Boxelder Trees - What do they tell us?

I've been an armchair quarterback in the whole permaculture thing for the past 3 years through Paul's work and Jack Spirko's. I now finally have a piece of land that has a huge yard a little wooded area, a humble little house toward the front. It's a long rectangle running East and West in town with neighbors on the north and south and a wooded area/pond in the east at the end of the yard. I'm in East Central Minnesota. I can't wait to start to apply a little of the permaculture knowledge I've accumulated over the past few years.

All areas with trees are infiltrated with Boxelder Trees. I know that we're supposed to learn from what happens naturally and work with nature, so here are my questions.

1. What does the existence of boxelder tell us? What is it about my land and the properties around it that makes boxelder happy?
2. Is there any practical use for this species besides making bonfires?
3. Are there any more useful permaculture species that would thrive in the same places that boxelders thrive?

Any ideas would be greatly appreciated.

Generally, they are a sign of heavy, wet soil, and a high water table. Makes sense with the nearby pond.

They make great maple syrup, better and richer than Sugar Maple in my opinion, though the yield is lower. They also produce a huge amount of edible seeds that get gobbled up quickly by deer and rodents, and the leaves / inner bark are both edible as well (surprisingly mild but definitely not a first choice).

They're crappy firewood, but are an excellent candidate for hugelkultur, and among the best woods for friction fire sets, if you're into that sorta thing. I have a few of them around my place, and find they attract a lot of insectivorous birds, due to the sap and interesting bark texture. While they grow fairly tall and produce a lot of mass, the shade is rather dappled, so many things still grow well under and around them that otherwise wouldn't with other maples. In our case, they host a naturally occurring guild of Motherwort, Chickweed, Poke, and Marshmallow. Around the drip line we've added Stinging Nettle, along with Alfalfa, Licorice, and a few other plants with DEEP root systems to break up the heavy soil and promote drainage. So far so good.

If you plan to remove them, I would do so a little at a time. They hold a lot of water and do a great job of keeping the topsoil in place - you may find it alters the water table quite a bit if done too quickly. Useful replacements under those conditions could include Black Locust, Alder, and Pin Oak.

-ian

I have 10 acres of wooded hillside above my house, extending along a wooded creek that parallels the yard, with quite a few boxelders. The boxelders only seem to grow in edge habitat here on my place; more than 30' into the woods the trees all seem to be cottonwoods, tulip poplars, and sycamores. The creek isn't very big, and is bordered by yard on either side, so the woodsy area is narrow and open. They're a quick-growing, brittle-wooded, quick to die and rot species. In nature it would be a useful species for rebuilding a devastated area--if a particularly fire were to sweep through and take out the adult trees in an area, the boxelders sprouting from seed afterward would re-establish quickly, stabilizing the soil, providing nesting areas for birds (who would reseed the area with other species through their droppings). In my yard I view it as a useful accumulator--the roots mine nutrients that are returned to the top layer of the soil through dropped leaves and twigs, the seeds are food for rodentia and birds that fertilize the wooded areas with droppings, and when the trees drop branches or fall over completely, the quick-rotting wood is useful for hugelkulture.

Welcome to permies, Jake, Ian and Kitty. Two great ,informative answers!
Ian I had no idea we could get syrup from boxelders. And are the seeds edible for us too?
Jake , use any dead trees for hugels.

These are great responses so far. Ian, thanks for the encourage to try out the syrup, I was told it made poor syrup. You sound more informed by real experience than the person who told me it made bad syrup.

How do you go about eating the seeds, leaves and inner bark? I'm curious to hear more.

I love the idea of developing a guild that compliments this ever present species.

Kitty and Wyomiles, I'm most definitely using these for small hugul mounds. I started some in the fall on contour in the far back yard, and there is an abundant supply of dead material. There's a lot of it that's down in the woods, it seems they are constantly losing dead branches, along with the other types of trees in my yard.

More about eating maples! http://www.eattheweeds.com/maples-how-sweet-it-is-2/

The syrup is fantastic. While the sap isn't as sugary straight from the tree as that of a Sugar maple (which just means you have to collect slightly more of it),
I find the end product is slightly richer and more maple-ey than Acer saccharum (Sugar) or any other maples that I've tried. Many indigenous folks preferred it for this reason. I suspect that this might also indicate a greater concentration of the health benefiting compounds found in standard maple syrup.

Maple seeds in general are edible and tasty if cooked. Just boil em up, add butter & salt, and enjoy.

