Wood chips, defined as shredded or chipped wood material created as a byproduct of tree removal and wood processing, are a widely utilized resource in residential and commercial settings. Their versatility makes them valuable across various applications, extending far beyond simple waste disposal. This organic material offers significant benefits in landscaping, gardening, construction, and safety due to its physical structure and natural composition.
Optimizing Soil Health and Plant Growth
Wood chips function primarily as an organic mulch layer, delivering multiple benefits directly to the soil and surrounding plants. Spread over the soil surface, they create a physical barrier that blocks sunlight, preventing most weed seeds from germinating. A depth of 7.5 to 10 centimeters of mulch is recommended for effective weed suppression.
The wood layer also regulates the soil’s moisture and temperature. The coarse texture of the chips helps retain water, significantly reducing moisture evaporation from the soil beneath. This conserved moisture allows plants to remain hydrated longer, reducing the need for frequent watering during warm or dry conditions. Furthermore, wood chip mulch acts as insulation, moderating soil temperatures by keeping the ground cooler in summer and warmer during cold snaps, protecting root systems from extreme fluctuations.
As the wood chips slowly decompose, they contribute organic matter to the soil, improving its structure and supporting beneficial microbial and fungal activity. A common concern is “nitrogen tie-up,” where microorganisms consume nitrogen to break down the high-carbon wood material. This temporary nitrogen depletion only occurs in the thin layer where the chips contact the soil surface, or if the chips are mixed into the soil. When used correctly as a surface mulch, the wood chips do not draw nitrogen away from the deeper root zone where most plants access nutrients.
Designing Functional and Attractive Pathways
Wood chips offer an affordable and aesthetically pleasing alternative to traditional hardscaping materials for creating walking surfaces. Their natural appearance blends seamlessly into garden settings, defining borders and providing a soft look for trails and informal paths. The material is easy to install, requiring minimal preparation compared to laying concrete or pavers.
The loose, porous nature of the chips provides excellent drainage, preventing water from pooling and making paths usable soon after rainfall. Walking on wood chips is softer and more comfortable underfoot than walking on gravel or stone surfaces. While they require occasional replenishment as the material breaks down or is displaced, this biodegradability is an environmental benefit, as wood chip paths naturally transition to soil over time.
Specialized Uses for Safety and Environment
Beyond horticulture and aesthetics, wood chips serve important purposes in safety and environmental stabilization. They are widely used as a loose-fill safety surfacing material beneath playground equipment due to their ability to absorb impact and cushion falls. Engineered wood fiber (EWF), a specific wood chip product, is designed and tested to meet safety standards for impact attenuation.
The depth of the material relates directly to the maximum fall height it can safely absorb, known as the critical fall height. For example, uncompressed wood chips at a depth of 300 millimeters (about 12 inches) can protect against falls up to 3.3 meters (about 11 feet). To maintain this protective function, the loose-fill material requires consistent maintenance, including regular raking and topping off, as the chips compact and get displaced.
Wood chips are also highly effective in controlling soil erosion, particularly on steep slopes or disturbed construction sites. When applied as a thick layer, they reduce the impact force of raindrops, preventing the dislodgement of soil particles and minimizing surface runoff. The fibrous nature of the chips helps to hold the soil in place, enhancing water infiltration and protecting the valuable topsoil layer from being washed away.
Selecting the Right Wood Chip Material
The proper selection of wood chip material depends on the intended application and desired longevity. Wood chips are generally coarser and decompose more slowly, making them suitable for long-term mulching, paths, and erosion control. Shredded wood is finer, has a greater surface area, and decomposes more quickly, often used where faster nutrient release or a smoother texture is preferred.
The type of wood also influences performance. Hardwood chips, sourced from trees like oak or maple, are denser and break down at a slower rate than softwood chips, which come from conifers like pine or cedar. Softwood mulch can also impart a slight acidity as it decomposes, which is beneficial for acid-loving plants such as rhododendrons and blueberries. Practical sourcing options include arborists, who often provide fresh “arborist chips,” or municipal recycling centers, which process yard waste into mulch. It is recommended to avoid using wood that has been chemically treated or sourced from diseased trees.