Crown Layer Research Articles

Study of the microhardness ensuring the contact endurance of structural materials

The strength of the working surfaces of gears depends on the mechanical properties of the material and the quality of parts. We present the results of studying the strength of materials and working surfaces of a gear mechanism due to structural changes attributed to chemical and thermal treatment. The surface strength of the gears of gas turbine engines was studied. Nitrocementation and ion nitriding were used for chemical and thermal treatment of the contacting surfaces of steel samples under study (20Kh3MVF-Sh, 16Kh3NVFMB-Sh, 18Kh2H4MA, and 12Kh2H4A). Changes in the microhardness of the component layers (diffusion, transition and basic) of the toothed crown were analyzed. Metallographic analysis of the structure of materials was carried out to describe the factors determining the surface strength of working surfaces. Systematized data on the change in the microhardness of materials obtained experimentally in conditions of mass production are presented. Presented experimental results on changes in the mechanical properties of materials are based on data on the microhardness and structural state of the surface layers of the working profiles of gears. A comparative assessment of the surface strength of the studied samples during contact interaction was performed. The dependence of the surface strength on the multifactorial volumetric structure and structure formation of the material in the process of operation is determined. It is shown that the method of surface saturation forms the structure of a material with different mechanical properties accompanied with the formation of a transition zone having characteristic distinctive values of the hardness. The results obtained can be used in the design of gears, taking into account changes in the mechanical properties and structure of materials to ensure the necessary operational requirements.

Simulating vertical distribution of normalized leaf biomass for individual Moso bamboos under intensive management

Leaf biomass is a crucial parameter that influences forest growth and carbon exchange between ecosystems and the atmosphere. A clear understanding of the vertical distribution of leaf biomass is essential for accurate carbon sequestration estimations in Moso bamboo. We collected data on leaf biomass from each crown layer and the structural characteristics of 54 individual Moso bamboo plants. We then simulated the vertical distribution of normalized upward cumulative leaf biomass (CLBn) using three power functions. The first model (Model 1) estimates CLBn using unique and unadjustable parameters (a and b) of the power function. In the second model (Model 2), parameter ‘a’ was fixed at 1, and parameter ‘b’ was fitted for all samples. In the third model (Model 3), parameter b was adjusted based on the structural characteristics of each bamboo. Model 3 demonstrated the highest accuracy in estimating CLBn and normalized leaf biomass (LBn) in each layer, with RMSEr values of 20.34 % and 36.85 % for CLBn and LBn, respectively. When compared with Model 1 and Model 2, Model 3 reduced RMSEr by 12.27 % and 6.88 % for CLBn and 21.13 % and 10.49 % for LBn, respectively. However, uncertainty remained significant in low LBn estimates from Model 3. Variations in the vertical distribution of CLBn in individual bamboo plants were primarily explained by crown length, height to the lowest living branch, and age. This study proposes a viable method for elucidating the variation in CLBn among individual bamboo plants.

Zásoby uhlíku v lesních půdách a lesní hospodářství – review

The article summarizes and discusses studies focused on the carbon stock in forest soils and the way it is affected by forestry operations with a focus on the Central European (Czech) region. In general, the methods enhancing forests´ vitality and stability are more important than the procedures aimed at carbon sequestration only, as the major risk for carbon stock in forest soils is represented by large-scale disturbances. Important factors that will influence the mitigation potential include the change of tree species composition, as the majority of forests in the Czech Republic is still represented by Norway spruce or Scots pine even-aged monocultures. Careful practices of logging and forest restoration are recommended, with minimal opening of the crown layer. The use of clear-cuts should be reserved mainly for afforestation of light-demanding tree species. Care should be taken of sustainable nutrients content in forest soils, as the soil quality plays substantial role in the future forest vitality, productivity and resilience. Forest protection and all measures preventing large-scale forest disturbances are of key importance for carbon sequestration.

