Alder and nitrogen fixation-only native tree west of Rockies that does it

In searching out nitrogen fixing plants for my property I discovered that the red alder is the only large tree west of the Rockies which is capable of fixing atmospheric nitrogen. It is capable of producing more than 200 kg per hectare which compares favorably with legume crops such as soybeans and peas.

    Because it is singular in my environment on Vancouver Island in its ability to provide this natural fertilizer I will favor it above all other native species. Soybeans don't want to grow in my environment while alder can't be stopped. In some parts of the world lightning is responsible for fixing huge amounts of nitrogen but we seldom have thunderstorms and therefore almost all of our nitrogen is acquired through biological means.

    The north side of my large hugel beds are already lined with alder and with cedar. My plan is to use most of this cedar for building so that the entire strip along the north boundary is alder coppice. Within gardening areas whenever I need poles it would make sense to use this resource. I have several spots which are too wet for fruit trees but within close proximity of good fruit growing ground. Alder growing in these damp spots will fertilize the neighboring blocks with their annual leaf drop. In surveying the rest of the property I discovered that I have one ditch which is becoming rather full of organic material and most of it is alder leaves. There's about 1000' x 2' wide which will yield well rotted leaf litter. A much larger ditch and culvert are becoming clogged with organic debris. Most of the trees lining this seasonal waterway are alder so no doubt my dredging will provide top-quality soil. Since the water dries up completely every summer it won't really be dredging. I'll sling a giant slop bucket into the ditch with my crane and load up 500 pounds at a time. I may try to devise a bucket which can be filled as it is drawn forward  since there is a 150 foot cable winch on the crane.


        There is an area of about 3 acres which was completely clear-cut 11 years ago. It now contains many alder which are about 40 feet tall and they grow 6 feet every year. By the time I'm ready to farm this section there will be quite a bit of useful timber from the better logs and the low-grade stuff will provide as much as 100 tons of material for hugelkulture.

    When I look across the river onto a vast area of government controlled tree farm it is abundantly clear that this forest is largely devoid of hardwoods. In searching out old government literature on tree farming there are large amounts of literature concerned with how to eradicate red alder. In newer and more enlightened government forestry pamphlets they advise forest managers to leave at least 200 red alder per acre in order to maintain adequate nitrogen for Douglas firs and other conifers. Studies have shown that tree growth in an 80 year rotation is severely limited by lack of nitrogen during the last 20 years of that rotation. Of course Douglas firs can live for 500 years but in these artificial tree farm situations those forests would barely grow for much of that time due to an acute lack of nitrogen.

There is also a lot of interest in using alder coppices for biomass energy in the Maritime Provinces, although it isn't the red alder (Alnus rubra). Alders tends to grow vigorously in disturbed areas that have poor soil due to association with nitrogen fixing microbes, and the result is a high yield, especially when coppiced or pollarded.

I wrote some praise of red alder.  I have experimented with coppice.  It tends to get fungal infections easily (which makes it fast for spawning logs or chips if you can keep the bark on).  Also it doesn't produce a lot of primordia for forming epicormic shoots except at the whorls where terminal buds are located.  So if you cut it low it dies (which is good for some applications), and if you cut it high, it sprouts at old nodes and than dies.  So it is a good nurse crop and for biomass, but in my experience not coppice... Slide alder A. sitchensis or other northern shrub alders might suite better for coppice.

Just cleared a couple kept to boles for fuel and hugel and used the slash for mulch on a couple happy plums.

I don't know if this will grow in your area, but I believe the Mesquite tree is native to west of the Rockies, and certainly fixes nitrogen.

Alex

Mesquite is the champion of arid regions.  The only way to get rid of it is to have other species prospering it, and thus, shading it out.

I've never heard of mesquite being grown anywhere near here but black locust has been introduced and apparently has a very good growth rate. I cut quite a bit of it when I lived in Ontario and it made me a little sick. Probably the 4% fungicide. But I'm definitely going to try some of it. I have one area bounded by a swampy patch which should contain any invasive nature.

I've widened the road and thinned out other alder. This produced about 2000 trees ranging from 3 to 7 inches in diameter which have been incorporated into hugelkultur beds. There were also a few thousand maple and cottonwood. Within a year, my total volume of standing alder will be back to where it was. It's a young stand which doubles aprox. every 2 years. Much of the remaining alder was competing with closely spaced maple and cottonwood which have been removed. Most young conifers have been removed.

Here in the PNW, red alder is the wood of choice for smoking salmon. It gives a nice flavor, without overpowering, like mesquite or hickory would.

...looks like Dale has enough quantities to smoke a few gray whales!

I will add that I use living red alder at the end of raised beds and near fruit trees, and dead trees in raised beds and as side forms...
But I haven't been successful coppicing close to the ground -- should I treat the stump to prevent rot or just cut 5' up or so?

The road is 5/8 of a mile in length and nature is constantly encroaching. About 1/3 of this young forest is alder. In thining it, I've cleared out plenty of maple and cottonwood which will allow the alder to flourish.

