In the month since I began following the large, triple-trunked red maple (Acer rubrum) tree that grows beside my driveway, it has fully leafed out and has been producing seeds. As Bernd Heinrich has noted, the winged seeds (called samaras) of maple trees, are a marvel of design. They package the seed with some nutrients to give it a good start in life, but they can also fly away from the shadow of the parent tree. For more than a week now, I’ve been watching red maple samaras twirl down out of the trees like tiny helicopters. Sometimes a breeze gives them forward momentum. Occasionally, one catches an updraft and rises away from the ground for a few seconds before resuming its decent.
Most maple trees that grow in Maine produce their seeds in late summer and fall; only the red maple and the silver maple (Acer saccharinum) produce fruit in spring. The USDA Red Maple Plant Fact Sheet tells me that the “red maple has the smallest winged seeds (samaras) of all native maples, about 5/8-3/4 inches long.” The associated USDA plant guide tells me that red maples are prodigious seed producers and that “up to 95% of viable seeds germinate in the first 10 days.”
I can believe the part about red maples being prodigious seed producers. I seem to have these seeds everywhere; some have even managed to get inside the house. I have never noticed so many before. Am I seeing so many red maple samaras this year just because I’m paying attention to them in a way that I didn’t before? Or have the trees produced an unusually large number of seeds this year?
I seriously doubt, though, that the germination rate here is anywhere near 95%; so many of the seeds land in places not conducive to germination.
|Some land on decks, porches and steps.|
|…others on walkways.|
|Many twirl down onto the gravel driveway.|
|Many also end up in the gutters of my house, where they wash down the drainpipe and get caught on the screen of my rain barrel.|
|Some even get caught in spider webs.|
Even so, there are still plenty of seeds landing in soil where they can germinate and grow, and the USDA tells me that the seedlings can get established in 3-4 months. Most of these seedlings will be in places where I don’t want maple trees growing (e.g., in flower beds), and I will spend time next spring pulling them up.
One thing that puzzled me about all the samaras lying around on my property is that they are single, when all my reference information about Acer rubrum tells me that its samaras are produced in attached pairs. At first, I worried that I had misidentified my tree and that it was actually some other species of maple – but everything else about these samaras fit the red maple description except their being single rather than paired. Then I read in the USDA plant guide that the red maple easily forms varieties and hybridizes with other maples, which made me wonder if I had a distinct variety or hybrid that produces single rather than paired samaras. However, when I was out for my morning walk today, I noticed the much larger samaras of silver maples in the road by a stream where they grow – and they were all singles too! This leads me to believe that the single samaras are not a species characteristic, but an environmental effect. Perhaps our unusually dry weather as these fruits were being formed caused them to be more brittle and to break apart as they fell from the trees.
This post is linked to Lucy’s tree-following meme at Loose and Leafy. Following an individual tree is providing me with a great opportunity to learn more about trees that have been part of the background of my life for decades.