Invasive trees as a nitrogen source?

Brad Davies wrote:I'll go home tonight and check my reference, Permaculture Design Certification DVD collection, by Mollison and Lawton, but I am fairly confident that Lawton said exactly that. While I don't think that Lawton is saying this is an exact rule, he is using it as a generalization to answer the common question of when to chop.

cool! (I mean: temperate )
I am curious what they say on the DVD, but let's keep in mind that tropical and subtropical permaculture techniques are different: evaporation and precipitation is a whole different factor in cooler, temperate climates. There is no mention of this in Permaculture Two by Mollison but a quick search on Google brought me to several permie sites where it is the mantra of tropical management where growth is fast and shaded soil for evaporation control is favored.

If I think about our land here in Putnam County, NY in its first year of permaculture transformation (observation and mostly mulching preparation) I am not sure how to apply the advice: annual precipitation is around 55 inches here, on a lake with a stream that dries out only in longer dry runs and co-joining small wetlands—and capricious seasonal rainfall variation.

Very interesting discussion--thanks to all the participants. 

I completely hate the word invasive.  I have watched how Monsanto uses the word to recruit interns of all ages to push for the use of their products, sometimes through their allied non-profits, like The Nature Conservancy. 

At this point, I wish we could call humans animals, call this one planet, and get over the invasive thing. 

As many have said, there are uses for things we have so much of.  Blackberries now protect a native salamander that has lost all of what used to be its other plant protectors.  When people deal roughly with blackberry, they can be taking out a native animal that is very threatened. 

It's always complicated.

Blackberry leaves can also be made into tea.  The leaves are nutritious, which is probably a reason they are so well armed. 

Blackberry can be a good friend to those who are wildcrafting on logged out, recovering second growth, where even Indian Pipes, a threatened plant, has been found, despite its reputation of only growing in old growth.

A French way of interpreting permaculture is to call it diversiculture.  OK, so I admit I'm a Francophile, but I really like this word combination.  It saves some explaining with newbies who want a short version of what permaculture is.  They can often grok this within the short confines of U.S. attention span.

I love mimosa.  The flowers smell wonderful, which is perhaps why it is so favored by beneficials.  When you attract beneficials, you make diversity and the resilience of backing up functions within the system.  Albizzia is such a wonderful plant, I feel very bad when it gets demonized with a pejorative word that I have it in for anyway. 

My silver foil hat is in the shop, so I am this to say as well.  When we use those words that Monsanto gets served by, it does not stop some of their partners from distributing those very plants the interns get sent out to kill. 

The Arbor Foundation, for example, distributes plants that are classed as invasive. 

It is rather like the fuel industry's connection to carcinogens and to the pharmaceutical industry.  It sells its left-overs to both, thereby making profit on both ends.

Toby Hemenway has come out heavily against the use of herbicides and the massacre of plants like locust, on the Portland Permaculture Guild list-serve, pointing out that the city has used this awful stuff where kids play and near the river, to get rid of plants called bad names. 

I can't sit in the middle on this war.  I am thoroughly on the side of this being one planet in stressed times.  The life forms that show vigor, especially the plant ones, deserve to be talked about respectfully.  Using a marketing word of my least-favored corp sets me off.

cini wrote:
cool! (I mean: temperate )
I am curious what they say on the DVD, but let's keep in mind that tropical and subtropical permaculture techniques are different: evaporation and precipitation is a whole different factor in cooler, temperate climates. There is no mention of this in Permaculture Two by Mollison but a quick search on Google brought me to several permie sites where it is the mantra of tropical management where growth is fast and shaded soil for evaporation control is favored.

If I think about our land here in Putnam County, NY in its first year of permaculture transformation (observation and mostly mulching preparation) I am not sure how to apply the advice: annual precipitation is around 55 inches here, on a lake with a stream that dries out only in longer dry runs and co-joining small wetlands—and capricious seasonal rainfall variation.

I finished rewatching a couple videos over the weekend, Establishing a Food Forest, Lawton and DVD #7, Food Forests pt1, pt2 of the Permaculture Design Certificate Course DVD Collection, Mollison and Lawton. I have to say narrowing down a small chunk of information from a 60hr course is easier said than done. So I popped some popcorn, poured a homebrew, kicked my feet up and watched both DVD's again.

Lawton did give my exact example, well his example I guess since I learned it from him, for temperate climate chop and drop in the Establishing a food forest video. Mulching with herbaceous plants in the spring, letting things grow back out just before summer, then chopping stick mulch or woody mulch at the start of fall.

I couldn't find the S. America example. I am thinking now that it might have been in a Q&A session in a later video. Either that or it was a Mollison tangent, which there are a lot of in this series.

On that note there are a lot of tangents that Mollison goes off on in this series, some of them are very interesting, and some of them you’re like wtf Bill. The series was a little hard to get into at first, probably because I was so eager to learn the information, but as it moves on you start to appreciate his stories more and the experience he is trying to relate. Lawton is an amazing teacher, he does a great job doing post reviews of Bills lectures and Q&A sessions on the topics.

Lawton also talks a bit about N fixation in these videos, and gives a few strategies depending on what you’re trying to accomplish. He describes the N fixing bacteria as having a symbiotic relationship with the plants. The plants provide starches for the bacteria and the bacteria provides N for the plant. When the plant starts to fruit/flower/reproduce the roots will use up a lot of this N to set its seeds/fruit.  So if you want to fix N into the soil you should cut / coppice/ prune when the plant is just getting ready to start setting seeds, as this will be the peak of N in the roots. Or if you would prefer a N rich mulch you should wait until it has seeds/ pods then cut and use that material as N rich mulch. He goes into further detail describing what happens to the roots once the top is pruned and how the N will migrate away from the source through varies organisms in the soil consuming it then being consumed by the next and so on. He also talks about the N rich mulch and lists, in descending order, the N concentration as: Seeds, Pods, Flowers, Leaves, Twigs. I might have mixed up those last 3 but I think that’s correct. There is a lot more information in the videos, 4.5hrs worth, and I highly recommend them.