Looks nice Dale! My place has lots of wet bottomland where the alder survives the bestin groves -- but not with high survival rate. A few feet up the water table is mostly Red Cedar that doesn't give the alder much of a chance.
Whenever there is a freezing rain storm before the alder leaves drop, anything less than 10 years old is likely to fall over -- we had a bad one of these in Seattle about 15 years ago and it was mayhem for alder, plums and other young spindly trees... Looks like you're just as fine with alder logs as trees though!

Groves of alder can be managed for the production of humus that is used elsewhere. I cut this from my post in another thread that discussed the pros and cons of gathering soil from the forest floor. https://permies.com/t/27069/woodland/forest-floor-resource#214098

I have a nitrogen producing tree called Red Alder. They are a pioneer species that thrive on disturbed gravelly soil that is typical of my area after a clear cut. I have some low spots with very nice dark soil that was created by the alder leaf drop. The alder in this area are dying back, while those on gravelly silt are thriving.------ In talking to an old farmer and forester, I learned that these trees don't like the rich soil that they create and they eventually die back and are overtaken by maple and other species that love it. The farmer has been managing a grove for years by regularly clearing little patches and scraping the humus layer away with his front end loader to expose the mineral soil beneath. His wife uses the "muck" leaf mold in their big garden. The exposed soil is quickly colonized by alder which thrive.

Few forests could withstand this sort of harvest but I am utilizing this tree and the soil it produces. I plan to use the excavator to muck out around some of the dying alder. I'll replace this rich soil with gravelly silt left over from road improvements. Young alder have already rooted in the gravel edge of the improved road, so I'm confident that they'll like how I've "improved" their spot. Foresters view this short lived tree as a "trash" tree. I think it's a perfect cover crop. It thrives on neglect, is self seeding and requires no protection from anything. It's only requirement is that it would like someone to take away the rich humus every few years.

There are a few other legume trees that are known to thrive on poor soils. I wonder if they also tend to die back due to the nutrient load in their leaf fall. Luceana is a tropical tree that is used for fuel, fodder and soil improvement. I don't know if it can tolerate humus gathering. I'm going to investigate this further.

Landon Sunrich has created a new thread that covers many aspects of the red alder. -------- https://permies.com/t/27872/trees/Red-Alder-Alnus-Rubra

In southern CA have a lot of Western Redbud and Palo Verde trees - popular landscape trees which are quite and are n-fixers. Palo Verde has edible seed & flowers, but not worth growing for that purpose.

Alder catkins are edible and high in protein but not worth growing for that purpose

yukkuri kame wrote:In southern CA have a lot of Western Redbud and Palo Verde trees - popular landscape trees which are quite and are n-fixers. Palo Verde has edible seed & flowers, but not worth growing for that purpose.

Oh, how wrong you are. Wrong, wrong, wrong. There is nothing like palo verde string beans, steamed lightly with just a little butter on them. But you have to pick them at just the right time, when the pods are just starting to bulge and before they get too big and tough. I'll agree though that after the beans have dried out, they are inferior to pinto beans or black beans, but even then they still taste better than black-eyed peas.

John Elliott wrote:

yukkuri kame wrote:In southern CA have a lot of Western Redbud and Palo Verde trees - popular landscape trees which are quite and are n-fixers. Palo Verde has edible seed & flowers, but not worth growing for that purpose.

Oh, how wrong you are. Wrong, wrong, wrong. There is nothing like palo verde string beans, steamed lightly with just a little butter on them. But you have to pick them at just the right time, when the pods are just starting to bulge and before they get too big and tough. I'll agree though that after the beans have dried out, they are inferior to pinto beans or black beans, but even then they still taste better than black-eyed peas.

I'll be a happy man if I'm wrong and hope I can thank you next summer for setting me straight.

Dale. It would be worth checking to see if any species of ceanothus will grow in your area. Some are more medicinal than other. All have the potential to host nitrogen fixing microbes (according to my research). And it can be used to make a gentle body wash.

David Hartley wrote:Dale. It would be worth checking to see if any species of ceanothus will grow in your area. Some are more medicinal than other. All have the potential to host nitrogen fixing microbes (according to my research). And it can be used to make a gentle body wash.

I'm more interested in this as a tea substitute. I've never really liked most foo foo teas, but something that resembles regular black tea would be great.

This guy has compiled a big list of nitrogen fixing plants for temperate climates. I wanted to invite him to join us, but the system rejected my computer or my command over it.-- later that minute --- I figured it out. Looked around some more and found a picture of Paul and the RMH kickstarter.

http://tcpermaculture.blogspot.ca/2011/05/plants-nitrogen-fixers.html

Awesome-sauce! Has now been bookmarked

David Hartley wrote:Awesome-sauce! Has now been bookmarked

Sounds like a good name for a steak sauce.

