April 6, 2018
CapitalPress.com
7
UNBEARABLE DAMAGE
Foresters look to protect trees from black bears
By MATTHEW WEAVER
Capital Press
American black bear
For more than two de-
cades, Monika Wood has been
part of an effort to re-establish
trees native to the forests of
northern Idaho.
They
in-
clude western
white
pine
and western
larch, which
are planted for
their resistance
Monika
to fires, insects
Wood
and disease.
“We’re
really trying to restore what
should be here historically,”
said Wood, north zone culturist
for Idaho Panhandle National
Forests.
But Wood and other forest-
ers have to deal with a pest.
A really big pest, one that
can grow to about 600 pounds,
reach 5 to 7 feet tall standing on
its hind legs and has big claws.
It’s the black bear.
Much to the consternation
of foresters, white pine and
western larch are the exact spe-
cies favored by black bears as
they emerge from their winter
hibernation.
Wood has worked at the
Priest Lake ranger station for
23 years, and said bears snack-
ing on the trees has been a con-
sistent problem.
“When they come out of
their den, they want those sug-
ars and it just so happens those
trees are really starting to wake
up, too, so they smell deli-
cious,” Wood said.
Binomial name: Ursus americanus
Bark damage
The bears love to peel bark
off the trees to munch the new-
ly formed sapwood beneath. If
they scrape it all off, it kills the
tree, taking away the xylem and
phloem in the cambium of the
tree, which would otherwise
allow water to move from the
roots up the tree stem, said Ron
Durham, land resource supervi-
sor at the Idaho Department of
Lands office at Priest Lake.
A single bear can strip as
many as 70 trees a day, a USDA
study found.
“Sometimes it’s just one
side,” he said. “Sometimes it’s
not all the way around but still,
that just slows the growth of
the tree down and damages the
wood.”
The damage makes it easier
for insects to infest the wounds,
and for diseases and fungi to
enter the wood, Durham said.
“When you manufacture
that log, if and when the tree
does become harvestable, that
first 8 to 10 feet’s probably go-
ing to be all rotten,” he said.
Site, elevation and snow-
pack level vary, but trees in
Priest Lake typically reach 70
years old.
“At age 35 to 40, we go into
a stand and see that it’s been hit
— we’d normally want to hold
onto that stand another 20 to
30 more years,” Durham said.
“But then damage affects the
growth.”
Once bears hit a particular
area, they know they can re-
turn and cause even more dam-
age. Some areas are hit several
years, Durham said.
The cost of the damage adds
up for the state and federal gov-
ernments and a handful of pri-
vate landowners in the region,
many of whom raise the forests
to supplement their farming or
ranching income.
In 2014, the Department of
Lands estimated financial loss-
es on Priest Lake endowment
lands due to tree mortality from
bears. Five sites were inspected,
and the cost of the bear damage
was $968 to $1,582 per acre.
Wood estimates it costs
about $200 per acre to plant
new trees. Seedlings cost $1 to
$2.
“It’s something we’ve been
struggling with for quite some
time,” said Durham, of the IDL.
However, the damage has
become more costly in the last
10 years, mainly due to bears
damaging younger stands.
Black bears also eat lodge-
pole, cedar and ponderosa pine,
but their favorites are definite-
ly white pine and larch, Wood
said.
“It’s an easy, fast food
source for them, and they don’t
have to work very hard at it,”
Height: 3 feet at the shoulder, 5-7 feet tall standing upright
Weight: 100-600 pounds depending on age, sex and season
Average life span: 15-25 years
Diet: Omnivores, their diet consists mostly of herbaceous plants
and grasses in spring; adding insects, grubs, berries, fish and
small mammals in the summer and fall. Bears will take larger game
such as deer and elk. Although rare, bears have been known to
take livestock.
Known for: A keen sense of smell and curiosity make them skilled
scavengers. Their strength and surprising speed make them
potentially dangerous.
Range: Found throughout Alaska and Canada, American black
bears occur in the Pacific Northwest and California; from the
northern Rocky Mountains to the Southwest and northern Mexico;
the northern Great Lakes; and areas of Northeast, Southeast and
Gulf Coast states where habitat is plentiful.
Idaho Department of Fish and Game
Black bears are damaging beneficial trees in the Priest Lake Basin of Northern Idaho. Foresters are
working to find ways to stop the bears, including barriers and targeted hunting. The bears appear to
have learned the behavior.
she said. “I know it’s been
happening for as long as black
bears have been in the Priest
Lake Basin. It’s just part of na-
ture. I just think the checks and
balances are out of whack a lit-
tle bit, maybe.”
