Littérature scientifique sur le sujet « Urban environment, drought, excess light »

The water parameters of the leaves of 9 species of medium-sized trees (Aesculus pavia L., Aralia elata (Miq,) Seem., Broussonetia papyrifera (L.) L’Hér. ex Vent., Cercis canadensis L., Platycarya strobilacea Siebold & Zucc., Prunus dulcis (Mill.) D.A.Webb., Tetradium daniellii (Benn.) T.G. Hartley, Zizyphus jujuba Mill., Robinia viscosa Vent.) and 4 species of bushes (Cotinus coggygrya Scop., Cotinus coggygrya Scop. ‘Royal Purple’, Berberis vulgaris L. ‘Atropurpurea’, Corylus maxima Mill. ‘Atropurpurea’) were investigated in order to identify the most promising drought-tolerant ornamental species of woody plants from the temperate and continental climate zones, which are still not widely cultivated in the Polissia and Forest-Steppe zones of Ukraine. It will be a further recommendation to include them in the ecosystems of the urban environment to overcome the negative impact of the "urban heat island". In order to determine the relative drought resistance of plants, the following parameters of the water regime were measured: tissue hydration and water loss per unit of time. The test for drought resistance was carried out twice, when high temperatures are maintained: in early June (the leaves on trees and bushes are young), and also in early September (the leaves have already acquired all the features characteristic of their species). According to the results of the study, such medium-sized trees as: Aesculus pavia, Aralia elata, Cercis canadensis, Tetradium daniellii and Zizyphus jujube, as well as Cotinus coggygrya, Berberis vulgaris 'Atropurpurea' and Cotinus coggygrya 'Royal Purple' bushes can be recommended for urban landscaping as drought-resistant plants. Whereas, the tree species Broussonetia papurifera, Robinia viscosa, Prunus dulcis and Platycarya strobilacea, as well as the bushes Corylus maxima 'Atropurpurea' showed relatively lower drought resistance, which must be taken into account when landscaping, since, on the one hand, there is a need for additional watering, on the other hand in in one landscape exposure, it is appropriate to plant species with a similar level of drought resistance, which will facilitate further plant care. The slightly lower tolerance to drought of Corylus maxima 'Atropurpurea' may be due to the fact that only this species of the studied shrubs is shade-tolerant, while the other three species are light-loving plants, which must also be taken into account when creating plant compositions.

To understand the phenomena caused by nutrient applications on the quality of vegetables, some research has been done in Finland and in Scandinavia during the last decades. Purpose of this review is to evaluate this data against the information available on genetic and environmental factors. Genotype and light intensity highly affect the vitamin C content of plants. Optimal nitrogen level has a small effect, but excess of nitrogen decreases vitamin C content. Genotype, developmental stage of the plant, adequate photosynthesis, vigorous growth and relatively high temperature increase the carotene content of carrots. The effects of fertilization on the carotene content of plants have been contradictory and warrants more research. No research results could be found of the effects of fertilization or growing practices on the vitamin B content even though vegetables are an important source of vitamin B in diets. Increasing nitrogen fertilization, genotype, low light intensity, low temperature and drought increase the nitrate content of vegetables, but the levels are low in vegetables grown in the Nordic countries, except in lettuce grown under glass with the aid of lights during the dark season. The effect of fertilization on the sugar content is small, and the effect on dietary fibre warrants further study.

Abstract Trees play a crucial role in the urban environment. They fulfil aesthetic, sociocultural, ecological, health-promoting and economic functions. Urban development and related human activity bring many risks to green areas within urban space. Plants are exposed to stress connected with water, soil and air pollution. Living space, harmful light and thermal conditions, drought, high density and changeable soil pH with excessive salinity are further disadvantages. European and Northern American cities have to cope with a serious danger of tree death. A leading cause is the use of de-icing chemicals in winter, particularly sodium chloride, applied due to its cost-effectiveness and availability. The paper describes traditional de-icing chemicals used in urban areas (NaCl, solid aggregates, CaCl2, MgCl sulphates MgSO4, (NH4)2SO4, urea alcohols and glycols isopropyl alcohol, ethylene glycol, methanol) and newly developed sodium chloride substitutes (calcium magnesium acetate CMA), sodium formate and acetate NaFo/NaAc, potassium carbonate K2CO3). Moreover, prophylactic methods aimed at preventing the negative impact of de-icing campaigns, rules of planning and design of urban landscape, and reasonable management measures and pro-ecological modern technologies reducing and reversing the consequences of harmful actions are presented