I've been adding lots of alder mulch to my hugelkultur and it is doing well. This wood breaks down even faster than poplar does. For this reason, I save all of my alder wood for the top of beds. In some places I added very little soil. My plants are rooting in alder that has been down for two seasons. Soon, big bins full of tree waste from an excavating company will arrive. The alder will be sorted out, so that it can go on top of new beds. Alder stumps contain lots of small roots that trap soil. Machine operators often give stumps a good pounding so as to not send too much soil to the tub grinders that make hog fuel. My bins will load quickly, since there is no need to remove the soil. They save machine time and I get a nice muddy mess that works better in hugelkultur than clean stumps would.

I'm in a zone 5a spot on the interior of BC, and contemplating planting some alder. I'm pretty sure red alder is not hardy enough to grow here but I'd like to try a vigorous alder like black alder and am wondering if I need to import a red alder rootball to establish the N2 fixing abilities.

Dale have you tried tea from sea buckthorn leaves?

Also "native here now".....in other words, introduced in the last couple of centuries and not likely to leave any time soon, besides Black Locust there is also the common "mimosa" (Albizia julibrissin); although this is much less invasive than it is in the Southeast; and in the warmer parts of CA, various species of Acacia and also some Casuarina. I think for the mimosas and acacias at least, the bacteria disperse through the air. In any case I've seen active nodules on my seedlings in soil that, to my knowledge, had no contact with the roots of such plants before.

David Hartley wrote:Dale. It would be worth checking to see if any species of ceanothus will grow in your area. Some are more medicinal than other. All have the potential to host nitrogen fixing microbes (according to my research). And it can be used to make a gentle body wash.

yeah i am super interested in ceanothus lately, they are my new plant friends that i have been observing and getting to know them this year. it seems to be one of the most preferred deer food plants, since i've been tuning into it lately i have found many occasions when theres deer chowing down on it. whether thats a plus or a minus i suppose is an opinion, i think its a plus cause i would rather have them eating that then my plants! but it might also be a draw for the deer, then they go around to eat other plants in your area. they are quite lovely though, they are all over here and grow in total shade, neglect, and drought.

http://www.laspilitas.com/groups/ceanothus/california_ceanothus.html

theres a tree all over here with bean pods that spreads like crazy. i want to assume its native since its sooooo widespread.

I'm going to try sea buckthorn. People sometimes eat the catkins from alder. I'm going to give them a try in tea. I usually don't like the foo foo teas, but try them once.

I am building a free fence for my chickens with excess Alders that is on the property. I will post up pictures on my thread within the next few days, the thread is called ''making a living'' in the small farm section.

I'd give a bunch of thimbleberries a try under those alders!

Hi Dale;

I'm wondering if you tried coppicing alder, and if it worked well or not. We are in the same situation - lots of alder creeping in on the forest edge, where I want to create a new growing area. I'm heading out right now to check on the soil under the alders, to see if there is any there. The rest of our property is sand and rocks. I like the idea of being able to rob some good leaf mulch/soil from the alder stands to use in the garden.

Great and informative thread. Thanks!

Tracy

I went out this afternoon and took a stroll through the alder woods with trowel in hand. I did indeed find some definite soil-like substance under the leaf and twig covering. Very promising. I can see scraping up some of that goodness and using it to top off my garden beds. It's not a very thick layer of soil, and it's sandy, but it is definitely better than what is in the cleared areas. Thanks for sharing the info.

A short story about how perceptions can change over time.

My parents purchased a property in Alaska that had a great deal of aider on it.  It doesn't grow fairly attractively like the red alder grows in here in the PNW.  It grew short and stubby like a weed.   It was an old homesteader's property and you could clearly tell where he had clearcut due to the impassable thickets of alder.  My dad had me out there as a kid sawing down alder to try to give light to the baby spruce trees that were trying to repopulate the area.  As a result, as a child, I "hated" alder.  Obviously, we didn't know they were nitrogen fixers.

Knowing my dad, if he'd had any idea they were nitrogen fixers, the lessons would have been about how great alder could be as nurse plants and we would have thinned them out instead of chopping them all to the ground.  As it turned out, the homesteader has used his property as his landfill, including burying full oil tanks that then leaked.   My parents spent all their money on cleanup and I ended up growing up in an unfinished garage...which why you'll probably never see me out building a wofati...some deep childhood stuff there.  

But, the moral of the story is that alder were in there trying to mitigate all that damage and we didn't see it.  Now, when I see alder, I go look to see what the damage was on the property.  And I have an alder thicket on my current property, which tells me that the original owner of this property did a nice bit of damage to it.  Which he did.  So, I'm out there telling the alder what a good job it is doing instead of cutting it down.  

I have had little success in coppicing Alder. Once they are cut off, they seem to just die. Sometimes a bit of growth will come, but the stumps rot away. There are some portions of my property that I manage for constant Alder production. When other things are cleared away, Alder will invariably take over, given the right conditions.

Is anyone aware of the use of Grey Alder for nitrogen fixation? And if so what sort of inoculate is used?