The inner bark (cambium) can be eaten cooked or raw, though it's not very nice to the tree or palatable to us. IMO, the best way to consume the cambium of any edible tree is cooked in stew, or dried and pounded into flour, then mixed with other flours to the desired texture and flavor. They tend to combine well with flour made from cattail corms & pollen, acorn, hazelnut, or wheat if you're in need of a gluten fix

-ian

I love permies! Learn so much every day!

Jake,

Great question. Just to throw my two cents in... also to agree with much of what was said already... when one person says something, it may sound good, but when others say the same thing, it sinks in

Acer negundo (Boxelder)
- Common tree east of the Rockies
- Likes wet soil, so if you have a lot of them... maybe you are in a flood plain? maybe you have a low water table? maybe you are where a river or stream used to run? maybe your wood lot is where a pond used to be? I would seriously consider running some contour lines on your property... I wouldn't be surprised if your wood lot is in a low spot.
- In the Maple family, so yes, it has sap that cam be made into syrup. I agree with Ian, the sap has less sugar content, so it takes more sap to produce the same sweetness of syrup than a Sugar Maple; however, with more concentration comes more flavor. Also, you can just use the sap as a drink in its own right... a lightly sweet beverage.
- Wood is soft, light, and weak. Not good for construction, but not too bad for cheap, short-lived applications... like boxes (hence the name!)
- Since the wood is weak, it will not hold up well in strong wind storms or ice storms (you're in MN!)
- Bonfires are an okay use, but boxelder is really not a great firewood.
- The tree produces seeds that birds and squirrels like; deer will eat the browse (new growth of young sprouted plants/trees)
- In the Great Plains and other farming communities, Boxelders are great cover plants (trees) in shelterbelts for deer and cattle

It sounds like you don't have a lot of land... if you did, I would say keep them and let them be part of your Zone 4/5. But you don't have acres upon acres... so...

1) I would chop them down and use them to make small hugelkultur beds (real hugelkultur beds are massive... 6-10 feet high) on contour... under a swale on contour in your yard if this is possible.
2) I would consider keeping a couple of the larger trees for wildlife attraction. The birds will eat the insects that love the deep furrowed bark, and the birds will eat the seeds, and some of the birds will fly into your garden and eat insects, and more birds will attract other wildlife and increase your biodiversity in general. Also, the trees will attract squirrels. This again increases biodiversity, and this might not be too popular, but squirrels are good food and easily taken with a pellet gun or a .22
3) The few large trees that you keep will produce a large amount of biomass each year in leaves. Great for compost. Great for deep mulch in a chicken run.
4) The few large trees can produce quite a bit of sap to make a little syrup each year (check out TapMyTrees.com)
5) Consider trimming back the tree and growing something like Hardy Kiwi up some of the trees
6) The branches that fall each year from snow and ice can be chopped up and used in compost or as kindling - since it burns fast
7) Getting rid of these trees will open up the canopy and let more light it. This will allow you to maybe create a bit more of a patchy meadow effect instead of a wood lot. Then you can plant some more useful trees like dwarf fruits or nuts in their place. This will also allow you to plant some more herbaceous plants that desire a bit more sun - brambles and gooseberries and currents considering your location.
8. Getting rid of these trees will reduce the chance that the next ice storm will not knock the tree over and onto your house or fence or newly planted trees.

Just some thoughts off the top of my head.

Hope that helps! Have fun!
Doc K

i have been gathering boxelder saplings and transplanting them ONTO my property, they are wonderful for wildlife. No way I'd chop them down...unless you need the room for something that produces people food.

they also are a huge beautiful tree although yes they can sustain damage from wind and storms..also..they WILL coppice quite well when not too large as they grow back from the stumps fairly readily

I'm really excited to have learned so much more about one of my favorite trees, thanks you guys I had a favorite one once. It was in front of my store front, and it was as mentioned a nice dappled light under the tree and we had many flowerpots arraigned all over the front of the building. because it was trimmed ..I grew many sun-lovers under that tree. I also was told by the landlord that the trees have self nitrogenating roots. It also had humming bird nests up high. It has since fallen down.. luckily it did not crush anything in the alley due to an iron sculpture which held it up, one of life little miracles. It split down the center one half still standing, they took it all away. I still think the sky looks naked without it there. My two cents is.... I think you lucked out on trees and advice...congratulations on your new place!

I really like this question, and found the answers very informative and useful. Is there any sort of database that answers this questions concerning different types of trees? I'd be very interested in reading it if such a thing exists.

