Trees In Cities Research Articles

Environmental decision support system for Plane trees failure prediction: A comparison of multi‐layer perceptron and random forest modeling approaches

AbstractTree risk is the likelihood of property damage or personal injury from a potentially hazardous tree in cities. We aimed to compare multilayer perceptron (MLP) and random forest (RF) model techniques to predict Plane trees failure hazard in urban areas. In this research, 500 Plane trees in different urban structures were selected, and 12 variables were measured for target trees prediction as model independent variables. Tree failure hazard (tree fails along next 3 yr) was modeled by two machine learning techniques: MLP and RF. The RF model represents the higher accuracy in training (100%), test (94.4%), and all data sets (98.4%). The results of variable importance calculation of designed RF model revealed that wind‐protected aspects, soil depth, length of cracks and cavities, and internal decay are the most important variables respectively that influence the classes of Plane tree failure. The urban foresters or designers can easily determine the possibility of Plane trees risk by running the designed graphical user interface and entering 12 variables of Plane tree. As a result, it will help foresters and urban area managers to make better decisions and predict the proper time to decrease harm from Plane tree failure.

THE COLLECTION FUND OF TREE AND SHRUB PLANTS OF THE KRYVYI RIH BOTANICAL GARDEN OF THE NATIONAL ACADEMY OF UKRAINE AS A SOURCE OF ENRICHMENT OF THE ASSORTMENT FOR GREENING URBAN AREAS

THE COLLECTION FUND OF TREE AND SHRUB PLANTS OF THE KRYVYI RIH BOTANICAL GARDEN OF THE NATIONAL ACADEMY OF UKRAINE AS A SOURCE OF ENRICHMENT OF THE ASSORTMENT FOR GREENING URBAN AREAS

Modeling Black Carbon Removal by City Trees: Implications for Urban Forest Planning

Modeling Black Carbon Removal by City Trees: Implications for Urban Forest Planning

Reflections by a member of the Editorial Board

I thank Co-Editors Ass. Prof. Dr. Jože Kropivšek and Prof. Dr. Katarina Čufar for the opportunity to serve as an Editorial Board member of Les/Wood, an international journal firmly grounded in the broad sweep of Slovene wood science and technology. The Editorial Board works to extend the relevance and impact of Les/Wood within and beyond Slovenia to the international community of wood science and technology in the broadest sense. We see the journal as a tool to support research and development of specific technologies, as well as to develop common terminology.
 I would like to use this opportunity to sketch out how I came to be involved with wood science in Slovenia. In retrospect that involvement seems inevitable, but the path was not always clear at the time! After completing my postgraduate education in plant pathology and mycology in the USA in 1982, I accepted my current position as supervisory plant physiologist for the USDA Forest Service, a US federal land management agency with a strong commitment to research & development and to international forestry.
 Throughout my career, my personal research has involved tree growth and wood decay in response to injury, infection, and environmental change. These tree responses affect forest health, the economic value of wood for art and industry, the tree-ring record of environmental conditions, and the performance of trees in urban and community environments.
 My USDA FS mentor and colleague Dr. Walter Shortle met Prof. Dr. Niko Torelli and Prof. Dr. Katarina Čufar at the IAWA conference in Hamburg (1983) and at the IUFRO World Conference 1996 in Ljubljana, where the two of them were local organizers. Afterwards they obtained a joint Yugoslav American Project, “Possible alterations of wood in air polluted trees”, which defined my earlier collaborations with Professor Torelli and Katarina Čufar on silver fir decline in Slovenia and Europe. Later, Katarina Čufar, Dr. Tom Levanič, and I identified changes in the climatic responses of silver fir in Slovenia and of red spruce in the northeastern US. I also worked with Dr. Primož Oven on special considerations for the health and safety of city trees. Later, Katarina Čufar and I both served on the Executive Council of the Tree Ring Society, an international association for dendrochronological research. We co-taught a tree biology section at the Dendro Fieldweek as part of the World Dendro conference 2010 in Finland. We found that our combination of research experience both intensified and broadened our understanding and presentation of wood structure and function. Since then, we have worked to provide Slovene students and scientists a platform to share techniques and experiences that both extend the science and community of scientists in the international research community.
 As an active researcher, I see Les/Wood as noteworthy because of the potential breadth of articles reporting on topics from wood mechanical properties to technologies and industrial processing to underlying anatomy and the biological processes that result in wood formation and preservation. In addition to the high level of scholarship and technical expertise within Les/Wood, I find collegiality of spirit, openness of approach, and pride of history and context. These qualities lift up and support ongoing and future research for Slovenia, its geographic surroundings, and the broader world research community. I’m excited at the prospect of Les/Wood extending its traditional strengths to meet the critical need for wood science to optimize wood utilization, ecological understanding, and cultural patrimony.

