E
cosystem
servicesdelivered
Provisioning
Regulation & maintenance
Cultural
Abiotic
C
ontribution
topolicyobjectives
Water Framework Directive
Floods Directive
Birds & Habitats Directive
2020 Biodiversity Strategy
P
otential
biophysicaleffects
Runoff
Reducing pollution
Soil conservation
Habitat
Climate Change
High
Low
Medium
None
Trees in urban areas will increase
evapotranspiration
, which can reduce the amount of runoff entering storm drains and can increase the water holding capacity of the
soil. Because the area around urban trees is often permeable, they provide a
localised
(although limited) potential to store runoff. The effects on flood risk reduction may be
noticeable when
summed
across all the trees in an urban area. Under some circumstances, trees in urban areas can increase infiltration and enhance groundwater recharge.
Trees in urban areas are able to
intercept particulate air pollution
. This can result in improvements in air quality and the health of urban populations. Trees in urban
areas can contribute to reductions in water pollution by intercepting and retaining nutrients including nitrogen and phosphorus.
Trees in urban areas have high potential for
climate change adaptation and mitigation
.While individual trees do not sequester large amounts of carbon, when it is
summed across a city, the effect can be considerable. Trees in urban areas can also limit peak temperatures at ground level by both shading and cooling (through transpiration).
Trees in urban areas have high potential to create
terrestrial habitat
. The effects on biodiversity preservation are apparent for bird species and there are probably benefits
for insects and lichens.
Trees in urban areas can have high
aesthetic
value. They can be an important element of urban planning and design and can greatly improve the attractiveness of urban
environments.