Ethan, I think you'd be very impressed with the database that is being developed at TCPermaculture.com by Doc K. he's developing detailed informational pages about any species that peaks his interest. Based on the detail of his reply below, I'd guess you'll see an article about Boxelder on his site soon.

Again, many thanks to all of you for your amazing answers to my humble questions. Now I need to find some taps for my my boxelder trees and start saving milk jugs!

A lot of others have posted good information, I'd add a couple of things. I've lived in a number of places where boxelders grow, but there are more in southern Minnesota than anywhere else I've seen. Where I live now in southern Missouri, they are around, not rare, but not what I'd call abundant either. They like moisture, and tolerate poorly drained soil and areas with a high water table, but don't necessarily need all of the above. In MO they're mostly in river valleys, where the soil is often loose and deep, with plenty of groundwater for them but not necessarily a heavy soil. They are early-successional and grow often in disturbed areas, near buildings and the edge of fields. I'm pretty sure there are a lot more of them around than there were pre-European settlement, as they are encouraged by our disturbance patterns. In my part of MO where most of the upland soils are too drought for them, I've seen them move in where runoff from buildings and other human-made impervious surfaces flows their way and makes the area wetter. They also seem to have a particular fondness for being near railroad tracks. I sometimes see young boxelders on drier sites, but they tend not to persist or live very long if they don't have enough moisture.

I am glad for the existence of boxelders, they are one of those healers of disturbed land that get dismissed as "weed trees" by so many. However, since it seems you have a small area to work with, you probably need to cut some of them down to make room for other things. I'd definitely remove any that are near structures, as they are brittle and break easily in storms. Walnuts do well in many of the same sites as boxelders, in fact I often see black walnuts and boxelders growing on the same site in areas within the native range of both species, although walnut is not as tolerant of poor drainage as boxelder.

One thing to know if you have Japanese Honeysuckle in amongst your trees--because it wraps around the trunk, fast-growing trees can be badly damaged in their early growth by them. Many of the boxelders along my creek have such damage and are dying back--the area was infested with honeysuckle, which is an invasive, non-native weed. I've since torn out most of the honeysuckle (leaving the less-winding/less-damaging native trumpet vine for the hummingbirds).

Rox if the tree still has roots and an above ground stump it likely will grow back..just encourage ONE trunk to grow up into a new tree.

Hi from Oz. I joined urgently to warn about the suggestion of black walnuts. I have pet sheep and one died and another became very ill, nibbling lower leaves of black walnuts. If you have only a small area, the roots carry toxins that effect everything in tomato family, asparagus, etc. They can spread 20 metres, circling a mature tree. The list of plants effected by the roots is long, as well as spuds, sunflowers and aforementioned, I believe lilacs are effected and don't thrive - many more...

As little as 10 % in wood shavings in stables, can cause founder in horses in 48 hours, and there are warnings about horses eating leaves, etc, and that they can cause asthma in horses and humans. at the right time of year.

The green hull is nibbled by the native cockatoos, at my place, possibly as a vermicide, and in careful amounts, though the tree is not a native. In Oz, the problems of black walnut are almost unknown, and I have been warning on animal forums. I found the warnings on American and Canadian gov agriculture sites, after the distress of losing my sheep. Most other walnuts are grafted onto black walnut rootstock, as it is SO successful - now you know why. Also, warnings against using the walnut woodshavings in any small animal cages, as bedding.

I have a few box elders at my place, on red clay that sets like concrete in drought. It is VERY dry here, and I'm on a hill. The box elder is one of the toughest of 'pretty' exotics on dryland farms. I must say, I rather love mine.

One site even advises against using the walnut leaves in compost. Don't ever take a stranger's word, so many odd people about, but please use my warning to investigate.

I might add I was warned off using the letter 'you' as a silly abbreviation. As I was using it as in 'youS as in American, I suggest the problem is not with me.

This deals with some plants that suffer and some that flourish or aren't effected.

http://www.ahs.org/publications/the_american_gardener/11/07/web_special_2.htm

I also have a number of box elder in the area of our land that is a seasonal creek/flood plain. We had a wonderful guy from Missouri's dept. of conservation come to our property and he was extremely knowledgeable and helpful about with identifying plants and trees and what it meant about our soil and whatnot. He suggested cutting all the box elder to make room for the oaks and walnuts and other more "valuable" trees to take their place. I cut a couple small ones in areas we were wanting to clear anyway, and like people have said, the trunks shot out a lot of suckers. Later I learned about tapping the trees for their sap so I thought I'd hold off on cutting them, and then in the fall I started to notice a mushroom that I was unfamiliar with that was growing almost exclusively on the box elder. After lots of research I was 99% sure that it was hypsizygus ulmarius, and I felt sure enough to try a couple. It was incredible! And is now one of my favorite wild mushrooms. Sometimes called the elm oyster since it sorta resembles oysters in taste and will grow on elm trees. Info from MuchroomExpert.com Later I also found an abundance of wood ear, or something similar, growing on the box elder as well, which is also an excellent mushroom.

