Can urban forests overcome climate change and urban environmental pollution? What actions and scenarios can be taken to combat the process of urban climate change and save us from the rapid process of climate change? How much role do the opinions of climate change experts play? Are politicians aware of the role of climate experts and atmospheric scientists? Is it possible for meteorological researchers to predict the future climate of a geographical area and the time series of floods and droughts? So why is no action being taken and no attention being paid?

Urban forests play a crucial role in enhancing the resilience of cities. However, they encounter significant challenges due to climate change and environmental pollution, threatening their survival and functionality amidst rapid economic growth and urbanization. Cities serve as the economic powerhouses of nations that necessitate sustainable, resilient ecosystems to safeguard the well-being of their residents. Urban forests provide a range of invaluable services and benefits to city dwellers. They improve air quality, mitigate the urban heat island effect, foster biodiversity, and ultimately contribute to the health and well-being of urban populations. Recognized as “Green Guardians,” urban forests act as nature-based solutions (NbS) to combat global air pollution and climate change impacts. Climate change and environmental pollution are formidable threats to the integrity and functionality of urban forests. This chapter provides a detailed exploration of the biological ramifications of these phenomena on urban forests, with a specific focus on phenological, physiological, biochemical, molecular, and gene expression aspects, elucidating their profound effects on plant growth and development. The influence of climate change on urban forests is evident in disrupted phenological patterns, induced physiological stress, biochemical imbalances, and molecular-level alterations in gene expression, all of which hinder plant growth and development. Similarly, environmental pollution instigates morphological, physiological, biochemical, and molecular changes in urban forest ecosystems, jeopardizing their overall health and resilience. This chapter delves into adaptation and mitigation strategies to boost urban resilience against these challenges. These strategies encompass selecting climate-resilient tree species, enhancing urban forest management practices, improving soil health and fertility, and implementing green infrastructure projects. Furthermore, it addresses the policy implications of these challenges, providing recommendations for policymakers to devise and implement effective strategies for alleviating the adverse impacts of climate change and environmental pollution on urban forests. The insights derived from this chapter have the potential to assist urban planners and policymakers in safeguarding the indispensable ecological functions and services provided by urban forests. Ensuring the sustained contribution of urban forests to the well-being of urban ecosystems and communities paves the way for a more resilient and sustainable future.Climate change presents an urgent global emergency unfolding at a pace exceeding predictions. The gradual elevation in global temperatures arises from the amplification of the greenhouse effect caused by the excessive release of greenhouse gases (GHGs). These gases absorb infrared radiation, producing atmospheric heat (Kweku et al. 2018; Kumar et al. 2022; Singh 2021). Urban forests are critical components of urban ecosystems, providing numerous ecological, social, and economic benefits. However, they face significant threats from climate change and environmental pollution, which have profound biological consequences (Lu et al. 2018; Kumar et al. 2024; Singh et al. 2024a). Climate change exacerbates existing stressors on urban forests, leading to altered precipitation patterns, increased temperatures, and more frequent extreme weather events. These changes disrupt the phenology of urban trees, affecting flowering, leaf emergence, and fruiting, consequently impacting wildlife populations dependent on these resources (Kumar et al. 2021a, b, c, d, e, f; Singh et al. 2024b). Furthermore, rising temperatures and prolonged drought periods contribute to increased tree mortality rates and reduced canopy cover, diminishing urban forests’ overall health and resilience.

Environmental pollution, including air pollution and soil contamination, poses additional challenges to urban forest ecosystems. Elevated levels of ozone, nitrogen oxides, and particulate matter impair photosynthesis and nutrient uptake and induce morphological, physiological, and biochemical changes, impacting tree growth and development. Soil pollution from industrial activities and improper waste disposal lead to nutrient imbalances, soil compaction, and toxicity, inhibiting root growth and microbial activity essential for tree health (Singh et al. 2023; Dhyani et al. 2021). The biological consequences of climate change and environmental pollution on urban forests extend beyond individual trees to entire ecosystems (Singh and Verma 2013a, b; Prakash et al. 2022). Declines in tree health and biodiversity have cascading effects on associated fauna, including birds, insects, and mammals, disrupting ecological interactions and ecosystem functioning. Moreover, compromised urban forests provide reduced ecosystem services, such as air purification, carbon sequestration, and stormwater management, affecting urban residents’ well-being and quality of life (Rahim et al. 2024).

