Heavy metal contamination in soils and vegetation poses a significant problem due to its toxicity and persistence. Toxic effects on vegetation include not only impaired growth, reduced yields, and even plant death but also biodiversity loss and ecosystem degradation. Addressing this issue requires comprehensive monitoring and remediation efforts to mitigate the environmental, human health, and ecological impacts. This review examines the state-of-the-art methodologies and advancements in remote sensing applications for detecting and monitoring heavy metal contamination in soil and its subsequent effects on vegetation. By synthesizing the current research findings and technological developments, this review offers insights into the efficacy and potential of remote sensing for monitoring heavy metal contamination in terrestrial ecosystems. However, current studies focus on regression and AI methods to link spectral reflectances and indices to heavy metal concentrations, which poses limited transferability to other areas, times, spectral discretizations, and heavy metal elements. We conclude that one important way forward is the more thorough understanding and simulation of the related physico-chemical processes in soils and plants and their effects on the spectral signatures. This would offer a profound basis for remote sensing applications for individual circumstances and would allow disentangling heavy metal effects from other stressors such as droughts or soil salinity.

The paper presents the results on resistance of Aesculus hippocastanum Linnaeus, 1753 trees to Cameraria ohridella Deschka & Dimić, 1986 (Lepidoptera, Gracillariidae) impact under conditions of a modern urban environment on the example of Dnipro city as the largest industrial city in Ukraine. Field experiments were conducted in all park areas of the city, which allowed covering the full gradient of the existing urban environment and considered the different degrees of the tree settlement by the invasive insect species. The research of the impact of C. ohridella caterpillars’ vital activity on the photosynthetic apparatus state was carried out by applying a chlorophyll fluorescence induction technique. Diagnosis of photosynthetic dysfunction of fresh Ae. hippocastanum leaves was conducted using a portable “Floratest” fluorometer manufactured in Ukraine. Interpretation of the obtained Kautsky curves showed that significant changes in their critical parameters associated with the degree of leaf damage by C. ohridella caterpillars were not detected. The influence of tree growth site conditions on the following 4 main indicators of chlorophyll fluorescence induction was established: the initial value of fluorescence induction after irradiation; the value of “plateau” fluorescence induction; the maximum value of fluorescence induction; the stationary value of fluorescence induction after light adaptation of the plant leaf. It was found that the efficiency coefficients of photochemical processes in Ae. hippocastanum trees growing in low terrain levels differed significantly, which can probably be interpreted as their response to the specific characteristics of the urban environment.

Green spaces in an industrially polluted city are extremely important for the physical activity and mental health of its inhabitants. The study aim was to analyze the urban green space dynamics and the greening degree of different functional zones typical for a big Ukrainian industrial city (Dnipro, Ukraine). This article used the remote sensing methods and geographic information systems (GIS) to assess the percentage of green spaces in the city of Dnipro, its eight districts, parks, ravines, and sanitary protection zones. The Normalized Difference Vegetation Index (NDVI) was used for mapping the urban green spaces within the ravines, parks, and sanitary protection zones. According to our results, 67% of Dnipro city is greened (NDVI >0.3). On average, there are 219 m ² of green spaces per person, which is 24 and 4 times more than the minimum and optimal values recommended by the World Health Organization (WHO), respectively. It was found that the NDVI values were significantly lower in the territories of sanitary protection zones, compared to the other functional zones. The results of NDVI analysis indicate a significant variation of the studied parameter during the vegetative season, with two typical peaks of the green space vegetative activity. The peak of plant vegetative activity occurs in the first decade of June, followed by slight decline for 2–3 weeks, then there is another increase in the activity, reaching the maximum in mid-July. Even in autumn, the photosynthetic activity remains relatively high for most of the urban areas, declining only from mid-October. In addition, a method and algorithm for estimating and standardizing the level of the urban area greening based on the remote sensing methods and zonal statistics tools are proposed.

