Invaders a monoculture?

Here's me wondering.
We live in South Africa and have a major invasion of black locusts on our property.  Which makes me wonder - isn't this a monoculture?  Nothing grows under/over/next to them.  Same goes for various weeds that can overtake.

So does nature sometimes create a monoculture?  Granted, as a result of human actions, but still...

And wondering if anyone knows how to deal with a black locust invasion........ If we leave them they will do what they've done successfully in the area over the last ten years - multiply and make it impossible to do anything on the piece of earth that they mark for themselves...


Regards and thanks,

Suzie

aren't they basically a nurse tree? similar to aspen. They take over areas where nothing is growing ..as nature abhors a vacuum..so they fill in the vacuum?

or are they taking over an area where it is already forested??

my guess is if they are taking over an unforested area, that if you want to keep them out, you will either have to forest the area, or mow it..or weed them out.

Hi Brenda,

No vacuum, we have grasslands - native to our area.  They are taking over the grasslands. 

Looks like they grow back faster and harder if you hurt them (cutting or weeding).  But we are trying to weed them with the backhoe at the moment.  You cannot do any of these by hand, they are growing back too aggressively. 

Doesn't look like they are fazed by other trees either.  They grew in and out of an existing wood in the area and took over around the existing trees. 

They make nice fenceposts though.........

Thanks

EDIT: Hey i took too long to write my post, didnt see brenda and your new posts yet

Hey suzie,

When exotics enter a different ecology they might find some sort of niche and become invasive and create monoculture. It is natural, but a disbalance. that in the end over time balances out again.

When an exotic enters a different eco system it doesnt have a place in it. It doesnt have natural enemies or competitors (yet). It doesnt serve a role for other organisms. Generally though, even the most invasive exotic will in the end find its place in an ecology. Animals that could restrain its growth by eating it for example first have to learn that it is edible, and that doesnt happen overnight.

Shorter living species adapt faster to an ecology, than organisms that per generation live 100 years. 

Obviously the ecologie of human influenced landscapes might not be able to restrain really invasives, even over a longer period of time. And even if it would, you dont have time to wait for the eco system to adapt.

how to get rid of black locust???
there are some parasites that are now spreading here in europe (i dont know the english name in latin its: Obolodiplosis robiniae) that harm black locust, but if introducing those in south africa is such a good idea....? 

We have a big black locust in our 50mX25m cityplot, and it is declared monumental by the city council, so it has to stay unharmed. We have found that the more we cut back their suckers, the faster they grow, and the longer their spikes get. apart from cutting it back each year, we are just planting really competative stuff amongst them, like sunchokes and comfrey.

On the plus side the wood is a very high quality, if leaving one sucker, and clearing the suckers around it, in the second year they will grow straight up, and in the third year can be harvested as stickwood, as in broomsticks, trellis etc. older, thicker trees (minimum 30 years) are supposed to deliver really good hardwood.

The flowers will provide great honey, so if you cant get rid of it, getting some beehives might be a good option.

Also, and i dont know much about it, since it is not my climate, i heard that when creating a food forest in arid or semi tropic regions the black locust is usually planted(!) as a leguminous tree, to fix nitrogen.

check out the movie 'how to create a food forest' from geoff lawton, for more info on that.

succes

(ps, and oh, if you find an effective way to fight back the suckers, i am more than interested.)

it's a very useful plant, but if you come to the conclusion that you really must get rid of it, it shouldn't be too difficult.  cut them down and pen goats where the grove was.  the goats will eat the many new root suckers as they sprout.  could take a while to exhaust the roots, but goats will do it in time.

Thanks for all the info and ideas.

Yes, we've though off grazing them until they die down, but with a little more research it looks like the bark is poisonous to animals.  There's a bit of a discrepancy there, as some sites say it is used as fodder and others advise not to use it as it can cause your animals to die.......... don't know if I'm willing to take the chance.
Plus they grow at the bottom of the farm where there is a bit of human traffic and I'm not willing to let my goats become meat for a happy bypasser (is that the right word??) as it often happens here.

I've seen people advising to plant it as the wood is very useful.  That it definitely is......... but oh boy, when it takes over.............  maybe in other climates it won't grow as aggressive as it is here. They've invaded almost 2 hectares of our property in the last two years.

We're currently taking out the roots with a backhoe and planting radishes for the cattle in the area so we can work the soil again if needed.  Weeding by hand only hurt the hands - nothing else.  Will let you know if the backhoe is working. 
And it does wonders for the soil.  Most beautiful soil builder.  I'm using the soil for my raised beds.

In the mean time the bees are indeed enjoying the flowers and we've created a whole windbreak with the  smaller sticks we've taken out.  Maybe I should post a photo.

Regards,

Suzie

suez wrote:
Thanks for all the info and ideas.

Yes, we've though off grazing them until they die down, but with a little more research it looks like the bark is poisonous to animals.  There's a bit of a discrepancy there, as some sites say it is used as fodder and others advise not to use it as it can cause your animals to die.......... don't know if I'm willing to take the chance.
Plus they grow at the bottom of the farm where there is a bit of human traffic and I'm not willing to let my goats become meat for a happy bypasser (is that the right word??) as it often happens here.

