Thuja Research Articles

DENDROFLORA UZHHOROD CITY RIVERFRONTS: CURRENT STATE AND DEVELOPMENT PROSPECTS

The paper presents the results of inventory surveys of tree and shrub plantations on six riverfronts of the city of Uzhhorod: Pravoslavna, Kyivska, and Slovianska are on the left bank, Botanichna, Nezalezhnosti, and Studentska are on the right bank. The taxonomic composition of the dendroflora was determined and analysed, the ratio of introduced and native species, as well as the distribution by age and height were established. The general condition of green areas was characterised. The main species that dominate the plantings are species of the genus Tilia L., Aesculus L., Populus nigra L. var. italica Duroi, Platanus acerifolia (Ait.) Willd., Sophora japonica L., Ginkgo biloba L., and less often highly decorative, flowering sakura Cerasus serrulata (Lindley) G. Don ex Loudon, Malus niedzwetzkyana Dieck ex Koehne, Catalpa bignonioides Walter, as well as coniferous trees of Pinus sylvestris L., Platycladus orientalis (L.) Franco. Among the exotic species, S. japonica and P. acerifolia have proved to be particularly well established in the landscaping of Uzhhorod. Trees of these species in Uzhhorod are durable, resistant to falling out, and differ little in size and shape in plantings, so they retain their aesthetic appearance for a long time and are suitable for forming linear plantings. In total, 1147 specimens of 51 species of trees and shrubs belonging to 23 families grow on the five riversides of Uzhhorod city (excluding Botanichna). The most widespread is linden, with different species totaling 332 specimens present on four riverfronts (Nezalezhnosit, Studentska, Kyivska, Slovianska). By origin, 33 species (63.5 %) are introduced. Trees are represented by 37 species, shrubs by 15 species. Among the species represented, the total number of introducing is 984 specimens (68 % of the total number). The age gradations of the riverfront tree species coincide with the historical periods of planting: Czechoslovakian (70-90 years), Soviet (30-50 years), and modern (5-25 years). Most of the trees on the riverfronts, even those that have been growing since their planting, have not yet reached the limit of their biological age and have a good or satisfactory condition. The analysis revealed the need for a number of measures to improve the riverfronts in order to improve the existing landscapes and enhance their recreational properties.

Dispersal Limitation Dominates the Spatial Distribution of Forest Fuel Loads in Chongqing, China

The forest fuel load influences the spreading rate and fire intensity during a forest fire. However, the mechanism of environmental filtering and dispersal limitation that affects the spatial distribution of the forest fuel load remains unclear. In this study, live (tree, herbaceous, and shrub) and dead fuel loads (litter and humus) were estimated based on the plot investigation results of 4 typical stands ( Pinus massoniana , Platycladus orientalis , Ficus microcarpa , and Cinnamomum camphora ) in Chongqing, China. The results demonstrated that the tree, shrub, herbaceous, litter, and humus fuel loads of the 4 typical stands were 66.92 to 118.54 Mg/ha, 2.93 to 4.04 Mg/ha, 0.77 to 1.01 Mg/ha, 0.90 to 1.39 Mg/ha, and 1.49 to 1.98 Mg/ha, respectively. The forest fuel load varied significantly among the different stands. The Mantel test revealed that the forest fuel load had significantly positive correlations with the geospatial distance and stand environment but no significant correlation with the topographic factor. Additionally, the redundancy analysis demonstrated that the stand factors, canopy density and average canopy height, and the topographic factor, altitude, had significant impacts on the forest fuel load. The variance partitioning analysis revealed that the spatial heterogeneity of the forest fuel load was mainly attributed to the covariation of environmental and spatial factors (29.55%). Moreover, the geospatial distance was a dominant independent factor for the fuel distribution (14.66%), followed by the stand environment (9.51%) and topographic factor (0.35%). In summary, the spatial distribution of the forest fuel load was dependent on niche-based and random processes, and dispersal limitation was the dominant factor.