Counting trees in a subtropical mega city using the instance segmentation method

Counting the trees in a given area or city is meaningful when making decisions for government policies and administration, including the international afforestation effort (i.e., the Trillion Trees Campaign). Determining individual trees on a large scale poses significant challenges, especially in subtropical and tropical areas, because of their diverse crown characteristics. Using very high-spatial-resolution images, we can see the tree crowns clearly. In this study, we counted the population number of trees in the subtropical mega city of Guangzhou, and we used an end-to-end tree-counting deep-learning framework in the regional-scale tree detection by delineating each tree crown. It is a simple framework in which individual trees can be detected directly without manual operation. We used the cascade mask regions with convolutional neural networks (CMask R-CNN) as the backbone and added three types of attention modules to build the derivatives of the CMask R-CNN. The experimental results showed that the CMask R-CNN performed the best among all of the methods, and more than 112 million individual trees with crown sizes of large than 1 m2 were detected. The experimental assessment indicated that the accuracy was 88.32% in terms of the R2 value and 82.56% in terms of the F1-score. This study not only revealed the number of trees, but it also provided the tree density at different scales, which is a prominent component of the ecosystem structure. We also analyzed the tree density at the 30 m and 1000 m scales. The experimental results showed that Guangzhou has a high canopy cover with a tree density of 150 trees per hectare. For the entire city, the tree density is highest in the northern area of Guangzhou, followed by the central part. From the central-western part to the central-eastern part, the tree density increases. The lowest tree density is located in the southern part of Guangzhou near the Pearl River estuary, which is a basic farmland conservation area. It is notable that the tree density of the urban land is about 15 trees per 900 m2, indicating a good living environment. The method developed in this study provides a flexible means of large-scale tree counting without manual operation based on very high-spatial-resolution images.

The project VERDECITTÁ (GREEN-CITY). The renewal of trees in cities – green, beauty and health: the “made in Italy” of Italian horticulture

ISHS IV International Symposium on Woody Ornamentals of the Temperate Zone The project VERDECITTÁ (GREEN-CITY). The renewal of trees in cities - green, beauty and health: the “made in Italy” of Italian horticulture

Beyond the luxury effect: Individual and structural drivers lead to ‘urban forest inequity’ in public street trees in Melbourne, Australia

Urban trees are increasingly being used to help cities adapt to climate change, improve health and wellbeing, and promote biodiversity. Yet these benefits are distributed unequally, mirroring the uneven distribution of the urban forest in many cities. Contrasting theories have been proposed to explain these observed patterns that focus either on the economic wherewithal of individuals (the ‘luxury effect’), or the outcome of structural factors such as municipal decision-making processes. Here, we explore patterns across 10 municipal authorities in greater Melbourne, Australia to compare the relative importance of these competing mechanisms. We show that both individual and structural processes are both major determinants of the density and diversity of trees in this large Australian city. Interestingly, education level was strongly related to tree density, while household income was negatively related to tree density and diversity in some municipalities. The luxury effect was not able to adequately explain the patterns observed in Melbourne. This finding has important implications for the planning and management of urban forests and the equitable distribution of the benefits they provide, in the context of the rapid expansion of urban populations across the globe. To counteract inequity, local municipalities must acknowledge and deliberately overcome internal biases that favour the provision of street trees to more advantaged sections of the community.

Are street trees friendly to biodiversity?

