Search Results (13)

The world’s big cities, including Budapest, are becoming more crowded, with more and more people living in smaller and smaller spaces. There is an increasing demand for more green space and trees, with less vertical and less horizontal space. In addition, deteriorating environmental conditions are making it even more difficult for trees to grow and survive. Tree species in urban areas have multiple functions and high ecosystem services when in good health. Among taxa with diverse habits, sizes, crown shapes, growth vigor, longevity, urban tolerance, and canopy habit, our research aims to evaluate urban specimens of spherical species with smaller space requirements and sizes but have regular geometric crown shapes in public plantations in Budapest. In the restricted urban habitats, the city’s cadastral records include 4676 specimens with spherical crowns. Among the species examined, eight species with globular crowns (Acer platanoides ‘Globosum’, Catalpa bignonioides ‘Nana’, Celtis occidentalis ‘Globosa’, Fraxinus excelsior ‘Nana’, Fraxinus ornus ‘Mecsek’, Platanus × hispanica ‘Alphen’s Globe’, Prunus × eminens ‘Umbraculifera’ and Robinia pseudoacacia ‘Umbraculifera’) were evaluated in relation to age, health, wood type, crown size, and shade projection in order to show which species are or will be suitable in the future. Full article

Air pollution, including particulate matter (PM), impacts public health in urban areas. Vegetation acts as a natural filter, removing environmental pollution by absorbing large quantities of toxic substances on the foliage. Ambient air pollution problems are real in Armenia’s cities. This article presents the results of a study based on field sampling in July 2022 undertaken in urban parks and streets in the Armenian cities of Yerevan, Gyumri, and Vanadzor. The three cities have different climates and geographic conditions. The main research goal was a comparative study of the accumulation of PM by urban greenery. The most widespread tree species were selected for the study in each city: in Yerevan, Platanus orientalis and Quercus robur; in Gyumri, Fraxinus excelsior and Tilia caucasica; and in Vanadzor, Aesculus hippocastanum and Acer pseudoplatanus. The ecological status of trees was assessed through visual observation. Tree species with high PM uptake potential were identified and selected for inclusion in urban greening systems (Platanus orientalis, Fraxinus excelsior, and Quercus robur in Yerevan; Tilia caucasica, Sorbus persica, Fraxinus excelsior, and Populus alba in Grumri; Acer pseudoplatanus, Fraxinus excelsior, Aesculus hippocastanum, and Thuja occidentalis in Vanadzor.). High PM accumulation was found on the leaves of tree species in all of the investigated cities, with the largest amount recorded in Yerevan. In these cities, PM levels were higher in street plantations than in parks. All studied tree species have a high potential for PM absorption, demonstrating strong phytofilter properties. Therefore, they can be effectively used in their typical climatic zones and included in street plantings, gardens, and parks. These results can help urban planners and policymakers make informed decisions about urban greening initiatives to improve air quality and overall wellbeing. Full article

Historically, tree sap has been used globally for medicinal purposes, in fermented beverages, and for syrup production. Maple tree sap is notably concentrated into syrup and is valued as a natural sweetener rich in phenolic compounds and minerals compared to refined sugar. Recently, syrups from other trees like black walnut (Juglans nigra) and sycamore (Platanus occidentalis) have gained popularity, yet their properties are not well understood scientifically. To address this gap, we collected sycamore, black walnut, and maple syrup samples and analyzed their physicochemical and functional properties. Our findings showed significant differences among the syrups in pH, browning intensity, and water activity (p < 0.05). Sycamore syrup had the highest total phenolic content, followed by black walnut and maple syrups. Both black walnut and sycamore syrups exhibited similar antioxidant activity, significantly higher than maple syrup (p < 0.05). High-resolution mass spectrometry identified 54 phenolic acids and 22 flavonoids in these syrups, including Acetylsalicylic acid, 3,5-Dihydroxybenzoic acid, and syringic acid, known for their antioxidant and anti-inflammatory properties. Additionally, sycamore syrups and most black walnut syrups displayed varying degrees of antimicrobial activity against Gram-positive and/or Gram-negative microorganisms. This study offers insights into the properties and potential health benefits of these specialty tree syrups. Full article