Additionally, climate change may increase the risk of wildfires in regions where urban forests interface with wild lands. Warmer temperatures and drier conditions create favorable conditions for fire ignition and spread, posing significant threats to human communities and urban forest ecosystems (Radeloff et al. 2018; Singh 2021; Sharma and Singh 2021). Importantly, these changes in urban forest dynamics have implications for ecosystem services provided by urban forests, such as improved air quality, carbon sequestration, and urban cooling (Gupta et al. 2019b). Climate change alters urban forests’ capacity to deliver these services, potentially impacting human health and well-being (Escobedo et al. 2011; Singh et al. 2021). Therefore, urban planners and policymakers must implement various adaptation strategies to mitigate climate change and environmental pollution impacts. These strategies include selecting climate-resilient tree species, improving soil management practices, enhancing green infrastructure, and promoting community engagement in urban forest stewardship (McDonald et al. 2020; Singh et al. 2020; Kumar et al. 2021a).

2 Climate Change Effects on Urban Forests

Climate change influences tree health, biodiversity, and ecosystem services of urban forests. Rising temperatures induce heat stress, reducing growth rates, heightening vulnerability to pests and diseases, and elevated mortality rates (Allen et al. 2010; Kumar et al. 2021b). Besides, it disrupts pest and disease dynamics, influencing the distribution and behavior of urban forest pests and pathogens. Rising temperatures may facilitate the expansion of pest ranges, while changes in precipitation patterns create conditions favorable for disease outbreaks (Pureswaran et al. 2015; Kumar et al. 2021c, d). Furthermore, shifts in climate may lead to changes in urban forest composition, favoring species more tolerant to warmer conditions or altered precipitation regimes. This could result in biodiversity loss and reduced ecosystem resilience as native species struggle to adapt or migrate (Kumar et al. 2022).

2.1 Phenological Modulations

Urban forests, crucial components of urban ecosystems, provide many ecological, social, and economic benefits to urban communities. However, these forests are increasingly susceptible to the impacts of climate change, particularly in terms of phenological shifts—the timing of critical biological events in plant and animal life cycles (Pureswaran et al. 2015; Yadav et al. 2019a, b; Gupta et al. 2019a). Understanding the phenological responses of urban forests to climate change is essential for effective management and conservation efforts (Singh and Kumar 2022a, b).

Climate change influences various aspects of phenology, i.e., leaf emergence, flowering, fruiting, and leaf senescence. Besides, the temperatures and precipitation patterns change photoperiods, triggering phenological events (Kumar et al. 2019b). The urban heat island effect causes earlier leaf emergence and keeps their leaves for extended periods in response to rising temperatures. Similarly, variations in precipitation patterns influence flowering and fruiting, potentially altering pollination and seed dissemination processes in urban forests (Gupta et al. 2019a; Kumar et al. 2019c; Tiwari et al . 2021). For example, the imbalance between the timing of plant flowering and the emergence of pollinators may lead to reduced reproductive success for both plants and pollinators. Furthermore, changes in leaf emergence and senescence timing alter nutrient cycling and carbon sequestration rates in urban forests, affecting ecosystem productivity and resilience (Polgar and Primack 2011; Kumar et al. 2019c).

2.2 Physiological Modulations

Temperatures induce heat stress in urban trees, disrupting physiological processes like photosynthesis and transpiration. This stress is compounded by water scarcity in urban areas, exacerbating tree challenges, reducing growth rates and leaf scorch, and heightened susceptibility to pests and diseases (Kumari and Singh 2018; Sharma et al. 2018; Singh et al. 2018). Furthermore, precipitation patterns, such as increased droughts and heavy rainfall, disrupt the water balance of urban trees. Drought conditions lead to water scarcity, causing wilting, leaf loss, and even mortality in vulnerable tree species. Conversely, intense rainfall triggers soil erosion, root damage, and nutrient leaching, compromising tree health (Wikle et al. 2021; Gupta et al. 2018a).

Moreover, rising atmospheric CO2 levels in urban premises, while potentially stimulating photosynthesis and growth in some species, alter leaf chemistry and nutrient content, influencing tree-insect interactions and ecosystem dynamics (Kumar et al. 2021a; Singh 2024). In addition, climate change impacts the distribution and abundance of pests and pathogens affecting urban trees. Urban heat and milder winters facilitate the spread of pests like bark beetles and pathogens such as fungal diseases, leading to outbreaks and decline of susceptible tree species (Raffa et al. 2015; Gupta et al. 2018b). Mismatches between leaf emergence and peak insect activity impact herbivory levels and tree fitness (Meineke et al. 2021). Hence, climate-induced shifts in the phenology of urban forests and insect pest incidences ultimately affect the overall functioning of the urban ecosystem.2.3 Biochemical Modulations Climate change poses significant challenges to the biochemical processes of plants, with potential implications for ecosystem functioning, productivity, and global food security. These changes in biochemical processes have direct and indirect consequences on human health, including disease distribution shifts and productivity disruptions, leading to nutritional deficiencies (Haines et al. 2006).