The implementation of the SPAD-502 Chlorophyll meter for the quantification of nitrogen content in Arabica coffee leaves

The utilization of a non-destructive SPAD-502 chlorophyll meter, which enables the measurement of nitrogen status in plant leaves, has gained popularity in agronomic crops. Its application to horticultural crops like coffee remains relatively uncommon. The device provides quick and real-time measurements, helping to provide on-time nitrogen fertilizer to coffee plants before deficiency signs occur. Coffee leaves are characterized by thick and waxy leaves, together with many layers of tree crown. Therefore, the objective of this study was to develop a method for measuring nitrogen levels in coffee plants using the SPAD-502 Chlorophyll meter for an appropriate nitrogen fertilizer application rate in Arabica coffee plants.•Coffee trees were separated into upper, middle and lower levels. Data on SPAD values and total nitrogen were analyzed.•Pearson Correlation Coefficient (R), Coefficient of Determination (R2) and linear regression were calculated for different three levels of both SPAD-502 and total nitrogen values.•The results revealed a strong correlation (R2 = 0.63) between the SPAD readings of coffee leaves obtained from the upper canopy and their nitrogen content.These findings can provide a good concept of which coffee crown level will be a better part for measuring N content using a SPAD-502 Chlorophyll meter.

Effect of Crown Layers on Reproductive Effort and Success in Andromonoecious Aesculus indica (Wall. ex Camb.) Hook (Sapindaceae) in a Temperate Forest of Garhwal Himalaya.

The andromonoecy is an unusual sex expression in trees in which an individual plant bears both functionally staminate and hermaphrodite flowers on the inflorescences. This study aims to investigate the effect of crown layers on the floral biology and reproductive effort of Aesculus indica (Wall. ex Camb.) Hook. The results revealed that the peak period of anthesis was between 06:00 and 08:00 h of the day. Male flower production was predominantly higher as compared to the perfect flowers on the inflorescences. There was no significant variation between total pollen production in staminate and perfect flowers. Features like protogyny and inter-level asynchrony promote xenogamy; however, intra-level asynchrony results in geitonogamy. Controlled pollination treatments revealed the existence of self-incompatibility in flowers. Pollination syndromes in flowers support ambophily. A trend of consistent improvement in reproductive success from lower canopy layers to upper crown layers in the analyzed trees was recorded. The crown layers have a significant impact on flower production, fruit, and seed set. An increase in male flower production due to the increment in the crown is a mechanism of reproductive assurance as a pollen donor and pollinator recipient and also due to the differential cost of expenditure of reproduction in crown layers. Andromonoecy in A. indica promotes self-incompatibility, and there was a tapering trend of reproductive success in the crown layers.

Intraspecific plasticity and co-variation of leaf traits facilitate Ficus tinctoria to acclimate hemiepiphytic and terrestrial habitats.

Despite intensive studies on plant functional traits, the intraspecific variation and their co-variation at the multi-scale remains poorly studied, which holds the potential to unveil plant responses to changing environmental conditions. In this study, intraspecific variations of 16 leaf functional traits of a common fig species, Ficus tinctoria G. Frost., were investigated in relation to different scales: habitat types (hemiepiphytic and terrestrial), growth stages (small, medium and large) and tree crown positions (upper, middle and lower) in Xishuangbanna, Southwest China. Remarkable intraspecific variation was observed in leaf functional traits, which was mainly influenced by tree crown position, growth stage and their interaction. Stable nitrogen isotope (δ15N) and leaf area (LA) showed large variations, while stable carbon isotope (δ13C), stomata width and leaf water content showed relatively small variations, suggesting that light- and nitrogen-use strategies of F. tinctoria were plastic, while the water-use strategies have relatively low plasticity. The crown layers are formed with the growth of figs, and leaves in the lower crown increase their chlorophyll concentration and LA to improve the light energy conversion efficiency and the ability to capture weak light. Meanwhile, leaves in the upper crown increase the water-use efficiency to maintain their carbon assimilation. Moreover, hemiepiphytic medium (transitional stage) and large (free-standing stage) figs exhibited more significant trait differentiation (chlorophyll concentration, δ13C, stomata density, etc.) within the crown positions, and stronger trait co-variation compared with their terrestrial counterparts. This pattern demonstrates their acclimation to the changing microhabitats formed by their hemiepiphytic life history. Our study emphasizes the importance of multi-scaled intraspecific variation and co-variation in trait-based strategies of hemiepiphyte and terrestrial F. tinctoria, which facilitate them to cope with different environmental conditions.