The short-rotation coppice (SRC) culture of trees provides a sustainable form of renewable biomass energy, while simultaneously sequestering carbon and contributing to the regional carbon feedstock balance. To understand the role of SRC in carbon feedstock balances, field inventories with selective destructive tree sampling are commonly used to estimate aboveground biomass (AGB) and canopy structure dynamics. However, these methods are resource intensive and spatially limited. To address these constraints, we examined the utility of publicly available airborne Light Detection and Ranging (LiDAR) data and easily accessible imagery from Unmanned Aerial Systems (UASs) to estimate the AGB and canopy structure of an American sycamore SRC in the piedmont region of North Carolina, USA. We compared LiDAR-derived AGB estimates to field estimates from 2015, and UAS-derived AGB estimates to field estimates from 2022 across four planting densities (10,000, 5000, 2500, and 1250 trees per hectare (tph)). The results showed significant effects of planting density treatments on LIDAR- and UAS-derived canopy metrics and significant relationships between these canopy metrics and AGB. In the 10,000 tph, the field-estimated AGB in 2015 (7.00 ± 1.56 Mg ha⁻¹) and LiDAR-derived AGB (7.19 ± 0.13 Mg ha⁻¹) were comparable. On the other hand, the UAS-derived AGB was overestimated in the 10,000 tph planting density and underestimated in the 1250 tph compared to the 2022 field-estimated AGB. This study demonstrates that the remote sensing-derived estimates are within an acceptable level of error for biomass estimation when compared to precise field estimates, thereby showing the potential for increasing the use of accessible remote-sensing technology to estimate AGB of SRC plantations. Full article

Forested wetlands are common ecosystems within the Great Lakes region (Michigan, Minnesota, and Wisconsin), USA. Projected increases in extreme flooding events and shifting disturbance regimes create challenges for tree regeneration. Forest managers are considering the use of enrichment planting to increase tree species diversity, but limited information is available that quantifies the interactions between the flooding and shade tolerances of candidate tree species. We used a microcosm experiment to manipulate shade and flooding conditions to determine the effects on early survival, growth, and leaf gas exchange of 23 different tree species that vary in shade and flood tolerance. Seedlings were planted in pots and placed in 227 L tanks that were randomly assigned to light reduction (full sun, 40% and 70% reduced sunlight) and flood treatments (water levels of 0, 14, or 27 cm below the soil surface). In general, flooding treatments had a greater influence on seedling growth and leaf gas exchange rates than light reduction treatments. Of the species studied, bald cypress (Taxodium distichum (L.) Rich.) was the most flood-tolerant, but American sycamore (Platanus occidentalis L.) and river birch (Betula nigra L.) were also highly tolerant of flooding conditions throughout the entire growing season. The flood tolerances of the remaining species varied, but none were tolerant of water table depths within 14 cm of the soil surface for the entire growing season. Most species did not respond to the shade treatments in terms of early growth, survival, and leaf gas exchange. When considering species for planting in forested wetlands, matching the flood tolerance of candidate species to local site hydrology is an important step. Full article

Since its infestation was first discovered in Wuhan, Hubei Province, China, in October 2006, Corythurcha ciliata has become an important piercing-sucking pest of Platanus occidentalis. In this paper, the content of secondary plant products, nutrients, and resistance enzymes in damaged leaves of P. occidentalis was determined, and the leaves infested by different numbers of adults (0 head, 1–3 heads, or >7 heads) were tested via spectrum analysis. The results showed that the tannin content of the damaged leaves was 1.47 mg/100 g, which was higher than that of the undamaged leaves (1.20 mg/g). The tannin content in the control poplar (Populus × euramericana cv.‘74/76’) leaves was 0.2 mg/100 g higher than that in damaged leaves. The soluble sugar content in intact leaves of P. occidentalis (1.35 mg/100 g) was significantly higher than that of damaged leaves and poplar leaves. C. ciliata feeding can induce an increase in defense enzymes, such as peroxidase, polyphenol oxidase, and phenylalanine ammonia lyase, in host leaves. In the west and south part of the crown, 580–680 nm is a sensitive band for monitoring C. ciliata. The results of this study can be used to reveal the host-selection mechanism of C. ciliata and to explore new infestation-monitoring technologies. Full article

