Tree roots in walkways:
Trees are important elements in streets. they provide shadow, decrease carbon emission and make street more beautiful. In Sydney there are large number of walkways which damaged by tree roots. These walkways are not proper for biking, walking and to carry trolley or trolley bags. In order to keep trees and also prevent and minimise the damage to walkways there are several thing that could be done. According to Gliman (2002) removing some part of walkways can help to reduce damage to walkway. Furthermore using barriers and channels to change the direction of roots to open soil could be helpful. Using gravel under the pavement causes roots to stay under pavement. Well drained soil is important to reduce the damage. Roots in this sort of soil can receive more oxygen because water will scattered in the soil instead of pooling in certain part of soil.

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source: 
Gliman,F (2002) Urban Design to Accommodate Trees: Sidewalk Solutions,Department of Environmental Horticulture,pp3-22