The role of tree species as a tool for bioaccumulation of heavy metals is an important current issue within the context of the increase of anthropogenic pressure in urban ecosystems. The article presents the results of research on the level of soil contamination with heavy metals and the processes of their accumulation by native and introduced tree species in green spaces of Dnipro city. Inductively coupled plasma mass spectrometry (ICP-MS) was used to detect concentrations of heavy metals (Zn, Cu, Cd, Pb) in soil samples and the assimilation component in trees of black locust (Robinia pseudoacacia) and Norway maple (Acer platanoides). The ranges of mean concentrations of heavy metals at different study sites within the city’s green infrastructure were as follows (mg/kg): 30.7–185.5 for Zn, 5.7–22.4 for Cu, 9.0–31.3 for Pb, and 0.213–0.598 for Cd. With respect to all four of these metals, the soils of the Metallurgists Square location were characterized by the highest concentrations of the metals, and the Pridneprovsky Park in the area of the outskirts of Dnipro city was characterized by the lowest ones. Compared to soils, the two investigated tree species had a significantly lower content of all studied metals in leaves. The heavy metal accumulations in the leaves of both R. pseudoacacia and A. platanoides were observed in the following decreasing order: Zn > Cu > Pb > Cd. Regarding the migration of heavy metals in the soil-plant system, the concentrations of ecopollutants in the plants were found not to be dependent on their content in the soil environment. The calculated bioaccumulation coefficients of heavy metals for both tree species were < 1. However, the results of heavy metal concentration in leaves of both introduced and native tree species evidenced their special role in heavy metal bioaccumulation. Compared to R. pseudoacacia, such native species as A. platanoides can be considered to be a more “sensitive” bioindicator of environmental pollution caused by heavy metals. Planting fast-growing tree species such as R. pseudoacacia and A. platanoides can in a short time be an environmentally appropriate and cost-effective measure to mitigate the unfavourable effects of heavy metals on the environment.

The parameters of wood density (WD), bark density (BD) and tree crown characteristics are not only important for estimation of the aboveground biomass, but they also serve as indicators for the timber quality. This study had two objectives: Black locust ( Robinia pseudoacacia L.) – an introduced species; Scots pine ( Pinus sylvestris L.) – an aboriginal species. Black locust and Scots pine from the Steppe zone in Ukraine were compared in their WD and BD, and in the morphological parameters of their tree crowns. There were determined basic WD and BD for differently aged individuals of Black locust and Scots pine. Generally, a higher WD was found for Black locust trees. The average Black locust WD was 518 kg m ⁻³ , ranging from 375 kg m ⁻³ to 612 kg m ⁻³ ; with the average BD – 294 kg m ⁻³ , ranging from 214 kg m ⁻³ to 421 kg m ⁻³ . The average Scots pine WD was 414 kg m ⁻³ , ranging from 254 to 491 kg m ⁻³ ; with average BD – 317 kg m ⁻³ , ranging from 178 to 433 kg m ⁻³ . The dependences between WD, BD and biometric tree parameters were identified by correlation analysis. The crown diameter for Black locust and Scots pine was described with fixed prediction models. We proposed particular equations for relationships between foliage biomass and branch biomass, derived from the crown volume of the investigated species.

Purpose. Determination of the relationships between the concentrations of Zn, Cu, Pb, Cd in the atmospheric air and in the assimilative organs of the false acacia (Robinia pseudoacacia) trees the most common species in the system of landscaping of industrial cities. The objectives of the study included finding out the peculiarities of the spatial distribution of metal pollutants in green spaces of Robinia pseudoacacia in Dnipro city. Methodology. The study was conducted in the system of green spaces of the industrial city of Dnipro, in the atmospheric air of which pollutants dominate, whose source is emissions from metallurgy, energy and motor transport. To carry out the experiment, the method of atomic absorption spectrophotometry was used to determine the concentrations of heavy metals. The trend of technogenic emissions into the atmosphere was estimated by statistical methods. The spatial distribution of accumulation of essential and toxic metals in the Robinia plantations of the industrial city was built on the basis of the obtained experimental data. Findings. Among the studied pollutants, the maximum concentration in the assimilation organs was found for Zn, whose range was 1530 mgkg-1. Almost the same level of accumulation was reached for Cu and for Pb: 3.917.2 and 8.610.8 mgkg-1, respectively. The presence of Cd, which is not an essential element, has been established, which allows considering Robinia plantations as a potential depositor of Cu and Cd in conditions of polyelemental pollution of industrial cities. Originality. It was established that Robinia plantations as an element of the green infrastructure of industrial cities are characterized by the maximum effect of Cu (among other heavy metals) translocation and are effective potential depositors of Pb when its normative values in the atmospheric air are exceeded.. Practical value. On the basis of the obtained experimental data, the spatial distribution of accumulation of metals as pollutants in Robinia plantations was constructed, which can be considered in the plane of optimization of the state of atmospheric air in the city. The cartographic materials that can be used by the subjects of environmental monitoring and green construction of industrial cities were obtained.