Chips (BRF) are not just wood chips. They are an exceptional organic material, primarily used to naturally regenerate depleted soils
Find out everything you need to know about BRF: its composition, benefits, limitations, the best application times, how to produce or obtain it, and at what price.
Table of Contents
What is BRF?
Ramial wood chips (BRF) come from the grinding of young, freshly cut branches, mainly from hardwood trees such as oak, ash, or acacia. These twigs, aged one to three years, are chosen for their richness in nutrients still present in living tissue: sap, buds, lignin, minerals, proteins, amino acids, and cellulose. At this stage of growth, the branches still have a flexible structure and a high concentration of bioactive substances, which makes them particularly suitable for rapid decomposition that is beneficial for the soil. The diameter of the twigs generally does not exceed 5 to 7 cm to ensure uniform fragmentation, easy to handle, and biologically effective.
The concept of RCW was developed in the 1970s in Canada, notably at Laval University, following studies on forest soil regeneration. Researchers observed that in natural forests, the litter of young branches that had fallen to the ground was quickly colonized by wood-eating fungi. These fungi have the unique ability to degrade lignin, a complex and highly resistant molecule found in wood cell walls. This biological process triggers the transformation of woody material into stable humus, enriched with nutrients accessible to plants.
BRF thus seeks to reproduce this forest mechanism in an agricultural or gardening setting. By promoting the activity of fungi and soil fauna, it reactivates natural fertility cycles, without plowing or fertilizers . Far from being a simple mulch, BRF acts as an engine for the ecological reconstitution of depleted soils, restarting the chains of transformation of organic matter that make up the vitality of a living soil.
🔍 Practical advice: avoid pruning trees between March and August to preserve bird nesting periods.
The advantages of BRF
Promotes soil biodiversity
BRF, when spread over the soil in a 3 to 5 cm layer, acts as a biodiversity catalyst. It provides a protected and stable habitat for a multitude of living organisms, ranging from microorganisms invisible to the naked eye (bacteria, actinobacteria, yeasts) to soil invertebrates such as earthworms, springtails, and decomposer insects. These living beings interact in a network and form what is called the underground trophic chain.
Each plays a key role in the gradual breakdown of organic matter: fungi break down complex woody compounds like lignin and cellulose, while bacteria transform simpler compounds into nutrients that can be directly used by plants. Soil animals, meanwhile, break up residues, stir up the substrate, aerate the soil, and help create stable humus.
This abundant life increases the soil's ability to structure itself naturally, retain water, recycle nutrients and resist external aggressions (erosion, drought, diseases). By recreating an environment close to that of a forest litter, BRF allows the soil to function as a true living and autonomous ecosystem, in constant regeneration.
Stimulates mycorrhizae
One of the most interesting effects of BRF lies in its ability to promote the development of fungi, particularly those forming mycorrhizae. These fungi, by colonizing the fragmented wood, gradually extend their filaments (mycelium) into the surrounding soil and enter into a symbiotic relationship with the roots of neighboring plants. This natural phenomenon, called mycorrhization, is a mutually beneficial association: the fungi draw water and mineral elements (notably phosphorus, zinc and certain trace elements) from the soil, which they transmit to the plant via its roots, in exchange for the sugars produced by photosynthesis.
This interaction helps improve plant nutrition, particularly in poor or compacted soils, while strengthening their resistance to abiotic (drought, deficiencies, pH variations) and biotic (diseases, soil pathogens) stresses. The fungal network also acts as a system of communication and redistribution of resources between plants, participating in a dynamic of ecological cooperation.
By stimulating the growth of these beneficial fungi, BRF does not just enrich the soil with organic matter: it re-establishes a functional link between plants and their underground environment, the foundation of a living, balanced and sustainably fertile soil.
Humus product
As it decomposes, BRF generates a stable and rich humus. This humus is essential for a living soil, as it stores water and nutrients and improves soil structure. It helps restore depleted soil, even in dry climates.
Aerates and structures the soil
Soil organisms attracted to BRF, particularly earthworms, dig tunnels that facilitate aeration and drainage. This helps loosen clay or compacted soils without mechanical intervention.
Regulates humidity
BRF mulching limits evaporation, protects the soil from bad weather, reduces watering needs, and limits nutrient leaching. In some dry regions, its use can reduce water requirements by up to 50%.
Reduces green waste
Using residues from pruning trees and shrubs to produce branch wood chips (BRF) is an approach that is both ecological and economical, and consistent with the fundamental principles of permaculture. Rather than viewing this plant waste as something to be disposed of or burned, it is transformed into a valuable resource for the soil.
This practice is part of a closed loop , where nothing is lost, everything is recycled on site. Young wood, still rich in nutrients, once fragmented, becomes a natural amendment which nourishes the life of the soil, improves its structure and promotes the regeneration of its fertility.