I look at this as just one source of information and not the end all be all of N fixation and chop and drop. I agree that the Holzer, Fukouka method of observation, trial and error is probably the best model, but not everyone has the luxury of having 20+ years to observe and test. Any generalizations or practices that we can share will only help to fast track us, and make it so everyone doesn’t have to start from scratch, IMHO.

cini wrote:
If I think about our land here in Putnam County, NY in its first year of permaculture transformation (observation and mostly mulching preparation) I am not sure how to apply the advice: annual precipitation is around 55 inches here, on a lake with a stream that dries out only in longer dry runs and co-joining small wetlands—and capricious seasonal rainfall variation.

On a side note Putnam County, NY and Clarkston, MI have almost the same Latitude. Hopefully we can share experiences on timing, and plant selections.

da_wanderer wrote:
Greetings from a newbie,

I am slowly learning about permaculture and have been working my garden in the right direction. I have noticed that we have Chinese silk trees all over the place. I now know that they are classified as an invasive exotic. However, since they are already all over the place, and they fix nitrogen, I would like to use them as companions with my fruit trees. I am thinking I could prune them into a large shrub form and plant them in relative proximity to my semi-dwarf fruit trees. I could probably control the number of pods they produce with fall pruning.

Anyone have a better suggestion? I like the idea of using what is already here.

go for it, sounds wise to me.  You are learning already faster then the US Forestry service that spent millions in Alaska to learn Alders are N fixing trees that appear as the first trees in the forest cycle.

It is interesting that I am not seeing Nitrogen fixers that produce edible fruit or fodder for animals discussed.
One thing I have found in history is that many cultures tend to use plants that are easy to grow in their areas.
This is only done by understanding the plant and managing the plant.
I am currently collecting a number of nitrogen fixers to work with on my property.
Since 1997 I have worked with a number of 'invasive species'. Several of these I am now in the process of reintroducing because certain animal species removed all of these.
I an currently working on a balance of invasive species and selective feeders to acheive a balance.
It is very likely I will be using pollarding and coppicing along with controlled grazing to acheive this balance.
I would be interested in others who have found that invasive to others is first food eaten by their animals.

I have a small back yard with one huge Mimosa.
Because of the limited space I was considering replacing this tree. But, I researched it first, and found that the blooms are edible. Prairie Mimosa has more edible parts.
I found simular lessons about my fifteen foot tall Rose of Sharon hedge.
I don't know if waste not want not is a permaculture principal, but it works for me.
Btw, you can strip sprouts of either of these species of all thier leaves, at any time, and be pretty certain they will regrow.

I'm loving all the Mimosa's in bloom right now in Portland. Do y'all think I could propagate some baby Mimosa's to live next to my fruit trees in the classic nurse plant/chop'n'drop pattern?

My grandfather in Belleville Illinois had a big mimosa tree in his yard - they can take some snow and ice and yet look so tropical. . .

I hear much talk about roots. But there are roots and there are roots.
A tree has structural roots that keep it in place.
A tree has transport roots that bring nutrients up food down.
A tree has feeder roots that work with fungus to feed.
It is the feeder roots that come and go. Many trees will not support a large percent of their very fine feeder roots when the tree is dormant in the winter.
So you have leaf litter and root mass that will be recycled in a woodland setting.
Fungus will play the key role in this recycling.

Now you cover crop will be primary bacteria doing the recycling.

One thing that was not mentioned is that a dense canopy can kill weeds. If you chop and mulch you now have an area that you can transplant or direct seed.
There is a balance between canopy and roots. You remove a bunch a canopy the tree will adjust the amount of root it supports.
That is why some large coppices are cut half on year and the other half the next to get a better regrowth due to less impact on the roots.

Also, some of these nitrogen fixers can be eaten by livestock.
Barberpoll worms are rampant and killing goats in some areas. Many parasites love moist or wet grazing lands during the heat of summer.
Having a stand of fodder trees can give you a place to put your animals to get them away from areas with high parasite loads
The fodder can also be cut and taken to animals that are more prone to parasites.

I don't like the term "invasive", I prefer "extinction accelerator"!

I have a few hundred Mimosa trees in my backyard and a couple of dozen on my roof and about as many in my gutters.

THAT to me is pretty much the textbook definition of "invasive"! The bees sure do love it, to the point of not bothering to pollinate anything else in my garden. I love the idea of the tree, its roots produce nitrogen, the flowers feed the bees, the seedpods produce fodder for animals and in general, produces a lot of mulch but the costs of having one seem rather high as they do reseed heavily. Like most things, in some areas they will not be as agressive and perhaps are not the PIA they are for me.

But my all time most despised tree are those damn Chinese tree of heavens, they are aleopathic and toxic and grow and spread like weeds are are almost impossible to kill once established.

I remember reading Bill Mollisons: Alternate in planting your apple with nitrogen fixing. I planted 3 pecans from pots. One had a nitrogen fixer 'Mimosa cross tree' in it which I left when planting and that pecan took off. So now I plant my N fixer less than 2 feet away from fruit and nut trees. This is on a 'no tree' plain in hot, sometimes windy and night freezing winters in S California. I took the hint from that one pecan tree what have others witnessed on the subject of companion trees?