Functional traits of urban trees: air pollution mitigation potential

Abstract

In an increasingly urbanized world, air pollution mitigation is considered one of most important issues in city planning. Urban trees help to improve air quality by facilitating widespread deposition of various gases and particles through the provision of large surface areas as well as through their influence on microclimate and air turbulence. However, many of these trees produce wind‐dispersed pollen (a known allergen) and emit a range of gaseous substances that take part in photochemical reactions – all of which can negatively affect air quality. The degree to which these air‐quality impacts are manifested depends on species‐specific tree properties: that is, their “traits”. We summarize and discuss the current knowledge on how such traits affect urban air pollution. We also present aggregated traits of some of the most common tree species in Europe, which can be used as a decision‐support tool for city planning and for improving urban air‐quality models.

Mapping and Assessment of PM10 and O3 Removal by Woody Vegetation at Urban and Regional Level

“…A far sighted management of GI should take into account the different dynamics of the two atmospheric pollutants, which are particularly harmful for human health, inside and outside the city [77], and the different removal patterns of different ecosystems. Many authors pointed out the relation between functional diversity and the enhancement of ES [8,25,78], highlighting the importance to reach an appropriate balance between different ecosystems. Such an achievement would contribute to improving ES provision to further improve nature-based solutions.…”

Modeling Ecosystem Services for Park Trees: Sensitivity of i-Tree Eco Simulations to Light Exposure and Tree Species Classification

“…However, uptake processes may need to be differentiated in terms of stomatal uptake and deposition onto the surface of the leaves, both of which are related to further environmental conditions. Stomatal uptake was found to depend on the photosynthetic activity, turgor pressure, and removal time in the intercellular spaces, particularly for O 3 and NO 2 , which were almost immediately metabolized [4]. Therefore, stomatal uptake through stomata could possibly be influenced by drought stress, which the standard i-Tree Eco model neglects, assuming sufficient water availability or irrigation for the street and park trees.…”

“…Deposition capacity in turn is also dynamical, since washing the deposited content from the leaf reduces the pollutant storage at the leaves [84]. In the case of NO 2 and SO 2 , it is also possible that pollution removal occurs by means of dissolving directly into the water film on the plant surface [4]. Although it might have a minor impact compared with the influence of the stomata on the gaseous uptake, the uncertainty associated with leaf-surface properties and the dependency on rainfall are currently underexplored in i-Tree Eco.…”

Do linden trees kill bees? Reviewing the causes of bee deaths on silver linden (Tilia tomentosa)

“…Linden are among the most common urban trees throughout Europe and North America [29], and so have the greatest potential to affect urban pollinators. Madel [12] T. tomentosa …”