In Situ Controlled Growth of Strongly Quantum Confined CsPbBr3/FAPbBr3 Core/Crown Nanoplatelets for Blue Light Emitting Diodes

AbstractA few unit cells of thick colloidal CsPbBr3 nanoplatelets (NPLs) exhibit strong quantum confinement. However, due to the increased surface‐to‐volume ratio, they show poor photoluminescence quantum yield (PLQY) resulting from surface traps. Here, a unique, quantum‐confined core/crown perovskite is reported for the first time, where the CsPbBr3 NPL surface is passivated by laterally grown thin FAPbBr3 crown layers. Unlike regular core/shells, the FAPbBr3 is coated around the core NPLs resulting in blue emission. Careful control of the growth kinetics while monitoring growth using in situ PL led to the formation of core/crown perovskites with nearly two times improvement in thin film PLQYs. HR‐TEM analyses show that the interplanar distances of the core match with CsPbBr3 and the crown match with FAPbBr3. The XRD and TEM analyses revealed that their thickness remains the same even if Cs+ to FA+ ratios are varied, indicating lateral growth of FAPbBr3 around the CsPbBr3 core. Further, FA+ ions in the crown lattice are confirmed by FTIR and 1HNMR. Finally, considering their high PLQYs and narrow linewidths, the core/crown NPLs are employed as blue emitters in light‐emitting diodes, and a maximum external quantum efficiency of 0.4% at 2.71 eV (457 nm) with a luminance of 513 cd m−2 is achieved.

Optical model of a conifer shoot

Description of the entire structure of a conifer shoot, which forms a radiation scattering pattern, has been challenging, and the previous respective components of radiative transfer models for conifer stands were rather coarse. The progress of 3D scanner technology made it possible to collect high-density point clouds of Norway spruce shoots and describe the shoots’ geometrical shape and parameterization in full detail in this paper. The skeleton of shoots was created using custom clustering of point clouds for detecting separate needles. Needles and shoot twigs were modeled as circular cylinders, with their inclination and azimuth corresponding to the shoot skeleton.Specular reflection of incident radiation on the convex surface of needles in the border stripe of the shoot’s silhouette was found to be directed to the forward hemisphere, which increases the ratio of forward to backward scattering of radiation in a shoot. This allows multiple collisions of incident photons inside the same shoot and in the neighbor shoots in deeper layers of the crown layer in a forest, which increases the probability of incident photons being trapped in shoots and crowns of needle-leaf trees.

Derivative-based time-adjusted analysis of diurnal and within-tree variation in the OJIP fluorescence transient of silver birch

The JIP test, based on fast chlorophyll fluorescence (ChlF) kinetics and derived parameters, is a dependable tool for studying photosynthetic efficiency under varying environmental conditions. We extracted additional information from the whole OJIP and the normalized variable fluorescence (Vt) transient curve using first and second-order derivatives to visualize and localize points of landmark events. To account for light-induced variations in the fluorescence transient, we present a time-adjusted JIP test approach in which the derivatives of the transient curve are used to determine the exact timing of the J and I steps instead of fixed time points. We compared the traditional JIP test method with the time-adjusted method in analyzing fast ChlF measurements of silver birch (Betula pendula) in field conditions studying diurnal and within-crown variation. The time-adjusted JIP test method showed potential for studying ChlF dynamics, as it takes into account potential time shifts in the occurrence of J and I steps. The exact occurrence times of J and I steps and other landmark events coincided with the times of significant differences in fluorescence intensity. Chlorophyll fluorescence parameters were linearly related to photosynthetic photon flux density (PPFD) at different times of day, and the values obtained by the time-adjusted JIP test showed a stronger linear regression than the traditional JIP test. For fluorescence parameters having significant differences among different times of day and crown layers, the time-adjusted JIP test resulted in more clear differences than the traditional JIP test. Diurnal ChlF intensity data indicated that differences between the southern and northern provenance were only evident under low light conditions. Taken together, our results emphasize the potential relevance of considering the time domain in the analysis of the fast ChlF induction.