Elevated atmospheric carbon dioxide (CO2) levels stimulate photosynthesis in plants, as they take up more CO2 for photosynthetic processes. However, prolonged exposure to high CO2 levels over threshold value leads to a down-regulation of photosynthetic enzymes, reducing the efficiency of photosynthesis over time (Dusenge et al. 2019).

Water stress in urban areas disrupts biochemical processes like photosynthesis and respiration, as well as nutrient uptake and transport. Water stress produces reactive oxygen species (ROS), causing oxidative damage to plant cells (Zeppel et al. 2014). In addition, high temperatures denature enzymes involved in photosynthesis, respiration, and other metabolic pathways, reducing their efficiency (Manoj et al. 2021). Conversely, some plants may experience cold stress if temperatures fluctuate unpredictably, leading to altered enzyme activity and metabolic rates.

Furthermore, it is very interesting to note that climate change influences the production of secondary metabolites in plants, including phenolics, flavonoids, and terpenoids. These compounds are essential in plant defense against biotic and abiotic stresses (Qaderi et al. 2023). Changes in temperature, water availability, and CO2 levels alter the synthesis and accumulation of these compounds, impacting plant resilience to environmental challenges (Kumar et al. 2021b; Joshi et al. 2020).

Changing climatic conditions cause nutrient imbalance, disrupting nutrient cycling and leading to nutrient availability imbalances in the soil. This affects plants’ essential nutrient uptake, impacting biochemical processes such as nitrogen fixation, protein synthesis, and enzyme activity. Nutrient imbalances in urban areas compromise plant health and productivity, making plants more susceptible to pests, diseases, and other stressors (Sistla and Schimel 2012; Singh and Verma 2013a, b; Kumar et al. 2017).

Changing climatic variability in urban premises alters the symbiotic relationship of organisms with plants. The modulations in symbiotic relationships directly impact plant biochemistry through mechanisms such as herbivory, pathogen infection, and mycorrhizal symbiosis (Van der Putten et al. 2010). Further, changes in biotic interactions influence plant metabolism, defense mechanisms, and adaptive resilience of plants to urban climate.

2.4 Molecular and Gene Expression

Climatic variability impacts urban forests, modulating molecular and gene expression dynamics. Elevated temperatures prompt the upregulation of genes associated with heat shock proteins, which is crucial for thermal tolerance. Concurrently, alterations in precipitation patterns induce drought conditions, activating genes linked to drought tolerance mechanisms, including the synthesis of osmoprotectants and antioxidants, crucial for water retention and stress mitigation (Lamelas Penas 2023). Moreover, elevated atmospheric CO2 levels directly influence gene expression, potentially altering photosynthetic rates and carbon assimilation processes (Kumar et al. 2022). Changes in phenology, driven by climate-induced shifts in environmental cues, disrupt the timing of biological events, influencing gene expression patterns related to developmental stages (Heard et al. 2012). Climate-driven changes in pest and pathogen distributions affect gene expression in plant defense mechanisms, including the modulation of genes encoding pathogenesis-related proteins (Pureswaran et al. 2015). Furthermore, climate-induced stressors trigger epigenetic modifications, altering gene expression without changing DNA sequences, thus contributing to phenotypic plasticity in urban forest trees. Therefore, a strong understanding of these molecular responses is pivotal for formulating effective strategies to support the resilience of urban forests in the wake of climate change.

2.5 Plant Growth and Development

Urban forests, though vital for mitigating the impacts of urbanization. The urban climate affects various processes, impacting the growth and development of urban forests. Temperature-induced plant heat stress affects photosynthesis, water uptake, and nutrient absorption (Nowak and Greenfield 2012; Gupta and Singh 2017). Altered precipitation patterns may stress urban trees by affecting soil moisture levels. Drought stress leads to leaf scorch, premature leaf drop, and decreased growth, particularly in species with shallow root systems.

Conversely, heavy rainfall and flooding inundate urban soils, leading to water logging and root suffocation (Rosenzweig et al. 2011). Flood stress in urban areas during the rainy season causes tree decline, root rot, and even mortality in some cases. Increased atmospheric CO2 concentrations stimulate photosynthesis and plant growth to some extent, known as the carbon fertilization effect (Sharma et al. 2018). However, the importance of this benefit is limited by other factors such as nutrient availability, water stress, and temperature extremes.