Urban areas are home to more than half the world’s population, but also habitats for a wide range of plant and animal species. While street trees in urban areas have been recognized as important for human well-being, however, how they can contribute to wildlife conservation is less explored. Here we compiled a database of street tree inventories in China, that included species diversity, abundance and origin information of street trees from 59 cities to explore how different cities rank with regards to the use of native and diversity of street trees, which are both considered beneficial to urban biodiversity. We found the most abundant species contributed an average of 35.8% of all street trees in the studied cities, and non-native species contributed an average of 40.6% of the street trees. Most cities are dominated by only a few species of trees, and a large proportion of these trees are non-native tree species, indicating that streetscapes are likely not friendly to biodiversity. Our proposed ranking schedule provides an easy tool for classifying cities according to their street tree wildlife friendliness, while also providing clear management directions on how to improve city tree composition for biodiversity conservation. To build a sustainable society in which nature and humans can coexist, we recommend that city planners should consider biodiversity conservation as a core value of urban planning. Specifically, we encourage the planting of more native trees and use of a more diverse set of species capable of attracting wildlife, thus promoting biodiversity in cities. Furthermore, awareness of biodiversity friendly tree planting systems needs special attention in developing regions and densely populated areas. We emphasize that more regional research needs to go into identifying local species that can be used as street trees while simultaneously functioning as wildlife attractants.

Vulnerability of Street Trees in Upper Midwest Cities to Climate Change

Urban trees play an important role in helping cities adapt to climate change, but also are vulnerable to changes in climate themselves. We developed an approach for assessing vulnerability of urban tree species and cultivars commonly planted in cities in the United States Upper Midwest to current and projected climate change through the end of the 21st century. One hundred seventy-eight tree species were evaluated for their adaptive capacity to a suite of current and future-projected climate and urban stressors using a weighted scoring system based on an extensive literature review. These scores were then evaluated and adjusted by leading experts in arboriculture in the region. Each species or cultivar’s USDA Hardiness Zone and American Horticultural Society Heat Zone tolerance was compared to current and future heat and hardiness zones for 14 municipalities across Michigan, Wisconsin, and Minnesota using statistically downscaled climate data. Species adaptive capacity and zone tolerance was combined to assign each species one of five vulnerability categories for each location. We determined the number of species and trees in each category based on the most recent municipal street tree data for each location. Under a scenario of less climate change (RCP 4.5), fewer than 2% of trees in each municipality were considered highly vulnerable across all 14 municipalities. Under a scenario of greater change (RCP 8.5), upward of 25% of trees were considered highly vulnerable in some locations. However, the number of vulnerable trees varied greatly by location, primarily because of differences in projected summer high temperatures rather than differences in species composition. Urban foresters can use this information as a complement to other more traditional considerations used when selecting trees for planting.

Assessment of the Diversity of Large Tree Species in Rapidly Urbanizing Areas along the Chao Phraya River Rim, Central Thailand

Urban trees provide numerous ecosystem services in cities such as pollution absorption and reduced urban heat island intensity, energy use, and mental fatigue. Understanding urban tree species diversity can enhance tree planning and management in rapidly urbanizing areas. However, few studies have examined the effects of urbanization on urban tree diversity in Thailand. This study assessed the diversity of large trees in urban landscapes including 11 cities along the 372 km Chao Phraya River Rim in central Thailand. Species diversity, importance value, and distribution were evaluated in each city. Our survey documented 987 large trees belonging to 65 species, 48 genera, and 31 families. The dominant species of Dipterocarpus alatus and Hopea odorata had the highest importance and relative abundance. The highest abundance of large trees was seen in the rural city of Sing Buri, while large urban cities such as Ayutthaya and Bangkok exhibited the highest species diversity. Detrended correspondence analysis indicated that the diversity of unique species was high in large urban cities, while dominant and common species were ubiquitous in rural cities. These findings suggest that large trees are few in number but exhibit high species diversity in large rapidly urbanizing cities. Therefore, preserving good site conditions is critical for the survival of large trees in urban cities. Heritage tree registration may aid preservation efforts and enhance the benefits of these large trees in rapidly urbanizing areas.

Qualitative and Quantitative Indicators of Foliar Mass of Woody Plants in Urban Greenspaces According to the Level of Air Pollution

The purpose of this study is to conduct a comparative analysis of the leaf fall timing and parameters of fluctuating leaf asymmetry among two commonly used plant species for street landscaping in Detroit city, namely, American elm and American ash. The study was completed between summer and fall for the year 2019 in and around Detroit, US. Phenological leaf fall timing of elm and ash was studied, and the fluctuating asymmetry index of their leaves was estimated within the city limits (80 trees of ash and 40 of elm) and outside the city (control site, 20 trees of each species). Leaf fall in city ash trees was recorded from November 1st to 4th and 5-8 days prior to the leaf fall in elms (p ≤ 0.01). Elm trees in the control group shed their leaves 10 days later compared to the city trees, i.e., on average, on November 25th (p ≤ 0.01). Ash trees in the control group shed their leaves earlier than the elm control group, on November 11th (p ≤ 0.001). In the city streets, the average fluctuating asymmetry ranged from 0.065 to 0.086 (point 1), from 0.049 to 0.078 (point 2) and from 0.063 to 0.082 (control site, near the highway).