Comparative Anatomical Study of Leaves in Five Cupressaceae Gray. Taxa in Kurdistan Region - Iraq

This study investigates the leaf anatomy of five Cupressaceae taxa in the Kurdistan region-Iraq. Using the light microscope for numerical and descriptive anatomical variations of three species and two varieties belonging to Cupressus, Platycladus, and Juniperus genera were examined for Taxonomic value. These include the characters of epiderm, hypoderm, mesophyll layer, resin canals, transfusion tracheids, pith, and vascular bundles. There are significant differences among studied species and genera. Cupressus taxa exhibit a similar cross-sectional outline. Cupressus arizonica has a larger resin canal (125.4 µm) and longer palisade cells (91.8×27 µm) compared to C. sempervirens varieties. Platycladus orientalis form a wide rhombic outline, with an abaxial resin canal similar to Juniperus oxycedrus and C. arizonica. J. oxycedrus has a triangle outline with a thick hypoderm that extends below the entire epiderm, except under stomatal depressions. While in Cupressus and Platycladus taxa, the hypoderm is restricted only to the abaxial surface of the leaf. J.oxycedrus lacks pith entirely, unlike Cupressus and Platycladus taxa where they form polygonal or slightly straight pith at the center of the vascular bundle.

Study on Government Managed Gardens in Public Buildings of Kathmandu Valley

An area embellished with ornamental plants near the city area and office can give a pleasurable, picturesque and naturalistic effect which creates a refreshing and conducive working environment for both staff and service seekers. A study was carried out to elucidate the existing situation of the government managed gardens in public buildings located in the Kathmandu valley. The gardens were selected purposively and the study was made based on the number of plant species, composition of plants, styles of gardening, maintenance of garden and appreciation of the garden. The maintenance and the appreciation of gardens were evaluated by the Likert scale (1-4). The abundance of tree was higher followed by herbaceous perennial, herbaceous annual, shrub, cacti and succulent. The garden of Narayanhiti Palace Museum was found to be dominant in tree, shrub and herbaceous perennial while the Garden of Singha Durbar and Supreme Court was found to be dominant in herbaceous annual. The frequency of Thuja orientalis (tree), Bougainvillea spp (shrub), Cuphea hyssopifolia (herbaceous perennial), Calendula officinalis (herbaceous annual) and Petunia hybrida (herbaceous annual) were higher. This study shows that formal gardens (66.66%) dominated informal gardens (33.34%). It was found that the maintenance and the overall appreciation of gardens were fair to good. The gardens need improvements in various aspects to make them artistic and beautiful.

Utility of Deep Learning Algorithms in Initial Flowering Period Prediction Models

The application of a deep learning algorithm (DL) can more accurately predict the initial flowering period of Platycladus orientalis (L.) Franco. In this research, we applied DL to establish a nationwide long-term prediction model of the initial flowering period of P. orientalis and analyzed the contribution rate of meteorological factors via Shapely Additive Explanation (SHAP). Based on the daily meteorological data of major meteorological stations in China from 1963–2015 and the observation of initial flowering data from 23 phenological stations, we established prediction models by using recurrent neural network (RNN), long short-term memory (LSTM) and gated recurrent unit (GRU). The mean absolute error (MAE), mean absolute percentage error (MAPE), and coefficient of determination (R2) were used as training effect indicators to evaluate the prediction accuracy. The simulation results show that the three models are applicable to the prediction of the initial flowering of P. orientalis nationwide in China, with the average accuracy of the GRU being the highest, followed by LSTM and the RNN, which is significantly higher than the prediction accuracy of the regression model based on accumulated air temperature. In the interpretability analysis, the factor contribution rates of the three models are similar, the 46 temperature type factors have the highest contribution rate with 58.6% of temperature factors’ contribution rate being higher than 0 and average contribution rate being 5.48 × 10−4, and the stability of the contribution rate of the factors related to the daily minimum temperature factor has obvious fluctuations with an average standard deviation of 8.57 × 10−3, which might be related to the plants being sensitive to low temperature stress. The GRU model can accurately predict the change rule of the initial flowering, with an average accuracy greater than 98%, and the simulation effect is the best, indicating that the potential application of the GRU model is the prediction of initial flowering.

