There are three topics related to red maple in agroforestry systems that have come up in my consulting practice this year, which I think are useful to share about. One is the successful use of red maple poles for commercial production of shiitake mushrooms. A second topic is the use of red maple for commercial production of maple syrup. A third topic which I am still exploring is the relative unsuitability of red maple in silvopasture systems that involve horses. I will address these three topics below.
1. Red maple for shiitake logs
Foresters in Ohio often instruct land managers to cut down the red maples in the mid-story of the woods, with the goal of helping oaks come back. Foresters view these red maples as weeds, because this fast-growing species can grow where the soil is wet or dry (so anywhere), and in full shade as well as full sun. People have thought for the longest time that the wood from these mid-story red maples was not valuable for much, including growing culinary mushrooms on. It turns out, it is! According to a SARE-funded research project (link in comments), red maple is a potentially viable substrate for shiitake cultivation on logs. But, you have to follow some different guidelines than you might be used to, from inoculating the logs from other tree species. Here are guidelines that their research uncovered:
-larger diameter, coarser-barked logs are more productive than smaller diameter, smooth-barked logs. The diameter at the short end of the log should be at least 5″.
-while normally you cut a log and let it rest for 2 weeks before inoculation, that’s not sufficient for optimal shiitake colonization and subsequent fruiting success. Logs that were rested greater than 14 weeks prior to inoculation were significantly more successful and produced higher yields of mushrooms.
-the logs cut in March “when the sap was flowing” produced by far the most mushrooms. This was in Wisconsin. In Ohio, this would be more like February- talk to your friends who are maple sugaring I guess, and get out there and do Timber Stand Improvement (TSI) while they are near their sugar shacks. This coming season (late winter 2024), if you did a week of TSI February 11-17, waiting 14 weeks would mean inoculating the week of May 19-25, or after.
-the longer wait period meant that other fungi could get in there, so taking steps to decrease the incidence of that is helpful
-the “Night Velvet” strain of shiitake spawn produced larger mushrooms, which were more valuable to the restaurants that were purchasing the mushrooms.
While taking these caveats into consideration, Field and Forest says that red maple logs are capable of producing yields comparable to other wood species commonly used in commercial cultivation of shiitake such as Sugar Maple and Oak species. Though the logs won’t last as long as oak logs, they fruit sooner, and are less expensive to buy ($2 rather than $3 per log, 2016 prices).
More information available here: https://projects.sare.org/sare_project/fnc15-1021/
2. Maple syrup as a commercial NTFP from red maple
Xinyuan Shi, a colleague who currently does agroforestry technical assistance for Savanna Institute, out of Indiana, said something surprising to me the other day. “Apparently, red maple has a lower sugar content than sugar, but it produces more sap, so you actually end up with a higher syrup yield if you have the patience to evaporate it down. If you have RO (reverse osmosis) tech, it almost makes no difference. I learned this from Cornell Maple. They’ve got plenty of reds in their woods and they’re tapping them all in their vacuum system”. I had heard people say that red maple can make syrup, but I had always dismissed this possibility because of how little sugar is in the sap. However, between Xinyuan’s comments, and follow-up comments from Joey Aloi at Future Generations University in West Virginia, I am coming around to the idea that this “trash tree” might have serious utility for producing sweeteners.
I can imagine many forested sites where despite my bias towards conducting cull-tree removal, and mid-story removal, of red maple to support hard mast species (oaks, hickories and maybe chestnuts someday), there are plenty of stands where if you removed all canopy-dominant red maples, the stand would be under-stocked. So I can see red maple syrup production being integrated into a diversity of different stand types on the western and central portions of the Allegheny Plateau.
The Out of the Woods: Growing Income from your Forest lecture series recently featured Dr. Abby van den Berg, talking about the high utility of red maple in sugaring. You can review that presentation here: https://www.youtube.com/watch?v=mq114jJlF_I
Dr. van den Berg has done research that supports what Xinyuan and Joey had relayed to me. Between this welcome news about the usefulness of red maple for shiitake logs and maple syrup, I have been forced to re-evaluate my assessment of red maple as a “trash tree”, and now view it as my “problematic fave”.
3. Red Maple not ideal for silvopasture systems involving horses
When designing silvopasture (either by addition or removal of trees, and management or establishment of suitable ground flora as livestock forage), red maple is not great. By all means, I invite you to write me and change my mind. Red maple foliage can and does kill horses, just as surely as wild cherry does. This is true for wilted leaves, but not fresh living leaves, from what I can tell.
Here is a from Ohio State University’s extension service to to support my assertion.
By contrast, people have shared with me that horses enjoy eating chestnuts, and that this is a safe food for them.
Paradise Ecological Services 