Despite the rapid advances in drug R&D, there is still a huge need for antibacterial medications, specifically for the methicillin-resistant Staphylococcus aureus (MRSA). Inspired by the research where a viable class of MRSA inhibitors was found in the species Platanus occidentalis, a S. aureus inhibition screening-guided phytochemical reinvestigation on Platanus × acerifolia (London plane tree) leaves were performed with four flavonoid glycosides garnered, including two new compounds, quercetin-3-O-α-l-(2″-E-p-coumaroyl-3″-Z-p-coumaroyl)-rhamnopyranoside (E,Z-3′-hydroxyplatanoside, 1) and quercetin-3-O-α-l-(2″-Z-p-coumaroyl-3″-E-p-coumaroyl)-rhamnopyranoside (Z,E-3′-hydroxyplatanoside, 2). All of the isolates showed significant S. aureus ATCC 25904 inhibitory activity with MICs ranging from 4 to 64 μg/mL, suggesting the potential of discovering drug leads for the control of S. aureus from such a rich, urban landscaping plant in the Platanus genus. Full article

Bioenergy is one of the most considered alternatives to fossil fuels. Short-rotation woody crops (SRWCs) as bioenergy sources are capable of alleviating energy constraints and sequestering atmospheric CO₂. However, studies investigating soil carbon (C) dynamics at SWRC plantations are scarce. We studied American sycamore (Platanus occidentalis) as a model tree species for SRWC at different planting densities ((1) 0.5 × 2.0 m (10,000 trees·ha⁻¹ or tph), (2) 1.0 × 2.0 m (5000 tph), and (3) 2.0 × 2.0 m (2500 tph)) to examine seasonal variation in total soil respiration (R_total), partitioned into heterotrophic (R_h) and autotrophic (R_a) respiration, and we evaluated climatic and biological controls on soil respiration. R_total and R_h exhibited larger seasonal variation than R_a (p < 0.05). During the nongrowing seasons, the average R_total was 0.60 ± 0.21 g·C·m⁻²·day⁻¹ in winter and 1.41 ± 0.73 g·C·m⁻²·day⁻¹ in fall. During the growing season, R_total was 2–7 times higher in spring (3.49 ± 1.44 g·C·m⁻²·day⁻¹) and summer (4.01 ± 1.17 g·C·m⁻²·day⁻¹) than winter. Average R_total was 2.30 ± 0.63 g·C·m⁻²·day⁻¹ in 2500 tph, 2.43 ± 0.64 g·C·m⁻²·day⁻¹ in 5000 tph, and 2.41 ± 0.75 g·C·m⁻²·day⁻¹ in 10,000 tph treatments. Average R_h was 1.72 ± 0.40 g·C·m⁻²·day⁻¹ in 2500 tph, 1.57 ± 0.39 g·C·m⁻²·day⁻¹ in 5000 tph, and 1.93 ± 0.64 g·C·m⁻²·day⁻¹ in 10,000 tph, whereas R_a had the lowest rates, with 0.59 ± 0.53 g·C·m⁻²·day⁻¹ in 2500 tph, 0.86 ± 0.51 g·C·m⁻²·d⁻¹ in 5000 tph, and 0.48 ± 0.34 g·C·m⁻²·day⁻¹ in 10,000 tph treatments. R_h had a greater contribution to R_total (63%–80%) compared to R_a (20%–37%). Soil temperature was highly correlated to R_total (R² = 0.92) and R_h (R² = 0.77), while the correlation to R_a was weak (R² = 0.21). R_total, R_h, and R_a significantly declined with soil water content extremes (e.g., <20% or >50%). Total root biomass in winter (469 ± 127 g·C·m⁻²) was smaller than in summer (616 ± 161 g·C·m⁻²), and the relationship of total root biomass to R_total, R_h, and R_a was only significant during the growing seasons (R² = 0.12 to 0.50). The litterfall in 5000 tph (121 ± 16 g DW·m⁻²) did not differ (p > 0.05) from the 2500 tph (108 ± 16 g DW·m⁻²) or 10,000 tph (132 ± 16 g DW·m⁻²) treatments. In no circumstances were R_total, R_h, and R_a significantly correlated with litterfall amount across planting densities and seasons (p > 0.05). Overall, our results show that R_total in American sycamore SRWC is dominated by the heterotrophic component (R_h), is strongly correlated to soil environmental conditions, and can be minimized by planting at a certain tree density (5000 tph). Full article