High External Quantum Efficiency Light-Emitting Diodes Enabled by Advanced Heterostructures of Type-II Nanoplatelets

Colloidal quantum wells (CQWs), also known as nanoplatelets (NPLs), are exciting material systems for numerous photonic applications, including lasers and light-emitting diodes (LEDs). Although many successful type-I NPL-LEDs with high device performance have been demonstrated, type-II NPLs are not fully exploited for LED applications, even with alloyed type-II NPLs with enhanced optical properties. Here, we present the development of CdSe/CdTe/CdSe core/crown/crown (multi-crowned) type-II NPLs and systematic investigation of their optical properties, including their comparison with the traditional core/crown counterparts. Unlike traditional type-II NPLs such as CdSe/CdTe, CdTe/CdSe, and CdSe/CdSexTe1-x core/crown heterostructures, here the proposed advanced heterostructure reaps the benefits of having two type-II transition channels, resulting in a high quantum yield (QY) of 83% and a long fluorescence lifetime of 73.3 ns. These type-II transitions were confirmed experimentally by optical measurements and theoretically using electron and hole wave function modeling. Computational study shows that the multi-crowned NPLs provide a better-distributed hole wave function along the CdTe crown, while the electron wave function is delocalized in the CdSe core and CdSe crown layers. As a proof-of-concept demonstration, NPL-LEDs based on these multi-crowned NPLs were designed and fabricated with a record high external quantum efficiency (EQE) of 7.83% among type-II NPL-LEDs. These findings are expected to induce advanced designs of NPL heterostructures to reach a fascinating level of performance, especially in LEDs and lasers.

Seed Distribution and Phenotypic Variation in Different Layers of a Cunninghamia Lanceolata Seed Orchard

The phenotypic characteristics of forest seeds are the basis of germplasm innovation, genetic improvement, and biological research, and they also are the reference for the development of seed orchards. In this study, we analyzed seed quantity characteristics, phenotypic differentiation, and variation patterns in three seed-bearing clones from different crown layers of the Chinese fir (Cunninghamia lanceolata (Lamb.) Hook) orchard located in Fujian Province, China. We divided the clones into six layers according to crown height and the sunny and shady sides, 14 phenotypic characteristics, and five quality indexes, and we measured the germination rate of seeds. The rate of seeds filled with tannin-like substance in the upper sunny layer was low, but it was high in the lower shady layer. The germination rate was highest in the upper sunny layer and lower in the middle and lower shady sides. Values of most of the 14 phenotypic traits tested differed significantly among clones and layers. The average value of the phenotypic differentiation coefficient was 81.16%, indicating that variation among clones explained most of the total phenotypic variation. The repeatability of the 14 phenotypic traits was high (R > 0.80), indicating that these traits are highly heritable. The phenotypic characteristics of cones and seeds varied from 6.86% to 129.51%. The 14 phenotypic traits exhibited different degrees of correlation, and seed weight, seed circumference, seed width, and seed area can be used to predict other seed traits. However, the correlations between cone traits were not strong. Our results show that when establishing a dwarfing Chinese fir seed orchard, the distribution and variation of seeds in different crown layers of clones should be considered, and clones with more cones in the lower crown layer should be selected as parents.

