Ramial Chipped Wood, or RCW for short, is a type of mulch that maximizes forestry waste. When trees are harvested for wood, their branches and twigs can become nutrient-rich mulch for gardens and vegetable beds.
RCW is also called BRF, from the French Canadian researchers who developed the technique: Bois Raméal Fragmenté.
In this article, we’ll share about the advantages of RCW and which tree species it’s best to source it from.
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RCW/BRF and soil pH
Plots of land where conifers have been growing for a long time tend to turn acidic. Conversely, soil that is above limestone bedrock tends to be rather alkaline.
- You can control soil pH with Ramial Chipped Wood.
- Practically, the resulting soil is very slightly acidic, at 6.8, which suits plants better than strictly neutral “ph 7”.
Applying RCW over a couple seasons will significantly impact the pH.
- Soil that was too acidic for higher-value wood leads to planting without fear in soil that is more neutral.
- Excessively alkaline soil reverts to a more acidic pH.
This is very relevant in tropical island countries, where most of the soil is alkaline due to pH-raising coral bedrock.
Adapting soil for new plant species
Ramial chipped wood has the capacity to enhance and increase the quality of all types of soil. This is due to long, woody compounds called lignins and cellulose that take up to several centuries before breaking down entirely.
- This is a very long-lasting humus that is much richer than that derived from grassy plants and lawn trimmings.
In a way, it’s the ultimate natural slow-release fertilizer!
→ More natural fertilizers for the garden and veggie patch
Best trees to use to make RCW from
- in spring, new growth bursts with rich sap
- in summer, tree crowns are where most of the photosynthesis occurs
- during fall and winter, buds form for the next season and contain many nutrients.
Ramial chipped wood is a great way to maximize forestry revenue. Just as a wheat farmer sets stalks aside as straw fodder for animals, tips of trees are also a potential resource.
Thinning rows of cultivated trees, a practice that maximizes growth of the most promising specimens, results in a lot of extra material. Wood is either sold or kept for firewood, but until recently, leafy fronds were simply left behind.
With ramial chipped wood mulching, this rich material can benefit fields in a completely organic and environment-friendly way.
- Note that you should still leave a portion of the materials behind. This is important for the forest soil to keep improving.
Best tree species for Ramial Chipped Wood
Deciduous for the richest RCW mulch
Deciduous trees such as birch, poplar, maple and hophornbeam are often used for RCW. They are fast-growing. When harvested at mature size, these trees can earn an extra amount from the very rich branch tips they leave behind.
Ramial Wood Chips from garden plants and trees
In a garden, many ornamental tree trimmings are suitable for recycling into RCW.
- If you need to fell a tree, prune a hedge or hatrack a runaway shrub, don’t let this precious material leave your garden!
Evergreens that aren’t conifers also make excellent ramial chipped wood, even up to 100%.
- This is good news for people growing hedges out of boxwood, cotoneaster, photinia and yaupon for instance.
- Ornamental shrubs such as Azalea, Camellia, Rhododendron also can be converted to RCW.
- You can go 100% trimmings from olive tree, citrus, and even all the waste from pruning apple & pear trees.
To avoid spreading diseases, don’t include diseased branches. If you do, don’t use the resulting mulch under the same type of tree.
- For instance, apply Bois Raméal Fragmenté from an orchard in the vegetable patch.
- BRF from forest trees can go to an orchard and vice-versa.
Non-tree sources for RCW/BRF
Don’t discriminate when clearing a lot. Simply add it all in.
- You can throw in any blackberry, ferns and other invasive plants, greens or bramble as you chip the original RCW tree branches.
- Chip finely. If any stems are over an inch long (3 cm), they might take root and sprout like a cutting.
However, mulch made exclusively from these isn’t as nutritious as that of tree-based ramial wood chips. Since not made from tree branches, the name Ramial Chipped Wood isn’t appropriate anymore.
- Such chipped plant material is still far better than lawn trimmings however.
What not to use for BRF/RCW
A few trees (and plants) exhibit strong allelopathic properties. It’s the accurate term to say “it kills its peers”. Known examples are eucalyptus, walnut and mahogany: these exude compounds that prohibit germination and stunt growth of other plants and trees. In a way, the acidic soil under conifers is also a form of allelopathy.
As such, conifers, eucalyptus and pine trees are acceptable but only in a small proportion, under 1/10th. Indeed, they would tend to acidify soil or render it less suitable for growing compared to more “generous” deciduous tree ramial wood chips.
→ Read also: What is BRF mulch?