Phosphatic fertilizer 32,373
PVC plastic 35,130
Every attempt should be made to reduce the quantity of materials that have a relatively high amount of embodied energy or to substitute salvaged and recycled materials for them. Btu/lb
Copper pipe 73,100
Cut granite 2,537
External oil-based paint 42,962
3/4" ext. For example, the embodied energies for a few selected landscape materials are as follows.
Common brick 1,075 to 4,085 ave. One of the most popular and available remanufactured materials is “plastic lumber,” a good substitute for deck surfaces. One caution is to check the exact content of remanufactured materials to avoid using those that contain PVC or have a relatively large amount of embodied energy. A surprising number of remanufactured materials and products are now available for use in the landscape, with new ones becoming available all the time. Used construction materials can be obtained directly from a site that is being demolished, from a retail company that specializes in reclaimed and refurbished materials, or sometimes from a municipality that has saved materials from various public works projects. A compost area can be used to collect a range of organic waste, including leaves, lawn clippings, plant pruning debris, and even vegetable discards from the kitchen (Figure 3-52). Old rubber tires may be used in some instances for retaining earth or to augment earth used as fill. A compost area should be easily accessible and screened to block drying wind and views. Transportation costs and air pollution are likewise minimized or eliminated when materials are reused and recycled. Other remanufactured materials include tile, brick, and concrete pavers made with crushed glass or ground rubber. As previously discussed for minimizing site impact, existing vegetation should likewise be preserved as much as possible. When a compost area is not feasible because of space limitations or other restraints, then provisions should be made to take green landscape material to municipal compost, where it serves a larger community good. Embodied energy is the term used to describe the collective amount of energy it takes to obtain the resources for, manufacture, and transport a product to a site and is typically an invisible cost that can be surprisingly large. Crushed glass or “cullet,” available in different aggregate sizes, finishes, and color, potentially lends itself to the same uses as gravel. Plastic lumber is available in a range of colors, is considered a safer material than pressure-treated lumber, and potentially lasts many years, thus reducing long-term maintenance. Some site furnishings such as benches, tables, pots, and so on are also available with recycled materials. Salvage Materials on Site
A number of materials on a site can potentially be salvaged and used in the design. Use Salvaged Materials from the Region
Salvaged materials that exist in the community or region can also be used to supplement or substitute for those found on a residential site. There are a number of ways of reusing and recycling materials on the residential site. Local remanufactured materials and suppliers can often be found in the Yellow Pages or on the Internet. Materials that are given a second life do not add to the volume of already burgeoning landfills, either. If extra soil exists, then creative ways, such as earth berms or sculptural mounds, should be created to eliminate the need to haul soil away. Reusing and recycling materials that are already on-site or in the nearby region can save raw material resources and the energy that is required to manufacture them. When existing plant materials are in the wrong location for the design, they should be transplanted to a different location where they fit the design rather than being cut down. A comprehensive reference for such materials is The Resource Guide to Sustainable Landscapes, by Wesley Groesbeck and Jan Streifel. Further, numerous other materials found in junkyards provide limitless opportunities for creative solutions that give each design its own uniqueness. Boulders and fieldstone that are found on a site can be used for retaining walls, pavement, or steps whenever their size and shape permit. Pavement materials, wood, and scrap metal are some of most readily available salvaged materials. Depending on the brand, plastic wood may be composed of only recycled plastic or a combination of recycled plastic and sawdust. A new coat of paint or stain frequently disguises the fact that wood was reused. Construction materials that already exist on a residential site should be salvaged, too. In addition, less common materials such as crushed glass and rubber tires might be considered as well. One is the soil. In some instances, construction costs are reduced as well when materials are reused and recycled. Some remanufactured materials may actually be more harmful than beneficial. The ideal and most direct way to do this is to integrate existing pavement, decks, fences, and other structures into the new design without moving or reconfiguring them. The use of on-site stone further establishes a site character that is compatible with the region.