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This Spring, I pruned all my shrubs and pulled out a few pine stumps. My first thought was just to pile them all up on their own. I have never had good luck trying to compost such material with the rest of my compost. But I'm concerned that these heavy materials will take years to compost all by themselves. What can I do to speed up the decomposition of such materials?

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    Time to get a'chipping. Commented Jun 23, 2011 at 22:55
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    I really don't have the money to rent or buy a chipper nor do I know someone who could lend me one. Good thought tho
    – Fatmuemoo
    Commented Jun 23, 2011 at 23:16
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    You need to make big bits into little bits. It'd be a pain, but an axe might work as well. Give you something to to do over the weekend when nothing else is going on. Commented Jun 23, 2011 at 23:26

8 Answers 8

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That is very woody material. Wood takes time to compost - probably years for your stuff. You need to do two things: break it into small pieces, and mix it with other material.

The shrubbery cuttings might be choppable by hand - but it could take time. That isn't practical for a tree. You really do need to rent a chipper. And if this is a regular occurrence, then you'll want to eventually buy one (rent one first so you don't over-buy or under-buy).

As for mixing stuff: I would mix with grass clippings (and start collecting them if you currently use a mulching mower) and kitchen waste (vegetable peelings, coffee, etc). You want to get a good mix. For a large heap, most people do this by layering.

An alternative would be hugelkultur. I'd never heard of it until it came up in a question on this site last week. This is a form of slow in-situ composting. Basically you put the wood in the base of your beds and it decomposes over years, slowly releasing nutrients. Never tried it but if renting a chipper really isn't an option, then this is probably the only alternative (other than giving it to your local city's trash/tip services).

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    I looked up huglekutluer. I'm going to try this! Thanks for the tip
    – Fatmuemoo
    Commented Jun 23, 2011 at 23:47
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I also agree with the Hugelkulture beds mentioned above. You can just place all the branches and logs in a pile or several piles and put everything that you want to compost over top of them and then cover with either soil or invertred sod and mulch.

If you cover with soil you can plant in it right away. I have made several hugel beds in my gardens and they have all done wonderfully. As the wood rots it feeds the soil and holds moisture.

These can be done as raised beds, or dug into the soil

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I'd second the hugelkultur idea. I made a couple of raised beds using nothing but branches and a few logs, buried with about 6 inches of soil...The peppers and eggplants that grew out of that bed were possibly the best I've ever had.

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Yes, more recently I made lasagna beds piled with the finer twigs from my copious biomass production 'machines'. A year later they just looked so messy, so I took to them with a machete, and they almost crumbled under the blade, very fragile.. soon the bed was flattish and looked like it was covered in finer mulch rather than 'branches'. This definitely will be part of my mulching strategy. Still, I do so want a chipper, just to get through the stuff quickly and I need lots of fine chip too for the compost toilet. An hour of using the machete on a wood block doesn't make the material fine enough and my wrists suffer.

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As another option, you could make garden decorations with your spare branches and fruit canes. Check out rustic branch arches, wattle fencing, and garden decorations with branches. From experience most branches you prune are spindly and easily split when screwed or nailed. Wrapping branches in jute is nice because it degrades but it often doesn’t last the year. Stainless steal wire doesn’t rust so you could wrap your branches with that until the branches degrade and then reclaim your wire for your next project.

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I've been reading permaculture blogs on chippers and what to do with piles of branches as I have the same problem. The permaculture argument is that making the material small with a chipper does cause more rapid decomposition, but in a compost pile there is so much loss of nutrients like carbon and nitrogen, which evaporate during composting, before the material even touches your garden bed. They advocate using wood chipping with discretion, only when you need fine material, only when it is really the only way forward. Otherwise the branches should lie on the soil as mulch, or be buried. Not having a chipper, and having done massive amounts of pruning to curtail the abundance of our urban plot spilling onto the street and inconveniencing the public, I tried to adhere to the permaculturist's recommendations and resorted a stuffing the twigs and branches tightly in under the bushes I had cut them from. There they will shed their leaves and return those nutrients to the soil. When they dry out I will smash them with a garden fork and reduce the volume. Larger branches will be shortened with the chain saw and used for the pizza oven. I cannot afford the time to stand lopping and clipping to reduce the tree branches in volume, sorting them into sticks for mulching, firewood etc. However it is a very effective option if you have the time. The last time I reduced a pile with hand clipping, it took several days to process a few cubic meters. I have a tiny garden and I don't have the space to leave large composting piles everywhere. The garden is 'full' so burying the wood is not an option. Hugelkultur doesn't work here, its so dry that the pile just oxidizes. To reduce branches you either need time (to cut them by hand) or space (to leave them lying around till they rot) or energy for the chipper fuel and your own labour. No way around that, so stuffing the branches out of site, in the dead space under the bushes and trees was the best and most close to nature compromise. You can see the photos on my current post on Home [email protected] on facebook.

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  • Good points...In drier areas of the world piling brush or chips on your property would be an issue if there were brush fires
    – kevinskio
    Commented Mar 29, 2019 at 11:49
  • Interesting note about loosing the carbon too early. I've a medium sized garden, and used to have an area I could just throw green waste. But it grew, and grew! Into a sizeable amount. I take out large pieces for firewood. I've had large logs - drilled for beasts - and recently noticed they have totally disintegrated three years on. When dry/aged you can jump up and down on sticks to break. Agree, it all adds up, and space runs out.
    – Progrock
    Commented Feb 1, 2020 at 23:30
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While the hugelkultur approach is a great idea, in my experience it requires a huge amount of soil to cover even a small depth of branches since there are so many air gaps to fill. My hugel beds do little more than encourage bramble type weeds to flourish and poke their heads out of the top of the beds.

One approach that works for me is to use the principle that the closer the woody material is to the ground the faster it decomposes, presumably because it has less time to dry out after rains. So after cutting saplings and removing the small twigs quickly with a billhook the new material is sorted into different piles: 2" diameter and larger intended for fuel when dry, 1" types for bean poles, 1/2" types for pea sticks, and the little stuff. Set the bean and pea sticks aside since they are valuable, pile the little stuff and then plonk the big heavy stuff on top. This achieves two things, presses the thin stuff close to the ground where it can decompose and keeps the heavy stuff high where it can air dry for a season or two before use as firewood.

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Ultimately it's a question of thermodynamics and biology:

these [woody] materials will take years to compost all by themselves

The wood is the problem here, specifically its lignin content. Lignin is a class of polymers that is very stable. Like, a naive chemist looking at its structure might think it an artificial plastic. Most things can't digest it but it's the preferred diet of some fungi (even termites eat fungus-digested wood)

So the way to get wood to break down faster is to accelerate its fungal digestion:

  • Environmental/process conditions: Make a happy home for fungi (airflow, moisture, temperature, etc - experts have opinions on it, damp and breathable seems fine)
  • Mass transfer: I don't have a reference for this but in all likelihood roughly chipping everything would speed up colonization and metabolism by increasing surface area / volume ratio
  • Innoculating with hungry fungi / engineered fungi: If you search for e.g. "compost accelerant" there are a number of commercially oriented products that claim to be really good at eating wood. I would be inclined to believe these claims from experience growing mushrooms in logs.

But this seems like a lot of effort to optimize unless you have a big chipper sitting around. The answers about lasagna composting / hugelkultur etc are minimal-effort ways of accomplishing this, i.e. break up the woody material and dilute it into damp material with active fungus.

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