Discover BRF or RCW, Ramial Chipped Wood, the next mulch revolution!

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BRF is a common term in forestry. It is derived from the French “Bois Raméal Fragmenté”, or Ramial Chipped Wood. Anybody can make this mulch from crushed and shredded green wood branches. It’s the best mulch for enriching and protecting garden soil.

While still under the radar of the public at large, BRF/RCW is a technique known to organic gardeners the world over. Canadian scientists developed and studied the practice in the 1990s.

The basic concept is to cover the soil with a mulch of shredded and crushed young branches and sprigs freshly cut from trees. These branches, usually under 3 inches (7 cm) in diameter, act to fertilize the soil, retain water to reduce watering and eliminate the need for fertilizer and chemical treatments.

• The main difference with wood chip mulch is that ramial chipped wood requires fresh branches. That way they’re still loaded with live buds, sap, microbial life, and nutrients.
• Branches should be processed within a few weeks to still retain the specific RCW / BRF advantages.
• Older, drier wood isn’t as nutrient-rich, although it still has all the advantages of wood chips.

BRF, RCW, an organic solution

Indeed, like any other mulch, BRF (or RCW in English) protects soil from erosion, evaporation and inhibits weed growth. On top of that, it retains water very well. Young branches tend to contain a great many nutrients: that’s where buds, leaves and flowers are located. These nutrients are transformed by underground fauna and flora (worms, fungus, thrips…). In the end, everything breaks down into organic building blocks that enrich, aerate the soil and balance its pH.

Result: beautiful, healthy plants and more productive fruits and vegetables.

BRF / RCW is thus particularly well suited to poor soil, especially if sandy, clayish or chalky.

• Note that fungus is what breaks the wood bits down into healthy nutrients.
• These fungus require nitrogen to set up shop.
• Over the first few months, nitrogen-needing plants might have a tough time, but this is more than offset after a season has passed.

Which wood makes good ramial chipped wood?

Not every prunings pile gives the same result. Here is what each kind of wood brings to the mulch, and how to handle it.

Mixed deciduous prunings, shredded soon after cutting, remain the safest and richest choice.

Ramial Chipped Wood, a practical solution

Best spread your BRF or RCW out at the end of winter or at the beginning of spring.

• Collect branches and shoots whenever you prune shrubs and trees in your garden.
• If you don’t have enough, check with your local municipality. Often, they will let you avail of pruning waste from various landscape and gardening companies in your area.
• Crush and shred this material in a chipper shredder.
• If possible, reduce the portion of conifer branches that tend to make the soil more acidic. Keep conifers to under 10-20% of the content (one part conifers for at least four parts deciduous).

How to use Ramial chipped wood for mulch

Spread the mulch in a layer 1 to 2 inches (2 to 5 cm) thick atop your flower beds, future vegetable beds and fruit beds.

• Studies show BRF or RCW to be effective in increasing harvests for tomato, zucchini and strawberry.

Lather it under your trees and shrubs – don’t cover the soil right around the trunk though, to keep the root crown free. Run the cultivator along the ground to stir in some of the ground bacteria. There’s no need to deep till or turn the ground. That’s all!

You can also add it as an underlayer to plastic sheeting or organic landscaping fabric, or other types of mulch.

After that, simply sow and plant whatever you wish, as usual. Apply a new layer of BRF or RCW atop the previous one in fall of the following year. Wood chips from the first layer will already have been broken down and mingled with the soil.

→ In more detail: best wood to make RWC

Laure Hamann edited by Gaspard Lorthiois

Sources shared to Nature & Garden:

• Gilles Lemieux and Diane Germain, Ramial Chipped Wood, the clue to sustainable fertile soil (University of Laval in Quebec, Canada)