52 Nebraskaland • May 2025
MIXED BAG
Old Wolf Oak at Ponca State Park,
one of Nebraska's oldest trees, has died.
It was a bur oak living more than 380
years and had become an often-visited
woodland destination for parkgoers.
But it's not the only oak to die this year
from stresses from natural causes.
Visit state parks along Nebraska's
eastern edge, and you'll fi nd large
areas of mature trees that are dead or
in decline. While trees are resilient and
rarely succumb to a single stressor,
Nebraska Game and Parks
and its partners identifi ed
multiple ones leading to
massive die-off s among the
region's deciduous trees.
The plight they face is
immense, but so is the plan to save as
many trees as possible and embrace
renewed landscapes going forward.
The Role of Drought
The past two years have seen
extreme drought conditions across
Nebraska. While native species like
the bur oak are drought-tolerant,
they do have their limits. Prolonged
drought causes dieback in the canopy
and root systems, weakening the tree's
defenses. This creates an opening for
pests and pathogens. When the tree's
ability to compartmentalize decay
or produce biochemical defenses
declines, it becomes more vulnerable
to infection.
Bur Oak Blight and the Two-
Lined Chestnut Borer
Before the drought, Nebraska Game
and Parks Commission staff had
already been monitoring and, where
possible, treating bur oaks for bur
oak blight (Tubakia iowensis). While
this disease is unlikely to kill a tree,
it weakens it, allowing other pests,
like the two-lined chestnut borer, to
invade. Bur oak blight primarily aff ects
a subspecies of bur oak, Quercus
macrocarpa var. oliformis, which
is found in upland areas, hilltops,
ridges and southwest-facing slopes
— regions that have been especially
stressed by the drought.
WHAT'S HAPPENING TO OUR OAKS?
By Rich Wehmeyer, Game and Parks Horticulturist
Photographed two years ago in 2022, Ponca State Park's historic Old Wolf Oak is
now dead. This bur oak was aged and found to be a sapling in 1644, making it one
of the oldest of Nebraska's trees. ERIC FOWLER, NEBRASKALAND
Two-lined
Chestnut
Borer (Agrilus
bilineatus). PHOTO
COURTESY OF JENN FORMAN
ORTH
