Ramial Chipped Wood: A Complete Introduction

A Nutshell Explanation

Ramial Chipped Wood (RCW) is used to improve soil on farms and in gardens. It is made from smaller, younger branches, typically up to 7cm in diameter, which are freshly harvested from hedges, coppices or annual prunings. The word ramial comes from the latin ramus, meaning branch. The technique was pioneered by the Canadian, Gilles Lemieux, who summed up the approach as, ‘copy pasting forest soil into agricultural soil, minus the trees’. 

Image: Ramial Chipped Wood with fungal activity

Young branches form the most vigorous growth of a tree, which means they are much higher in nutrition than older, thicker wood, and are more easily digestible by beneficial organisms in the soil. They typically contain up to 75% of a tree’s minerals, sugars, starches, amino acids, proteins, phytohormones and enzymes. Most species of tree can be used - deciduous trees are preferred, but up to 20% of material from coniferous, eucalyptus or chestnut trees can be added before its acidity or allelopathic (growth inhibiting) aspects become an issue. To avoid spreading disease, discard material from infected trees.

Once chipped, more of the material’s surface is exposed to fungi and other microorganisms. It is then broken down and incorporated into, or on top of, the soil. It has been found to have numerous benefits to crop yields and quality by improving soil structure and water retention, increasing the number of beneficial microorganisms, providing frost protection and reducing weeds, and helping to neutralise acidic soils. 

Common Applications

RCW can be incorporated into the soil, applied directly to the surface as a mulch, or it can be composted first before applying. Although Iain Tolhurst, from Tolhurst Organic in the UK, found in trials that there was no benefit to composting the RMC first, and it worked just as well applied directly as a mulch.

Image: Another application is using it in pathways to increase soil life and allow the roots of plants to enjoy; in this case strawberries

The ideal time to incorporate RCW is in the autumn and winter. This allows enough time for the material to break down, which temporarily reduces nitrogen content in the soil. Nitrogen levels will then bounce back in time for the spring planting of crops. If used as a mulch or the material is composted first, it can be applied any time of the year. A good option is to mulch paths between beds, bringing benefits to the soil flora and fauna without the short term nitrogen depletion in your growing area. Once broken down, it can then be added to the bed (or as Ian Tollhurst says, let the worms do it for you!). RCW is best used as soon as possible after harvesting, for optimal nutritional value. 

Case Studies

After reading about Jean Pain’s spectacular results using ramial chipped wood in his vegetable garden - even in an area where rainfall is very rare and where the temperature often exceeds 40 °C in the summer - the biologist Edith Smeesters decided to use the approach in her new vegetable garden forty years ago, with huge success. Her garden, built on what was essentially landfill, became lush and productive in less than two years, and has continued with RCW to this day.

A study in Senegal found that using ramial woodchip resulted in a yield increase of up to 1000% for tomatoes, and a Quebec study found a 300% yield increase on strawberries. 

When and What to Chip

RCW is best collected in the autumn when the material is full of the nutrients it is storing for the winter. Most types of trees are suitable, with the exceptions raised above, but the following are particularly recommended. A mixture of species is ideal for RCW as they will all have particular benefits.

Pioneer trees - these are the species that are first to return to degraded or deforested areas in your locality. They are a good choice as they are particularly adapted to improve the health and nutrient density of soils. 

Ash - the tall, graceful trees are members of the olive and lilac family. Due to its strength and density, it was traditionally used to make the shafts of spears and many tools. It also gives its name in Welsh to our experimental regenerative gardening site Dan Yr Onnen, meaning under the ash tree. If you have an Ash tree with symptoms of die-back, you should follow the disposal recommendations for your area.

Oak - a favourite of carpenters for its durability and workability. There are two species found in the UK, the Common (or English) Oak, and the Sessile Oak, which has a more upright trunk and straighter branches. The acorns sustain wildlife, and with the right preparation, humans too!

Willow - is fast growing, very easy to propagate, making the perfect species for regular coppicing.  As well as making an excellent constituent for ramial chipped wood, it has also been traditionally used for weaving baskets and making the frame of the Welsh coracle boat. 

Hazel - one of the most useful trees for its flexible stems, and delicious nuts - loved by people and squirrels alike. When coppiced, a hazel tree can live for several hundred years. Willow has a mutualistic relationship with at least 21 species of fungus, making it an ideal ingredient in a RCW mix.
Sycamore -  the sycamore maple is the most common maple species in Europe, while field maple is native to the UK. Their sturdy broad leaves support wildlife as well as being great at resisting air pollution.

Making Your Own Ramial Chipped Wood

As a guide, a 100m2 garden would require roughly 3m3 of RCW. For the quantities needed for a garden, it’s best to use a wood chipper. We use the Forestmaster 14 HP Professional, which is perfect for community gardens and larger sites. The Forestmaster 6HP Compact is more suited for individuals and smaller gardens. The Professional will chip wood up to 100mm (4″) diameter and is capable of chipping any freshly cut wood from hard to soft. The Compact chips up to 50mm (2 inches) diameter and its light weight and compact size make it extremely manoeuvrable and easy to store. There is also a 4HP Electric chipper which runs off the standard household mains and is well suited to the smaller branches used for RCW. 

Image: Forest Master 6HP in use in our orchard

Huw's Personal Thoughts

I believe that ramial chipped wood is an untapped resource within the horticulture world, and that it hold lots of fascinating potential which needs to be researched further. This is why RCW is going to play a key role in my growing seasons moving forward especially at our trial sites with the hopes of showcasing hard evidence of results. 

In the future I can imagine communities having their own short rotation coppice woodlands and a shared chipper and harvest the suitable wood to make this resource at scale and take a big step closer at being more resilient in terms of producing their own fertility and compost.