Why may urban trees have a shorter life span in cities?

Urban trees often face a variety of challenges that can significantly decrease their lifespan, and one of the primary reasons for this is the adverse effects of vehicle emissions and the lack of natural soil. Urban environments can be highly polluted, with vehicle emissions releasing harmful pollutants that can damage tree foliage and negatively impact their health.

Additionally, urban soils are frequently altered or compacted due to construction and the presence of infrastructure, which can limit the availability of nutrients and water essential for tree growth. Unlike their counterparts in rural areas, urban trees may struggle to establish deep root systems because of limited soil volume and the presence of impervious surfaces, such as concrete and asphalt. This combination of poor air quality and compromised soil conditions can lead to stress, making trees more susceptible to disease, pest infestations, and environmental stressors.

Thus, the impacts of urbanization on air quality and soil quality play a pivotal role in reducing the lifespan of urban trees, making this choice the most accurate in explaining their shorter life expectancy in city environments.