beech allelopathy

[Jeff Joseph]

     I am wondering if anyone has any information regarding allelopathy in beech leaves, as I have areas of my woodlot that receive adequate sunlight, yet have NO tree seedlings/regeneration to speak of other than beech. There is generally a thick layer of beech leaf litter in these areas. Could the thickness of the litter be enough to starve seeds before their roots are able to reach the mineral soil beneath, or could there possibly a chemical process involved? The areas in question have other mast producing trees nearby (maples, birch, ash, etc.), so there ARE seeds being deposited there in good mast years, and while deer are a problem here, I am specifically referring to small seedlings at ground level, not larger ones that would be a more likely target for browsing. For perspective, in other areas of the same stands, I have spots with literal 'carpets' of tiny maple or birch seedlings, so thick that they seem capable of overcoming the deer pressure through sheer numbers. Thoughts?

[jerry saab]

I have a very similar situation in my woods. I always thought the lack of other species was due to the beech regenerating from root suckers , but had never considered allelopathy as a cause. Could well be.  I suppose a heavy dosing of glyphosate on the cut stumps might result in improvement someday. I cut the heck out of these patches for firewood instead. I play the hand nature dealt.

[Peter Smallidge]

Given the abundance of beech in our northeastern woods, this is a really interesting question.  I did some quick looking and found this title

"Phytotoxicity of American beech leaf leachate to sugar maple seedlings in a greenhouse experiment."  This isn't conclusive (remember science can only fail to reject or fail to accept a hypothesis) and greenhouse studies lack real world biofeedback loops, but it provides  information related to Jeff's observation.  Here is the link for more information on this one study. (article)

[Jeff Joseph]

     Thanks for the link to the study Pete. It certainly does seem to corroborate the prospect of allelopathy in beech leaf litter. While this is only anecdotal, I remember reading years ago in a Rodale publication (about composting I believe) that the author strongly recommended against using beech leaves either in compost or as mulch, as she had found that it severely suppressed the growth of her garden crops.