Most days, a city tree is just a tree. It stands there, out of the way, but close enough if you need a shaded parking or walk. Other days, a tree will make one pause and wonder.
Cities all over the world remember to add trees to their streets and build parks from scratch to bring some nature closer to citizens. Parks and city gardens will have collections of beautiful trees which, much like a city’s inhabitants, are brought together from near and far.
Tall, elegant palm trees along the side of roads, or trees with spreading crowns so people can walk beneath; flowering trees that add hints of color, and trees with round crowns to soften the city landscape.
How do we choose which trees move to the city with us?
Tree choices can tell us something of the history and importance of a place, and the nature of the tree.
Cities built in the colonial era have plenty of introduced trees, sometimes because more was known about them than native trees. Newer parts of an urban area might have trees that mature faster so they are ready to adorn the city.
Trees that make it to the city are usually tougher, so to speak, chosen for their ability to withstand disturbances like road vibrations and strong winds, and their tolerance for fumes. There are also practical considerations. Trees that bear heavy, falling fruits or have large roots near the ground surface are not good choices where they pose hazards to people, property or infrastructure.
Urban trees are also chosen for their aesthetic or distinguishing qualities, especially those we find in public parks, open spaces or around prestigious public buildings. They are chosen depending on the context to produce a certain effect: comfort, grandeur, delight.
How trees benefit cities
Just like in their natural habitats, the roles that trees play in urban ecosystems are much more than meets the eye. Like all plants, they help keep excess carbon out of the air within their trunks and roots; their leaves and textured wood filter particulate matter and gases that are released by engines.
Our building materials and activities in cities make urban temperatures higher than they would be otherwise. Trees can cool cities as they release water vapor through their leaves and also by creating shade cover. The right tree selection and arrangement can also help block some of the noise we create as we travel, build and work in cities.
Trees and urban biodiversity
Urban trees also cater to the city wildlife. Tree flowers offer nectar to many kinds of bees, butterflies and moths, and fruits and seeds feed birds, squirrels and shrews. Tree branches and canopies provide spaces for nests and shelters and oftentimes, convenient transit throughout the city.
Trees also make it possible for more plants to flourish in cities as they offer shade for young shoots growing beneath their canopies and support for ferns and climbing plants.
Perhaps cities can offer trees something in return too.
City residents can experience and appreciate trees in a slightly different way than they would in the wild.
A bird’s-eye view of massive trees from atop the LRT, or high rise windows that offer a view of tree tops laden with tiny flowers and hidden nests.
And the luxury of time to watch and follow a sapling’s growth into a grand tree that flowers and fruits, nurtures and shelters, in a suburban backyard.