Managers estimate one
black bear per square mile in
the Priest Lake Basin — one
of the highest densities in the
state, Durham said.
The entire 185,000-acre
state forest has damage
throughout, he said.
The biological carrying ca-
pacity is 1.5 to two bears per
square mile, said Kiira Siitari,
environmental staff biologist
with the Idaho Department of
Fish and Game.
‘A new tool’
The behavior appears to be
learned, said Chris Schnepf,
University of Idaho Extension
educator for forestry in Coeur
d’Alene.
“I think it’s just a new tool in
the bear toolbox,” he said. “One
bear figured it out and taught
the cubs, and then those cubs
grow up and teach their cubs.”
Forest stewards hope to find
a way to help the bears unlearn
the behavior.
“Since it’s passed on social-
ly, you hope those bears don’t
get out much,” Schnepf said
with a laugh.
Wood has tried directional
felling of trees to create slash
mats that bears don’t like to
climb through or over — “make
them work a little harder” —
and found limited success.
“The bears sometimes stay
away, but often it just causes
them to go higher in the cano-
py,” Wood said.
Managers also tried leaving
8-inch spacing between trees to
create a bear barrier.
“And that hasn’t worked,”
Wood said. “They go after un-
pruned trees with canopies all
the way down to the bottom.”
The bears may be going
after trees with blister rust
cankers. Trees send sugars to
points of injury to seal off in-
fections, Wood said.
“It’s been a struggle,” she
said.
considering
extending the
hunting sea-
son, which is
currently April
1 to June 15.
No expansion
dates
have Kiira Siitari
been proposed,
Siitari said.
Any season changes would
be subject to public comment
and the approval of the Idaho
Fish and Game Commission.
The earliest that process
could begin is next year, Siitari
said.
About 150 to 200 black
bears are harvested each year.
Because of the grizzly re-
strictions, increasing harvest
quotas may not help foresters
in Priest Lake, Siitari said.
“This is an evolving issue,”
Siitari said.
Durham, with the lands de-
partment, hopes numbers be-
come available in future years
to show whether increased
hunting has helped.
“What do you do? We’ve
been managing an asset for 30
to 40 years, and all of a sud-
den, that asset gets wiped out
by a bunch of bears,” he said.
“We’re working diligently, me-
thodically and thoughtfully try-
ing to resolve (the situation).”
Through good communica-
tion with the game department
and the public, Durham hopes
to help reduce tree mortality
to “a level we can accept,” he
said.
Feed the bears?
Most research indicates the
best option is to feed the bears,
which would be too costly for
resource managers, Wood said.
Black bears are also a prob-
lem in parts of western Ore-
gon and Washington, where
agencies do feed the bears. But
Black bears in Idaho: The Gem State has approximately 30,000
square miles of black bear habitat. Although the exact population is
unknown, their social system limits density to 1.5 to 2 bears per
square mile in the best habitats.
Sources: USDA Forest Service;
National Park Service; Idaho
Dept. of Fish and Game;
Washington Dept. of
Fish and Wildlife
Matthew Weaver and Alan Kenaga/Capital Press
Schnepf, with UI Extension,
said that can be controversial.
“One is the whole issue of
feeding wildlife — there’s a
number of issues associated
with that,” he said. “The other
is that you’re giving these bears
food at a time when they’re
most limited. Do you end up
growing more bears as a re-
sult of that and just making the
problem even worse?”
Applying some sort of bitter
chemical to the tree also isn’t
feasible. It would be a huge
cost, Wood said, and the U.S.
Forest Service doesn’t have the
necessary work force.
Wood is open to sugges-
tions. She’d welcome a re-
searcher to help her figure
something out, she said.
“I have had nobody give
me a real solid answer,” she
said.
“I am not a wildlife biol-
ogist, I do not know bear be-
havior. I know trees.”
Targeted hunting
To help protect older trees,
foresters are directing hunt-
ers to specific areas where the
bears are targeting trees that are
30 to 40 years old, particularly
white pine stands, said Siitari,
the biologist for the game de-
partment.
“We’re a little limited on re-
action time,” she said. “A lot of
times when you go out and see
the damage, it’s years old. So
that’s a big frustration.”
Black bears are managed
as a big game species. In other
parts of Idaho, dogs and hunt-
ing over bait may be used. But
because the grizzly bears that
are also in the area are federal-
ly protected as an endangered
species, dogs and bait aren’t
allowed in most of northern
Idaho.
The Priest Lake area is in
grizzly bear country, which
limits black bear management
options, Siitari said.
The cause of the damage
appears to be limited to black
bears, Schnepf said.
The game department is
14-1/102