Open bogs are plant communities where sphagnum moss (Sphagnum spp.) biomass dominates the ground vegetation. Bogs are also home to many species of sedges, shrubs and wildflowers and strange carnivorous plants like Round-leaved sundew (Drosera rotundifolia). The peat soils of bogs are acidic and low in nutrients.
Bogs can go by many names throughout the world, regionally, and even locally. This is because bogs vary throughout the world due to unique vegetation, nutrient and mineral content, weather patterns, and land use practices. This gives rise to these synonyms for bog wetlands: mire, fen, fenland, peatland, swamp, marsh, swamp, and meadow. A bog can also refer to a wet muddy area where vehicles can get stuck. With such a wide variety of terms, it can be easy to confuse bogs with other wetlands when they are discussed among people from different areas. The same is generally true of all wetland classifications.
Above: Aerial video of a bog lake.
Coniferous Bogs have a similar ground layer of sphagnum mosses and sedges, but has the addition of mature tamarack and black spruce trees. Here the trees may dominate the scene by what the eye sees, but the canopy is not dense enough to prevent the mosses and other plants from covering the ground. The trees of coniferous bogs are not commonly harvested for their lumber because the trees are of low value, and it is difficult to move heavy harvest equipment in coniferous bogs except when the ground is frozen in winter. Because of the harsh growing conditions, trees are often too small for the saw mill, but may end up sold for pulp and made into paper products.
A floating layer of mosses, sedges and other plants often rings small northern lakes, creating what is known as a bog lake. This layer will slowly extend over the lake until it encapsulates the open water. As the years go by the floating bog will be colonized by trees and eventually turn into forest. The floating mat is an interesting feature. Stepping on the mat is similar to walking on a water bed. Your feet bend the mat down around yourself,
and as you walk waves travel through the mossy layer. This is sometimes called a quaking bog. It is possible to fall through the mat and there can be many feet of water and soft muck, so walking a floating mat can be dangerous.
Trees can grow on the floating mat, and as they become heavier they can slowly sink down into the layer of living and dead mosses, sedges and other plants. When Black Spruce trees sink in this way their branches sprout roots. This process is called layering, and when this occurs individual branches can appear as independent trees. When you see a Black Spruce growing on a floating bog there may be as much of it below the moss as there is above it!
Bogs are amazing wildernesses because they have little economic value. Stepping into a bog is like stepping back in time for two reasons. In the southern half of the Midwest they are remnants of the landscape that flourished after the glaciers retreated 10,000 years ago. Second, they are seldom visited in modern times. Maybe a deer hunter wanders through every once and while, but on a large bog there is a good chance you might be the first person to walk through in decades, perhaps a century or two. Even if that is just wishful thinking, look around and you will probably be hard pressed to find any sign of man. Most designated wilderness areas in WI, MI, and MN will have an abandoned logging road or railway, the remains of a camp, or garbage left behind by hunters and hikers, but usually a bog is free of such artifacts.
This of course does not apply to all bogs, and bogs are far from safe from the modern world. Putting climate change aside, bogs are still being severely degraded for cranberry production, and the harvesting of peat for gardeners and fuel. In my home state of Wisconsin we celebrate our growing cranberry harvest, and the destruction of some of our last unspoiled wilderness.
Select Bog Species
- Sphagnum Moss (Sphagnum Spp.)
- Grass Pink (Calopogon tuberosus)
- Northern Blue Flag Iris, (Iris versicolor)
- Pitcher Plant (Sarracenia purpurea)
- Round-leaved sundew (Drosera rotundifolia)
- Broadleaf Cattail (Typha latifolia)
- White Beak-Rush (Rhynchospora alba)
- Wool-grass (Scirpus cyprinus)
- Royal Fern (Osmunda regalis
- Leatherleaf (Chamaedaphne calyculata)
- Bog Rosemary (Andromeda glaucophylla)
- Speckeled Alder (Alnus rugosa)
- White Meadowsweet (Spiraea alba)
- Northern Leopard Frog (Rana pipiens)
- Southern Bog Lemming (Synaptomys cooperi)
- Arctic Shrew (Sorex arcticus)
- Spruce Grouse (Falcipennis canadensis)
- Canada Goose (Branta canadensis)
Bog People or Bog Body
The term bog people, bog body, or bog man instantly conjures up an old black and white B movie. Crazy zombie-like people lurking in the bog and coming out at night to kill people in their sleep, but this is not what bog people are. Bog people, or bog bodies as they are also called, are found in European bog wetlands. Ancient people sometimes disposed of their dead in bogs. The harsh chemical environment of the bog embalmed the bodies and lack of oxygen prevents decomposition. The results are leather-like corpses that are well preserved for hundreds of years. They are so well preserved that scientists have been able to look in their stomachs to discover what their last meal was. People have been buried in bogs for thousands of years, some of them are believed to be human sacrifices. Bog people might make a good horror movie after all.
The most famous example of a bog body was Tollund Man. He was found in 1950 in Denmark with a rope around his neck. Archeologists believe he was sacrificed, rather than executed because of the position of his body and other factors. His last meal was a kind of porridge made from vegetables, and domestic and wild seeds. They estimate that he was about 40 years old and died somewhere between 375–210 BCE. Tollund Man resides in the Silkeborg Museum. Bog people are also found in North American bogs, but they are much less common.
Another common thing found in European bogs is bog butter. Bog butter is butter that was stored in the bog in wooden containers by ancient people. The butter was either of dairy or animal fat origin. Bogs are usually cold places, and the acidic, low oxygen environment in the bog would aid in the preservation of this food supply. This butter was either forgotten or abandoned for some reason. Some people say that it even appears edible.