At some point in the evolutionary process, a filament penetrated into the outer cells of a primitive plant root. Once there, it accommodated itself so nicely that a new, more complex entity emerged, the mycorrhiza. The increased absorbing area provided by an elaborate system of fungal filaments allowed aquatic plants to leave the marine environment and exploit a relatively harsh soil environment. In today's man-made environments plants can be greatly stressed and the relationship between fungus and root is critical. Unnatural conditions such as concrete, asphalt, roadsides, sidewalk cut outs, trenching, drain fields, air pollution, shopping malls, business districts, and suburban developments adversely effect the presence and abundance of mycorrhizal fungi.
Artificial landscapes effect the mycorrhizal relationship in two fundamental ways.
Fortunately, recent advancements in mycorrhizal research and application have made landscape applications with mycorrhiza easy and inexpensive. New products and knowledge result in increased transplant survival and lower long-term maintenance. However, to be successful the landscape contractor requires an appreciation of fungi beyond itchy toes and moldy bread. Figure 3 Construction sites typically compact the soil and remove organic matter and topsoil. These practices reduce or eliminate mycorrhizal fungi.