Refuge Notebook
Peninsula Clarion Article
Dated
13 October 2000
Bark beetles hit west side of Cook Inlet in the 1870-80s
by Ed Berg
In late July 1899 the steamship
Geo. W. Elder of the Harriman Alaska Expedition sailed into lower Cook Inlet,
as far north as Iliamna volcano. The Expedition was financed by railroad magnate
Edward H. Harriman and had recruited some of the top scientific and literary talent
of the day. The goal of the Expedition was to collect as much data as possible
on the natural history of Alaska and its native inhabitants. Nature writers John
Burroughs from New York State and John Muir from California were the grand old
men on board, as was William Dall (as in Dall Sheep) who was renowned as the first
American naturalist to study in Alaska. Also on board was a young photographer
Edward S. Curtis, later to become famous for his striking portraits of American
Indians throughout the West. Mammalogist C. Hart Merriam, head of the U.S. Biological
Survey, was chief of the 25 scientists recruited for the two month trip.
The
Harriman Alaska Expedition collected great quantities of specimens, photos, artifacts,
and interviews, and ultimately published 12 volumes of technical studies. Homer
writer Nancy Lord has recently revisited the Expedition in her delightful book
Green Alaska: Dreams from the Far Coast (1999, Counterpoint), when she and her
fish tendering partner Ken Castner retraced the Expeditions route along
the Alaska Peninsula and the Aleutians.
Nancy Lord points out that when
the Expedition cruised through lower Cook Inlet extensive tracts of dead forest
were noticed. John Muir wrote, On the stratified deposits (Tertiary) on
the west side of Kachemak Bay and Cook Inlet considerable areas were covered with
dead forest, said to have been killed by showers of ashes and cinders
from
Iliamna; some say by ordinary forest fires. Having survived the spruce bark
beetle outbreak of the 1990s, as well as various eruptions of the Cook Inlet
volcanoes, Nancy rightly balks at the suggestion that volcanic ashes and cinders,
or fires in the damp coastal forests, might be the sources of mortality in these
dead forests. She suggests that Expedition naturalists were observing the results
of precisely the same kind of spruce bark beetle outbreak that we know so well
today.
My curiosity was more than piqued when I read this observation and
discussed it with Nancy Lord. At the Kenai Refuge we have spent several field
seasons collecting tree-ring (dendrochronology) evidence of past spruce bark beetle
outbreaks. We have looked at 16 sites from Seldovia to the Swanson River Oilfield,
and east to the Mystery Hills and Cooper Landing. In the northern sites we can
see regional beetle outbreaks in the 1810-20s, 1900-1910s, and 1970s.
The southern sites were heavily hit in the 1870-80s, especially the north
side of Kachemak Bay.
Several years ago we discovered William Langilles
1904 report on the forest conditions on the Kenai Peninsula. (Langille was the
right-hand man in Alaska of Gifford Pinchot, Teddy Roosevelts architect
of the US Forest Service in 1905-06. Langille became supervisor in 1905 of what
today is called the Tongass National Forest.) In his 1904 report Langille described
the standing dead forest with 40-100% mortality between Coal Bay (Homer) and Anchor
Point. In 1994 we studied a clearcut on the west side of Homer in great detail,
cutting more than 500 slabs from stumps. Virtually every slab showed a major growth
spurt (wider rings) in the early 1880s, due to a severe thinning of the
forest canopy which released the survivors from competition. The fact
that Langille described the dead trees as standing ruled out blowdown
by wind as the mortality agent in this stand and left spruce bark beetles as the
most plausible candidate.
The Harriman Expedition report of dead forest
on the west side of Cook Inlet raised the possibility of a second historically
confirmed dead forest. But could we find it? No specific location was reported,
beyond being in the vicinity of Iliamna volcano. Nevertheless, if this was a beetle-kill
event, it was probably a widespread regional event on the west side of the Inlet,
just as it is today, and as it was on the southern Kenai Peninsula side in the
1870-80s and 1990s. Probably any forest from Kamishak Bay to Iliamna
to Redoubt volcano should show evidence of this outbreak.
I decided to
try Polly Creek, north of the Crescent River and Tuxedni Bay. Conversations with
loggers and local setnetters indicated that this area possessed abundant mature
spruce forest with trees old enough to have a good tree-ring record of 19th century
growth. On July 10th Refuge Biotech Doug Fisher, forest ecologist Andy DeVolder
and I flew over to the Polly Creek beach, where we met John Swiss who homesteaded
a setnet site here in 1949. John and his sons Tyler and Jack described their extensive
efforts to clear fire-defensible space around their buildings, because the surrounding
spruce forest was almost 100% beetle-killed. For the next three days we cored
trees with increment borers to sample the tree-rings, collecting 120 cores, with
the oldest dating back to 1696.
Back in our lab at Refuge Headquarters,
Biotechs Candy Godin and Archer Larned set to work measuring the tree-ring widths
in our core samples. When we analyzed all these measurements we could see a general
period of accelerated growth from 1870 to 1890, especially in 1878-1880 when 24%
of the trees initiated a growth release. With almost a quarter of the trees releasing
in this three-year period, we can infer the occurrence of a major thinning of
the forest canopy, i.e., substantial death of large overstory trees. When the
Harriman Expedition in 1899 observed dead forests on the west side of Cook Inlet,
they were presumably observing this mortality, which had peaked 20 years earlier,
just as it had peaked earlier on the Kenai Peninsula side of the Inlet.
Polly
Creek is the only site we have examined on the west side of the Cook Inlet, but
it tends to confirm our view that the present bark beetle outbreak is basically
a replay of the of the 1870-80s outbreak. Both outbreaks have affected hundreds
of thousands of acres of spruce forest on both sides of the Inlet, and the outbreaks
have lasted ten years or more in a given area. In both outbreaks, sites with sunny
southern exposures have been hit the hardest, presumably due to drought-stressed
trees. Conversely, sites on cool, steep north-facing slopes have experienced less
beetle kill, or in the case of Neptune Bay, they escaped the 1870-80s outbreak
altogether.
The comments, however brief, of the Harriman Expedition writers
about the dead forests in Cook Inlet have added another valuable piece of information
to the spruce bark beetle story of southcentral Alaska. I would be very interested
in hearing from readers who might know of other such historical reports of dead
forests. This might take the form of old letters, newspaper articles, maps, or
photos. The spruce bark beetle puzzle is slowly coming together, but we need more
pieces!
An excellent collection of photos from the 1899 Harriman Expedition
can be viewed on the web at http://128.95.104.14/index.html (University of Washington
archives).
-------------------------------------------
Ed Berg has been
the ecologist at the Kenai National Wildlife Refuge since 1993. He can be reached
at Refuge Headquarters at 262-7021. Previous Refuge Notebook columns can be viewed
on the Web at http://kenai.fws.gov.
|