Red Alder (Alnus Rubra)

The red alder. Largest of the alders and generally considered by forest monocropers to be a pesky weed worthy of eradication. In fact there have been large scale herbicidal sprayings by the timber industry to discourage its growth. Fools. I feel this magnificent tree to be a powerful ally in the wet/temperate permaculturalists tool kit and here is why:

Red alder is a fast growing nitrogen fixing deciduous tree which accomplishes the majority of its growth in the first 3rd of its life. It thrives in bare compact soils serving as a vanguard species. It is a tree with many uses. Alder wood in addition to being an excellent wood for indoor use (cabinetry and the like) is a favorite for smoking and its quick growth makes it a fairly good choice for burning. Further the alder is a rapidly decomposing wood which makes it perfect for soil building via hugelkultur.

Grow a stand of alder to fix nitrogen in the soil. Chop and bury said alder to further build soil.

Alder is a preferred substrate for many useful mushroom species including (and not limited to) Oyster Mushrooms, Turkey Tails, and Shiitake.

Alder bark contains several know medicinal compounds including Salicin (of aspirin fame). It also contains Betulin and Lupeol which have been show as effective in fighting a variety of different types of tumors. It was used traditionally by the tribes of the pacific west as well as the Blackfoot who's homeland lay outside of the Red Alders growth area - indicating that this species was an important enough medicinal to be obtained through trade. It was also used as a natural dye.

Red Alder Propagation:


Red alder can be propagated by seed or cutting . Red alder is primarily wind pollinated via Catkins. These catkins go on to form 'cones' about the size of the end joint of a finger. Each alder cone contains 40-100 tiny flat seeds. Alder trees begin to produce seeds at the tender young age of 3 and can produce over 5 million seeds per acre.

Seeds germinate best after a prolonged period of cold. Seeds should be sown directly on the surface of the land and not buried as they need full sunlight to trigger germination.

Alder will naturally coppice and does so best when cut in the winter leaving at least 4 inches of stump

For its myriad of uses and soil building capacity I believe red alder is one of the most promising trees for use in converting marginal land to permaculture paradise. Hopefully I've convinced at least one reader out there of its merit as well.

We have an unknown variety of alders at one side of the house. While I never would cut them down they have some downsides. First stuff does not grow incredibly well underneath and I wanted to have something like an European/North American forest garden there. They are very brittle and in each storm branches are breaking. I don't know how they behave in case of a bushfire, but my impression is as they are so brittle that they would burn well.

Landon; I 100% agree

This is one of the few trees that can thrive while being robbed of the humus that it creates. This is part of my reply to a thread that discusses gathering soil from the forest floor. ---------- the thread is entitled --- Is the forest floor a resource ? https://permies.com/t/27069/woodland/forest-floor-resource#214098 The short answer for those of us with alder is, yes.

I have some low spots with very nice dark soil that was created by 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.

I started this thread entitled --- Alder and nitrogen fixation-only native tree west of Rockies that does it --- https://permies.com/t/10609/plants/Alder-nitrogen-fixation-native-tree#218745

Angelika Maier wrote:We have an unknown variety of alders at one side of the house. While I never would cut them down they have some downsides. First stuff does not grow incredibly well underneath and I wanted to have something like an European/North American forest garden there. They are very brittle and in each storm branches are breaking. I don't know how they behave in case of a bushfire, but my impression is as they are so brittle that they would burn well.

Angelika, Where are you located? I have found that many native edibles grow nicely along with alder. Stinging nettle is one of the primary ones I can think of. There are also a variety of berries which thrive under an alder canopy as well as many edible fungi.

I agree that they are a hazard in storms. Especially as they age. Alder is prone to heart rot and large alders are often referred to as widow makers around here because of the tendency of mature alder to snap, snag, and fall on peoples houses.

Angelika - Here in the NW, Red Alders are common canopy to salmonberry, thimbleberry, red elderberry, devil’s-club, whortleberry, osoberry, evergreen blackberry, western swordfern, and hedge nettle

A series of observations over a long period of time have led me to make this speculative assertion: Red Alder is salt tolerant.

I often see red alder thriving on bluff slides all the way down to the beach including in areas that are below the extreme high (but not average high) water mark. Where conifers and madrona die quickly I see alder of both established age a new growth seeming to thrive. Alder seem to ride land slides very well. I have also noticed them growing and thriving in sand dunes littered with driftwood. Again above the average high tide line but within the extreme high tide line. These observations lead me to believe that Alnus Rubra is a salt tolerant tree.

Hi,
I was wondering if anyone has experience growing red alder east of the Rockies. I would like to plant some in mid Missouri (zone 6a), if possible.
Thanks,
Hugh

Landon,

Thank you for a great post and some wonderful information about Alders. I see by your thumbs up count that it is well received and valued. I have one question on Red Alders that hopefully some here will be able to address. These are prolific on the Western slopes the Cascades. I seldom (don't recall ever, actually) seeing these on the east side. What is it about the Eastern Slope Steppes that prevent this wonderful legueme from growning there? Do they require the high rainfall of the west? Is their cold tolerance not low enough for the colder winters? It seems to me that other than rainfall there is not REALLY that much difference from say - King County to Kittitas County. Any thoughts?

Also to add a bit to the knowledge base and virtues of Alders, it is one of the four main food sources of Elk in the Cascade and Olympic Range. (Red Alder leaves, Sword Fern, Sorrel, Hemlock-new growth.)

Hugh Kay wrote:Hi,
I was wondering if anyone has experience growing red alder east of the Rockies.  I would like to plant some in mid Missouri (zone 6a), if possible.
Thanks,
Hugh

I'm with Hugh (somewhat literally).    

Any thoughts/experience on their ability to survive in Mid-MO?
Their invasiveeness?
Ability to withstand regular coppicing?

Thanks!

Landon Sunrich wrote:Alder will naturally coppice and does so best when cut in the winter leaving at least 4 inches of stump

How often should red alders be coppiced? And how wide and tall does the canopy get when the tree is ready to be coppiced? I'm planning on growing a lot of red alder on my property but need to figure out the spacing first.

Regeneration from Vegetative Sprouts
Young red alder will sprout vigorously after cutting (coppicing). Coppices with rotations of 4 to 6 years have been managed successfully for a few rotations. Red alders more than 10 years old do not sprout well after cutting; regenerating red alder by coppicing older stands is not feasible.

The above quote is from Oregon State University: owic.oregonstate.edu/red-alder-alnus-rubra

I read a report from the forest service that stated red alder needed to be younger than 7 years to readily coppice but that the survival of the coppice tree decreased with each harvest.

Based on these reports I have been thinking about coppicing red alder on a 5 year rotation but after the first harvest I was going to only harvest half of the regrowth at a time with the second half being cut a year later. My theory is that this might increase survival of the trees since they would always have some shoots left growing.

As far as spacing I think 6 or 8 feet would work fine. Could likely make 4 feet work if you wanted a hedge between harvests. Or further apart if you don't need to maximize space. For my place I plan to just mix them in amongst my other plantings such as fruit trees.