Right now the forest is alive with the “beads on a string” whistling of Cedar Waxwings. I wanted to include a pic of what they’re doing – gorging on mulberries, but mostly it’s a way-high-in-the canopy sort of party. This social, frugivorous (fruit eating) bird is here because in some parts of our forest, every tenth tree is a mulberry. Desirable as these mulberries are to birds, most of them are not the native Red Mulberry, Morus rubra.
Chances are you don’t know the Red Mulberry, since it isn’t the weedy tree that grows along sunny backyard edges and fence rows. Growing up I thought that mulberries were just an insipid little fruit that birds pooped all over the car; too flavorless for human tastes. Like most people, I had encountered only Morus alba, or White Mulberry (introduced in the early 1800’s in hope of starting an American silk industry https://connecticuthistory.org/connecticuts-mulberry-craze/ ). This is also the mulberry that inhabits our urban preserve; its prolific fruits cause an avian feeding frenzy every spring. They literally rain down from the canopy when the wind blows.
I might never have noticed the low-key Red Mulberry if it hadn’t been for one tree; at the edge of the woods behind the LNC stands a much-branched mulberry tree, bent over by years of bearing the prodigious weight of thousands of big juicy berries. They’re ripening now, and I’ll say without reservation, these are the best wild berries I’ve eaten. I can’t walk by without snacking on them, and giving a few to the captive Box turtles in their pen.
This tree appears to be a native Red Mulberry by the look of the bark, large size of the leaves, and its graceful arching form. However, I’ve never seen berries like these on any Red Mulberry in the forest. And though I’m not a trained botanist, I noticed an important discrepancy – the leaves of Red Mulberry should be rough above and hairy below, but this tree’s leaves are smooth and hairless. A nice link to ID mulberries: https://www.extension.purdue.edu/extmedia/fnr/fnr_237.pdf
It’s very likely my favorite mulberry tree is a hybrid, possibly even a named variety like “Illinois Everbearing”. A link to help ID mulberries: https://www.extension.purdue.edu/extmedia/fnr/fnr_237.pdf
So what gives here? It’s the “Asian Connection” again; if you’re a long time reader you may remember that our Eastern forests share a great many genera with Asia. In fact, more than any other two disjunct regions on earth. See blog posts: 8/29 The Global Forest and Say Goodbye, Again feb.25
Quoting from a research study you may or may not want to read: “Like many North America – East Asian disjunct taxa (Wen 1999), Red and White mulberry are only weakly genetically differentiated (Awasthi et al. 2004) and highly interfertile.” In regular English this means the two mulberries are closely related and hybridize easily. https://besjournals.onlinelibrary.wiley.com/doi/full/10.1111/j.1365-2745.2006.01152.x
And as is the case with many Asian introductions, the White Mulberry has gotten the upper hand. This is due to several factors, but primarily modern land use practices which favor sun-loving, weedy Morus alba. It also thrives in disturbed open forests like Beargrass Creek SNP. And the uncommon, habitat picky Morus rubra is becoming a victim of “genetic swamping” (for once, a scientific term that easy to understand).
In the Northeast and Canada, Red Mulberry is an endangered species with recovery plans to ensure its continued survival there. But, as with the USFW Service’s Spotted Owl recovery plan that involves killing Barred Owls, the chances of success are low. The “dominant species” horse is already out of the gate, and there’s no putting it back. Or rather, it will have to be put back over and over again as long as government money is available. Much like the situation we’re in with invasive plants here at Beargrass Creek SNP.
Though Red Mulberry is a really beautiful understory tree, its low viability in this forest means White Mulberry will continue to dominate. Removing White Mulberry, as some land managers do, seems a losing proposition considering how many are already here – from small trees to huge multi-trunked ones with spreading canopies. No doubt its berries are a boon to Box turtles and other animals besides birds. A more realistic plan is to plant Red Mulberry extensively in the preserve to ensure its continued presence.
But “hybrid vigor” is a well-known horticultural phenomenon that obviously applies to mulberries. Remembering the taste of the berries from my favorite tree, perhaps I should bet on the hybrid!