May 2025 • Nebraskaland 53
The Emergence of Hypoxylon
Canker
A new threat, hypoxylon canker
(Biscogniauxia atropunctata) has also
emerged among drought-stricken
trees. This fungus is normally
benign, found on the bark of many
tree species. But with tree defenses
already compromised, it has invaded
the vascular systems of many species.
Hypoxylon canker feeds on the
sapwood, cutting off the tree's ability
to transport water and nutrients. As
the fungus spreads, it causes the bark
to slough off , revealing a grey-white
fungal mat beneath, which produces
spores that can infect other nearby
trees.
Once hypoxylon canker enters the
vascular tissue, the tree is doomed.
This disease is not species-specifi c;
it has also been found on elms and
hackberries in the same woodlands.
Unfortunately, no treatments are
currently available to eradicate the
fungus.
Embracing Change
Though discouraging, Game and
Parks sees this as an opportunity
for ecological renewal. The loss of
trees represents a natural reset of the
ecosystem, allowing the reimagination
of management strategies for these
areas that have remained unchanged
for so long.
After consulting with experts from
states facing similar challenges,
Game and Parks has developed a
comprehensive response plan that
includes the immediate removal and
destruction of infected trees and limbs.
To prevent the spread of infection,
infected material must be destroyed
on-site without further stressing the
surrounding still-healthy trees.
Additional focus will be needed
on controlling the spread of invasive
species and taking advantage of
the newly exposed areas of land to
encourage native vegetation to grow.
These eff orts will include testing
diff erent management techniques —
including periodic prescribed burns
— to ensure a resilient, sustainable
landscape in the future.
Long-Term Vision
Land managers, including Game and
Parks, must approach this challenge
with a blend of science and creativity.
The problem cannot be eradicated
swiftly, and responses will aff ect the
broader ecosystem moving forward.
Game and Parks is committed to using
this setback in our deciduous forests
as an opportunity for growth, both
in land management practices and
in the interactions with the public
witnessing these changes fi rsthand
during their ventures among the trees.
Bur oak (Quercus macrocarpa) native species range in Nebraska. Source: U.S. Geological Survey. MAP ARTWORK BY TIM REIGERT, NEBRASKALAND
An example of advanced hypoxylon
canker on a tree.
PHOTO COURTESY OF HUGH DARLINGTON