Paolo Veneziano’s arbor crucis in Dubrovnik and the Rhetoric of the Frame in the Mid-Trecento

Abstract The paper analyzes the wooden frame of Paolo Veneziano’s monumental Crucifixion, the largest trecento composition in the Adriatic to survive, on the triumphal arch of the church of St. Dominic in Dubrovnik. By including the scrolls’ foliage, the Old Testament prophets, and censing angels, this frame transforms a stylistically inventive yet typologically conventional “croce dipinta” into one aligned with the iconography of the arbor vitae by way of an unprecedented shift of attention to its margins. The full power of the Crucifixion is vested both in the body of the crucified Christ and its frame. At the same time, its overarching theme of the genealogy of Christ and his Passion can be subject to different readings, i.e. “doctrinal,” “liturgical,” or, as the paper tentatively proposes, “Dominican.”

The Influence of Stand Structure on Understory Herbaceous Plants Species Diversity of Platycladus orientalis Plantations in Beijing, China

Species diversity is a crucial index used to evaluate the stability and complexity of forest ecosystems. Studying the relationship between stand structure and understory herbaceous plants species diversity is useful for managers to formulate the best forest structure optimization method with the goal of improving herbaceous species diversity. In this research, Platycladus orientalis plantations in Beijing were taken as the research object. Pearson’s correlation analysis was used to explore the single-factor correlation between stand structure and understory herbaceous plants species diversity; furthermore, a typical correlation analysis and multiple linear regression were used to explore the multi-factor correlation and analyze the dominant stand structure parameters affecting understory herbaceous plants species diversity. In the range of stand structures studied, the results showed that canopy density was negatively correlated with the Shannon–Wiener index and Simpson index (p < 0.01), and tree density was negatively correlated with the Shannon–Wiener index (p < 0.05). In terms of stand spatial structure, the mingling degree was positively correlated with the Shannon–Wiener index, Simpson index, Margalef richness index and Pielou evenness index (p < 0.05), while the uniform angle was negatively correlated with the Pielou evenness index (p < 0.05). The correlation coefficient of the first group of typical variables in the typical correlation analysis was 0.90 (p < 0.05); from this group of typical variables, it can be concluded that canopy density is the most influential indicator affecting the comprehensive index of understory herbaceous plants species diversity, with a load of −0.690, and the Shannon–Wiener index and Simpson index are the most responsive indicators of changes in the comprehensive index of stand structure, with loads of 0.871 and 0.801, respectively. In the process of the management of Platycladus orientalis plantations under a low altitude, south slope, thin soil layer and hard soil parent material, in order to improve the herbaceous species diversity, the canopy density of the overstory and tree density should be appropriately reduced. Additionally, it is necessary to regulate the horizontal spatial structure of stands. When the trees are randomly distributed and the mingling degree is high, the species diversity of herbs can be increased.

Evaluation of Insecticidal Potentials of Five Plant Extracts against the Stored Grain Pest, Callosobruchus maculatus (Coleoptera: Bruchidae).

