Installing a play area surface presents a landscaping challenge. The surfacing material must be attractive, but also be resilient enough to withstand heavy traffic. The material must also provide some protection from injury in the event of a fall from playground equipment, and be intrinsically safe and free from toxic chemicals or substances that could cause injuries or illness. Of the various wood mulches on the market, there are two that are useful for playgrounds.
Engineered Wood Fiber
Engineered wood fibre is a product made from virgin wood scrap with a binder added. The binder allows it to adhere to the ground so that it stays in place. Engineered wood fibre produces a surface that is soft, stable and resilient. At a 6-inch depth, this product can break a fall from 6 feet. Engineered wood fibre has been the product most widely used as playground surfacing for the past 20 years. This mulch must meet ASTM standards with regard to particle size and contaminate levels so the product won't pose any danger of causing puncture wounds or being toxic if accidentally ingested. The virgin wood that goes into the product has never been painted or had chemicals added, so there should be no concentration of toxic agents or heavy metals. The binders used are inert, so there is little possibility of the product triggering an allergic reaction. Engineered wood fibre mulch is marketed under a number of brand names.
Hardwood chip mulch is the next best product to use in play areas. The product can break falls from a height of 6 feet effectively, hardwoods don't contain saps or resins that trigger allergic reactions, and the weight of the chips keeps it in place. However, hardwood chips are expensive compared with other mulch products. A load of wood chips can also contain large, sharp pieces of wood that are potentially hazardous. Wood chips also create a surface that is uneven, so handicap-accessibility may be impeded.
Forest fines consist of tree trimmings, bark and wood that are ground to a fine grain. The product is small-textured, containing pieces that are 1 1/2 inches or less. Forest fines tend to knit down and adhere to soil surfaces. The medium brown colour makes it an attractive surfacing material, but it does not perform well in heavy traffic. This product is intended to break down fairly quickly, and the top layers tend to blow away during windy weather.
Redwood or Cedar Mulch
Mulch made from redwood or cedar should never be used on the surface of playgrounds. Redwood mulch, specifically the finely-ground product known as "gorilla hair," is highly flammable. The possibility of fire from a dropped cigarette or other lit object is great. Redwood and cedar mulch also contain resins that cause skin irritation in many people. Children playing in an area surfaced with redwood or cedar may develop skin rashes after exposure to either of these mulches.