Urban temperatures facilitate the range expansion of pests and pathogens that affect urban trees, increasing the prevalence of diseases (Raum et al. 2023; Singh et al. 2017a). Further, urban forests face new challenges from invasive species or novel disease outbreaks. Climate stressors weaken the immune systems of plants, making them more susceptible to pest and disease attacks (Tubby and Webber 2010). Stressed trees exhibit symptoms such as dieback, canopy thinning, and increased vulnerability to secondary pests.

Urban soils often suffer from compaction, contamination, and nutrient depletion, impairing plant root growth and nutrient uptake. Climate stressors exacerbate soil degradation, compromising urban trees’ health and resilience (Kumar et al. 2020a, b; Singh et al. 2017b). Intense rainfall events associated with climate change increase soil erosion in urban forests, leading to topsoil loss, tree roots destabilization, and overall soil structure degradation, resulting in reduced growth and development of urban forests (Peterman and Bachelet 2012; Meena et al. 2011; Kumar et al. 2019c).

3 Environmental Pollution Impacts on Urban Forests

Environmental pollution and climate change often interact synergistically to impact urban forest ecosystems. For example, air pollution exacerbates climate change’s effects on plant physiology, making trees more susceptible to heat stress, drought, and other environmental challenges (Gupta et al. 2018a, b; Kumar et al. 2020a, b; Singh and Kumar 2022a, b). Conversely, climate change influences pollutants’ dispersion and deposition, altering their impacts on urban forest biochemistry.

3.1 Morphological Changes

Urban environmental pollution is a significant issue that globally impacts the morphology of forests, leading to changes in their structure, growth patterns, and overall health. Air pollutants such as ozone, sulfur dioxide, nitrogen oxides, and particulate matter cause visible damage to leaves, including necrosis (dead tissue), chlorosis (yellowing), and stippling (tiny spots). These pollutants interfere with photosynthesis and chlorophyll production, reducing leaf size, altered shape, and abnormal vein patterns (Thomas and Hendricks 1961; Singh 2024). High levels of air pollution inhibit plant growth by disrupting metabolic processes and nutrient uptake. Pollutants like ozone and sulfur dioxide penetrate leaf stomata, interfering with gas exchange and reducing carbon dioxide uptake, essential for photosynthesis (Kumar et al. 2022; Yadav et al. 2019a, b). As a result, plants may exhibit reduced shoot elongation, smaller overall size, and delayed or suppressed flowering and fruiting. Soil pollution, often associated with heavy metals, industrial contaminants, and excess salts, harms root systems and inhibits water and nutrient uptake (Sandeep et al. 2019; Jangra et al. 2024).

Compacted urban soils, a common issue in urban areas, restrict root growth and oxygen availability, further exacerbating plant stress. Damaged or restricted root systems can lead to poor anchorage, reduced stability, and increased susceptibility to drought and disease (Bauhus et al. 2017). Pollution-induced stress causes canopy thinning and dieback in urban trees, reducing foliage density and canopy cover (Kumar et al. 2022; Kanta et al. 2024). This may display cascade effects on urban microclimates, increasing solar radiation and surface temperatures, further stressing plants, and exacerbating environmental conditions. It has been reported that environmental pollution disrupts plant phenology, affecting the timing of leaf emergence, flowering, and fruiting. For example, exposure to air pollutants may delay budburst or flowering in certain species, leading to mismatches with pollinators or changes in seed dispersal patterns (Neil and Wu 2006). Pollution-tolerant species may dominate urban forests, replacing sensitive or less-adapted species. This leads to species composition shifts and reduced biodiversity, potentially impacting ecosystem stability and resilience. Chronic exposure to pollution demonstrates cumulative and long-lasting effects on plant morphology and fitness. Over time, repeated exposure may lead to genetic changes within plant populations, favoring traits that confer tolerance or resistance to pollutants.

3.2 Physiological Changes

The urban environmental pollution impacts various aspects of plants. Few changes in urban plants are pollutant-specific. Elevated ozone levels in urban areas lead to plant oxidative stress, damaging cell membranes and disrupting photosynthesis (Tiwari et al . 2021). This leads to lower chlorophyll concentration, lower photosynthetic rates, and slower growth. Besides, particulate matter from vehicle emissions and industrial activities settles on leaf surfaces, blocking stomata and reducing gas exchange, hindering photosynthesis, limiting carbon dioxide uptake, and increasing plant water stress (Sandeep et al. 2019).

