I would happily take your leaves. I don't have enough.

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Yeah. Sounds horrid but I like trees and would find it difficult to bring myself around to remove even lousy trees in my similar climate in So Cal.

I suppose if you were prepared to plant new trees knowing that you would not reap their benefits for quite some time it would be a saving grace.

I don't know if the trees provide you any shade and if there would be additional mitigating strategies that could be applied to mitigate the loss of those benefits.

to sense
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No, they've been there for decades and I wouldn't even think of getting rid of them. They do provide shade. What frustrates me is that the huge amount of leaves from these three trees can't be used at all for mulch, and to lose their allelopathic qualities they must be composted for at least a year or more. My household compost is ready in a few months.
Add to that that the ground around is full of roots and nearly impossible to dig, no soil at all and the rest, as I say, is building rubble that I've gotten the huge rocks out of. Not the glass and metal and wire, broken tile and chunks of concrete, etc!
My question is if leaving "bad" ironwood leaves on the already stressed ground - which my web searches tell me prohibits any growth but the most stubborn of weeds - is better than nothing at covering up bare turns-to-brick ground, or raking them off to the side and letting them sit while leaving our rainless, 100+ days from now till October to scorch ground. My garden beds are either lasagne, or raised, lots of compost and are doing fairy well. I was just wondering how to utilize the massive amounts of ironwood (and euc) leaves is at all possible.

What about getting planter boxes? Fill them with some kind of quality soil mix, raised above ground growing.

My veggie, herb and flower gardens are raised bed or lasagna, with lots of homemade compost from kitchen scraps and shredded paper. Does anyone know about using ironwood leaves (they look more like pine needles) either in compost itself or as mulch? My searches say they retard or actually prevent growth of other plants and change the soil much for the worse. I can see this in the area around the tree - bare and useless without raised beds, etc. I want to know if anyone has experience with using them as mulch for paths and in existing beds around healthy plants. My "soil" has enough trouble becoming fertile without me piling mulch that would - if I believe what I've read - kill my plants!

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For the health of the trees, leaving the leaves in place would be better than the bare scorched ground. Less erosion from wind and, when it gets there, the rain.

I have to expect something to grow there, just not much.

to sense
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I know nothing about the leaves of those trees, but assuming they are as you say, then:

I guess there is absolutely no place else you could raise some of your produce or you wouldn't be asking this question?

Pruning those trees (gradually, so as not to shock them) back to reduce the leaf-fall and eventually shrink the onerous root zone and thusly increase the garden size is not a possibility?

Would pruning make the tree roots shrink?

Probably not, they've been there maybe 20-30 years. I grow, as I said, in raised beds. Any new gardens get hacked out of rubble, which I lasagna and plant. It's the massive amounts of ironwood (and euc) leaves that are about 6 inches thick in some places, which if my info is correct robs the ground under them from being fertile, as opposed to a thick leaf mulch of better trees which would, if left alone, simply create a lovely forest duff. Raking them off encourages the rubble to become concrete, letting them mulch the paths and as yet un-gardened places supposedly "poisons" the ground. There is a very little selective branch cutting I can do, but all three trees are at least 3 stories high. And they do, as said, provide some shade in our hellish sunny days. I don't want to over think this, I was just wondering if anyone else had experience with ironwoods, and mulchh/compost, etc with the litter. I've tried searching the tree forums, no info there. Birds use the stuff to make nests, but that would have to be one, um, big bird to make a dent......

I think I would vote for discarding the leaf litter in the city wide compost. I can not say why, but if it's allelopathic making into compost or mulch would only be good for the ground, but not for the beds.

If the leaves lose their allelopathic quality after a year of composting then it is simply a matter of a year lag time while you make staggered piles, at the end of which time you will be able to start tapping the fertility locked up in the leaves, right?

But, will they lose the allelopathic in one year? Since I can't even confirm if those are allelopathic on wikipedia maybe they are forever? I don't know, but I assume the soil is already fully full of allelopathic anyway and they could be used to suppress weeds in the non growing areas. Better to error on the side of caution but who knows? You could be right. I could be wrong.

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I avoid the eucs myself but I have composted their leaves a little bit at a time. If you follow the 10 percent rule where any batch contains no more than 10 percent eucs, and I assume the ironwood crud too, you should be OK on a slow composting process like 6 months to 1 Year cycles. That sounds like a large composting operation in your case.