ERZURUM KENTSEL AÇIK YEŞİL ALANLARINDA MEYVE AĞAÇLARININ KULLANIMI

As in many countries, as a result of the rapid population growth in Turkey, distorted urbanization occurs in cities. Due to this process, the people of the city are becoming deprived of nature day by day. For the urban people who want to find opportunities to meet the need for recreation but cannot find it in urban living spaces, residential gardens, children playgrounds, parks, botanical gardens and such places located in outdoor green area systems, these places undertake a significant role. The vegetation used in these areas seen as an essential element for providing a natural environment. In this study, plant materials used in plant design applications which constitute the urban open-green area system determined in Erzurum city, the plant material used in the main streets, public institution gardens, park and recreation areas, villa gardens, detached residential gardens and site-public housing gardens, were analyzed. Within the survey study conducted and other outdoor plants to the city investigated. With this study, the usage of fruit trees in Erzurum city determined and its contribution to the city and its aesthetics discussed. As a result of the analyzes carried out in this scope, 14932 plants counted in 6 different area usage types. 1716 out of 4292 plants used in the main streets, 910 out of 3426 plants in public institution gardens, 615 out of 3289 plants in park and recreation areas, 476 out of 949 plants in villa gardens, 311 out of 445 plants in detached residential gardens, 1114 out of 2531 plants in site- public housing gardens were determined to be fruit trees. In all land use types, it investigated that fruit tree usage rate among broadleaf trees is 48.85%, 43.88% in main streets,50.50% in public gardens, 30.40% in park and recreation areas, 76.77% in villa gardens 4.64% in detached residential gardens and 61.68% in site-public housing gardens. Research results show that fruity trees are preferred in independent living spaces regardless of income.

Exploring Fruit Tree Species as Multifunctional Greenery: A Case of Its Distribution in Indonesian Cities

Planting multifunctional trees (e.g., fruit species) in cities can promote genetic conservation, economic activity, ecosystem services, and social cohesion. However, in Indonesia, the relationship between the abundance of fruit tree species and different city characteristics, including their involvement in the national smart city project, is still unknown. In this study, published reports and field surveys were used to evaluate the fruit tree distribution and its relationship with the characteristics of 224 of 514 Indonesian cities in order to identify tree species for multifunctional city greenery. This is the first study on the distribution of fruit tree species at the national level. The study identified 151 fruit species of 90 genera and 40 families, including large-sized fruits, such as avocados, breadfruit, coconuts, durians, jackfruit, and mangos. On average, cities contained 54 tree species, of which 21 (38.9%) were fruit trees. These findings indicate that cities are important contributors to the genetic conservation of local fruit trees, which can be further evaluated as new city greenery. However, a city’s involvement in the smart city project bore no relationship (p > 0.05) with the number of identified fruit species. Conversely, non-fruit species tended to be more diverse in smart cities. Since the presence of fruit species is associated with the city population, geographic position, climate, altitude, and attitude towards the fragility of sustainable conservation, introducing and maintaining these species as city greenery requires advocacy to city stakeholders.

Evaluating the Impact of a Wall-Type Green Infrastructure on PM10 and NOx Concentrations in an Urban Street Environment

Nature-based solutions can represent beneficial tools in the field of urban transformation for their contribution to important environmental services such as air quality improvement. To evaluate the impact on urban air pollution of a CityTree (CT), an innovative wall-type green infrastructure in passive (deposition) and active (filtration) modes of operation, a study was conducted in a real urban setting in Modena (Italy) during 2017 and 2018, combining experimental measurements with modelling system evaluations. In this work, relying on the computational resources of CRESCO (Computational Centre for Research on Complex Systems)/ENEAGRID High Performance Computing infrastructure, we used the air pollution microscale model PMSS (Parallel Micro-SWIFT-Micro SPRAY) to simulate air quality during the experimental campaigns. The spatial characteristics of the impact of the CT on local air pollutants concentrations, specifically nitrogen oxides (NOx) and particulate matter (PM10), were assessed. In particular, we used prescribed bulk deposition velocities provided by the experimental campaigns, which tested the CT both in passive (deposition) and in active (filtration) mode of operation. Our results showed that the PM10 and NOx concentration reductions reach from more than 0.1% up to about 0.8% within an area of 10 × 20 m2 around the infrastructure, when the green infrastructure operates in passive mode. In filtration mode the CT exhibited higher performances in the abatement of PM10 concentrations (between 1.5% and 15%), within approximately the same area. We conclude that CTs may find an application in air quality hotspots within specific urban settings (i.e., urban street canyons) where a very localized reduction of pollutants concentration during rush hours might be of interest to limit population exposure. The optimization of the spatial arrangement of CT modules to increment the “clean air zone” is a factor to be investigated in the ongoing development of the CT technology.

