"Trees and cities are not rivals – at least, no longer entirely. The ambitious
tree-planting programmes we have witnessed in cities over the past years are
proof of urban dwellers’ passion for them.
But there is a paradox in this: cities continue to spread at the expense of
natural areas, breaking up habitats and removing woodland to make way for
impervious surfaces that store and give off heat, such as concrete.
Urban trees are often presented as a “nature-based solution” that helps cool
down cities. However, trees also play a more understated role that is just as
vital: they provide lasting support for the living world.
Researchers have long gauged biodiversity according to the number of species
present in a given environment. They are now increasingly realising the
importance of another dimension: the extent to which species interact with one
Indeed, species have been able to adapt to environmental restrictions thanks to
their interactions with others than their own. Such connections are hard-wired
within them through evolution. For instance, urban white clovers were recently
found to have lost their capacity to emit chemicals in defence of herbivores.
While we increasingly understand how urbanisation impacts upon plants and their
enemies, there effectively remain significant research gaps, be them
geographical (Africa or South America are current blind spots) or scientific
(how our towns shape species interaction or local food chains)."
*** Xanni ***
Chief Scientist, Xanadu
Partner, Glass Wings
Manager, Serious Cybernetics