Managing black locust

Hi,
I'm reposting this post here, in a new thread, since I probably misposted where it was initially.

I'd like to ask at what stage from planting time can you start cutting back black locust for mulch (chop and drop style)? And how often can you do it.

I'm thinking of using it (along with other NFTs) as nurse (inter) plant beside fruit trees. So I am looking at a good management strategy for both obtaining mulch material, N-fixation and may be other yields (honey, firewood?). Am aware of how much multifunctional this tree is. The question here is, how big should be allowed to grow when next to a fruit tree (both high and wide) or even how far (or close) should be planted?
I saw a video yesterday where there is some explanation about the management of BL (which is where I originally posted) on another thread, But I think my questions have not been addressed there.

Also, it is said that it needs specific rhizobia strains of bacteria in order to fix Nitrogen so, if one is not sure whether these bacteria are available in the soil where the tree is intended to be planted, you can go to existing BLs stands and collect the soil underneath, because this is supposed to include the right NF bacteria. The question I have here is: how do I know that those already existing trees will have the right bacteria? Because they may have also grown without those bacteria in the first place? Or does this mean that the tree can only grow if those bacteria ARE in the soil otherwise they just die without ever becoming adult trees or remain stunted???
Cheers

Antonio,

I am not certain that you really want to use black locust as woodchips.  Black locust is prized by many for being fast growing, strong, excellent long-slow burning firewood and being extremely rot resistant.  This last quality may pose problems if you want decomposing mulch, which is what comes to mind when I think of “chop and drop.”

There are other trees that are nitrogen fixing that may help out as both a nitrogen fixer and a mulch—around me, autumn olive does this, grows like mad (actually it’s invasive), and can be cut every 1-3 years to make mulch.  There are other possibilities as well.

But if you do want to try black locust anyways, I would offer the same advice I would for any nurse tree.  Basically I would let it grow till it interferes with the main crop.  This is usually when the nurse crop starts to crowd out the main crop, though also consider any damage that might be done while removing the nurse crop.

Ultimately I wish you good luck and hope that your project works out for you.  Please let us know how things work out.

Eric

Hi Eric,
thanks for your feedback!
I am wondering if actually it isn't interesting for the mulch to stay put (if it doesn't decompose easily) for a long time, so the need for bringing in more mulch material can actually be reduced.
Of course this would prevent the BL wood to become humus, at least if it is not thinly chipped. But yeah I read that the wood seems to have anti-fungal compounds.

On the other hand, your advise of pruning the BL when it starts to interfere with the productive tree seems very logical and common sense. The only caveat that I see with this
management style, is that the productive tree would only get a spark of N (form its nurse tree) only every so many years (same with autumn olive by the way) and I wonder if it makes it worth interplanting with, when for example I might actually do get N more often with NF shrubs that I can chop & drop at least once a year.
What do you think?

Hi Antonio, I'm using my BL more as a way to colonize grasslands and very poor/rocky soils without much organic matter.  I'll probably trim them to keep them about 9 feet tall or so, allowing them to root sucker into some areas but mowing them off of the pathways (I have a separate area where I'm allow them to form a permanent grove.

Eventually (maybe 10 years out?) I'd like to see all of my BL more or less mowed or coppiced down, to make way for my productive trees. That said, I did just plant about 300 of them over 1.5 acres (I have a lot of poor soil)!  I realize this does not fully answer your question, but this is my plan at least.