I eventually found a book that referenced native americans who lived near the Missouri river would tap the trees for the sap and then return in the fall to harvest hypsizygus from the wounds they made. Later that fall, a neighbor of ours hosted a short, 2-day, mushroom log cultivation workshop on their land with Mark Jones from Sharondale Farm in Virginia. In his presentation he mentioned that hypsizygus ulmarius was a mushroom he had just recently figured out how to cultivate and he was very excited about it since he considers is such a choice edible. After the class I told him we had some on our land and took him to see some older specimens that were too high on the tree to harvest, and they were the first ones of that variety that he had seen in the wild.

After all this I was very excited about the box elder and have much respect and appreciation for them.

-WY

Has anyone had problems with box elder beetle infestations as a result of these trees?

Mike Tennyson wrote:Has anyone had problems with box elder beetle infestations as a result of these trees?

maple beetles, love all maples but box elders in particular, they lay their eggs on the trees and eat seeds from that family pretty much exclusively, but seem to really like the box elders in particular(maybe they know something we don't about the seeds nutritional value) . To me, it seems like a built in soil building system, a fast growing, quick living tree that creates a lot of biomass and can grow in pretty much any soil(prefers wet/compact soil however). The beetles eat all those seed and break them down into 'soil'.

I'd use the tree as a mulch crop, it coppices so readily, its amazing. keep taking smaller branches or get a wood chipper and i think it would work amazing in that manner. Some one said it collects nutrients, and it seems to not be such dense wood so it breaks down much faster than most also.

Basically, you typical 'weed'. soil builder, nutrient accumulator(and like most weeds, some edible/medicinal use).

they are great for wildlife and coppice very easily..will grow back from the stump...the reason you have so many is they spread quickly by seeds..and theya re quite nice for a quick cover of shade..but difficult to get rid of if you choose to do that..you'll have to grind out the stump..but you can do that.

we had two really close to our house (pre house fire) and did that to remove them and it wasn't that difficult.

I planted a new baby by my pond.

there is a beautiful hybrid one called flamingo..pink, white, green, like the kiwi leaves in color..gorgeous !

Wanted to add, my mini donkeys preferentially stripped the bark off the boxelder trees in their pasture. It must be delicious (maybe a little sweet?) because they went to a lot of trouble to get to some of them.

I thought we had lots of poison ivy in the woods but it was boxelder seedlings! They look like poison ivy when they first sprout. Where my husband had cleared a walking path the boxelder sprang up in a continuous carpet.

I need to tap mine this winter, that is so cool!

ETA: wild grapes seem to like growing under my boxelder trees.

Also in Minnesota--we are surrounded by box elders and love the wildlife they bring. We do cut down four that were hovering over the house. They had some rot and many ants living inside them and big branches were dropping randomly when our little one was running about underneath! But the forest of elders down the slope seems to stabilize the soil, attractant woodpeckers and small mammals. And we are using the wood that falls for various projects around the yard...

Best, Jenny

Occasionally Box Elder has very pretty wood grain coloring which causes carvers and woodturners to drool. Usually in the butt & upper root areas of a trunk. Here's a prime example by a fellow woodturner:
http://www.aawforum.org/photopost/showphoto.php?photo=2384

and something I turned almost a decade ago:
http://www.aawforum.org/photopost/showphoto.php?photo=673

Another name for the wood is Manitoba Maple.

Hello Ken Grunke! Glad to see a familiar name here from the wood turning world.

I was going to point out that Boxelder (a.k.a. Manitoba Maple in Canada) can sometimes harbor that fantastic pink streaking (from a fungus carried into the wood by the Ambrosia Beetle), and sometimes can form large, benign tumors, or burls, which make fantastic craft, carving, or turning wood. Not related to either Box or Elder trees, but one of the softest of the Maple species that grows in eastern North America.

