Green removal of invasive trees - Knysna, South Africa

Hallo,

Our community in the garden route (Knysna, South Africa) is battling with infestation of non-indigenous trees (mostly blue gums and wattle). The only solution that local conservation bodies recommend is a toxin called Garlon which you paint on the stump of the tree soon after it has been cut down. Sadly the effect of this toxin is indiscriminate and poisons the soil for years after application. Please could we ask the permaculture community if there is any other 'green' strategy/method for controlling non-indigenous tree growth? The blue gums in the garden route sadly contribute greatly to the fire risk in the area and throttle the growth of the natural (and endangered) plant life which we are trying to establish after the fires ravaged the area in June.

Thanks for any assistance you can offer.

I wonder if this is where goats could help usually you would want to keep them off the trees but in this case concentrated goats would help in killing off the trees . Another thought I had was making charcoal/ biochar out of these trees . Let's try to make good use of these trees people are more likely to work hard to get rid of them if they gain something tangible from doing it
Have you any pictures of the area that could show us the scale of the problem

David

We managed to kill one eucalyptus successfully by cutting it down then cutting the regrowth every year for about three years.

Eventually the tree's root system runs out of energy if you keep doing that.  

I've also heard rumours about putting copper nails into the stump, but the more I research, the more it seems as though it's just a myth.

Here's one that we cut down about seven years ago and removed all the re-growth from for three years or so.



And a couple more.



And here's one that we failed to remove one of the new shoots from.

In some situations you could cut it down and build a compost heap on top of it. Looks kinda straight, might make good fencing if not used for biochar.