Alder vs Black Locust

Looking for a nitrogen fixer that can be used as firewood.

Black locust is seen as an excellent choice but is a non native species here in northwestern BC. Don't really want to be responsive for breaking up a natural ecosystem so looking for an alternative.

Alder is native and nitrogen fixing. Does anyone know if it coppices? Is it any good as firewood?

Thanks guys

My notes say it does coppice.

Do you see a lot of Black locust in your area?

Sometimes things are non-native but have become so ubiquitous that they might as well be native. Something like black locust is so useful that (similar to mesquite in africa) that it's really a shame that people aren't out there using what's available, as it's sometimes so amazingly abundant it gets put on the nasty list. If people would just use it for any one of it's many uses, on a massive level, I think the problematic nature of the plant would change.

The other thing is that if you see it everywhere anyway, planting yours really isn't going to change the ecosystem that much. But there are limits to that. I would say that for Black locust, but I probably wouldn't make the same claim for Tree of Heaven (Ailanthus altissima). Depends on the tree.

William

I have a friend who grew up in group homes in Washington. This Dickensian system hired the kids out to do all kinds of forestry related menial labor. One of his tasks was to harvest alder poles from coppices. These poles were used in the copper smelting industry--they were thrown onto the molten metal to remove oxidation impurities. Alder coppices well, according to him.

Black locust is not common in BC and not seen at all in Rosswood. According to a study of trees in the province or has "escaped" in the lower mainland and there are a few in the interior but not the Northwest.

So do I bring in a useful but potentially invasive species or use an inferior (for my purpose) but native tree ..

Tough call

And thanks for the info on alder

There is no reason not to try both - black locust is pretty great and you probably wouldn't regret planting some of these. Red alder is also great and local. You can separate them as it makes sense - in my case, I prefer red alder in the wet and marshy areas where a fallen tree won't cause much damage (red alder will lay a pole across a fence or road in no time!)
As for coppice, I find black locust works great (but suckers as well!), and red alder is not so great as it often dies. Red alder is successful if it already has a sucker coming up that you leave - just cutting 1/3 of the lower branches seems to encourage suckering so it sets you up to harvest a nice pole and have a few suckers following up..

I have black locust. I recently harvested poles for various construction projects. Planning to let 5 or so reach maturity as I coppice the 8-10 year old ones, and there are a lot of those.

If I was planting black locust, depending on the place it was planted, but if I'm going to be walking or gardening or harvesting near the tree I would want it to be of the thornless variety. Chopping and dropping thorns just doesn't seem like a great idea, and my hands and feet don't think so either.

Alder has the benefit of not having thorns.

Here's some info on firewood btu
https://chimneysweeponline.com/howood.htm

As for other native n-fixers that aren't firewood, "Artemisia tridentata (though not a tree) is both drought tolerant and nitrogen-fixing (and native [to BC], as well!)" -- You could divide the function of n-fixation and firewood if you wanted by using this bush.

Also of note: "BC doesn't have any native tree-size legumes."
http://www.botanicalgarden.ubc.ca/forums/showthread.php?t=33969

More discussion about n-fixiation west of the rockies.
https://permies.com/t/10609/plants/Alder-nitrogen-fixation-native-tree

That's the trouble with mixing climatic limits, native preferences, n-fixation, and plant roles (like firewood). You can do it with Alder, but you might have more fun with black locust and others who have been introduced. As long as you are able to keep things under control, the non-native issue is really a non-issue. In a well-designed, succession-based plan, black locust eventually gets shaded out by higher canopy species. Especially if you're coppicing to release nitrogen.

Persimmons, while entirely non-native but entirely not invasive, has a btu that's almost double Alder. While not a coppice species, if you had enough of them, you could have fruit and save enough pruned sticks for a rocket mass heater. One strategy is to divide the functions you're looking for and find the 10 best species for that function that work in your area and then try to make some connections and go heavy on the species that have the most connections, privileging ones that are native, but not eliminating those whose traits you desire.
William

I manage quite a bit of red alder which is the same one in your area. It is valuable as a pioneering nitrogen fixer. It's about the worst choice for firewood. With free good quality wood readily available, I would seldom burn it other than when cooking. Coppiced alder is weak and the trunks can split. If allowed to get large, they could be dangerous.

Black locust has been introduced to many parts of BC and hasn't become a problem. It could be a problem along a river or in an estuary. On regular dry ground, the big native trees force it to exist in the understory.

I agree with Eric. Black locust will last longer as poles. Red ALder will grow faster, is native, can be sold to people making furniture, and can be used to grow mushrooms. Black locust can not be used to grow mushrooms.
John S
PDX OR

Back when I was living in the mountains of Idaho, I just loved cooking with Red Alder. The smoke has a delicious flavor.

William James wrote:
If I was planting black locust, depending on the place it was planted, but if I'm going to be walking or gardening or harvesting near the tree I would want it to be of the thornless variety.

I've never heard of thornless Black Locust - only Honey Locust.

Cj Verde wrote:
I've never heard of thornless Black Locust - only Honey Locust.

Honey locust has thorness cultivars. An example is the Sunburst honey locust is Gleditsia triacanthos var. inermis 'Suncole.' But I think there are more varieties (Skyline) with other names and with more or less zero thorns.

Thornless Black Locust exists too, Bessoniana and Inermis are its cultivars, sometimes sold as "Umbraculifera"
http://www.treehelp.com/black-locust/


William

I'd be looking to plant something with a secondary yield... you want an n-fixing, firewood producing tree... well why not look at one of the cultivated thornless honeylocusts that have been bred for pod production?

I agree Michael but there is another yield you can get from BL - fodder for livestock. Good for all except maybe horses. My free ranging sheep went AWOL for almost 3 weeks and now I see at least 25 baby trees that must have had their tops eaten. I think these trees are suckers coming off the roots. The sheep are back but wont have access to that spot anymore.

I think I've read that Honey Locust, although an attractive tree, produces no or almost no nitrogen fixation, so it doesn't really do double duty.
John S
PDX OR

New research says it does but I can't remember the source, sorry. The Permaculture Orchard DVD definitely uses it as an N-Fixer. Wikipedia discusses both side of the issue.