If you have the space, maybe there's some spare rubble about, form some windrows or a whole bunch of pallet bins with donated feedstocks from some place that needs to unload large quantities of something and then mix in the dreaded leaves at 1 part for 10. Then add water.

On 1 year cycles, depending on the feedstocks being used, you might be able to get away with out having to turn them. A 1 year cycle would be the minimum though and you still have to keep them watered in that hot sun and I imagine a lot of wind at times.

I don't think you have an easy way out any way you look.

to sense
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Op has a huge amount of these bad leaves, and not a large amount of good leaves. To cut it down to 10% of bad leaves only would leave a large amount 90% of bad leaves to be removed. I would just let them stay on the ground and not bother to add 10 percent. If you had to bring in other materials to equal 90 percent, one should just omit the 10 percent to begin with a just do a compost bin pile without the bad leaves. I would put them in city wide compost. This is another reason why I never use city wide compost.

Most places do not have municipal yard waste pick-up.

No city compost. City picks up just to take to landfill.

I was putting in my totally MacGyver-ed watering system and I soaked the phone, which is my only camera. So the cheap, DIY irrigation (which works like a charm) ended up costing me the price of a new phone. As soon as I figure out the new dinky camera, I'll post pics.

So far I'm leaving all the leaves where they fall, as I figure out my next step. I agree that uncovering the bare ground would be worst. No feedstocks, no anything trucked in from anywhere - just these browns in a long term pile under the ironwood, and a regular, happy compost pile with greens and browns produced right here. Every now and again when I have extra water the long term pile gets some - otherwise it's dry and sits there until October when we get our first rains.

That is a shame. They can save space in a landfill if they make a city compost dump. Even if the compost turns out not to be sellable at least it can decompose back into nature.I hope people will think about voting the idea in the future. I use it all the time. I don't have a branch shredder. How would I get rid of big branches? The garbage cans here are very small. They will not allow you to buy your own big can. These tiny cans, if you fill it up, you are out of luck. You have to wait until next week and keep the garbage in your house until then. But, the compost and the recycle cans are super big sized.

Its ISREAL I think they have bigger concerns than worrying about a city wide compost dump...lol

Irans nuclear capabilities or installing a city compost dump...Worry about Hamas or a city compost dump...constantly shifting borders and land disputes or a compost dump...Lol Im messin with ya ;-)

I was replying to pnbrown from MA. I don't see why you think that Israel could not adopt composting if they wanted to. I don't understand what you are implying. Maybe they don't think they have a landfill problem, but they will as time goes by. It would be much easier to put bad leaves in a composting program run then try to compost them A good service for citizens all over the world to have government run compost dumps. Change won't happen until people demand change.

You guys are funny.........Haifa is the 3rd largest city. Many smaller communities have composting programs, and lots of the smaller rural communities are quite forward thinking. A number of our southern desert communities are world leaders in green low tech. We have here the same problem of many places: with all the other problems, why should we put effort into clean air, water, good garbage practices, etc. Piffle I say, and I'm in good company and we are growing.
Yes, politics, neighbors, racism, social inequality, truly bad leaders, we are like you. Compost used to be an unknown word and not mentioned as in, why are you worrying about garbage when we have these other problems? Now most people at least know what it is and it's not weird anymore. But slowly the permaculture folks and the good eating organics folks and the recycling folks are making headway. Just like you. Making our daily quality of life better, looking to a future where we aren't worrying about war or bombs or what They are planning in back rooms, whether They are speaking Hebrew or Arabic or Farsi or English, and when that day comes we will have clean water, air and really good veggies to share.
I march against the bad things, I vote for the good things, I knit, I garden. I have sent sons to war, I have seen them come home, and I garden. I and my very diverse friends rail against the stupidity, change what we can, and I garden. I hold my finger in the dam of creeping theocracy here, and I hope y'all are doing it there. And I garden. Peace

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I remember when Israel was big on drip irrigation when that was cutting edge. I recall reading about a couple of permaculture experiment going on out there and I was interested because I live in a similar climate. I think we might learn a thing or two, if we pay attention, on how things are done there.

to sense
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I suspect Israel's obligatory military service creates a de-facto broad-based support of Israel's policies, even still. Once opposition becomes more powerful they will have to follow the lead of the rulers of the US and make service voluntary or risk a major political revolt of the sort that occurred here during the Vietnam era.

