μg/mL), 5k (0.10-7.70μg/mL) and 5n (2.08-11.21μg/mL). Among them, compound 5k provided comparable protection and curative effects to chloroticonil and boscalid against B. dothidea and V. mali infection in apple and apple tree branches, respectively, and it could exert antifungal effects by inhibiting the differentiation of mycelium spores, spore germination, and bud tube growth. This study provides high-efficiency and inexpensive candidate compounds for managing of diseases caused by plant pathogenic fungi.

Analysis of the Impact of Treatments Stimulating Branching on the Quality of Maiden Apple Trees

Nursery material intended for establishing intensive apple orchards should be characterised by a dominant and straight leader with an appropriate number of shoots that develop at the right height and are regularly spaced along the leader. The use of well-branched trees can lead to fruiting in the first year after planting. However, many apple varieties have difficulty forming lateral shoots due to strong apical dominance. The aim of the study was to assess the effectiveness of treatments stimulating the branching of maiden apple trees of the ‘Gloster’ variety. The research was carried out in 2017–2019 at a private nursery farm located in eastern Poland. The studied trees were subjected to a mechanical branching stimulation treatment, which consisted of pinching off 4–5 of the youngest leaves located below the growth cone, and chemical branching stimulation treatments, which consisted of applying growth regulator mixtures in the form of an aqueous solution, i.e., BA+GA3 and BA+GA4+7. The conducted studies showed that the type of branching-stimulating treatment had a significant effect on the height and trunk diameter of the maiden trees, the number of lateral shoots, the average length of one shoot and the sum of the lengths of all sylleptic shoots. The maiden trees treated with BA+GA3 were characterised by the best quality among the analysed combinations. Maiden apple trees treated with BA+GA3 were the tallest (2017—167.7 cm; 2018—175.3 cm; 2019—164.4 cm), produced the largest number of shoots (2017—6.5 pcs; 2018—6.8 pcs; 2019—6.3 pcs) and had the largest sum of lateral shoot lengths (2017—148.0 cm; 2018—155.4 cm; 2019—140.6 cm) among the evaluated combinations. The number of treatments and the concentration of applied growth regulators had a significant effect on the structure of the crown of the maiden apple trees of the ‘Gloster’ cultivar.

Biophysics of protist behaviour

Protists, an umbrella term first coined by Ernst Haeckel in 1866, are a vast collection of (primarily unicellular) eukaryotes that are "neither animals nor plants". This basic definition by exclusion has been exercised for centuries, even though recent advances have led to more rigorous taxonomic assignment of various protist groups. Pioneering comparative phylogenetic approaches have been applied to these organisms to reconstruct the deep branches of the eukaryotic tree, revealing essential clues about early eukaryotic evolution. Protists, including amoebae, flagellates, ciliates, and algae, are also vital constituents of global ecosystems, where they appear at the base of food chains, control the relative abundance of other microbes, and participate in global biogeochemical recycling. Due to their typically small size and lack of nervous systems, protists are often associated with the unfortunate label 'primitive'. Yet they exhibit remarkable behavioural sophistication and are able to feed, predate, navigate and interact with their surroundings. Unlike macroscopic animals, many protists reside in a non-intuitive physical regime where viscous forces dominate over inertia, and where they use diverse propulsion and navigation strategies. Interdisciplinary research into these cell-scale phenomena, characterised by a complex interplay of physical forces and mechanical constraints, has significantly advanced the emerging fields of active matter, microhydrodynamics, and non-equilibrium statistical physics. This primer discusses the biophysics of protist behaviour, with a focus on locomotion and feeding. I will highlight the most extensively studied principles and describe some more esoteric behaviours that have not yet been systematically explored.

Fossilized soft tissues in tentaculitids from the Upper Devonian of Armenia: Towards solving the mystery of their phylogenetic affinities

The tentaculitids represent a significant and diverse group of mysterious fossils found in Palaeozoic strata. Their biology and evolutionary relationships remain poorly understood due to limited information about their soft body anatomy. The discovery of fossilized soft tissues in tentaculitids from the Upper Devonian of Armenia helps to resolve the old mystery of tentaculitid phylogenetic affinities. The thick bundles of phosphatic bars in the tentaculitid interior closely resemble the musculature of several tubicolous invertebrates, such as phoronids and bryozoans. Based on this similarity, we interpret these structures as fossilized muscles of the tentaculitid animal. The attachment of tentaculitid body muscles in a honeycomb pattern to the body wall is unlike that of any mollusc. Based on this muscle arrangement, molluscan affinities of tentaculitoids can be refuted. The muscle arrangement in tentaculitids is more akin to that of bryozoans than to phoronids. Presumably, tentaculitids and bryozoans shared a common ancestor. This ancestor was probably a solitary animal, with coloniality emerging later in the bryozoan branch of the phylogenetic tree. Alternatively, tentaculitoids might have evolved from a bryozoan-like ancestor by losing their coloniality.

From Glory to Decline: Uncovering Causes of Oak Decline in Iran

ABSTRACTOak decline is a major concern in Iran. A literature search with the terms ‘Iran’ AND ‘oak’ OR ‘Quercus’ from 1963 through 2023 resulted in 635 articles with over 200 dealing specifically with oak decline. In Iran, oak decline is most severe in the Zagros forests, followed by the Arasbaran and Hyrcanian forests. Of Iran's 11 native oak species, Quercus brantii is the most affected. Several factors have been identified as contributing to oak decline in Iran. Some economic and social factors include high rural unemployment, livestock overgrazing and uncontrolled cutting of live tree branches with the wood used for firewood and foliage used as food for farm animals. These pruning wounds can serve as entry points for pathogens and attract insects. Important abiotic factors included extended drought, increasing air temperature and wind speed, and increased levels of airborne dust and heavy metals. Important pathogens identified in the early 2000s included Armillaria mellea and charcoal rot fungus (Biscogniauxia mediterranea). More recently, many other fungal pathogens (e.g., Discula quercina, Neoscytalidium dimidiatum, Obolarina persica, Paecilomyces formosus and Phaeoacremonium tuscanicum) and bacterial pathogens (e.g., Bacillus pumilus, Brenneria goodwinii, Gibbsiella quercinecans, Rahnella victoriana and Stenotrophomonas maltophilia) were found in association with declining oaks. Among the insects, severe oak defoliation has resulted from various Lepidoptera in the families Erebidae, Geometridae and Tortricidae. Similarly, several bark‐ and wood‐boring beetles in the families Buprestidae and Cerambycidae were reported from declining oaks, with the buprestid Agrilus hastulifer being one of the most common. It is hoped that this review will improve our understanding of the many factors involved in oak decline in Iran and promote the development of management strategies.