The relevant insights provided by 3D City models greatly improve Smart Cities and their management policies. In the urban built environment, buildings frequently represent the most studied and modeled features. CityJSON format proposes a lightweight and developer-friendly alternative to CityGML. This paper proposes an improvement to the usability of 3D models providing an automatic generation method in CityJSON, to ensure compactness, expressivity, and interoperability. In addition to a compliance rate in excess of 92% for geometry and topology, the generated model allows the handling of contextual information, such as metadata and refined levels of details (LoD), in a built-in manner. By breaking down the building-generation process, it creates consistent building objects from the unique source of Light Detection and Ranging (LiDAR) point clouds.

From the days of primitive society, human and animals have used the resource of the earth to support life and to dispose waste. Rapid population growth and uncontrolled industrial development are seriously degrading the urban and semi-urban environment in many of the developing countries placing enormous strain on natural resources and undermining efficient and sustainable development. Industrial operations lead to considerable generation of hazardous waste and in rapidly industrializing countries such as India the contribution to hazardous waste from industries are largest. Hazardous waste genarations from industries is also critical due to their large geophysical spread in the country, leading to regionwide impacts. Due to liberalization policy the pace of industrialization has been accelerated, which has resulted in increasing amount of hazardous waste every year. This long with a growing amount of municipal solid waste due to rapid urbanization and inadequate policy and technological measures continues to remain a daunting issue of environmental concern to India. In this scenario the present paper discusses various aspects of hazardous industrial waste like its origin, distribution and environmental and health hazards. Hazardous waste from industrial sectors contains heavy metals, pesticides, radioactive materials and other chemicals, which are toxic, flammable, reactive, corrosive, or have explosive properties. Normally Arsenic, Cadmium, Chromium, Copper, Lead, Zinc, Boron etc are found in pulverized fly ash. Cement industries emit huge quality of fluoride into the environment. Large quantity of mercury emitted from caustic soda industries using mercury electrodes, from chemical industries, paper and pulp industries etc. Tin mines emit tin in the vicinity of the mines. The metals such as Cadmium, Lead, Chromium, Arsenic etc, if present in the body, are hazardous to the health. Presence of fluoride within the range of 0.5 to 1.5 ppm is very essential in water for health, if present in excess leads to Florosis. Fouride may cause harm not only through water but also through air by way of respiration and soil. In river estuaries, the concentration of metal traces will reach to a high degrees of contamination because of stagnant water, when industrial effluents are fed into rivers and streams. This paper throws light upon many more such factors and also suggest measures to control and manage hazardous waste.

Rain gardens have become a widespread stormwater practice in the United States, and their use is poised to continue expanding as they are an aesthetically pleasing way to improve the quality of stormwater runoff. The terms rain garden and bioretention, are now often used interchangeably to denote a landscape area that treats stormwater runoff. Rain gardens are an effective, attractive, and sustainable stormwater management solution for residential areas and urban green spaces. They can restore the hydrologic function of urban landscapes and capture stormwater runoff pollutants, such as phosphorus (P), a main pollutant in urban cities and residential neighborhoods. Although design considerations such as size, substrate depth, substrate type, and stormwater holding time have been rigorously tested, little research has been conducted on the living portion of rain gardens. This paper reviews two studies—one that evaluated the effects of flooding and drought tolerance on the physiological responses of native plant species recommended for use in rain gardens, and another that evaluated P removal in monoculture and polyculture rain garden plantings. In the second study, plants and substrate were evaluated for their ability to retain P, a typical water pollutant. Although plant growth across species was sometimes lower when exposed to repeated flooding, plant visual quality was generally not compromised. Although plant selection was limited to species native to the southeastern U.S., some findings may be translated regardless of region. Plant tissue P was higher than either leachate or substrate, indicating the critical role plants play in P accumulation and removal. Additionally, polyculture plantings had the lowest leachate P, suggesting a polyculture planting may be more effective in preventing excess P from entering waterways from bioretention gardens. The findings included that, although monoculture plantings are common in bioretention gardens, polyculture plantings can improve biodiversity, ecosystem resilience, and rain garden functionality.