Nitrogen deposition from vehicle exhaust and fertilizer runoff on leaf and soil surfaces, respectively causes nitrogen saturation. Nitrogen deposition disturbs nutrient balance, alters root morphology, and makes plants susceptible to diseases and pests (Singh and Verma 2013a, b; Malik et al. 2024). Urban soils contain elevated levels of heavy metals from industrial activities, vehicle emissions, and improper waste disposal (Kumar et al. 2022). Accumulation of heavy metals such as lead, cadmium, and mercury inhibits root growth, impairs nutrient uptake, and disrupts physiological processes within plants (Meena et al. 2011; Singh et al. 2017b).

Soil compaction is a crucial problem in urban areas. Urbanization often leads to soil compaction due to construction activities, foot traffic, and heavy machinery. Compacted soils have reduced porosity, limiting oxygen availability to roots and impeding water infiltration (Peterman and Bachelet, 2012). All these changes result in root asphyxiation, reduced nutrient uptake, and stunted growth.

In addition, water sources in urban areas are contaminated with pollutants such as heavy metals, pesticides, and industrial chemicals (Singh et al. 2022a, b). Irrigation with polluted water introduces toxins to plant roots, leading to physiological stress, reduced growth, and leaf damage (Kumar et al. 2021f; Kumar and Singh 2024). Furthermore, nutrient runoff from urban landscapes leads to eutrophication of water bodies within or adjacent to urban forests. Excessive nutrient levels promote algal blooms, deplete oxygen levels, and disrupt aquatic ecosystems, indirectly impacting plant health through altered water quality and availability (Janke et al. 2017). This problem is more prominent in blue-green urban areas. Urban areas are warmer than surrounding rural areas due to heat-absorbing pollutants and surfaces (Haines et al. 2006). Elevated temperatures can accelerate plant metabolism, increase water loss through transpiration, and exacerbate heat stress, causing physiological drought, leaf wilting, and ultimately declining growth rates of urban vegetation (Kumar et al. 2022).

3.3 Biochemical Changes

Environmental pollution leads to biochemical changes in urban forests, affecting the health and functioning of trees and other vegetation. Urban air pollutants directly damage plant tissues and disrupt biochemical processes (Chmielewski et al. 1998). For example, ozone impairs photosynthesis by damaging chloroplasts and interfering with the functioning of photosynthetic enzymes.

Heavy metals accumulate in plant tissues and soil, disrupting enzyme activity in various metabolisms and impairing plant growth and development. Soil pollution alters soil microbial communities and nutrient cycling processes, affecting the availability of essential nutrients to plants. Plants absorb contaminants and translocate to aboveground tissues, impacting biochemical pathways and plant health. Further, water pollution leads to nutrient imbalances, salinity stress, and the accumulation of toxic substances in plant tissues (Meuser 2010). Contaminated water in urban areas modulates physiological processes such as osmosis, nutrient uptake, and transpiration, affecting overall plant health and vitality.

Environmental pollution influences the production of secondary metabolites in urban vegetation. Pollution exposure may induce the synthesis of defensive compounds such as phenolics, flavonoids, and antioxidants (Lahiri and Krishna 2024). However, chronic exposure to high levels of pollutants may also suppress secondary metabolite production, compromising plant resilience to stressors such as pests, pathogens, and environmental extremes.

3.4 Molecular and Gene Expression

Pollutants such as heavy metals, ozone, nitrogen oxides, and volatile organic compounds (VOCs) incite oxidative stress in plants by generating reactive oxygen species (ROS) within their cells. Plants activate diverse defense mechanisms to counteract oxidative stress, including regulating genes involved in antioxidant production, detoxification pathways, and repair mechanisms (Garg et al. 2019). Pollution disrupts plants’ normal regulation of gene expression, resulting in modified gene transcription and translation patterns. Genes associated with stress responses, such as those coding for heat shock proteins, pathogenesis-related proteins, and stress-responsive transcription factors, may undergo upregulation in reaction to pollution-induced stress (Rehem et al. 2012). The disruption in photosynthesis triggers alterations in the expression of genes responsible for carbon fixation, photosystem protection, and stomatal regulation (Heber et al. 1995). Pollutants potentially impede plants’ uptake and assimilation of essential nutrients, leading to nutrient imbalances and deficiencies. Genes responsible for nutrient transport, uptake, and metabolism may exhibit differential expression in response to pollution stress as plants endeavor to maintain nutrient homeostasis. Plants react to pollution stress by triggering defense and detoxification pathways to alleviate the adverse effects of pollutants. Genes encoding enzymes involved in detoxification processes, such as cytochrome P450 monooxygenases, glutathione S-transferases, and ABC transporters, may be induced to detoxify and eliminate pollutants from plant tissues (Aioub et al. 2021). Environmental pollution induces epigenetic alterations in plants, such as changes in DNA methylation, histone modifications, and small RNA expression. These epigenetic modifications influence gene expression patterns and phenotypic adaptability, enabling plants to adapt to pollution stress across successive generations.