Uprooting as a pre-commercial thinning operation in young Norway spruce stands

Uprooting, as a mechanical pre-commercial thinning operation (PCT), removes competitive, undesired trees with roots to prevent or reduce the need for a second PCT. The state of 66 young Norway spruce (Picea abies (L.) H. Karst.) stands was explored 3–5 years after uprooting to assess the quality of uprooting in terms of the number of competing birches (Betula spp.) and the probability of freely growing crop tree spruce (no competing trees taller than 2/3 of the crop tree’s height). In the uprooted spruce stands, the number of birches was, on average, about 3800 stems ha−1, and in every fifth stand, it was less than 2000 stems ha−1. The number of birches increased with increasing site wetness (TWI), site fertility and thickness of the humus layer. In 80% of the stands, there were at least 1000 freely growing spruces ha−1, which is approximately the stem number to be left growing after first thinning in a spruce stand. If the height of crop tree spruces was 125 cm at uprooting, the probability of freely growing stems varied from 0.6 to 0.8 in typical cases. According to simulations at the first thinning stage, in most stands, birch was less than 10% taller than spruce, and the volume of birches was low enough that, in the future, spruce and birch would grow in the same crown layer as a mixed spruce–birch stand. The results showed that uprooting can serve as the only PCT operation in a planted spruce stand. The quality obtained by uprooting can be improved with careful selection of timing and conditions for uprooting; the optimal uprooting time is when crop tree spruces have reached about breast height.

Effect of Almond Milk on Tooth Enamel Surface Hardness

Introduction: Enamel is the hardest substance in the human body and serves as the wear-resistant outer layer of the dental crown. Demineralization releases mineral ions which cause a decrease in the enamel surface hardness. Demineralization could be neutralized to recover minerals, and this process is called remineralization. Almond milk was an alternative to cow’s milk, supporting tooth enamel surface remineralization. Purpose: To determine the effect of almond milk on enamel hardness. Methods: Twenty maxillary premolars were divided into group A (control) and group B (almond milk). Before treatment, samples were soaked in 1% citric acid. Enamel hardness was tested with Vickers Hardness Tester. The statistical tests used in this study were Paired t-test and Independent Sample t-Test. Results: The results of the paired sample test got significant results in groups A and B in the comparison of pretest - 1% citric acid, and 1% citric acid - posttest, which means that there was a significant difference in enamel hardness values. However, the results obtained were not substantial in groups A and B in the posttest- pretest comparison. There was no significant difference between Group A and Group B in the independent sample test results. There was an increase before and after, but it was not much different when compared to the control. Conclusion: Almond milk can increase enamel surface hardness but cannot reverse the initial enamel surface hardness value.

The Transition and Spread of a Chaparral Crown Fire: Insights from Laboratory Scale Wind Tunnel Experiments

Fire occurring in the chaparral behaves as a crown fire, a dual-layer fire that typically ignites in a dead surface fuel layer and transitions to an elevated live crown layer where it continues to spread. In chaparral fuels including chamise, a dominant species in southern California, flame transition to live crown fuels is associated with higher spread rates and greater fire intensity. Despite the relative importance of surface-to-crown transition and crown fire spread, most fire models represent chaparral fire as surface fire, therefore omitting key behavior processes driving this fire system. The purpose of this study was to characterize transition and spread behavior in chaparral fires modeled experimentally as crown fires. We examined heat release rate in the surface and crown fuel layers, time to transition, flame height, and rate of spread in wind-driven and nonwind-driven fires at two crown base heights. Our results showed that wind increased heat release rate, rate of spread, and flame height. A marked increase in heat release rate was observed in wind-driven fires, where adding wind produced an increase from 328 kW to 526 for a crown base height of 0.6 m and from 243 kW to 503 kW for a crown base height of 0.7 m. Further, crown base height served to decrease heat release rate and rate of spread for wind-driven and nonwind-driven fires.