Plant based insecticides are considered among the most economic and ecofriendly chemicals for the protection of plants and stored grains. The cowpea weevil (Callosbruchus maculatus) causes more than 90% damage to sored grains in three to six months. The current study investigates insecticidal potentials of five selected botanicals: Melia azedarach, Nicotiana rustica, Azadirachta indica, Nicotiana tabacum and Thuja orientalis. They are explored at six different concentrations (0.5, 1.0, 1.5, 2.0, 2.5 and 3.0%) against C. maculatus and compared to effects of distilled water which is used as a control. Toxicities of 3%(V/V) extracts of N. tabacum, N. rustica, A. indica and T. orientalis against C. maculatus were 100%, 86.11%, 80.56% and 72.22%, respectively. Maximum mortality was caused by N. tabacum and N. rustica (100%), followed by A. indica (82%), whereas minimum mortality was observed in T. orientalis (64%) at 2.5%. Several phytochemicals, alkaloids, saponins, diterphenes, phytosterol, flavonoids and phenols were identified in N. tabacum and N. rustica, while few were present in A. indica. Phytosterol was present in greatest abundance. Saponins were only detected in aqueous extracts of N. rustica and N. tabacum. Taken together, these results indicate the utility of N. tabacum, N. rustica and A. indica as potential botanicals to control pest beetle and cowpea weevil.

Response of Fluorescence and Chlorophyll Physiological Characteristics of Typical Urban Trees to Ozone Stress

In this study, four typical urban landscaping tree species were selected, three open top air chambers with different ozone concentrations were set, and the responses of chlorophyll fluorescence, chlorophyll content and relative conductivity of the trees to ozone stress were studied. The results showed that with the increase in ozone concentration, the maximum photochemical efficiency, electron transfer quantum yield, electron transfer rate (ETR) and chlorophyll content of the different tree species decreased significantly, while the relative conductivity of the different tree species increased significantly. Compared with the ozone concentration of NF, under an ozone concentration of nf40 and nf80, the decline in the rate of Fv/Fm of Koelreuteria paniculata and Ginkgo biloba was 2.47 and 2.28 times that of Pinus bungeana and Platycladus orientalis, respectively, and the increase in the rate of relative conductivity of K. paniculata and G. biloba was 2.11 and 1.28 times that of P. bungeana and P. orientalis, respectively. Under different ozone concentrations, the photochemical efficiency, electron transfer rate, chlorophyll content and relative conductivity of P. bungeana and P. orientalis were higher than those of Ginkgo biloba and K. paniculata, indicating that K. paniculata and G. biloba were more sensitive to ozone. This study is of great significance for improving urban environmental quality and ozone control and also provides a basis for selecting tree species with strong ozone tolerance.

Transcriptome and metabolome analyses of lignin biosynthesis mechanism of Platycladus orientalis.

Platycladus orientalis, as an important plant for ecological protection, is a pioneer tree species for afforestation in arid and barren mountainous areas. Lignin has the functions of water and soil conservation, strengthening plant mechanical strength and resisting adverse environmental effects and plays an important role in the ecological protection benefits of P. orientalis. In this study, annual dynamic observations of the lignin content in roots, stems and leaves of one-year-old seedlings of a P. orientalis half-sib family were carried out, and combined transcriptome and metabolome analyses were carried out during three key stages of P. orientalis stem development. The lignin contents in roots, stems and leaves of P. orientalis showed extremely significant spatiotemporal differences. In the stems, lignin was mainly distributed in the cell walls of the pith, xylem, phloem, pericyte, and epidermis, with differences in different periods. A total of 226 metabolites were detected in the stem of P. orientalis, which were divided into seven categories, including 10 synthetic precursor compounds containing lignin. Among them, the content of coniferyl alcohol was the highest, accounting for 12.27% of the total content, and caffeyl alcohol was the lowest, accounting for 7.05% only. By annotating the KEGG functions, a large number of differentially expressed genes and differential metabolites were obtained for the comparison combinations, and seven key enzymes and 24 related genes involved in the process of lignin synthesis in P. orientalis were selected. Based on the results of the metabolic mechanism of lignin in P. orientalis by biochemical, anatomical and molecular biological analyzes, the key regulatory pathways of lignin in P. orientalis were identified, which will be of great significance for regulating the lignin content of P. orientalis and improving the adaptability and resistance of this plant.

