Why Is That Tree the Street Tree in Our Neighborhood?

Complete Guide to Street Trees Series #2

Street trees aren't just any random trees

Cherry trees in front of schools, ginkgo trees along major roads, zelkova trees in apartment complexes... Have you noticed? Different trees are planted as street trees in different locations.

They're not just randomly planted - they're carefully selected considering various factors. In Korea, there are as many as 160 species that can be used as street trees!

What criteria are used to select street trees?

When selecting street trees, these factors are considered:

First, whether the tree is well-suited to the local climate and soil. You can't plant cold-sensitive trees in cold regions, right?

Second, whether it fits the local history and culture. In old villages, trees that have grown in that area for a long time are more suitable.

Third, whether it harmonizes with the surrounding landscape. Areas with tall buildings and low residential areas require different types of trees.

Fourth, whether it has any negative effects on people's health. Trees that cause severe allergies should be avoided.

Fifth, whether it helps with air purification and temperature regulation. These are important roles of street trees!

Each tree has its own personality

Trees, like people, each have different personalities. Some trees are resistant to exhaust fumes, while others are sensitive. Some trees can withstand cold well, while others cannot.

Pollution-resistant trees vs pollution-sensitive trees

Major city roads have lots of cars and therefore lots of exhaust fumes. So we need to plant trees that are resistant to pollution.

Pollution-resistant trees include ginkgo, zelkova, London plane tree (platanus), and Japanese pagoda tree. On the other hand, pine, cherry, hackberry, and katsura tree are sensitive to pollution, so they're rarely planted along busy roads.

Cold-resistant trees vs cold-sensitive trees

Crape myrtle and Chinese scholar tree are sensitive to cold. So they're only planted in places where special winter care can be provided.

Trees with spreading root systems

Some trees don't send their roots deep underground but spread them horizontally. These are called "shallow-rooted trees." When these trees are planted, their roots can push up sidewalk surfaces, making them uneven.

Different trees are planted according to location

Commercial areas (places with many shops)

What's most important in areas with many shops? Making sure signs aren't blocked! So we plant trees whose branches don't spread too much to the sides and whose lower branches are positioned high up.

Trees like ginkgo, Chinese fringe tree, horse chestnut, zelkova, and Japanese pagoda tree are good choices.

Office districts

In areas with tall buildings, large and majestic trees that complement the buildings are preferred. These include ginkgo, zelkova, Chinese fringe tree, Japanese pagoda tree, and dawn redwood.

Around apartment complexes

Around apartments, we plant trees that provide good shade and are beautiful to look at. Popular choices include zelkova, hackberry, Japanese pagoda tree, Chinese fringe tree, maple, and Korean cherry.

Historic sites and tourist attractions

In old palaces and tourist sites, traditional trees that match the local atmosphere are planted. These include ginkgo, cornelian cherry, pine, hawthorn, and elm.

Roads connected to forests

On roads next to mountains or parks, we plant fruit-bearing trees that can provide food for animals like birds and squirrels. These include Chinese fringe tree, Japanese pagoda tree, cornelian cherry, hawthorn, and Korean mountain ash.

Different trees are planted according to road width

Wide roads (over 40m)

On really big roads, we plant large trees that grow over 25m tall when mature. They create important urban landscapes. These include ginkgo, zelkova, Japanese pagoda tree, and London plane tree.

Medium roads (25-40m)

We plant trees that grow 15-20m tall, such as ginkgo, dogwood, ash, hackberry, tulip tree, and Chinese fringe tree.

Narrow roads (under 25m)

On narrow roads, we plant relatively smaller trees like cornelian cherry, maple, magnolia, and goldenrain tree.

It also depends on sidewalk width

If the sidewalk is narrow (under 3m), we plant small trees whose branches don't spread much. These include Korean mountain ash, kousa dogwood, hawthorn, and crape myrtle.

If the sidewalk is wide (over 5m), we can plant large trees that provide lots of shade, such as ginkgo, hackberry, zelkova, and Japanese pagoda tree.

Areas with power lines are special

In areas where power lines pass through, we can't plant trees that grow too tall. As trees grow, they might touch the wires. So in these areas, we plant shorter trees like cornelian cherry, kousa dogwood, crape myrtle, and rose of Sharon.

Conditions for good street trees

Trees used as street trees aren't just randomly selected and planted. There are quality standards.

To be a good street tree:

• The tree shape should be beautiful and healthy
• Branches and leaves should be appropriately dense
• There should be no pest or disease damage
• Roots should be well-developed
• Lower branches should be at a certain height so people can pass by comfortably

Interesting facts

Male and female ginkgo trees are planted selectively! Have you ever smelled ginkgo fruit? It's really awful, right? So in areas where many people walk, we specifically choose male trees that don't bear fruit.

Fast-growing trees aren't planted near power lines! Trees like dawn redwood grow quickly, so we avoid planting them where there are power lines.

Conclusion

Next time you walk down the street and see street trees, think "Why is this tree here?" There's definitely a reason. Road width, sidewalk width, surrounding buildings, presence of power lines... Various factors are considered to select the perfect tree for that specific location!

Sources

Korea Forest Service, "Street Tree Creation and Management Manual," 2022