| Sylvania
WIlderness and hemlock |
Lee
E. Frelich |
|
Mar
28, 2003 11:11 PST |
Michele:
Sylvania Wilderness is in Ottawa National Forest in western
Upper
Michigan, and right on the Wisconsin border near Land O'Lakes.
It was in the big package of wilderness areas signed into law in
1984 by
President Reagan. Sylvania includes about 15,000 acres of forest
that was
never logged, mostly hemlock, but also with some large patches
of sugar
maple, and some small groves of white pine. There is no hemlock
looper or
woolly adelgid there at this time. It gets down to -35 there in
winter, so
the adelgids are going to have a tough time if they reach the
area.
The wilderness area is one township (6 x 6 miles) and was the
summer
retreat for the Fisher Family (of Fisher Body Corporation, the
automobile
bodies of which were used in GM cars for several decades). They
sold it to
the forest service in the early 1980s. There is a good system of
hiking
trails and also about 20 lakes, some of which are linked by
portage trails,
so you can either hike or canoe to the lakeside campsites.
The are is far enough north and also 1000 feet above Lake
Superior in
elevation, that tree heights are not impressive (or should I say
they are
impressive given the location?), ranging from 90-100 feet for
hemlock and
sugar maple and up to 110 feet for basswood, and 130 feet for
white pine.
That's strange, its the only forest I know of where basswood is
the tallest
except for white pine.
Sylvania has been one of our (Univ. of WI and MN) research sites
for
large-scale patch dynamics caused by disturbances and
neighborhood effects
since 1981.
If you thought the bugs were bad in northern MN, you should see
Sylvania.
Lee
|
| Re:
Wilderness and George Catlin |
Lee
E. Frelich |
| May
21, 2002 06:53 PDT |
Bob
and Miles:
You have hit upon one of my favorite topics: the great mysteries
of
paleoecology. Paleoecologists do the same thing as
archeologists, except
that we study forests of the past rather than human settlements,
although
obviously there is a strong link between the two. We use every
form of
evidence you can imagine--old paintings, written accounts of
forests, tree
cores, and fossil wood, leaves, cones and needles (macrofossils)
and pollen
(microfossils)--to reconstruct the forest of hundreds or
thousands of years
ago. I can't tell you what a thrill it was when as a graduate
student
during 1987 I met Margaret Davis--arguably the world's foremost
forest
paleoecologist--and she decided on the spot after talking with
me for 20
minutes or so, to hire me as her post-doctoral associate at the
University
of MN, even though I had no paleoecology experience. So I packed
up and
moved to MN and learned how to do pollen analysis. The first
sedimentary
core I analyzed has been named 'Lee's Hollow' in the scientific
literature. The hollow is in the hemlock and maple forest of
Sylvania
Wilderness in Upper MI, which started out as a black spruce
forest after
the retreat of the glaciers about 9700 years ago, then
progressed to jack
pine for a few thousand years, then white pine and red oak for a
few more
thousand years, until hemlock entered the picture 3100 years ago
as the
interglacial started to wane and the climate became wetter. As
far as we
can tell, that hemlock stand has never had a severe disturbance
of any sort
in 3100 years, making it one of the oldest forest stands in the
Midwest.
How do I know the black spruce forest was there 9700 years ago?
Well, there
were black spruce needles at the bottom of the sediment core. I
sent 35 of
these needles to the atomic accelerator dating facility at the
University
of AZ, and after a rather long wait of 6 months (they were
dating the
Shroud of Turin at the time and I had lower priority, so I had
to wait),
the date came back of 9700 years before present.
By the way, Miles, you may be interested to know that 7000 years
ago, at
the height of the interglacial, when summers were substantially
warmer than
now and the prairie-forest border at the latitude of Minneapolis
had moved
into Wisconsin, there was a maple-basswood forest in the middle
of
Iowa. Richard Baker's fossilized plant remains from the banks of
meandering streams proves it. It makes one wonder if big chunks
of mesic
forest can arise in the middle of the prairie just by chance, or
because
the trees themselves alter the local climate. Its another
mystery yet to
be figured out.
Lee
|
| Sylvania
Wilderness, MI |
Lee
E. Frelich |
| Aug
23, 2005 07:11 PDT |
ENTS:
Yesterday I returned from a trip to Sylvania Wilderness in Upper
Michigan,
which has about 15,000 acres of forest that was never logged
other than a
few white pine removals.
Sylvania has a mosaic of hemlock and sugar maple forest patches,
and the
origin of this spatial pattern has been the subject of much
research among
paleoecologists (including Margaret Davis and Shinya Sugita) and
forest
ecologists such as myself, resulting in over 20 papers published
in the
scientific literature. The story seems to be that there was a
mosaic of
white pine and oak forest. Hemlock tried to enter the area 5500
years ago,
but was wiped out across its range by the hemlock looper, and it
took 2000
years to recover (similar to what the response will be the
second time the
species disappears due to the wooley adelgid). So, 3300 years
ago, a
recovering hemlock began to replace white pine in Sylvania, and
this
reinforced the trend towards a cooler and wetter climate that
was taking
place at the time, by shutting off the flow of fire across the
landscape,
which in turn allowed sugar maple to replace oak in the
intervening
patches. The mosaic of maple and hemlock has been maintained for
the last
3000 years by neighborhood effects. Hemlock seedlings are
unsuccessful in
maple patches, because there are not any rotting hemlock logs
there, which
are their best seed germination sites, and because they are
smothered by
maple leaf litter, since they only reach a height of 1 inch
their first
year. Maple is unsuccessful under hemlock because they do not
get the
period of high sunlight in the spring that they get under a
maple canopy,
leading to a negative carbon gain once the energy in the seed is
used.
Unfortunately at this time the forest is starting to be
converted to some
sort of savanna due to high deer populations and European
earthworm
invasion. There has been no successful tree recruitment for
almost 80
years. When I worked in Sylvania during the 1980s, there was a
continuous
green layer of herbs and tree seedlings on the forest floor.
Now, even that
is gone, most of the forest floor is brown, and only about 10%
had
vegetation. As trees in the 200-400 year age class die, they are
being
replaced by suppressed saplings and smaller trees that are
80-150 years old
in some cases, and in other cases, there is nothing underneath
and the gaps
are remaining empty. Pennsylvania sedge (Carex Pensylvanica) is
a native
grass-like herb that is starting to appear in these gaps. In
other forests
we have seen Pennsylvania sedge take over the understory,
returning green
to the forest floor, but also preventing seedlings from
surviving. So my
guess is that there will be some sort of sedge savanna for a few
hundred
years, and after that I can't guess at what will happen.
At this point there are still a lot of 200-400 year old sugar
and red
maples, yellow birch, hemlock, black ash, and basswoods (the
latter
probably only 100-200 years old). in areas with rolling pitted
outwash,
trees around the hollows reach 100-110 feet tall, which is the
maximum
height for a place at 47 degrees latitude and 1700 feet
elevation.
Starting next summer, we are going to recensus 27 ha (about 67
acres) of
old-growth forest plots where every trees was mapped during
1988-1989. We
will get quantification of the disappearance of the herbs and
seedlings,
and decreasing density of trees caused by the forest decline
syndrome of
deer and earthworms.
Lee |
| Re:
Sylvania Wilderness, MI |
Kirk
Johnson |
| Aug
23, 2005 14:23 PDT |
|