I find burls often form on larger trees grown on a steep slope (holding back erosion on a stream bank, for example), or when squeezed between rocks, buildings, or fences. When the trees are stressed or irritated, such as growing between rocks that move with the frost, they can produce burls around the roots almost like a big fleshy scab. The wood of Boxelder burl is highly prized by woodworkers of all sorts.

The straight grain wood is also good for carving. Like Basswood, it is soft, and has a fine, even texture, so it carves well. Has an odd smell when green -- especially if not fresh -- but won't transfer bad tastes to food if you carve spoons or salad tongs out of clean, fresh-cut green wood.

Just joined Permies and just getting into this conversation late. Live in the Red River Valley (RRV) outside of Fargo-Mo'head. Have been considering tapping box elder as my Dad does maples in Wisconsin not far from St. Paul, MN. I'm curious about a few things as I'm completely new to tapping.

1) Can you "tap for testing", not for production, outside of the normal tap time of year (spring)? My interest here would be in using a refractometer to rank trees from best to worst in preparation for next spring.

2) Has anyone published or have generalized information on soil type and characteristics and how that impacts sugar content in maple and/or box elder? RRV soils are heavy clay.....have killed off many a fruit tree and then some that were approved for much farther north, but could not handle the heavy clay and high water table.

3) Every heard of "improving" box elder for sugar content by crossing those trees that do the best or producing cutting-clones and planting them closer together so that they might interpollinate? I have no idea if box elders/maples are naturally outcrossing or not.

I realize that box elder is often considered among plants as the pesky possum of the plains and prairies, but I like what others have been saying here about their potential. My spouse loves anything that will thrive here.....and outside of corn, soybeans, and sugarbeets, (which of late has taken over wheat, wheat, and more wheat) that ain't much.

A great site that I've enjoyed reading for several years and am glad to finally be joining.

New to the forums! Hoorah of permies.com and for the permies of the world to unite!

We have a Box Elder tree that is well over 100 years. It is massive! There is potential for many if the large branches to come down upon our house ( our bedroom to be precise). Any suggestions on whether to cut it back, or to remove it completely? Has anyone cut one back and has good re- growth?
Thank you for any input!
-Tiauna

We had to (sadly) take down a beloved, but very sick, Box Elder that had a tree house in it this past fall. I'll be using it for Hugelkultur, kindling, firewood (likely mostly outdoor, as its not high quality for that use), some longer pieces as poles, and a couple of things not yet mentioned:

1. Mushroom production: Oyster and Elm Oyster grow on box elder wood.
2. Coppice for Ramial Woodchips (description below:)

When (inevitably) new shoots come up from the stump, it's said to be a great 'nutrient pump.' Because it has deep roots that mine nutrients from the soil, it works as something you coppice for fruit tree mulch. The technique would be to prune off a long piece of new growth, leaves and all, any time in the season (unless you are trying hard not to kill it - but the likely hood of killing it without working hard at it would be low), then clip it into smaller pieces at the base of a fruit tree. Ramial woodchips, like these, are said to be very good mulch for fruit trees.

Boxelders have a few uses that come to mind from my own experience with them.

The trees do well holding soil together on a hillside with spreading fibrous roots. Spaced evenly, they have done a great job on my property over the last thirty years. They tolerate poor soil, drought, cold and keep on growing.

I really appreciate Boxelder leaves in fall because they drop early and they drop curled up and crunchy. They decompose quickly and don't tend to get picked up by the wind and spread from where they fall. Out of all of the leaves, boxelder is a 10/10 leafmold leaf.

The boxelder canopy is not a perfect canopy. It allows light to come through allowing things to grow underneath the trees. This has been useful for planting slower growing but longer lived trees to eventually succeed the boxelders when they grow too old. This has worked for both oak and ginko trees that were interplanted.

We have an old "Boxelder Bug House" in Logan, UT. The backyard forest has several large Boxelder trees which support a population of Boxelder Bugs (Boisea rubrolineata). In the fall the bugs gather in clusters on the foundation of the south side of the house. As the weather gets cooler, a few of the bugs make their way into the house where they can be found walking around near the windows.
We rent the place to grad students who are made aware of the harmless Boxelder Bugs and that we won't get rid of the trees and we won't poison the bugs. Cheap rent two blocks from Old Main go a long way in making for peaceful coexistence between humans and Boxelder Bugs.

Really useful thread!  And I finally got my maple seeds question answered by reading the whole thing!  And I think I still want to guerilla tap the maple trees behind my apartment, probably at night or else we'll get caught?  And yay in spring I can maybe eat some fresh leaves.

