What is the use of trees on the roadside?

Answer 1

Trees have numerous uses on roadsides, though it may depend on the density and alignment of the trees in how effective they are for any specific purpose:

1. Aesthetic, trees (generally) look nice. Trees and flowers can have a calming effect on drivers and promote a pleasant work commute for frequent drivers.

2. Wind / Dust / Snow screen. Trees can help break up incoming wind from surrounding areas, this may help prevent some of the problems caused by dust or snow blowing across the road. In areas without trees you may see wind/snow screens (fibrous plastic netting) used to attempt the same thing. Or mixing netting with trees can produce a screen while making it look better than an ugly plastic net by itself, and the trees may also act as additional anchoring points for the screen.

3. Natural drainage and/or soil erosion prevention. Trees will soak up some of the natural water in an area and along with other plants will help keep an area from becoming swampy or smelling bad from sitting pools of water. Or if the water is flowing frequently than the trees can be used to help keep soil anchored in place so that it does not completely erode an area quickly. While trees alone are not enough to keep water from either building up or washing away the soil, they can be used as part of an overall plan at handling water issues in a natural way.

4. Sound screen. If a roadway is near housing, there are really only three options to try and manage the sound levels: Walls, trees or a mixture of both. Depending on how far the housing is from the road and the level of traffic on the road it may be beneficial to reduce noise levels for the comfort of residents. Walls and trees (alone or in combination) are commonly used to help absorb some of the noise levels.

5. Pollution reduction. Cars create carbon dioxide, trees absorb it and turn it back into oxygen. With enough trees a highway's pollution levels can be reduced and help discourage smog from forming in high traffic areas. Some of the smoggiest cities in the world have highways systems that predate the now common practice of adding trees to roadsides during their building process. Cities with the largest density of trees near their roadsides consistently have better scores on air pollution tests. Trees alone will not solve pollution problems, but they are a measurable step in the right direction.

A highway engineer could probably list even more reasons for trees, but the bottom line: they are a helpful attempt at combating several of the drawbacks of building roadsides while also improving the overall look of the area.

Answer 2

Trees help to muffle the sound of the traffic.