Responses of Rhizosphere Soil Chemical Properties and Bacterial Community Structure to Major Afforestation Tree Species in Xiong’an New Area

To explore the response of rhizosphere chemical and biological properties to eight major afforestation species in Xiong’an New Area, we measured rhizosphere soil properties in their pure stands and analyzed the bacterial community structure using a high-throughput sequencing platform. The results showed that: (1) Compared with coniferous species, broadleaved species had higher total nutrient concentration and pH in the rhizosphere but lower available nutrient concentration and soil moisture. Nitrate nitrogen deficiency was found in all stands. (2) Uncultured_bacterium_f_Longimicrobiaceae and RB41 could distinguish Platycladus orientalis (Linn.) Franco from other trees. Compared with other tree species, Sabina chinensis (Linn.) Ant., Armeniaca vulgaris Lam., and Fraxinus chinensis Roxb. gathered more Actinobacteria, Planctomycetes, and Gemmatimonadetes, respectively. Uncultured_bacterium_o_Rokubacteriales, uncultured_bacterium_f_Gemmatimonadaceae, and uncultured_bacterium_c_Subgroup_6 were major contributors to the differences in bacterial communities among most tree species. (3) Species characteristics changed soil chemical properties, further affecting the bacterial community. Total carbon, organic matter, total nitrogen, and pH were the main factors explaining these variations. In general, Sophora japonica Linn. and F. chinensis could increase soil total nutrient significantly, which meant that they were more suitable for afforestation in the studied area than the other species. P. orientalis and Pinus tabuliformis Carr. were better choices among conifers. We suggest planting more mixed forests to improve the rhizosphere nutrient status of conifers. A suitable way to alleviate prevailing nitrogen and phosphorus limitations is also required, such as introducing understory vegetation or supplementing organic fertilizers.

Usability of some woody plants in monitoring and reducing the Mn, Zn, Ba, and Sr concentrations in the air

The advancements worldwide in the last century made air pollution one of the most important problems threatening human health on a global scale. One of the most harmful components of air pollution is heavy metals. For this reason, monitoring and reducing heavy metal pollution has been one of the main research subjects in recent years. In the present study, the accumulation of Mn, Zn, Ba, and Sr, which were included in the preliminary pollutant list by ATSDR (Agency for Toxic Substances and Disease Registry) since they pose a significant threat to human health, by plant species and organ was investigated. As a result of the present study, the highest concentrations were found in the leaves. The most useful species to be utilized in monitoring the change of the concentrations of heavy metals examined here in the air and to reduce the level of pollution were found to be Cotoneaster franchetii and Platycladus orientalis.

Study of Tree Diversity and Biomass in Natural and Managed Site of Ridge Forest Ecosystem, Delhi Forest, India

Tree diversity and biomass (above and below-ground) were studied in natural and managed sites of Delhi Ridge Forest. The study was conducted in the Northern Ridge (NR) and South-Central Ridge (SCR) of the forest ecosystems. In the natural site of both the ridges, Prosopis juliflora (IVI= 105) was the dominant species due to its invasive nature. Eucalyptus tereticornis (IVI =41.7) and Pongamia pinnata (IVI= 63.5) was were dominant species in the managed site of NR and SCR, respectively. Rare species in the natural site was Wrightia tinctoria. In managed site, Thuja orientalis (IVI=4.08) and Ficus bengalensis (IVI= 4.6) were rare. The maximum biomass was found in aboveground biomass of the natural site of Delhi NR forest i.e. aboveground biomass (AGB) ranged was from 44.59 Mg ha-1 to 89.99 Mg ha-1 while the belowground biomass (BGB) was 17.29 ranged from 9.16 Mg ha-1 to 17.29 Mg ha-1. The least AGB was in the managed site of SCR (44.59 Mg ha-1). The total biomass of the NR ranged between 70.35 to 107.28 Mg ha-1. In SCR, it ranged between 53.75 to 96.22 Mg ha-1 which was low as compared to NR due to high human disturbance and poor soil quality. AGB and tree density was found to be maximum in 10-30 cm diameter class in all the sites of Ridge Forest. Prosopis juliflora was the most important tree species in ridge ecosystem as it allocated approximately 50% of the total biomass. Trees of Delhi ridge forest falls under lower diameter classes due to disturbance regime. Variations in species composition, density, diameter distributionpattern, biomass and Carbon stock in the Northern and South-Central Ridge were attributed to two different forest management practices adopted. Hence, both the Ridge Forest had potential for carbon sequestration due to presence of large number of trees belonging to small dbh classes.