I did see some uses for the actual lumber of the tree being used as turning stock.I am in the kitchen cabinet industry,box elder is a very useful and beautiful wood for cabinetry or other indoor wood projects.It is considered a "soft maple" species which include red maple and water maple,it accepts stains very easily which creates a really deep and rich color.Unfortunately it is soft so it will dent easily if abused so please be gentle with it, but this also makes it easy to machine and sand to create a very nice end product.

Hi Everyone,

Thanks to all contributors for such great info. A couple of people said the seeds are edible. From reading the link to eat the weeds website, it appears the Acer negundo seeds are NOT edible. Seeds of other maples are though

Cheers

I trust Eat the Weeds, but I have eaten a few of the seeds, with no ill effects.
That doesn't mean they are safe but I wouldn't turn them down if I were starving.

I have one that's about 25' feet tall  that I kidnapped from the roadside and planted on a lark.
It has served me well , but now I want to let the sun in to the areas it shades.
I intend to cut it off at about 10' tall, and  hopefully leave enough foliage that it won't die.

I wouldn't plant another, nor do I let the seedlings grow, but that's just because I need the room for other, more useful trees.

Jake Olson wrote:

All areas with trees are infiltrated with Boxelder Trees.  I know that we're supposed to learn from what happens naturally and work with nature, so here are my questions.

1. What does the existence of boxelder tell us?  What is it about my land and the properties around it that makes boxelder happy?
2.  Is there any practical use for this species besides making bonfires?
3.  Are there any more useful permaculture species that would thrive in the same places that boxelders thrive?  

Any ideas would be greatly appreciated.  

How big are your boxelders?

I live in southern Illinois, about a block away from a creek, and also have a teeny tiny stream along the back of my property. I have several baby boxelders scattered randomly, according to my PictureThis app.

I spin yarn on supported spindles, and one of my spindles has a flame boxelder whorl.

As far as the soil goes, "heavy wet soil" is what I have here, based on Iain Adams' reply. I don't know if that's because we have been getting a lot of rain. I've only been here for 2 years, and don't know if this is normal or not. Last year's garlic didn't do well because of the wet conditions.

I'm responding to some very old posts, but this might help future readers. We bought a house with a huge, beautiful boxelder that was probably the same age as the house--about 100 years. It was on the west side, and it gave much needed shade in the afternoon. However, it started dropping huge branches--fortunately they never landed on anything but a bench I'd built.

We had a tree expert come, and he said that boxelders typically have a life-span of 60 years at most, so ours was living on forty years of borrowed time. We hired people to come and remove it. The tree-climber took one look and said, "I'm not climbing that." What the bidder for the company missed is that the tree was totally hollow. They brought in a cherry-picker and got it down successfully. The trunk of the tree was 3 to 4 feet in diameter, and it had maybe six to 8 inches of wood around the perimeter.

In short, I'd be wary of any large boxelders. They're beautiful, but not safe. I'm grateful the branches that fell didn't land on a car or a person. If the tree had blown down, it could have crushed our house and taken out the people inside.

The seeds of Acer negundo contain  hypoglcin A. If a large amount of these seeds are eaten by a horse. It can cause SPM,  or Seasonal Pasture  Myopathy, a neurological disorder. This can be a fatal illnes  although some horses survive. Seeds vary in the amount of hypoglcin A they contain, how many seeds the horse eats while grazing under a box elder varies, and how sensitive each horse is to the chemical  varies.

Hypoglycin A is not known to be toxic to any species except members of the equid family, such as horses, mules, and donkeys ( presumably zebras as well. Lol). It is not toxic to humans, any other livestock,or wildlife.

Eattheweeds.com is mistaken regarding the seeds of Acer negundo being toxic to humans. They are not all that yummy, but certainly are a legit emergency famine food. I am going to plant one in my large chicken run as a component of a self harvesting "food for poultry forest".

Mary Yett, DVM

I really appreciate that explanation!
Do you have any knowledge on feeding the seeds or foliage to rabbits?

I have not seen any data on rabbits eating box elder seeds, but the general veterinarian opinion is that only Equidae are poisoned by them, Box elders are native and prolific in their seed production. Surely many millions of rabbits have eaten their fill of box elder seeds. You don't see dead rabbits littering the ground under box elder trees during their seed drop season. I leave you to draw your own conclusion from that observation.

There are many other plants that are generally non toxic to other species, but horses can be poisoned by them, including black locust bark, alsike clover, wilted red maple leaves, etc. It seems to be a horse thing.

Mary Yett, DVM