3.5 Plant Growth and Development

Elevated particulate matter (PM) levels and gaseous pollutants directly damage plant tissues, particularly leaf surfaces of urban vegetation. This damage can impair photosynthesis, reduce the plant’s ability to uptake nutrients and weaken its overall health. Elevated ground-level ozone induces oxidative stress in plants, causing chlorosis (yellowing) and necrosis (death) of leaf tissues. Ozone damage reduces photosynthetic efficiency, inhibits growth, and makes plants more susceptible to diseases and pests, hindering plant growth and development.

Contamination of urban soils with heavy metals adversely impacts plant growth and development. Heavy metals like lead, cadmium, and mercury accumulate in plant tissues, inhibiting root growth, nutrient uptake, and photosynthesis growth and productivity (Escobedo et al. 2011). Moreover, acid deposition in urban areas guides soil acidification, affecting nutrient availability and soil microbial activity. Acidic soils hinder plant root growth and nutrient uptake, leading to stunted growth and nutrient deficiencies. Urban forests are exposed to water pollution from runoff containing heavy metals, pesticides, fertilizers, and other chemicals (Chatterjee et al. 2017). The contaminated water harms plants by affecting root health, inhibiting water uptake, and causing toxicity symptoms such as leaf discoloration, wilting, and necrosis.

The synthesis of global research presented in the abovementioned sections suggested that pollution exacerbates climate change’s impacts on urban forests, making plants more susceptible to heat waves, drought, and extreme weather events. However, combined effects of pollution and climate change alter plant phenology, distribution patterns, and species composition in urban forests, affecting ecosystem dynamics and biodiversity of urban areas (Allen et al. 2010).

4 Resilience Strategies and Adaptation Measures

4.1 Selection of Climate-Resilient Plantation Species

Selecting climate-resilient plantation species is crucial in adapting and mitigating urban climate change and environmental pollution through forestry interventions. This approach may guide urban planners and policymakers in maintaining the health and functionality of forest urban ecosystems.

Understanding the climate variable-plant interactions is crucial before selecting climate-resilient urban plantation species. Climate models and in-situ experiments (Open top chamber approach, free air CO2 enrichment experimentation, temperature gradient tunnel, etc.) provide valuable insights into future impacts of changing climatic and environmental scenarios on plant species, helping to identify suitable species that thrive under changing climatic and environmental circumstances.

Identifying resilient plantation species based on plant functional traits is suggested. Traits to consider include drought tolerance, heat tolerance, resistance to pests and diseases, ability to withstand flooding or waterlogging, and flexibility in phenological timing. The selected plantation species, based on functional traits, possess adaptive characteristics that enable them to tolerate or adapt to environmental stresses associated with climate change (Kumar et al. 2022).

Assessing species diversity is essential for ecosystem resilience, increasing the likelihood of some species adapting to changing conditions. Selecting a diverse mix of tree species with various adaptive traits may enhance resilience and reduce the risk of widespread losses due to climate change impacts, pollution, pest outbreaks, etc. (Thompson et al. 2009).

Promoting native species well-adapted to local climatic conditions and soil types makes them inherently more resilient to regional and urban environmental changes. Promoting the use of native species helps preserve biodiversity, support ecosystem functions, and maintain the genetic diversity necessary for adaptation to changing conditions (Keenan 2015).

While native species are preferred for their ecological benefits, incorporating non-native species in some cases exhibits desirable resilience traits that make them suitable for planting in urban and disturbed environments (Keenan 2015). Urban planners, policymakers, and land managers are advised to consider the risks of introducing non-native species, such as invasiveness or disruption of native plant communities (Kumar et al. 2019a).

Utilizing climate-resilience tools and resources are available to assist in selecting climate-resilient tree species, including climate suitability maps, species distribution models, and databases of species traits and tolerances (Singh et al. 2023). These tools help land managers and urban planners decide which species best suit specific environmental conditions and climate scenarios.

Monitoring the plantation performance of selected tree species over time is essential for assessing their resilience and identifying any unforeseen challenges or opportunities (Keenan 2015). Adaptive management practices allow for adjustments to planting strategies based on empirical observations and feedback, ensuring urban forests’ continued success and resilience in ongoing environmental changes.

Hence, prioritizing the selection of climate-resilient tree species and incorporating them into forest management and urban planning efforts offers stakeholders a way to enhance the resilience of forest ecosystems, support biodiversity conservation, and mitigate the impacts of climate change and environments in urban areas.

