Drummond Red Maples, Acer rubrum var. drummondii: The Color of Winter.

Thursday, March 12, 2015

Red Maple, Acer rubrum, is a native species that has crossed the line and become one of the most popular trees chosen for yards.  Their horticultural advantages are that they are fast growing and are deciduous, so the leaves give shade on hot summer days, yet allow warming sunlight through during cool winter periods.  Other wonderful features include their winter/early spring red flowers and buds, followed by showy red samaras, their winged “helicopter” seeds.  In fall, they are again showy when their leaves turn brilliant red to yellow, sometimes even orange, before they fall.  These make this species a much loved yard tree in the Greater New Orleans area.
Red Maple is arguably the most widely naturally distributed tree species in eastern North America, and this is due largely to it being a generalist – a very adaptable species.  It has many, many values in nature and beyond.  Many forms of wildlife feed and live on it, and hole-nesters love its cavities (the holes are called phytotelms).  Humans have discovered a wide array of uses for Red Maple, ranging from lumber to pulp to veneers to firewood, and much more.
Before we characterize the species, let’s visit the taxonomy of Red Maples.  When naturalists gather and Red Maples are encountered, someone will invariably mention Drummond’s Red Maple, Acer rubrum var. drummondii, and someone else will say that the varieties (including Common Red Maple, A. r. var rubrum and Trident Red Maple, A. r. var. trilobum) are no longer taxonomically recognized.  In fact, they are valid, and being “varieties” they are not burdened with the reproductive requirements of species and subspecies.  In fact, all three occur in Louisiana, being found in the same regions but arguably separated by habitats.
We will focus on Drummond’s Red Maple, as it prefers wet areas (swamps) and is the one we encounter most often.
Drummond’s Red Maple has a leathery upper surface on its leaves, and a lighter lower surface.  This is evident when looking from the ground into a tree at night.  It differs from the other varieties by being pubescent (“hairy”) on the silvery lower surface of its leaves.  Leaves are opposite and have 3-5 relatively shallow lobes, with irregularly tooth margins.  Petioles are normally red
Flowers appear in winter and are unisexual, with female flowers being red and male are red and yellow.  They tend to occupy different trees, but not always, because some trees have both male and female flowers present.
As mentioned above, the seeds are samaras, ranging in color from bright red to maroon, and make the tree very showy when laden with a large crop.  It is a thrill to be in the forest on a windy day when the samaras are falling.  They typically twirl about everywhere as they make their way to a potential germinating spot.
One of the thrills of driving down our highways in early spring is the normally continuous splashes of red caused by Red Maples being the predominant showy red vegetation.

One of the striking characteristics of Drummond Red Maples is the contrast between the color and texture of the upper leaf surface and the paler lower surface, as viewed here at night. Photo by Bob Thomas. Flowers on Drummond Red Maple appear in December. Photo by Bob Thomas. 
Red maple seeds, samaras, are the brilliant red colors we see in trees before they leaf out in mid-spring. Photo by Bob Thomas. Red maple leaves have the characteristic maple leaf shape and red petioles.  The upper surface of their leaves are rich green and somewhat leathery.  Photo by Bob Thomas.
A drive down a highway in late winter/early spring reveals the showiest of the period trees - reds are Drummond Red Maple, and yellow-greens are Black Willow. Photo by Bob Thomas

The bark of younger trees is rather smooth.  Photo by Bob Thomas.