Evaluating potential groundwater recharge in the unsteady state for deep-rooted afforestation in deep loess deposits

Groundwater recharge reduces due to high transpiration from shallow-rooted to deep-rooted afforestation. However, reaching a steady state in recharge process is challenging and no methods are available for assessing potential groundwater recharge under unsteady state. Hence, this study developed a new method to quantify groundwater recharge in the unsteady state by (1) calculating the water age (A2) at maximum root depth (D2) for deep-rooted afforestation using the chloride accumulative age method; (2) determining the soil depth (D1) corresponding to A2 under shallow-rooted vegetation using the multi-year average pore water velocity multiplied by A2; (3) calculating the reduction in groundwater recharge (∆R) from shallow- to deep-rooted afforestation as the depth difference multiplied by the average water content between D1 and D2, divided by stand age. The average groundwater recharge for deep-rooted afforestation is equal to the average annual groundwater recharge under shallow-rooted vegetation minus ∆R. Soil cores with >25 m soil profiles below four land-use types of Hippophae rhamnoides Linn. (H. rhamnoides), Platycladus orientalis (L.) Franco (P. orientalis), Robinia pseudoacacia L. (R. pseudoacacia), and grassland were collected to measure soil water content, root distribution, and chloride and tritium contents. The results revealed that: (1) maximum root depths were 11.0 ± 0.5, 20.2 ± 1.2, and 22.6 ± 0.8 m, with soil water deficits of 373.48, 823.65, and 1847.92 mm under H. rhamnoides, P. orientalis, and R. pseudoacacia, respectively; (2) groundwater recharge following land-use change has not reached a steady state; (3) an average annual groundwater recharge was 89.12 mm yr−1 under grassland, amounting to 16 % of the average annual precipitation; deep-rooted afforestation did not significantly differ, with 83.55, 84.91, and 85.65 mm yr−1 under H. rhamnoides, P. orientalis, and R. pseudoacacia, respectively. This study contributes to a rational assessment of groundwater resources under unsteady state during land-use change.

Factors of Natural Regeneration of Platycladus orientalis (L.) Franco in Guilin, China

Cypress (Platycladus orientalis (L.) Franco) is one of the important evergreen trees for afforestation in barren mountains, soil consolidation, and water conservation, but natural regeneration of cypress is complex and slow. An understanding of the influence mechanism of the natural regeneration of cypresses is essential for elevating survival and regeneration. This study aimed to clarify the relationship between stand factors, environmental factors, and regeneration of cypress plantations. A total of 42 cypress sample plots in Guilin, China, were selected to evaluate the impact of various stand factors and environmental factors on the regeneration of cypresses using survey statistics and Pearson and Spearmanrank correlation analysis. In this study, cypress has the highest frequency and density of regeneration among all the seedlings in the 18 surveyed forests, but the height structure of cypress seedlings distributes in uneven mode and mainly Grade I (height < 30 cm) seedlings. Low-density herbs and high-density moss mulching had a directly positive effect on the number of cypress regeneration seedlings. Larger soil stone content and gap area can promote cypress regeneration, which is appropriate for cypresses in the seedling stage. In conclusion, timely weeding, proper soil loosening, and improving light transmittance contribute to promoting the regeneration of cypresses.