I've seen people advising to plant it as the wood is very useful.  That it definitely is......... but oh boy, when it takes over.............  maybe in other climates it won't grow as aggressive as it is here. They've invaded almost 2 hectares of our property in the last two years.

We're currently taking out the roots with a backhoe and planting radishes for the cattle in the area so we can work the soil again if needed.  Weeding by hand only hurt the hands - nothing else.  Will let you know if the backhoe is working. 
And it does wonders for the soil.  Most beautiful soil builder.  I'm using the soil for my raised beds.

In the mean time the bees are indeed enjoying the flowers and we've created a whole windbreak with the  smaller sticks we've taken out.  Maybe I should post a photo.

Regards,

Suzie

goats are no mere 'animal' hehe.  here's a snippet i found online.

For those of you who don't like these trees, about the only way I've seen to get rid of them is to get goats. I thought these trees were invincible until I penned in some goats around them. Black Locust is one of their favorite foods. They eat the smaller branches, thorns and all. And they will bark the smaller trees. However, once the goats are removed, the new sprouts will be free to grow unhindered again.

also, here's a link to a study titled INTAKE AND DIGESTIBILITY OF BLACK LOCUST FOLIAGE FED TO
GROWING GOAT WETHERS
http://www.internationalgrasslands.org/publications/pdfs/id0951.pdf

that is the problem with agressive nurse type trees, they do tend to grow from suckers from the roots, esp if the trees are cut live or damaged..

i find cutting them live is the worst..as the stump and roots seem to send up thousands of suckers..

might be best to cause them to die on their own stump and then cut them after they are dead..completely dead..which won't send runners out.

girdling MIGHT work, and might not.

suez wrote:
Yes, we've though off grazing them until they die down, but with a little more research it looks like the bark is poisonous to animals.  There's a bit of a discrepancy there, as some sites say it is used as fodder and others advise not to use it as it can cause your animals to die..........

If there is lots and lots of other food in the area, the animals will eat only that which is good for them and avoid anything toxic. 

I recently saw sheep moved to a new pasture with black locust in it and they beelined for the black locust - that was what they wanted to eat most.

This is the first time I have ever heard of anything doing poorly around a black locust.  All of my previous information says that black locust is a great team player:  feeding the other plants around it.

For small areas; is it feasible for you to put down a sheet mulch  or simply a thick layer of leaves and/or grasses?

What about using black locust prunings to thickly mulch areas cleared for perennial plantings? 

Have you looked into cutting the trees and then pouring vinegar down the stumps? Apparently this works for european buckthorn, which is a major invader here in Ontario. The time of year this procedure is done makes a big difference, so I'm told

I used to spread flour over plants when I got invaded in a high desert climate.  It gummed them up and they couldn't eat readily.  However, finding out why they are doing it might be the start of learning how to deal with them.

It being grassland, and since you have access to heavy equipment, have you considered clearing a border and doing a controlled burn? Sometimes grasslands spring back from fire more rapidly than trees would.

He he he.

Yes these buggers got us all in the area running in circles for the last couple of years.

Goats - We have, but can't put them there because they will surely get stolen quicker than they can eat anything - this is Africa.

It is strange.  The black locusts make the most wonderful soil when you eventually get them out - but nothing is growing under / close to it - hence me seeing it as a monoculture.  They grow so close together that we cannot get in between them. 

and no, we had a veldfire running through the locusts in winter, they seem to flourish even more after that. 

I get the idea the black locusts is a more aggresive grower here than in other parts from what I'm reading and seeing...

But we are indeed using every part if the trees that we are taking out.  For windbreaks and fenceposts etc, but there is so many of them!!!

I will take a photo this afternoon and post it tomorrow. 

Some plants like alfalfa poison the soil to keep other alfalfa plants out.

In Aspen, kill over 40% of it and the whole lot dies. It is a mat and is inter connected.

Ask the old timers .. African .. what can be done.

Have a famous book on .. brain lapse gave the book to a friend that started an 80 bed orphanage in Africa .. aaah Livingstone .. he was dying and on a cot beside the trail and people passing all the time .. one black man stopped .. looked at him .. made a green tea from literally the grass growing under his cot .. fed it to him and he was up skipping rope in no time. That always cracked me up.

What you do when you don't have to .. determines where you will be when you can't help it.

I'm not sure if it's possible for you as they are so many as you said, but here people sometimes have troubles with false robinia, which can get invasive.
It's a rule not to cut it to the ground! Instead cut it at the head high and peel off all the bark. This is done when the summer hits in. The tree really tries to heal the wound and the roots get weak and then die.
But, don't try this at home, you can get the opposite effect. Just kidding, but consider this joke as warning.

paul wheaton wrote:
This is the first time I have ever heard of anything doing poorly around a black locust.  All of my previous information says that black locust is a great team player:  feeding the other plants around it.

Maybe competition for water (guessing based on grassland setting)?  I just inspected an old Robinia grove down in the Duwamish in Seattle, and found lots of nice fence posts, but very little understory compared to Alder.

Apparently Black Locust has some allelopathic properties.  Here is one abstract of a journal article:
http://www.springerlink.com/content/x172q2257p002674/