Biodiversity of urban street trees in Italian cities: a comparative analysis

Street trees are key elements in urban ecosystems from several points of view, and different species can have different functions (i.e., ecological, socio-economic). As such, a careful biodiversity assessment is pivotal. We evaluated urban street trees in 15 Italian cities along a geographical and bioclimatic gradient. The data was obtained from scientific literature and Garden Service Offices of the cities. The distribution patterns of the species were analyzed in terms of taxonomy, chorology, and tree size. We registered 277 tree species belonging to 48 families. The species richness is very variable in analyzed cities, and it is not directly correlated with the city’s size. Only three species (Platanus × hispanica, Celtis australis and Quercus ilex) are common to almost all cities, while 41.52% of the species are present only in one city. The comparative analysis of species, considering the floristic and city distribution, showed different results, highlighting Pinaceae as the most common family. The chorological analysis shows a predominance of exotic species and a good relationship with the bioclimatic conditions of cities. A selection of the species, as street trees to maximize their ecological and socio-economic functions, is pivotal in urban landscaping and green management.

Urban Green Infrastructure Inventory as a Key Prerequisite to Sustainable Cities in Ukraine under Extreme Heat Events

The frequency of extreme heat effects has recently increased in European cities due to climate change. The problem appears to be critical in urban areas where manmade structures significantly alter the temperature balance, thus highlighting the importance of sustainable management and proper inventory of urban green zones. Based on this, the paper provides a case study on using a combination of open-access and low-cost urban greenery inventory methods that could be used by municipal governments and private land managers to estimate the contribution of urban trees to the mitigation of urban heat impacts. The research focuses on the urban greenery inventory of courtyards in high-rise residential districts of the city of Kyiv (Ukraine), aiming to estimate the adapting potential of urban vegetation against heatwaves. Visual and thermal satellite images of Kyiv enabled us to estimate how the density of buildings and greenery is distributed and analyze the surface temperature in residential districts. A UAV thermal imaging survey was made in four selected locations with varying vegetation coverage, followed by leaf-based field instrumental analysis of photosynthetic activity in selected city tree species at hot temperatures. In addition, 16 portable temperature and humidity sensors were installed in shaded and sunlight-exposed areas of the locations in focus to assess the microclimate formation impact of trees in a high-rise residential courtyard. The Ukrainian legislation on the management of green spaces in cities was reviewed to find out whether it promotes the shaping of comfortable microclimates in residential districts; follow-up recommendations were made on how to improve the applicable provisions.

The art of care

Building on emerging work that considers urban life and designs through the lens of care, this article examines how a performative care practice might serve as an oppositional ethic and strategy in the late capitalist city. The analysis is based on the Guerrilla Grafters, an eco-arts collective that surreptitiously grafts fruit onto sterile city trees in San Francisco. Original data include interviews with participants and critics and a qualitative analysis of relevant media accounts. The article proposes that the Guerrilla Grafters are engaged in a performative care practice, a public facing set of actions that make visible and valuable the labor as well as ethics of attending to the interdependence of all life. This performative care practice is a discursive, relational and spatial strategy that seeks to interrupt relations of dominance and ideologies that cheapen certain life. Through a case study of performative care, this study provokes a more general examination of how care ethics and practices work in oppositional practices under dynamics of neoliberalism and ecological crisis in cities of the Global North.

