LASN is a photographically oriented, professional journal featuring topics of concern and state-of-the-art projects designed or influenced by registered Landscape Architects.
Issue link: https://landscapearchitect.epubxp.com/i/274582
110 Landscape Architect and Specifier News o rd i n a n c e s (Continued from page 16) The most critical sections of sidewalk ordinances are shading specifications, street tree selection and planting location. A sidewalk ordinance must set a shade standard. The designer must control the pattern and extent of shade. This is done through species, selection, sizing and proper spacing. It is suggested that a minimum of 40 percent canopy coverage after 15 years of growth is appropriate. Shading is measured by the projected diameter of the tree crown. With the use of class B trees with a 30-foot diameter, a 90 percent shade standard can be designed. Tree species ought be carefully selected for planting in tight urban street tree planting areas. Class A trees (50-ft. diameter of tree crown) is not always the best choice. Choose smaller trees with small fibrous root systems and that will thrive in dry urban conditions. Always select trees for texture, fall color, flowers, light fruiting and the ability to withstand storms. Tree planting should take place on the outside edge of the right-of-way if possible, and not between the sidewalk and the curb if it can be avoided. Class A trees, the usual native over-story tree of the community, should be planted within the "street garden" of adjacent properties. These trees, known as yard trees, are to be planted on private property. They should be furnished by the city since their purpose is public, yet maintained by the private property owner. Large trees that shade sidewalks must be on private property, and a private-public agreement must we worked out to allow this to occur. And, of course, trees must not be spaced too close together. Landscape Laws and Trees A quick review of the Los Angeles Municipal Code (American Legal, Chapt. I, IX, Art 2, Art. 7 and Art. 9 and Sec. 12.40-12.43), including design standards, building regulations, landscape code and green building practices, revealed no sidewalk shading requirements for street trees. So it is easy to see that even large communities fail to see the importance of sidewalk shading. For an outline for a sidewalk shading ordinance contact the author by email: lsugreenlaws@ aol.com. You may also call Abbey Associates Landscape Architecture at (225) 766-0922. This is the same street around the corner. A proper street tree ordinance would not allow such a large species of tree, or require root barriers or tree grates to prevent repairing the sidewalk (above). Boxed in by concrete (below), the tree roots, seeking room, have been forced up like molten rock in a lava tube and "bubbled" over the concrete. PhoTos: EdiTor sTEvE KElly I n f o r m a t i o n R e q u e s t # 6 7 1 110-111.indd 110 2/27/14 9:11 AM