I checked the usual scholarly sites, not gardening forums, and could NOT confirm that the roots or leaves are allelopathic. I found many papers saying they are "suspected","might be", etc. But no confirmation.

They may be like creosote in the desert of Arizona and just compete so efficiently for water that seedlings are suppressed. Creosote bush was thought to be allelopathic for a very long time ... then someone did actual research.

Or mesquite, which self-mulches under it's drooping canopy with several inches of leaf litter ... not alleopathic, just very efficient at squelching the competition. We don't rake under the trees very often, just when we need some dry leaves for something. If you prune the mesquite up and remove the leaves, they grow great pasture grass.

I would use the casuarina and eucalyptus leaves with the household compost material as a source of dry material, layering it or mixing it in.

The excess leaves can be packed into wire mesh bins and watered when possible, or left as a natural mulch to keep the heat down (every degree helps).

We have a similar problem with mesquite and palovverde leaves: waxy, small, and resistant. I found that if you can get them to the brittle and breaking apart stage they make a nice mulching material that lasts a couple of years. IU dump a couple of buckets of soapy water into the bins when I remember, which breaks down the waxy covering on the leaves.

I retract that statement ... apparently the GREEN leaves do have some phenolic compounds (resins, tannins, aromatic molecules, etc.) that come from the leaves when fog condenses on them. They dissolve into the condensate and then drip off with the water.

Nice way to reserve the fog moisture for the tree's roots :)

But unless Haifa has a "fog desert", this is a non-problem. Plants tend to pull the phenolic compounds (or most of them) out of the leaves before they drop.

It seems to inhibit sprouting of some species - like corn gluten does - but not inhibit seedling growth. So if you start the plants in potting soil, mulching them with the leaves and using the compost on them should not be a problem.

"not alleopathic, just very efficient at squelching the competition."

Thanks, LZ!! That sounds sensible. Around here, (and you're right, foggy it ain't) this season, when all is terribly dry and brittle everywhere and will be for months, I think I'll leave a layer on the ground of both eucs and the ironwood, and put the mucho extra in the long term bin, watering it every now and again. If I run out of browns for the house pile, in they'll go, in smallish amounts. The house pile is ready for the second pile after about two months - the second I do nothing to and in a month it's useable for lasagna.
A thought - our rainy season is October to March. That's it for the year, BTW. If all the allelopathic qualities drip down from fog, would rain do the same thing? That would make dripping leaves "poisoning" the ground 5 months, then the fallen dry ones relatively harmless, ergo useable.
I don't want to over think this, but it's very interesting as a general idea about which trees do what and how to deal with them.
Thank you all for your reasoned and thoughtful ideas on this!!!!
Yes, Israel is a world leader in drip irrigation. Oddly enough, mostly small gardeners use it, larger market farms and agricultural growers use it less. Most of the cutting edge green low tech is not used here, but exported - knowledge and tools - to Africa and Asia, but for some cuckoo reason, it's not used here including low water, solar stuff and all the rest.
And pn, see ya on HT!

This might sound like a stupid question but if the leaves are just left to compost into the ground wouldn't the poison be less and less over time? How long would it take if the leaves are just left to be? Would the ground be that poisonous or would the effects be very minor due to the time they have sat and composted? Would the leaves lose their potency once they fall from the tree and die? And if they do lost their potency, will they keep losing their potency the longer they lay?

So the big growers in Israel are using what for irrigation methods? Overhead? I can hardly believe that they would not be using drip.

Yes, Batya, come over to HT and start a thread on sending sons to war, I think it will get quite a bit of attention!

pnbrown - subsoil tubing, probably.

blazeaglory ... the problem is that the trees keep dropping more leaves.

All OP has to do is keep removing any leaves from the raised beds and place them on the ground where they will mulch and also block weeds. But, if it hard to picture the garden without a photo. I would think allelopathy would make the weeds not germinate, but maybe not weeds are very tough. We have a eucalyptus grove, but there are still weeds.

Hi Batya.

I skipped reading through the last half of the posts, but here's my thought - pile up the ironwood debris into its own compost pile, compost it, then spread the compost under the ironwood tree. Hopefully you can build up a ironwood leaf/mulch/compost under that tree. It might help the tree and it will help prevent the soil from drying out.

Your garden sounds like an archaeological dig. :)