Evaluation of the ambrosia beetles traps on Pterocarpus indicus in Indonesia

Abstract. Tarno H, Setiawan Y, Rahardjo BT, Wang J. 2021. Evaluation of the ambrosia beetles traps on Pterocarpus indicus in Indonesia. Biodiversitas 22: 1332-1339. Angsana, Pterocarpus indicus Willd., is a native tree of Southeast Asia. This tree is commonly planted in large numbers as an ornamental or shade plant along the roads, in parks, and in residential areas in Malang and Batu Cities of Indonesia. Ambrosia beetles Euplatypus parallelus (F.) and Treptoplatypus micrurus (Schedl.) have been reported to attack P. indicus trees in Malang and Batu Cities. Therefore, effective traps are required for early detection and monitoring of the spread of ambrosia beetles. This research aimed to evaluate the effectiveness of different traps and to investigate the diversity of ambrosia beetles on P. indicus trees in Malang and Batu Cities. This research was conducted along the roads in Malang and Batu Cities using four types of traps: funnel trap, window flight trap, bottle trap, and yellow sticky trap. Eleven ambrosia beetle species were collected in this research. The most abundant species were E. parallelus and Cryphalus laticollis (Browne). The funnel trap was the most effective for capturing ambrosia beetles, whereas the bottle trap was the least effective trap. The funnel trap captured more E. parallelus and C. laticollis individuals than other traps. The ambrosia beetles captured using different traps were categorized as having low diversity. The ambrosia beetles collected from Malang and Batu Cities were categorized as having moderate diversity.

Dumb and Forked: The Street Tree Poetics of Millay and Williams

This urban ecocritical study reads the poetry of Edna St. Vincent Millay and William Carlos Williams in the context of the American street tree movement, a civic health and beautification program that advocated for the planting of shade trees along urban thoroughfares. It argues that both poets critique the ‘ideal’ street tree forwarded by the movement. In ‘City Trees,’ Millay presents a shade tree whose therapeutic effects are overwhelmed by the noise pollution in New York City, much like the speaker herself. In ‘Young Sycamore,’ Williams eschews the visual ideal of symmetrical, evenly-spaced shade trees in favor of a wily, asymmetrical organism that actively torques toward the light. By extension, these poets present city habitats as alternately more toxic and more wild than the street tree movement had imagined, a critique with ramifications for contemporary urban reforestation movements today.

Effect of salt stress in urban conditions on two Acer species with different sensitivity.

BackgroundThe benefits of trees in urban areas include the following: an increase in ecosystem health, an increase in human health, the mitigation of the effects of heat and drought at microclimate level, the storage and sequestration of carbon, and a reduction in air pollution and noise. These ecosystem services can be provided only by trees that are in good health. The main cause of salt stress in urban environments is the use of de-icing salts on the streets in winter. Salt stress is a complex process that includes changes in plants on the physiological, histological, cellular and molecular levels, leading to limitations in nutrient uptake, disrupting the ionic balance of trees and resulting in the death of roadside trees. In response to salinity, trees have developed a variety of defence mechanisms that allow them to minimize the effects of stress and maintain homeostasis.MethodologyThe reactions of two species Acer species: A. platanoides and A. campestre, which have different sensitivities to the unfavourable conditions of the urban environments (mainly salt stress), were investigated. The research included two experiments: a field experiment with city trees and a controlled pot experiment with young trees treated with increasing doses of salt. In both experiments, the following were performed: an assessment of the health condition of the trees and the content of macroelements as well as the Cl and Na in leaves and a qualitative and quantitative analysis of polyprenols.ResultsA. campestre had a more specific strategy than A. platanoides for dealing with Na and Cl, which resulted in undamaged leaves. Under the same conditions, A. platanoides leaves contained more Cl and Na and were severely damaged. The disruption of the ion balance due to salt stress was lower in A. campestre than in A. platanoides. Compared with A. platanoides, A. campestre synthesized more polyprenols in the field experiment. This ability was acquired during the process of acclimation, because it occurred only in the mature trees in the field experiment and not in the young trees in the pot experiment.ConclusionsThe use of two experimental methods (i.e., the field and pot experiments) allowed for a more complete assessment of tree strategies to mitigate salt stress. A. campestre displayed a more specific strategy than A. platanoides. This strategy was based on several elements. A. campestre limited Cl and Na transport to the leaves, which resulted in a lack of damage to those organs. Under the same conditions, A. platanoides individuals contained more Cl and Na in their leaves and were seriously damaged. A. campestre synthesized larger amounts of polyprenols, which probably have the ability to mitigate salt stress. This ability was acquired during the process of acclimation, because it occurred only in the mature trees in the field experiment and was not observed in the young trees in the pot experiment.