4.1.1 Adaptation Strategies

Planting climate-resilient tree species adapted to local conditions may enhance the long-term viability of urban forests. Moreover, implementing soil conservation practices such as mulching, aeration, and amendment improves soil health and supports plant growth. Installing irrigation systems or rainwater harvesting techniques helps mitigate the impacts of drought stress and waterlogging on urban trees (EsperonRodriguez et al. 2022). Adopting integrated pest management strategies reduces reliance on chemical pesticides and minimizes the spread of pests and diseases in urban forests. Integrating green infrastructure and urban forestry principles into urban planning promotes resilient urban landscapes that support plant growth and biodiversity while mitigating climate change and environmental impacts (Mell 2009). Implementing these adaptation strategies and promoting sustainable management practices in urban forests better withstand the challenges posed by climate change, ensuring their contribution to urban ecosystems, human well-being, and urban environmental quality.

4.2 Improving Urban Forest Management Practices

Urban forests are critical in enhancing cities’ livability, sustainability, and resilience. Effective management practices are essential to ensure the health and vitality of urban forests in the era of climate change, pollution, and urbanization. Developing and implementing comprehensive urban forest management plans that integrate ecological, social, and economic objectives is a prerequisite for adaptive mechanisms. Establish policies and regulations to protect existing plantations, promote tree planting initiatives, and guide sustainable land use practices in urban areas (Ottitsch and Krott 2005). Similarly, collaboration with relevant stakeholders, including local governments, community organizations, and urban planners, is required to implement urban forest management strategies effectively. Prioritize selecting climate-resilient tree species that are well-adapted to local environmental conditions, including temperature, soil type, and moisture availability. Different species and age classes enhance species richness, genetic diversity, and ecosystem resilience within urban forests (Singh 2013). Implement proper planting techniques, including appropriate spacing, soil preparation, and mulching, to promote healthy root development and longterm tree growth. Establish regular maintenance programs for pruning, watering, fertilizing, and pest management to ensure the health and vitality of urban trees.

Apart from this, integrating urban forestry principles into green infrastructure planning and design significantly maximizes the benefits of trees and vegetation in urban environments. Green infrastructure strategically uses natural systems and vegetation to provide environmental, social, and economic benefits in urban and rural areas. Implementing green infrastructure projects is crucial for enhancing resilience to climate change and promoting sustainable development (Abunnasr 2013). Incorporating trees, green spaces, and vegetative buffers into urban development projects helps mitigate the impacts of heat islands, stormwater runoff, air pollution, and noise pollution. There is a need to design multifunctional green spaces that provide recreational opportunities, habitat for wildlife, and ecosystem services while enhancing urban aesthetics and quality of life (Abunnasr 2013).

Soil amendment is a critical activity that significantly contributes toward sustainable forest management. Implement soil conservation practices, such as mulching, composting, and soil aeration, to improve soil health, structure, and fertility in urban forests (Meuser 2010). Restore degraded urban soils through remediation techniques, including phytoremediation, biochar application, and green infrastructure development (Garg et al. 2019). Further, minimizing soil compaction, erosion, and pollution through sustainable land management practices, including limiting impervious surfaces and reducing vehicle traffic in urban areas, is another management practice enhancing ecosystem resilience. Recycling organic waste materials through composting may enrich soil with essential nutrients, improve soil structure, and enhance water retention capacity (Chatterjee et al. 2017). Applying organic mulches such as wood chips, straw, or leaf litter to the soil surface helps suppress weeds, conserve soil moisture, regulate soil temperature, and promote the decomposition of organic matter. Applying soil amendments such as gypsum, lime, or biochar adjusts soil pH, improves nutrient availability, and enhances soil structure. Implementing soil restoration techniques rebuild degraded soils, enhance biodiversity, and restore ecosystem services (Fajeriana et al. 2024).

Refining and implementing nutrient management strategies is crucial for maintaining the health and sustainability of urban forests. Precision management techniques, including soil testing and optimized fertilizer application, play pivotal roles in this endeavor. Furthermore, nutrient management in urban forests should prioritize using organic and slow-release fertilizers, which offer sustained nutrient availability while reducing the risk of leaching and runoff. Compost and other organic amendments in soil management plans enhance soil structure and fertility, fostering healthier root systems and tree vigor (Chaudhari et al. 2020).

5 Policy Implications and Recommendations

Urban forests play a crucial role in mitigating the impacts of climate change and environmental pollution while providing numerous benefits to urban dwellers. However, they face significant challenges due to the adverse effects of climate change and pollution, which disrupt ecosystem functioning and compromise the health and resilience of urban forests. Addressing these challenges requires comprehensive policies and strategic interventions.