The bioecological features of some species of the Cupressaceae introduced in the conditions of Tashkent City, Uzbekistan

Abstract. Temirov EE, Rakhimova NK. 2022. The bioecological features of some species of the Cupressaceae introduced in the conditions of Tashkent City, Uzbekistan. Biodiversitas 23: 5532-5538. For the first time, monitoring of the current state of previously introduced 19 species and 10 forms of the Cupressaceae family was carried out. Four species and five forms selected among them are distinguished by high decorativeness. The studied species and forms differ in the duration of the virginal period. Under the conditions of Uzbekistan, in forms of the genus Platycladus it lasts 4-5 years, in forms of the genus Thuja - 6-8 years, in the genera Chamaecyparis and Juniperus 6-9 years. The maximum growth and development indices under the conditions of Tashkent were observed in Platycladus orientalis f. compacta (East Asia), and the smallest ones are found in Chamaecyparis lawsoniana (North America) and Juniperus squamata (Western China). Seed germination in forms of the genus Platycladus under laboratory conditions is 56-78% (optimal temperature 20-22°C), in forms of the genus Thuja 31-46%, in Chamaecyparis lawsoniana - 21% (optimal temperature 28-29°C), the maximum rate of seed germination in the field was noted in Platycladus orientalis f. compacta (90-95%), and the minimum is Chamaecyparis lawsoniana (6-8%). For the first time, the possibility of vegetative reproduction in open ground with a rooting rate of cuttings up to 95% has been shown. Vegetative propagation gives effective results compared to a seed. For the first time in Uzbekistan, such a study was conducted on conifers, until now, no one has previously studied the biological characteristics of Conifers within the country.

Larvicidal potential of Thuja orientalis leaves and fruits extracts against Culex pipiens (Diptera: Culicidae)

Botanical pesticides targeted to avoid the pesticide resistance to synthetic ones that conventionally affecting ecosystems diversity. The study designed to evaluate the larvicidal potentials of leaves and fruits extracts (methanol, acetone, hexane, and aqueous) from Thuja orientalis (Pinales: Cupressaceae) against Culex pipiens 3rd instar larvae and to identify the extracts compounds by gas chromatography-mass spectrometry (GC–MS) method of analysis. Leaves and fruits extracts used in concentrations, 25, 50, 100, 200, and 400 ppm against the 3rd larval instar of Cx. pipiens in five replicates and larval mortalities recorded after 24 and 48 h post exposure. The larvicidal potentials of extracts showed concentration dependent and varied between leaves and fruits extracts. At 400 ppm concentration, leaves extracts showed 100 % larval mortality except in hexane extract exhibited 98 %. Acetone, methanol, aqueous and hexane leaves extracts recorded LC50 values, 58.04, 70.20, 77.19 and 84.25 ppm, respectively. Fruits extracts by hexane and methanol exhibited 100 % larval mortality and LC50, 68.26 and 83.21 ppm, respectively, while, acetone and aqueous fruits extracts showed 98 % and 96 % larval mortality and LC50, 92.81 and 102.97 ppm, respectively. Terpenoids and sesquiterpenoids, fatty acid esters mainly identified in both extracts.The present study showed that extracts from Thuja orientalis leaves and fruits acquired promising larvicidal potential for the control of Cx. pipiens larvae with the role of their chemical constituents.

Water Storage and Use by Platycladus orientalis under Different Rainfall Conditions in the Rocky Mountainous Area of Northern China