In 1985, San Francisco adopted a downtown plan on ground-level wind currents intended to mitigate the negative effects of wind on pedestrians’ perceived comfort in public open spaces. The plan mandates that new buildings in designated parts of the city associated with high density or development potential be designed or adopt measures to not cause wind in excess of accepted comfort levels. This study examines whether and to what degree the plan has successfully shaped an urban form that mitigates wind by comparing the ground-level wind environment in 1985 and 2013. A series of wind tunnel tests found that during San Francisco’s windiest season when the westerly winds are prevalent, the overall mean wind speed ratio measured at 318 locations in four areas of the city dropped by 22%. However, there still exist many excessively windy places that are associated with specific urban form conditions, including streets oriented to have direct exposure to westerly winds, flat façades on high-rise buildings, and horizontal street walls where building façades align. Recommendations based on the findings include incorporating more tangible guidance on the built form conditions, expanding the plan’s reach to cover more parts of the city, and learning from strategies used elsewhere. By evaluating the urban form impacts of a wind mitigation policy that has been in place for 30 years, the research offers insights for other cities that have implemented or plan to adopt similar approach and sheds light on issues related to wind comfort in high-density urban areas.

In light of global warming and the energy turn, sector coupling has gained increasing interest in recent years, from both the scientific community and politics. In the following article it is hypothesized that efficient multifaceted sector coupling solutions depend on detailed spatial and temporal characteristics of energy demand and supply. Hence, spatiotemporal modelling is used as a methodology of integrated spatial and energy planning, in order to determine favourable sector coupling strategies at the local level. A case study evaluation was carried out for both central and decentral renewable energy sources. Considering the high temporal resolutions of energy demand and supply, the results revealed a feasible operation of a district heating network in the central areas of the case study municipalities. Additionally, building integrated solar energy technologies are capable of providing large amount of excess energy that could serve other demand sectors, such as the mobility sector, or could be used for Power-to-X solutions. It is suggested that sector coupling strategies require spatial considerations and high temporal comparisons, in order to be reasonably integrated in spatial and urban planning.

Climate change and human activities in particular are important causes of the possible variations in Mediterranean basin forest health conditions. Over the last decades, deciduous oak-forest mortality has been a recurrent problem in central and southern Italy. Despite the perception of increasingly visible damage in oak forests in drought sites, the role of various environmental factors in their decline is not completely clear. Among the modern methods of monitoring terrestrial ecosystems, remote sensing is of prime importance thanks to its ability to provide synoptic information on large areas with a high frequency of acquisition. This paper reports the preliminary results regarding a replicable and low cost monitoring tool planned to quantify forest health conditions based on the application of the Normalized Difference Vegetation Index (NDVI), using the diachronic images provided by the Sentinel-2 satellite. The study area is represented by a peri-urban forest of natural Mediterranean deciduous oaks, characterized by a high variability in the composition of the species and in the silvicultural structures. In order to monitor the health conditions of a specific forest canopy cover with remote sensing data, it is necessary to classify the forest canopy cover in advance to separate it from other species and from the Mediterranean scrub. This is due to the spatial distribution of vegetation and the high rate of biodiversity in the Mediterranean natural environment. To achieve this, Light Detection and Ranging (LiDAR) data, forest management data and field sampling data were analyzed. The main results of this research show a widespread decline in oak health conditions over the observed period (2015–2017). Specifically, for the studied area, thanks to the specific localization of the oak canopy cover, we detected a high potential concerning the Sentinel-2 data application in monitoring forest health conditions by NDVI application.

