Trees, all trees, are wonderful things. But from my insectocentric viewpoint, the red maple, Acer rubrum, stands out as particularly admirable. And now is the season to best appreciate the ecological power of this plant.
While said to be able to grow to 120 feet or more under ideal conditions, red maple is more often encountered as a small to medium-size tree. Its alternative common name, swamp maple, gives a clue to the habitat preference of this tree; it does well in soils that are soggy for at least part of the year. Such soils, dominated by this tree, add up to a prominent natural community type called, aptly, red maple swamp. But if the competition from other species is not too intense, red maples grow just fine in drier settings, if the soil is reasonably fertile and mildly acidic.
Red maple leaves have the classic, lobed maple shape (think of the Canadian national flag), and tend to be a bit smaller than the leaves on most of our other maple species. The bark of young trees, especially, is grayish and often rather smooth, growing browner and rougher as red maples pass into old age. The root system of this tree is spreading but shallow, making red maples vulnerable to wind throw if they are growing in an exposed setting; in windy places like the Vineyard, I expect that red maples that manage to grow above 60 feet or so in height do so only because they are lucky in their location.
The red maple is at its most obvious in early fall. It is one of the earliest of our region’s deciduous trees to begin developing its autumn colors, and it is also one of the prettiest. Red maple leaves senesce to a broad range of intense colors, integrating from a bright yellow all the way to the deep red of a robust Burgundy wine. Given the frequent ability of this tree to dominate large areas of suitable habitat, red maples produce some of the best foliage displays the Eastern U.S. has to offer.
This tree is not as flamboyant in the spring, but it’s still easy to spot, especially early in the season, when few other trees have begun to flower. Red maple flowers, which typically begin to open in late March on the Vineyard, are deep red and plentiful on a healthy tree. By mid-April or so, the buds will all have opened into perfect little flowers, each sporting a prominent crown of tall stamens. A blooming red maple often stands out, subtly but unmissably, among the bare sticks of its later-blooming neighbors.
It is this flowering stage of the plant that, to my mind at least, gives it its greatest value. As implausible as it may sound, early spring is the season of activity for a surprising number of native bees and flies, challenged by but adapted to handling the vagaries of our marine climate at this time of year. Among native plant species, few are blooming in late March and early April to feed these insects or provide them with pollen to provision their nests. But red maple — plentiful, widely distributed, and covered with pollen-rich flowers dripping with nectar — stands ready to help.
On a warm, sunny, early April day, it’s worth finding a red maple in full bloom and looking up into its canopy with a pair of binoculars. Odds are good that you’ll spot an aura of insects darting from flower to flower, foraging on this valuable resource.
It’s a source of some frustration to me, loving as I do both bees and flies, to watch so much activity taking place too high for me to get close to. Given the difficulty of studying insects in tree canopies, even many naturalists don’t fully appreciate the value of red maple as a resource for pollinators. But make no mistake, this tree species is an essential early spring resource for a host of insects.
Given their adaptability, fast growth, generally reasonable size, colorful blooms, and stunning fall foliage, it is no surprise that the red maple is popular as an ornamental. Scores of cultivars have been bred, though I suspect that in many settings, the native wild form would probably do just fine in cultivation. You can see the Acer rubrum deployed as a landscaping plant, or perhaps a landscaping plant used in part because of its ecological value, at many sites around the Island.
Down-Island Cronig’s has a row between the parking lot and State Road; at the Oak Bluffs fire station, a similar line of red maples effectively delineates the property while providing a punch of color and structural grandeur. These and similar examples are, to my naturalist’s mind, strokes of inspired brilliance in landscape design: shapely, attractive trees well-suited to their locations and offering substantial benefits to wildlife.