Validation of the hot-spot model with terrestrial laser scanning

Validation of the hot-spot theoretical model was carried out with extensive terrestrial laser scanning (TLS) measurements in the Järvselja RAMI pine stand. A 120 m × 120 m × 12 m point cloud of laser hits of 1 cm resolution was built to describe the spatial structure of the crown layer. From this point cloud, foliage density was found at 1 dm resolution, and a Fourier analysis of the spatial structure of the crown layer was performed. The autocorrelation function of the transmittance of 1 dm slices of the crown layer, which controls the hot-spot profile of directional reflectance, was estimated directly from the point cloud. The determined value of the hot-spot parameter was found to agree well with the value estimated indirectly from the measurements of reflectance profile in the principal plane.

Advances in biomimetic mineralization of tooth enamel based on cell-free strategies

Tooth enamel is a highly-mineralized hard tissue covering the outermost layer of the dental crown, and amelogenesis is inseparable from the participation of necessary components such as ameloblasts, organic matrix proteins, and mineral ions, such as Ca2+ and PO43-. However, mature enamel is an acellular tissue and it is difficult to self-repair once damaged. The current treatment methods for enamel damage are filling or repairing with alloys, ceramics, or composite resins. However, the mechanical properties of these materials are quite different from the natural enamel and they can’t ensure a completely closed interface with the remaining enamel surface, which usually causes a series of post-repair problems. At present, the biomimetic mineralization of tooth enamel is a research hotspot in the field of prosthodontics, and has great clinical application needs and prospects, especially the researches on cell-free strategies have made significant accomplishment. Here, based on the cell-free strategies, we review the recent knowledge from ex situ and in situ two dimensions in the remineralization of tooth ename.

Marginal misfit of heat-pressed milled wax-pattern and CAD/CAM crowns and its effect on stress distribution in implant-supported rehabilitations

Aim: To compare the marginal fit of lithium disilicate CAD/CAM crowns and heat-pressed crowns fabricated using milled wax patterns, and evaluate its effect on stress distribution in implantsupported rehabilitation. Methods: A CAD model of a mandibular first molar was designed, and 16 lithium disilicate crowns (8/group) were obtained. The crown-prosthetic abutment set was evaluated in a scanning electron microscopy. The mean misfit for each group was recorded and evaluated using Student’s t-test. For in silico analysis, a virtual cement thickness was designed for the two misfit values found previously, and the CAD model was assembled on an implant-abutment set. A load of 100 N was applied at 30° on the central fossa, and the equivalent stress was calculated for the crown, titanium components, bone, and resin cement layer. Results: The CAD/CAM group presented a significantly (p=0.0068) higher misfit (64.99±18.73 μm) than the heat-pressed group (37.64±15.66 μm). In silico results showed that the heat-pressed group presented a decrease in stress concentration of 61% in the crown and 21% in the cement. In addition, a decrease of 14.5% and an increase of 7.8% in the stress for the prosthetic abutment and implant, respectively, was recorded. For the cortical and cancellous bone, a slight increase in stress occurred with an increase in the cement layer thickness of 5.9% and 5.7%, respectively. Conclusion: The milling of wax patterns for subsequent inclusion and obtaining heat-pressed crowns is an option to obtain restorations with an excellent marginal fit and better stress distribution throughout the implant-abutment set.

Gender plasticity uncovers multiple sexual morphs in natural populations of Cedrus deodara (Roxb.) G. Don

