The other night a phrase in The Holistic Orchard by Michael Phillips stopped me reading mid-paragraph.
I was surprised because I feel like horticulture is moving away from wood mulch with the interest in mixed plantings and covering the ground with plants. Or, at least with that desire in mind (like here and here) if we all aren't quite on board yet.
The action of mulching just isn't sustainable. Depending on dead organic matter to prevent weed growth around perennials in place of living plants is a fallacy that will have to constantly be remedied. It is Sisyphean task. Hardwood mulch also doesn't naturally occur, except maybe under a fallen, decaying tree. As Thomas Rainer says, you won't find mulch circles in the forest.
So, does mulch really happen as Michael wrote? To make sure that I'm not taking the quote out of context, here it is in full: "Nature builds soil from the top down: Leaves fall, tree limbs decay, mulch happens.
In the sense that we are used to seeing hardwood mulch strewn across the landscape, no . We do have an organic layer present in most soils, but it's not a few inches thick of hardwood. Instead, it's dominated by a mixture of the abscised and the fallen, the green and the brown, the leaf and the stem.
Michael wrote that when he mentioned mulch he was not talking about recalcitrant hardwood mulch that takes years to decompose. Instead, he was discussing ramial wood chips, a type of organic matter that comes from branches and stems that are less lignified and higher in nutrients. He advocated applying these wood chips in random patches throughout the orchard to feed the soil. His approach is to chop stuff up and then dump piles of it around his fruit trees. They don't form a solid cover, which encourages grasses and other forbs to grow to create a multiculture. He stated most fruit trees originated along ecosystem edges. Introducing rough, slowly decomposing organic matter helps to improve the soil similar to these plants' native habitat. While I haven't studied the use of these ramial wood chips much but want to learn more, the logic behind their use seems sound.
What I think is fascinating for these perennial cultures—mixed plantings and the use of ramial wood chips in orchards—both schemas ask the question how can we emulate nature and try to enhance the biological systems already in existence, especially with covering the soil. In both cases mulch happens, just not the way that we traditionally think about mulch.