A plant community, soggy yet exhilarating, almost as though a
person were in a different world, continues to be one of the
least visited habitats in this state. Very few members of the
small number of groups I have taken into a bog in the past had
ever experienced that incredible environment before.
Uncertain footing soon became the byword of each of those
memorable outings. A loud gasp, sometimes accompanied by a
chuckle, most often meant that someone’s foot had found a
concealed hole. As fast as the blink of an eye, the unfortunate
one found him or her knee-deep, or even thigh-deep, in black
muck.
Bogs, common in northern glaciated regions of the world such
as ours, are fragile places having more or less a continuous
carpet of sphagnum moss. Little to no drainage occurs there. A
visit to a true bog will reveal an enclosed water area whose
edges are being invaded by a mat of floating vegetation.
This spongy, water-soaked mat of plants is gradually
thickening from both top and bottom. Slowly the peat accumulates
consisting largely, or entirely, of organic material. Layers as
thick as 50 feet have been built up over the years as slowly as
from 100 to 800 years per foot.
What a surprise I received on my first teacher-led visit to a
bog around 42 years ago. Eager to examine a plant near the edge
of the mat, I suddenly and shockingly broke through up to my
waist in water. Luckily others were near to lend a helping hand.
An important lesson many of us learned was that the quaking
vegetation will support a person’s weight (or nearly so!) if you
walk as though tiptoeing on eggs so as not to break any.
Due to the lowness of bogs, the coldest air from the
surrounding terrain is constantly settling there. This, coupled
with constant wetness, leads to highly acid conditions of the
soil as well as the water in nearly all bogs. Tests as low as
3.5 and 4 on the pH scale, approaching the acidity of vinegar,
are quite common. These cold and wet factors limit plant growth
and decomposition, thereby increasing the acidity. Bear in mind,
however, that there are a small number of alkaline bogs in the
state which in turn feature entirely different plant
communities.
The temperature variation in a bog is unusually great. Push
your arm down into the sphagnum moss as far as you can and
chances are good that you will discover ice crystals there in
June. Leatherleaf, a typical bog shrub, will sometimes be in
full bloom while its roots are surrounded by frozen soil.
Mid-summer surface temperatures may reach 95 degrees F. while, at
the same time, plant roots will be experiencing a definite
deficiency of water at temperatures of around 50 degrees F.
Many of the shrubs of the bog are evergreen thereby allowing
for the maximum number of days for the manufacture of food.
Included in this group are Labrador tea, bog Rosemary,
leatherleaf and bog laurel. A few deciduous shrubs grow here too
such as blueberries and sweet gale. One of the very tiny trees,
resembling a shrub, is the dwarf or bog birch.
Sedges, including cotton sedge (called cotton grass) and saw
grass, are a common sight. For a long time I was baffled over
calling one of the typical bog sedges "saw grass" when
it really wasn’t a grass. A chemistry professor from
UW-Janesville, interested in plants, provided me with a temporary
answer by asking me, "Wouldn’t it be unfortunate to change
the name of saw grass to "saw sedge?" And in July you
may want to call it "summer saw sedge!"
Two of the most fascinating groups of bog plants are orchids
and carnivorous plants. Orchids of Wisconsin bogs include the
heartleaf twayblade, small round-leaved orchid, rose pogonia,
grass pink, swamp candles, pink moccasin lady’s-slipper and
arethusa.
The study and intricacies of carnivorous plants have attracted
botanists to the bogs for centuries. Northern pitcher plant,
both the round and the linear-leaved sundews and three species of
bladderworts will reward the ‘bog trotter’ in this region.
Round-leaved sundews, small to the point of going unnoticed by
many people, abound by the thousands in some bogs. Their leaves
contain tiny spines tipped with a glue-like substance along their
margins and on their inner surfaces. Unsuspecting insects,
trapped like flies on flypaper, set up a response within the leaf
whereby it slowly curls around and suffocates them. The spines
then release a proteolytic enzyme, very similar to peptic juices
found in the human stomach, into this little trap. Nitrogen,
nearly lacking in the soil of the bog, is now assimilated from
the insects’ bodies.
Bogs are truly fascinating. Henry David Thoreau summed them
up perfectly when he said; "Surely one may as profitably be
soaked in the juices of the swamp (or bog)…as pick his way
dry-shod over sand. Cold and damp – are they not as rich
experiences as warmth and dryness?"
Quaking bog
This column appeared in the Door County Advocate on 07/09/1999.
© Copyright 1999 Roy Lukes. All rights reserved.
