Like hemlock, it is so shade tolerant that it can survive in the understory for 100 years, waiting for a lucky break, and, when
given the opportunity, can then grow into the canopy.
But after being released, it’s still a slowpoke. When
chestnut blight opened the canopy over a large part of
the eastern forest, blackgum mostly lost out to faster
growing red maples and birches.
Possibly because of its slow growth – like that
of the even older bristlecone pines – blackgums
commonly live for hundreds of years; remarkably,
given the tendency of its wood to decay, this species
is one of the longest-lived hardwoods in the world,
certainly the oldest in the eastern forests of North
America. To date, a New Hampshire swamp dweller
holds the record at more than 679 years old. This longevity attests to blackgum’s ability
to survive hurricanes and ice storms better than many other tree species.
Blackgum is rarely severely affected by insects, perhaps because it keeps such a low
profile. The wood is not held in high esteem commercially, another factor that’s helped
some blackgums survive for hundreds of years. The wood – composed of tough,
interwoven fibers – is difficult to split and prone to warp, but very tough. In the past,
it was used for items that get rough treatment, such as rollers for cables and factory
floors, docks, and scaffolding.
The nutritious fruits of black gum are food for bears, foxes, and over 30 bird species,
including ruffed grouse, wild turkey, wood duck, robin, pileated woodpecker,
mockingbird, brown thrasher, thrushes, flicker, bluebird, purple finch, and crow.
Young twigs and leaves are eaten by deer but they are less popular as they age. Beavers
eat the bark, sometimes to excess, which may be nice for the beavers but is not good
for a species of tree that is already scarce.
Blackgums are picturesque wherever they grow, but the ancient examples in New
England are truly beautiful. Wild, sinewy branches droop from the twisted main
trunks, which lean and wobble toward the light. The bark is a work of art, grading
from deeply fissured on the undersides of leaning trees to almost flat on the upper
surfaces. It is broken into thick, irregular ridges that are checked across into short,
often hexagonal, segments. Fall color is especially appealing: a single branch may have
a mix of yellow, orange, red, and purple leaves.
Though there is much to be said for the tree as an ornamental, nurseries seldom
supply blackgum because its long taproot makes it difficult to transplant and it is
reliable only as far north as Zone 5.
Vermont’s best known blackgum swamp is in Vernon and is worth a visit. The trees
are within an easy walk on a well-marked trail in a 450-acre forest owned by the town.
Happily, the species still thrives there: you’ll see young trees and saplings in the understory. www.mapmyhike.com/us/bernardston-ma/black-gum-swamp-route-129211287