Camphor laurel leaf mulch - denaturing the aromatics

I couldn't find much info for camphor laurel on this great forum.

Where I live, NE-NSW, Australia, the environment is blanketed with them.
Everyone agrees their a pest, but they're tough to control and they're better at holding soil banks together than nothing (degraded pasture).

Most folks are scared to use any part of the plant because of it's allelopathic reputation.
Landowners routinely rake up the leaves and burn them to minimize bush-fire fuel.
However, many gardeners know that if you leave camphor woodchips outside for a few months, then it's fine for use as tree-mulch.

I've grown many flushes of oyster mushrooms on aged-logs and woodchips of camphor - though I had less luck with spawning stumps.
This a great way to improve the soil under the mushroom-beds, but camphor is a softwood and doesn't flush for more than a few years.

Whole, dried camphor leaves as mulch will seriously dry out a soil, I'm not sure by what mechanism.
I think they hold onto traces of camphor oil/aromatics with intense recalcitrance. (An old, dry, bleached leaf still smells of camphor when crushed)
However, if the leaves are quartered or mashed into a coarse powder, then kept moist - this will degrade very fast as mulch/surface-compost/worm food and can be applied to the veggie patch.

A less labour intensive method is to bag up the whole leaves (and some dry twigs) in a big grain bag with drainage holes, mix with 10% green leaves or compost, drench with compost tea, half-seal the bag and leave in the shade for 3 weeks.
The leaves are softened, moistened and just covered with fungi - use as spawn under the garden mulch.

Finally a more labour intensive method is to ferment them thoroughly over a few days:
1 cup compost, 2 cups urine, 1/4 cup of spit into a bucket of camphor leaves and water.
Kick bucket twice a day for three days to 'stir', separate and dilute the liquid [which can be 'extremely' hot with nitrogen and aromatic compounds], use the leaves as compost under mulch on fruit trees.
I like to think of this method as using enzymes, urea and bacteria to both nitrogenize and microbially-colonize the carbon of the dead leaves (greening the brown).

I hope others have stories to tell about denaturing both mechanically and chemically recalcitrant components associated with under-utilized tree-species for leaf mulch and compost.
:)

Jondo, I think that's exactly what's going on with your compost extract. You're cultivating large populations of the bacteria that naturally like to decompose camphor biomass, and inoculating everything.

A couple of things I would do would be to use something like a big spoon or paddle to stir it up daily, probably counter-spinning it (rapidly changing the direction of spin by stirring opposite the induced current). This will add more oxygen than just kicking it.

Another thing that could be used is anything you construct to fit your container that looks like a giant potato masher or the plunger to a french press, basically so if you churn your mix just like a butter churn, you add oxygen to the extract.

Finally, some people automate the brewing process with either a pump that "stirs" for you by shooting a stream of water in the desired direction of spin, or stir manually, but oxygenate with a bubbler like you'd find in a fish tank.

If you haven't perused them yet, Dr. Bryant Redhawk's list of Epic Soil Threads has more information there for you than, I think, has been accumulated anywhere short of a soil science section of a library, and lots of his stuff is first-hand experimental and experiential data.

I think your approach has great merit. I would look at your recipe, though, and make sure that there's enough bacterial food in the system to support the population sizes you're looking to grow. I would perhaps consider maybe a half-cup or so of molasses at the beginning, and then halfway through, the brewing process.

By the by, if you've had success colonising camphor biomass with oyster mushrooms, I suggest that you add elements of fungal slurry to your extract, or else brew up a separate fungal slurry.

If the dried leaves retain the essential oils, I wonder what the effect of essentially converting them to biochar in a sealed retort would be. Could the temperature get high enough in an oxygen-free environment to pyrolise the leaves so that everything but the carbon is vapourised?

Imagine stuffing a sealable drum full of camphor leaves with pressure valves for the vapourised volatile elements to escape and be burned as fuel, and then setting them to pyrolise in any available exhaust heat source, in a pit fire, or perhaps even over time in the sun, and being left with flaky biochar mulch?

Imagine inoculating that stuff with the camphor-specific compost extract, and it able to support populations of camphor-devouring microbes, and the effect it would have on the allelopathy of camphor laurel in the environment.

What if you could effectively negate the allelopathic effects of the camphor laurel, or at least its detritus?

