Ramial Chipped Wood
This fall I’m going to try a ramial chipped wood mulch bed. Ramial wood = young branches that have sprouted within the past year. The young branches are the richest part of the tree (10 times as nutrient rich as the trunk or wood from larger branches, according to the first video later in this post.)
RWC application is recommended during end of autumn, beginning of winter, and during winter. If the branches sit around after being cut for more than 3 months, the mulch would just be considered compost, and would no longer qualify as RCW. Ramial chipped wood is a blanket for the soil (soil cover) and promotes fungal growth. Chipping the young branches allows for more fungi development, giving fungi an opening. They cannot penetrate the bark.
Below are two videos on ramial mulch.
1) Humification and Ramial Wood Chips - this video has a lot of useful information and features Michael Phillips. He explains that minerals are stored in the cambium, and that of the cambium cells, 75% of minerals are stored in the smaller portions of the tree, while only 25% of minerals are stored in cambium cells in the tree trunk. “A greater proportion of cambium, buds and twigs in coarse chippings from small wood offer healthy nutrition that gets “banked” as long term humus”.
White rot fungi (a certain group of decomposition fungi that can break down the lignins in hardwood) and mycorrhiza make these nutrients available to a wide range of plants. The Carbon to Nitrogen ratio in the smaller parts of the tree range from 40:1 to 170:1 C:N - this is a sweet spot for fungi. In contrast, sawdust from the larger parts of trees can tie up/bind to nitrogen due to a C:N ratio as high as 700:1.
Michael also mentions that hardwood is better because white rot fungi will eat hardwood, and brown rot fungi is associated with softwood. He is the author of Mycorrhizal Planet: How Symbiotic Fungi Work with Roots to Support Plant Health and Build Soil Fertility, published by Chelsea Green Publishing.
2) Understanding rcw (ramial chipped wood) - In the words of Gilles Lemieux (1952-2009) “we’re copy-pasting forest soil into agricultural soil, minus the trees.” “RCW allows flora and fauna within the soil to flourish, whilst being protected from frost. Within the soil, fungi can continue growing at 20 Farenheit.”
“A small branch is supple and can almost be bent into a circle. Lignin that’s not fully formed means it’s a great environment for fungi to grow.”
A lot of research into RCW has been done through Laval University in Québec. 150-160% increase in productivity was found in one study. Using ramial mulch, 80% percent less water was needed on a farm in France. Fifty percent of water was saved in a Saharan project.
The video recommends a 1x1 meter area with 3-4″ thickness of RCW. Branches pruned off of a tree can be used. For a 100 square foot garden, 3 meters cubed of RCW coverings are suggested.