The increased abundance of historically rare native tree species is symptomatic of land-use change, which causes ecosystem regime shifts. I tested for an association between mean agricultural area, a proxy for land-use change, and native tree species. I first modeled agricultural area during the years 1850 to 1997 and the historical and current percent composition of tree genera, along with the dissimilarity and difference between the historical and current composition, for the northern part of the eastern U.S. I then modeled agricultural area and current genera and species for the eastern U.S. and regionally. For the northeast, agricultural area was most associated (R² of 78%) with the current percentage of elms and a diverse, uncommon “other” genera. For the eastern U.S., Ulmus, Juglans, Prunus, boxelder (Acer negundo), black cherry (Prunus serotina), and hackberry (Celtis occidentalis) best predicted agricultural area (R² of 66%). Regionally, two elm and ash species, black walnut (Juglans nigra), mockernut hickory (Carya tomentosa), red maple (Acer rubrum), sweetgum (Liquidambar styraciflua), and American sycamore (Platanus occidentalis) increased with agricultural area. Increases in historically rare and diverse species associated with agricultural area represent an overall pattern of invasive native tree species that have replaced historical ecosystems after land-use change disrupted historical vegetation and disturbance regimes. Full article

Short rotation woody crops (SRWCs) provide sustainable, renewable biomass energy and offer potential ecosystem services, including increased carbon storage, reduced greenhouse gas emissions, and improved soil health. Establishing SRWCs on degraded lands has potential to enhance soil properties through root and organic matter turnover. A better understanding of SRWC planting density and its associated root turnover impacts on soil–air–water relations can improve management. In this study, we investigate the effects of planting density for a low-input American sycamore SRWC (no fertilization/irrigation) on soil physical properties for a degraded agricultural site in the North Carolina piedmont. The objectives were (1) to estimate the distributions of coarse and fine root biomass in three planting densities (10,000, 5000, and 2500 trees per hectare (tph)) and (2) to assess the effects of planting density on soil hydraulic properties and pore size distribution. Our results show that planting at 10,000 tph produced significantly higher amounts of fine root biomass than at lower planting densities (p < 0.01). In the 25,000 tph plots, there was significantly higher amounts of coarse root biomass than for higher planting densities (p < 0.05). The 10,000 tph plots had lower plant available water capacity but larger drainable porosity and saturated hydraulic conductivity compared with lower planting densities (<0.05). The 10,000 tph plots total porosity was more dominated by larger pore size fractions compared with the 5000 and 2500 tph. Generally, our findings show similar patterns of soil hydraulic properties and pore size distributions for lower planting densities. The results from 10,000 tph indicate a higher air-filled pore space at field capacity and more rapid drainage compared with lower planting densities. Both characteristics observed in the 10,000 tph are favorable for aeration and oxygen uptake, which are especially important at wet sites. Overall, the results suggest that improved soil health can be achieved from the establishment of American sycamore SRCs on marginal lands, thereby providing a green pathway to achieving environmental sustainability with woody renewable energy. Full article

