Blackgum goes by many other names: you may know it as pepperidge, tupelo, black
tupelo, or sourgum. Why it is called a gum tree is something of a puzzle. Writer
However inappropriate, the name has not only stuck but has spread. The trees
are so often hollow that they were used by beekeepers in the past as beehives.
Hollow blackgum logs with boards nailed on top and filled with bees were called
“bee gums” in the south, a name that has since come to mean any kind of beehive.
Coincidentally, the tree’s flowers are loved by bees, and the honey, usually called
tupelo honey, is prized. Because so many blackgums have cozy rotten interiors, it is
ranked as a desirable den tree.
Nyssa sylvatica is a southern species that migrated north about 5,000 years ago
when the climate was momentarily – in geological terms – warmer than it is now, and
for a while blackgums grew throughout New England. When temperatures dropped,
In a profile of blackgum by Marc Abrams, a forest ecologist at Penn State,
this tree is described as a “consummate subordinate,” a description that first
made me think of a butler in Victorian times. But upon reflection, I’ve come
to appreciate that blackgum is more Zen than Victorian. Within its large range, the
tree can and does grow everywhere, at high elevations or in bottomlands, and is not
discouraged by flood or drought. It’s shade tolerant and late successional but will also
colonize neglected fields, mine spoils, and burned areas. It can grow vegetatively from
stump sprouts or root sprouts, and it is fire-resistant. Few other tree species can list
shade tolerance, drought tolerance, flood tolerance, and fire resistance on their CVs.
And did I mention resistance to windthrow?
All these features would seem to describe a species poised to take over the forest in
the blink of an eye, but instead blackgum appears to be content to play a truly minor
role, usually accounting for one to two percent of the trees in the canopy throughout
most of its range. By studying pollen in bogs and lake sediment, paleoecologists have
determined that blackgum has existed at about this same level for thousands of years,
with hardly any variation. And analysis of witness trees – trees noted by surveyors at
the beginning of European settlement – tells the same tale: just as it is today, blackgum
was widespread and widely scattered.
For all its strengths, blackgum has one notable weakness: it is very slow growing.
It grows best on nutrient-rich sites, but in these spots it rarely can compete with other
tree species. Unfazed by hardship, blackgum succeeds more often on nutrient-poor,
wet, low-pH soils, especially in the northern part of its range.
Story by Virginia Barlow
Illustrations by Adelaide Tyrol