Wooden-frame structures, with the capacity for continuous renewal, are key resources for urban regeneration and so comprise one of the most sustainable construction methods. This was true in the past for Japan, but following World War II, wooden-frame structures were demolished and replaced at a rapid pace. However, today, with Japan’s aging and dwindling population, the growing number of abandoned houses has become a socio-economic issue. In response to this crisis, local initiatives have been established to address this problem. Some novel design and management practices have arisen to restore the value of excess wooden-framed buildings. The purpose of this paper is to discuss the current design and renovation practices of vacant wooden-frame buildings in Japan, as well as to evaluate these practices in light of a sustainable future, by approaching this issue from the perspective of architects and designers and investigating their roles in these processes. The paper starts with the evolution of this building type from the past to the present. Data from in-depth interviews with specialists in wooden-frame construction as well as architects who are involved in the renovation of postwar timber dwellings are gathered and discussed. The emphasis here is on the expertise these specialists and architects have in successful cases of design and space management, as well as the incorporation of those buildings into the local community. Our case studies are located in different urban contexts; a regional city, a peripheral area of Tokyo, and central Tokyo. The findings highlight the crucial role of architects who mediate between benefits and drawbacks of current rehabilitation efforts, which are nevertheless still outnumbered by abandoned houses. Nonetheless, these experiences are crucial and valuable for the long-term viability of this building type in Japan.

The trees in the city, important from an economic, social and environmental point of view, are frequently found to vegetate under particularly severe micro- and macro-environmental conditions, due to the modification of the chemical-physical characteristics of the soil and the air atmospheric pollution, the reduced availability of space for root systems and foliage as well as the peculiar water balance of urban systems. There are also a multitude of abiotic stresses, especially during the summer season, in which there is a combination of high temperatures, high solar radiation and low availability of water in the soil, which further complicate the correct development of the trees. In this context there are some tree species that have at their disposal a series of morpho-anatomical, biochemical and physiological characteristics that contribute to increasing their tolerance to ‘drought’ and to light stress. In particular, ‘red’ plants are able to synthesize a wide range of metabolites including anthocyanins. These absorb in vivo the green and yellow light bands of light, commonly between 500 and 600 nm. They protect leaves from the stress of photo-inhibiting flows by absorbing excess photons that would otherwise be intercepted by chlorophyll. Furthermore, they serve as a useful optical filter, diverting the excess of high energy amount away from the already saturated photosynthetic electron transport chain. Anthocyanins reduce the oxidative load in a leaf by simply filtering the yellow-green light, since most of the reactive oxygen in plant cells comes from the excitation of chlorophyll. These compounds are also excellent scavengers of free radicals for which the induction of leaf anthocyanins has been implicated in the acquisition of tolerance to many different types of environmental stressors. In this context it becomes fundamental to know the physiological responses of the arboreal species, in order to enhance them and use them for a better urban green design. The objective of this thesis, therefore, is essentially to evaluate the ecophysiological strategies adopted by three cultivars of the species Acer platanoides ('Summershade', 'Crimson King' and 'Deborah') to two different types of light stress: the first a ‘sudden’ stress, the second a chronic one. What differentiates these cultivars is the colour of the leaves: the first cultivar is constitutively green, the second is constitutively red and the third is temporarily (in the juvenile phase) red. To this end, in 2016 and 2017 two experiments were conducted at the Minoprio Foundation in Vertemate con Minoprio (CO). During the first (duration 3 months) the sudden light stress was induced by a water stress, while during the second (duration 16 months) the chronic light stress was realized with the use of white concrete slabs that reflected an excess of light. Physiological measurements (gas exchanges, water relations and photochemistry of the photosystem) and optics were carried out. Overall, the results obtained from this doctoral project were as follows: 1. Leaf optical characterization of the three cultivars in question. 2. Cyanic cultivars are suitable for urban sites with very high irradiance through the year and are better equipped to cope with sudden, short drought spell. 3. Under optimal conditions the cultivars with green leaves provided higher benefits, in terms of CO2 storage and transpirational cooling than cyanic cultivars because anthocyanins are “costly” to plants.