Tree water transport and utilization are essential for maintaining ecosystem stability in seasonally arid areas. However, it is not clear how Platycladus orientalis absorbs, consumes via transpiration, and stores water under varying precipitation conditions. Therefore, this study used stem sap flow thermal dissipation probes and hydrogen and oxygen isotope tracing technology to observe different water control treatments in a P. orientalis plantation. We found that the average daily sap flow of P. orientalis under different water control treatments had the following order: no rainfall (NR) < half rainfall (HR) < double rainfall (DR) < natural rainfall (AR). The percentage of nocturnal sap flow was as follows: AR (13.34%) < NR (19.62%) < DR (20.84%) < HR (30.90%). The percentage of water storage was NR (4.13%) < AR (4.49%) < DR (6.75%) < HR (9.29%). The sap flow of P. orientalis was primarily affected by vapor pressure deficit and solar radiation, with a degree of influence of DR < NR < HR < AR. The response of P. orientalis sap flow to environmental factors differed due to the soil changes in relative extractable water (REW) before and after precipitation. During high REW conditions, environmental factors have a higher impact on sap flow. The source of water absorbed changed regularly with the precipitation gradient. When soil water content increased, the water source used by P. orientalis gradually changed to shallow soil. Compared to before and after precipitation, there was no significant change except for NR. P. orientalis could regularly adjust the activities of transpiration water consumption, water storage, and absorption. This adaptive property is conducive to survival through extreme drought stress.

Effects of carbon monoxide, nitrogen dioxide, and fine particulate matter on insect abundance and diversity in urban green spaces

The impact of three air pollutants, carbon monoxide, nitrogen dioxide, and fine particulate matter (PM2.5) on the diversity and abundance of insect fauna associated with Chinese thuja, Platycladus orientalis, was evaluated for the first time in Iran. Sampling was performed in Lashkar, Sadaf, and Sajjad, three urban green spaces in Mashhad, a city located in Razavi Khorasan province. A total of 29 insect species including 16 natural enemies and 13 herbivores were identified. The results indicated that herbivore abundance was positively and significantly correlated with the level of carbon monoxide and nitrogen dioxide, but not with the level of fine particulate matter. In contrast, herbivore diversity was negatively and significantly correlated only with the level of carbon monoxide. As for natural enemies, abundance and diversity both were not significantly correlated with the levels of none of all three pollutants. The aphid, Cinara thujafilina Del Guercio was the most dominant herbivore species in all the sampling sites with a relative abundance of 86% at Lashkar, 93% at Sadaf, and 95% at Sajjad. Regarding natural enemies, the ladybird, Coccinella septempunctata was the most abundant species both at Lashkar (49%) and Sadaf (35%) while the ladybird, Oenopia conglubata was the most abundant at Sajjad (21%). The highest diversity of herbivores and natural enemies across the four seasons were at the Lashkar and Sadaf sites. The results highlight that of the three air pollutants, carbon monoxide is the one that affects both on abundance and diversity of herbivore guild associated with Platycladus orientalis in urban green spaces.

Responses of biological soil crusts to different types of vegetation restoration on the Chinese Loess Plateau: a case study

Biological soil crusts (biocrusts) are important components of dryland ecosystems. Vegetation strongly affects the distribution of biocrusts by influencing the soil stability, moisture and light availability. The Loess Plateau has been subjected to large‐scale restoration efforts; however, the type, coverage, and biomass of biocrusts responses to different types of vegetation restoration remain uncertain. Here, we investigated the biocrust characteristics (type, coverage, thickness, biomass, dominant cryptogam species, and relative abundance of major cyanobacteria and algae) in areas restored with different types of vegetation (Caragana korshinskii, Platycladus orientalis, Armeniaca sibirica, Populus hopeiensis, Pinus tabuliformis, Tamarix chinensis) and in a natural grassland on the Loess Plateau. Our results showed that the coverage, thickness, and biomass of the biocrusts were higher in the natural grassland than in the afforested areas, which suggests that the natural grassland is more suitable than the afforested areas for biocrust distribution. The biocrusts were composed mainly of mosses in the Pi. tabuliformis area and of cyanobacteria and algae in most of the other vegetation restoration areas. However, no biocrusts were observed in the T. chinensis area, probably because the dense canopy prevented light from reaching the soil. In addition, soil properties influenced by vegetation restoration may also affect the characteristics of biocrusts. Overall, our study suggests that natural grassland recovery, rather than afforestation, is likely the most suitable method for the development of biocrusts and provides suggestions for restoration and reconstruction on the Loess Plateau.