Another one of those math things

A magnificent tall tree called Pycnandra acuminata grows on the island of New Caledonia in the South Pacific, and it does something strange – when its bark is cut it bleeds a bright blue-green latex that contains up to 25% nickel, a metal highly poisonous to most plants in more than tiny amounts.

An estimated 700 plant species have unusually high levels of metal, mostly nickel but not in all cases. The macadamia tree has leaves and sap rich in manganese, although fortunately not in the nut. If such metal-containing plants are dried and burned to ash they yield extremely rich, high-grade metal ore, with far less pollution and using far less energy than needed in conventional mining. Perhaps this could offer new sources of much needed metals. It is highly unlikely they could fully replace traditional mining, although they can also help clean up soils contaminated with toxic metals.


The nickel must be in the soil in order for the tree to concentrate it. So, what’s going to provide the nickel we want, waiting a century for the tree to grow, harvest, then plant again for the next cycle to lift 1% or whatever of the soil’s nickel?

Or dig up the soil the tree is extracting from and extract directly?

And when you say you want 50,000 tonnes a year of Ni…….

12 thoughts on “Another one of those math things”

  1. The Meissen Bison

    I’m not sure that this is one of those maths things and not simply one of those brain things.

    Progressive horticulturists with even a modest Islington windowbox should use basic NPK fertiliser for the good reason that these elements are taken up by the plant. Boron, on the other hand, is what a guardianista has a limitless capacity for.

  2. So we should cut down all the trees then?

    NB I find the 25% claim hard to believe, I suspect another innumeracy issue here.
    Long time since my lab days, but could you make a 25% Nickel solution using pure reagents…you’d need a strong arm to stir it…

  3. There’s an oversupply of trees, we need to stabalise their value, so fifthly, we need to remove trees from the supply and destroy them.

  4. ‘So we should cut down all the trees then?’

    I’m sure that a simple open pit mine would disturb far less of the environment than cultivating and cutting down nickel plants. If you could persuade something faster growing than a tree to extract it from the soil.

  5. @jgh

    Douglas Adams has been there already

    As I recall in HHGTTG the ‘B’ Ark crash landed and the survivors decided that the leaf should be their currency. But there were too many of them , inflation was rampant, and they commenced a programme of deforestation…

  6. @Tim

    I also found the 25% figure hard to believe, a minor Google suggests it is actually 25% of some form of nickel citrate, which itself would be around 30% by mass nickel. So maybe the sap is 8% nickel by mass (sounds more feasible).

  7. @Tim

    It’s bound as a citrate to a proteïn. It’s a trick that allows for high concentrations because the complex is chemically more or less inert, and large enough to be tossed out of a cell membrane while unable to return.

    It’s a pretty common mechanism found in plants. All of them use it to dump antifungals in their dead parts. Quite a few have evolved the trick to use metals for that.
    After all… What’s not to like about an osmotic regulator that also captures poison and uses that same poison as anti-predation measure… Triple whammy….

    Next time you see the humble violet, remember that it can deal with heavy metals if needed…

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