-CK

CK, I like where your minds at.

Certainly my camphor teas would benefit from more oxygen, however its nice to have something which I can kick in good conscience.
I strive to have no outside inputs in my gardening, using electricity to aerate a compost tea seems rather ostentatious, though I'm sure the results would impress.

I recently read Redhawk's entire series and was delighted to see that he was determining scientific reasons for why the 'biodynamic hoo-hah' might actually work (I had been working towards similar conclusions).

You're very right that the camphor tea needs a little bacterial food to be balanced, I add a handful of leafy green veg to help on that front.
However, the fermented tea is so hot that it can only be used around the mulch under fruit trees, where a fungally-dominated substrate is beneficial.

Sadly, I am out of both the fungi-game and the biochar-game due to poor health. Not sure if adding spawn to a hot camphor slurry would work, though I'm sure spores would be able to play the long game and survive the process. Leaves aren't going to generate mushroom fruit though, just another vector for cultivating mycelium on-site.

You'd need to finely manage your pyrolysis system if you wanted to make camphor leaves into biochar and not ash. Also, I seem to recall reading that if your biochar is too fine it's either less effective or has a very short half life in the soil. If you've got a camphor tree in my climate, you have infinite branches for char and fungi (the tree is known as 'the seven sisters', you cut off one trunk, it comes back with ten). I'm just really fond of the ease with which leaves can be utilized and moved around (and preventing them from being raked up and burned).

Camphor-specific compost ready to digest other camphor material - oh yeah! This is what my bagging of whole, wet camphor leaves in the shade produces. It's fungi-heavy, but I assume the fungi are devouring bacteria that started the process. I've been using this 'camphor spawn' as garden-border mulch, but it may be better used by being mixed with the hot wet camphor compost going under the orchard.
A hearty thanks for your advice!

Finally, I'd like to say a word about molasses for Any compost tea. This seems like a waste to me. Yeast (found in every mouth, fruit and on many flowers) is able to generate enzymes that directly convert starch to sugar, it will only do this if there is no sugar available in the medium. Human spit also has these enzymes in abundance (see traditional method for starch conversion in chicha production). Sure it's icky, but it only takes a piece of fruit or a few mouthfuls of spit to get a bucket of grass/leaves bubbling away.
I reckon you should save your molasses for baking vegan biscuits.  

I have the wood chops from downed tree. I dont think any leaves are in it. Is it safe to use in a garden? It does smell quite a bit, but much decreased since i got it two weeks ago. It is also mixed with soil and seems to be breaking down in the original pile since it has rained a lot here in central florida. Are the wood chips less toxic than the leaves? I saw no leaves in it. Will veges absorb the oils in the wood? Just afraid to use it. Neighbors cat comes in yard too. Will he be attracted to smell and be poisoned? Thanks for any feedback!

I was hoping someone with more experience with this tree would answer but this is an older conversation so they not be active but I have been assigned to watch for new questions in this forum.
This is a Permaculture forum and one of the principles is to observe. plan and test the results.  The previous posters gave you some good information. Another principle is that a problem is often just a solution wafting to be applied.  For example the strong smell may cause the cat to avoid using the area for a toilet. also many pests are deterred by the smell.  So the general advice is to experiment on a small scale and learn what works for your situation.

Welcome to permies  and please add more to your profile which may help others in your area make contact.

I just had 2 very large camphor trees removed from my yard. Now my yard is full of camphor mulch. How long will it be before it is safe to plant things in the yard due to the chemicals in the camphor trees? I know that things won't grow beneath them due to the chemicals. I presume my yard is now full of those chemicals...

Hi Tessa,
The OP said

many gardeners know that if you leave camphor woodchips outside for a few months, then it's fine for use as tree-mulch.

This thread about allelopathic leaves here also suggests that the effect disappears when composted, so I suggest doing what you can to compost in situ: add "greens " such as grass cuttings, any green leaves and fresh growth you can get hold of, maybe manure or urine watered in. You don't say where you are, but I'm guessing North America and pretty cold just now, so covering to raise the heat might also help the process speed up. I would use cardboard, but a top dressing of 'clean' compost could also do the trick.
Hopefully a few months will see the chips turning to compost and you can plant in it. I don't know if anyone has better advice to share.