BackgroundThe expression of gender in gymnosperms is challenging because the extent of variability in gender segregations in tree crowns and selection pressure of nature can modify the gender through time.MethodsAn in-depth investigation on spatial segregation of genders in tree crowns and sex expression of a total of 500 trees in five different natural populations of Cedrus deodara was carried out and verified the occurrence of subdioecious (co-existence of male, female, and monoecious) genders in C. deodara.ResultsFive different sexual morphs were apparent among the 500 selected individuals as (1) pure male (M): bearing only male strobili in the whole crown with 22.2%; (2) pure female (F): bearing only female strobili in the whole crown with 12.4%; (3) mixed-monoecious (MM): bearing both male and female strobili with 13.6%; (4) predominantly female (PF) with 25.6%; and (5) predominantly male (PM) with 26.2%. The occurrence of multiple sexual morphs resulted from the complex selection pressure, which increased the stability of the populations. The segregation of genders in crown layers deemed to increase the fitness that may be a mechanism for accelerating outcrossing. The results of the study suggest that the subdioecious gender expression in C. deodara is evolved through the monoecy–paradioecy pathway. The production of male strobili revealed non-significant effect of tree sizes whereas a significant effect was observed for the production of female strobili. Our study established that the total pollen and seed outputs in C. deodara changed frequently according to gender expression.ConclusionsThe size of the tree, resource availability, sex allocation, plant architecture, gender segregation in crowns, and habitat conditions are the prominent causes for gender plasticity.

Biological diversity of insects on woody plants of the Rosacea family in the northern forest-steppe of the Ob region

The aim of the study was to determine the influence of plant species and year conditions on the biological diversity and number of insects – inhabitants of the crown layer of woody plants of the Rosaceae family in the conditions of the northern forest-steppe of the Ob region. The research was carried out in 2017–2018. During the flowering period of woody entomophilous plants, insects were collected by mowing with an entomological net in the crowns and undercrown space (25 strokes in four repetitions). In the crown of woody introduced plants Pyrus ussuriensis (Ussuri pear), Prunus maackii (Maak plum), Amelanchier alnifolia (alder irga), Spiraea betulifolia (spiraea birch leaf), Physocarpus opulifolius growing on the territory of arboretum of RAS in the northern forest-steppe of the Ob region, a total of 2597 insect specimens from 7 orders and more than 30 families were found. The largest number of insects belonged to the order Diptera (49.4 %). Representatives of the orders Thysanoptera (23.7%) and Hymenoptera (11.4%) made a significant contribution to the formation of the entomofauna. The entomofauna of different species of woody plants from the Rosaceae family differed in the taxonomic groups of insects and their numbers. A high degree of enomofauna similarity (Jaccard coefficient is 0.75) was found between Amelanchier alnifolia and Pyrus ussuriensis with similar flowering periods. A low degree of similarity was found between Amelanchier alnifolia and Spiraea betulifolia (0.32) and between Pyrus ussuriensis and Physocarpus opulifolius (0.33). The species of the plant (38.1 and 26.1%, respectively) had the greatest influence on the biological diversity and the number of entomocomplexes, which indicates the adaptation of insects to a woody plant of the Rosaceae family. The conditions of the year significantly (by 9.8%) influenced the biological diversity of insects during the flowering period.

Tree canopy arthropods have idiosyncratic responses to plant ecophysiological traits in a warm temperate forest complex

Biodiversity studies on forest canopies often have narrow arthropod taxonomic focus, or refer to a single species of tree. In response, and to better understand the wide range of drivers of arthropod diversity in tree canopies, we conducted a large-scale, multi-taxon study which (a) included effect of immediate surroundings of an individual tree on plant physiological features, and (b), how these features affect compositional and functional arthropod diversity, in a warm, southern Afro-temperate forest. We found that tree species differed significantly in plant physiological features and arthropod diversity patterns. Surprisingly, we found negative correlation between surrounding canopy cover, and both foliar carbon and arthropod diversity in host trees, regardless of tree species. Subtle, tree intraspecific variation in physiological features correlated significantly with arthropod diversity measures, but direction and strength of correlations differed among tree species. These findings illustrate great complexity in how canopy arthropods respond to specific tree species, to immediate surroundings of host trees, and to tree physiological features. We conclude that in natural forests, loss of even one tree species, as well as homogenization of the crown layer and/or human-induced environmental change, could lead to profound and unpredictable canopy arthropod biodiversity responses, threatening forest integrity.