- Pinhook Bog
Indiana’s only true bog is a special geologic feature of this region which preserves a large variety of plants with extraordinary adaptations for survival. See insect eating plants and tamarack trees; walk on a boardwalk that is placed upon a floating mat of sphagnum moss. Pinhook Bog is about 580 acres, a quarter of which is a floating peat mat. The "moat" surrounds the bog from the uplands. Pinhook Bog is a
National Natural Landmark .Geology
The Bog is a glacial kettle. At the end of the Wisconsin Glacial epoch, (14,000-15,000 ybp) a large chunk of ice remained buried at this location as the ice retreated northward. When the ice melted, the clay soil sealed the basins. [ Indiana Dunes Education, National Park Service, Porter, Indiana, 2006]
The runoff from higher ground around the bog is the only water source. There are not streams or groundwater inflow or outflow. Evaporation from the open water and plants is the only loss of moisture. A bog is different than swamps, marshes or ponds because of this limited exchange of water. The water in the bog is stagnant, acidic, and nutrient-poor. [ 1997, Bud Polk]
Plants
The outstanding feature of Pinhook Bog is the tree covered mat of
sphagnum moss .Sphagnum moss is a stringy, delicate moss of a light-green color. It can hold to 18 times its weight in water. It was often used as bandages and baby diapers by Indians and early settlers. The mat floats on top of the water and can become three to six feet thick, yet it can have a pocket of a few inches in the middle. As the mat thickens, larger and larger plants take root and grow. Under the mat a peat bed develops. The acidic water slows the decay of the sphagnum moss and other plants. With time, the peat may fill the bog from the mat to the bottom. As the moisture becomes less acidic, typical land plants move and the bog disappears. [ 1997, Bud Polk]Orchids : orange-fringedorchias , pinkLady's Slipper ,grass pink , and rosepogonia and seven othersCarnivorous : [ Daniel, Glenda; Dune Country, A Hiker’s Guide to the Indiana Dunes; Illustrated by Carol Lerner; Swallow Press; Chicago, Illinois; 1984, pg 121]*
pitcher plant is heavily-veined with red or green leaves. The leaves are folded to form a pitcher or cup which is normally about half full of water. When an insect enters the plant to drink, tiny bristles on the leaf, which point downward prevent it from walking up and out. An enzyme in the liquid digests the insect. The flower is brownish-red, rose shaped and located on a separate stalk.*
Sundew is a tiny plant with two types of leaves, rounded and spatula shaped. The stems and leaves are coated with a red sticky substance. There is a white or pink flower that is hardly noticeable.*
Poison Sumac is prevalent in the bog area, particularly around the outer edge, the ‘”moat”. It is recognized by it compound leaves of seven to thirteen leaflets. The leaflets are smooth edge and pointed. [ibid, Daniel, pg 119]*
Tamarack orAmerican larch is an unusual tree for northwest Indiana. It is a conifer, but not evergreen. It drops its leaves in the winter. As fall approaches, the needles turn golden until they fall off. [ 1997, Bud Polk]*
Blueberry andcranberry shrubs are common along the margins. [ 1997, Bud Polk]Access
The Bog is open only for ranger-guided tours
References
ee Also
Indiana Dunes National Lakeshore Indiana Dunes State Park Bibliography
*Daniel, Glenda; Dune Country, A Hiker’s Guide to the Indiana Dunes; Illustrated by Carol Lerner; Swallow Press; Chicago, Illinois; 1984
*Greenberg, Joel; A Natural History of the Chicago Region; University of Chicago Press; Chicago, Illinois; 2004
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