5.1 Policy Implications

There is a need to implement comprehensive policies for urban forest management that prioritize preserving and expanding green spaces within urban areas. Establish sustainable land use regulations to prevent deforestation and ensure the integration of green infrastructure in urban development projects (Nowak and Greenfield 2010). Strengthen air quality standards to decrease pollutants like nitrogen oxides, sulfur dioxide, and particulate matter, negatively impacting urban forest ecosystems (McPherson et al. 2005). Besides, policies should be implemented to promote the adoption of cleaner energy sources and technologies to mitigate air pollution. This approach may reduce greenhouse gas emissions to alleviate the effects of climate change on urban forests. Reforestation and aforestation initiatives as nature-based solutions should also be promoted to sequester carbon dioxide and enrich urban biodiversity (Escobedo et al. 2011; Naumann et al. 2011a, b). It is very worthwhile to develop strategies for biodiversity conservation to safeguard urban forest ecosystems and shield vulnerable species from the detrimental effects of climate change and pollution (Givnish 2015).

5.2 Recommendations

📷 Reduction of GHG emissions by implementing policies to reduce greenhouse gas emissions and air pollutants. These policies include transitioning to renewable energy sources, promoting energy efficiency measures, and adopting stricter industrial and vehicle emissions regulations in urban areas (Escobedo et al. 2011). 📷 Incorporate green infrastructure and urban forestry into city planning and development processes. Designating green spaces, planting trees, and preserving existing urban forests can help mitigate the urban heat island effect, improve air quality, and enhance biodiversity (Benedict and McMahon 2002). Municipalities should prioritize and integrate green infrastructure projects into long-term urban planning strategies.

📷 Implement sustainable forest management practices in urban areas to enhance the resilience of urban forests to climate change and pollution. This includes tree planting programs, regular maintenance of urban green spaces, and removing invasive species (Keenan 2015).

📷 Promoting diverse tree species composition and age structure may improve urban forests’ adaptive capacity.

📷 Launch public awareness campaigns and educational programs to engage communities in environmental conservation efforts (Ottitsch and Krott 2005). Increasing public understanding of the importance of urban forests for mitigating climate change and pollution fosters support for policy initiatives and encourages individual actions such as tree planting and sustainable lifestyle choices.

📷 Investing in scientific research and monitoring programs to better understand the biological consequences of climate change and pollution on urban forests is strongly recommended. This includes studying the impacts of temperature fluctuations, air pollution exposure, and extreme weather events on tree health and ecosystem dynamics (Tiwari et al. 2021). The research findings strongly inform evidence-based policy decisions and adaptive management strategies.

📷 Encourage collaboration among government agencies, non-profit organizations, academic institutions, and community groups to address urban forests’ complex challenges (Tiwari et al. 2021). Collective expertise and resources leverage stakeholders to develop holistic approaches to climate change adaptation and pollution mitigation in urban environments.

📷 Integrate urban forestry goals into broader climate action and environmental policies at the local, regional, and national levels. Policymakers and urban planners should recognize urban forestry as an essential component of climate adaptation and mitigation strategies, with dedicated funding and institutional support to implement effective policies and programs.

📷 Promote the development of green economy initiatives that support sustainable land management practices and create green jobs in urban forestry and ecological restoration. Investing in green infrastructure projects and nature-based solutions generates economic benefits while enhancing urban ecosystems’ resilience (Jim 2013).

6 Conclusion

The synthesis underscores the profound and multifaceted biological impacts of climate change and environmental pollution on urban forests. From alterations in phenology and physiology to shifts in biochemistry and molecular processes, these stressors pose significant challenges to the health and vitality of urban green spaces. However, within these challenges lie opportunities for resilience and adaptation. Urban planners and policymakers may adopt strategies such as carefully selecting climate-resilient tree species, enhancing urban forest management practices, and implementing green infrastructure projects to fortify urban forests against the adverse effects of climate change and environmental pollution. Moreover, robust policy interventions such as emission reduction, integrating urban forestry into urban planning, public awareness, education initiatives, research and monitoring investments, collaborative partnerships, and support for green economy endeavors are imperative to mitigate the biological consequences of climate change and pollution on urban forests. Furthermore, implementing resilience strategies, adaptation measures, and policy recommendations may guide urban planners and land managers toward fostering more resilient and sustainable urban forest ecosystems. Ultimately, these interventions are required in urban ecosystems to continue to provide invaluable ecological, social, and economic benefits to urban communities, ensuring a greener and healthier environment for future generations.