This also significantly reduces the volume of green waste that needs to be transported or composted separately, while reducing the carbon footprint associated with its management. It's a simple gesture that fully embodies one of the pillars of permaculture: "every piece of waste is an untapped potential resource."
By making the most of what the garden already produces in excess, BRF transforms maintenance often seen as a constraint into an opportunity to sustainably enrich the soil, without external input.
Protects against climatic hazards
A layer of BRF insulates the soil from temperature variations, protects against wind, frost, intense sun and limits erosion caused by heavy rain.
Disadvantages and limitations of BRF
Nitrogen starvation at the surface
At the very beginning of its decomposition, Ramial Wood Chips (BRF) can actually cause a temporary nitrogen deficiency in young plants. This phenomenon is due to the delicate balance between carbon and nitrogen in the soil.
BRF, rich in carbonaceous organic matter, serves as an energy substrate for an active population of soil microorganisms—bacteria, fungi, and other decomposers. To efficiently degrade this carbonaceous matter, these microorganisms must consume nitrogen, an essential element for their metabolism and multiplication. However, this microbial nitrogen consumption causes a temporary immobilization of available nitrogen in the soil, making it unavailable to young plants at a critical stage of their growth.
This competition for nitrogen occurs mainly at the soil surface, where the BRF is spread. The surface layer is thus the scene of intense microbial activity, leading to increased nitrogen consumption. However, this phenomenon remains limited in time and space : as decomposition progresses, the microorganisms gradually release nitrogen in a mineralized form, restoring the availability of this element for plants.
Furthermore, the duration of this deficiency depends largely on the carbon/nitrogen (C/N) ratio of the BRF used. A BRF from young branches, with a lower C/N, will decompose more quickly and reduce this nitrogen immobilization, while a BRF with a high C/N will slightly prolong this phenomenon.
Finally, it is important to note that this phenomenon can be easily managed in the field. A supplementary supply of nitrogen, in organic (compost, manure) or mineral form, when incorporating the BRF helps to avoid any lasting deficiency and ensures optimal development of young plants.
Solution: Apply the BRF several months before planting, in autumn or winter, so that it begins to transform before the arrival of sensitive crops.
Attracts certain pests
BRF, especially if it remains moist, can attract slugs, field mice, or wild boars depending on the region. A balanced biodiversity in the garden (pond, hedges, natural predators) helps limit their impact.
Slows down spontaneous sowing
Thick mulch often inhibits seed germination, including those of vegetables that self-sow naturally (such as lettuce or cherry tomatoes). This can be a disadvantage if you rely on natural regeneration.
Some weeds can proliferate
Although BRF blocks many unwanted plants, some very robust species manage to penetrate the mulch. It is therefore important to monitor their development, or to learn how to use them according to their properties.
When and how to use BRF
When should it be applied?
The best time to install BRF is between fall and late winter, when hardwood trees are being pruned. The wood should be shredded and spread on the ground quickly, without being buried. Early application helps limit nitrogen starvation.
Where to use it first?
Around the fruit trees
In country or honey-producing hedges
At the foot of the small fruit bushes
For perennial vegetables (rhubarb, asparagus, artichoke, etc.)
In all cases, avoid sticking the BRF directly at the base of the plants: leave a clear area of 20 to 30 cm around the trunks or collars.
And in the vegetable garden?
The use of BRF in the vegetable garden should remain exceptional. A single light application (3 to 5 cm) can be beneficial if the soil is very depleted. It is best to apply it in the fall so that decomposition is well underway by spring.
How to produce or obtain BRF
Make it yourself
If you have a garden and deciduous trees, you can produce your own BRF. Simply prune the young branches (preferably between November and March) and shred them immediately. An electric or petrol shredder is ideal, but you can also do this manually for small quantities.
It is also possible to integrate a small proportion of conifers (less than 20%) into your BRF, according to studies from Laval University.
Where can I find them for free?
Municipal green space services
Pruning or gardening companies
Green waste recovery platforms
Neighbors or farmers with sizes to recycle
Don't hesitate to ask around or post a local ad: BRF is often available in large quantities, free of charge.
How much does it cost if we buy it?
BRF is sold in bulk or in bags, between €20 and €40 for 3 to 5 m³ depending on the supplier. The volume required is simple to calculate:
surface area (m²) x 0.05 = m³ of BRF required
Please note: investing in a shredder can be profitable in the medium term if you have a wooded garden.
Conclusion
Ramial chipped wood is a powerful lever for restoring soil fertility, promoting microbial life, structuring heavy soils, and improving crop resilience. When used properly, it becomes an ecological and economical tool for all permaculture gardeners.
By anticipating its installation and respecting a few simple rules, BRF will allow you to bring your soils back to life, while promoting your local resources.
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