We used the Air Pollution Tolerance Index (APTI), the amount of PM₅ and PM₁₀, and the elemental analysis of leaves to explore the sensitivity of tree species to air pollution. We assessed the tolerance of Robinia pseudoacacia, Acer saccharinum, Tilia × europaea, Acer platanoides, Fraxinus excelsior, Betula pendula, Celtis occidentalis, and Platanus × acerifolia to the amount of dust, APTI, and the elemental concentration of leaves. Leaves were collected in Debrecen (Hungary), which has a high intensity of vehicular traffic. The highest amount of PM (both PM₁₀ and PM₅) was found on the leaves of A. saccharinum and B. pendula. Our results demonstrated that A. saccharinum was moderately tolerant, while P. acerifolia was intermediate, based on the APTI value. There was a significant difference in the parameters of APTI and the elemental concentration of leaves among species. We found that tree leaves are reliable bioindicators of air pollution in urban areas. Based on the value of APTI, A. saccharinum and P. acerifolia, and based on PM, A. saccharinum and B. pendula are recommended as pollutant-accumulator species, while other studied species with lower APTI values are useful bioindicators of air pollution. The results support landscape engineers and urban developers in finding the best tree species that are tolerant to pollution and in using those as proxies of urban environmental health. Full article

Environmental pollution is an important issue in metropolitan areas, and roadside trees are directly affected by various sources of pollution to which they exhibit numerous responses. The aim of the present study was to identify morpho-physio-biochemical attributes of maidenhair tree (Ginkgo biloba L.) and American sycamore (Platanus occidentalis L.) growing under two different air quality conditions (roadside with high air pollution, RH and roadside with low air pollution, RL) and to assess the possibility of using their physiological and biochemical parameters as biomonitoring tools in urban areas. The results showed that the photosynthetic rate, photosynthetic nitrogen-use efficiencies, and photochromic contents were generally low in RH in both G. biloba and P. occidentalis. However, water-use efficiency and leaf temperature showed high values in RH trees. Among biochemical parameters, in G. biloba, the lipid peroxide content was higher in RH than in RL trees, but in P. occidentalis, this content was lower in RH than in RL trees. In both species, physiological activities were low in trees planted in areas with high levels of air pollution, whereas their biochemical and morphological variables showed different responses to air pollution. Thus, we concluded that it is possible to determine species-specific physiological variables affected by regional differences of air pollution in urban areas, and these findings may be helpful for monitoring air quality and environmental health using trees. Full article

Historical pollution can be elucidated with variations of elements’ concentration in tree rings by using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). However, the capacity of chemical elements’ absorption significantly depends on the tree species and element types. Metal concentrations in the rings for five species (Platanus occidentalis, Salix koreensis, Chamaecyparis obtusa, Pinus densiflora, Ginkgo biloba) were investigated in light of metal pollution history in ambient air of D industrial site located in Daejeon, Korea. The calibration for LA-ICP-MS was performed using cellulose-matrix matched standards with ¹³C normalization. Tree ring series except for Ginkgo sp. showed that the accumulation rates of Pb and Cd were higher between 1992 and 1999. Other elements, such as Fe, Cr, Mn, Cd, Zn, and Sr, showed a variation in the rings, likely due to the different physiological processes of element uptake and radial mobility. Concentrations of Pb and Cd in the annual rings of Pinus sp. corresponded to the metal monitoring data for the ambient air with the correlation coefficients of 0.879 and 0.579, respectively. Moreover, Cd in Platanus sp. and Pb in Salix sp. showed a positive correlation to ambient metal concentration compared to Chamaecyparis sp. and Ginkgo sp. Therefore, caution should be taken to select candidate elements as well as tree species to reconstruct the ambient air metal pollution history by measuring the concentration of metal in the tree ring. Full article