PART IV: Wetland Management

SWAMPS

wamps include a broad range port more woody vegetation. of wetlands that have stand- Occasional flooding or several Sing or slowly moving water years of wet weather can slow this and are dominated by trees or process, and several dry years can shrubs. Swamps differ from speed it up. marshes in that swamps do not contain large amounts of cattails, Swamps provide habitat for sedges, bulrushes, and other non- mink, muskrats, beaver, otter, deer, woody aquatic plants. However, black bear, squirrels, hares, barred these plants may appear around owls, various species of woodpeck- swamp edges or in openings. ers, wood ducks, nuthatches, sev- mink Michigan swamps include conifer eral kinds of warblers, black- swamps, hardwood swamps, mixed capped chickadees, snakes, turtles, prise much of the overall loss-- conifer-hardwood swamps, and frogs, toads, butterflies, dragon- about two-thirds of the original 5.5 shrub swamps. Swamps and low- flies, and many other insects. million acres of conifer swamps land forests are very similar and Uncommon animals such as red- have either been drained or con- are often one in the same. shouldered hawks, cerulean and verted by logging activity to low- However, swamps are often wetter prothonatory warblers, Indiana land hardwood, farmland, marshes for a longer period throughout the bats, smallmouth salamanders, and or shrub swamps. year and have deeper standing Blanchard's cricket frog, all rely on water than lowland forests. These swamps for survival. Types of Swamps lowland forests may be seasonal Northern white cedar and black wetlands. About one-third to one-half of spruce dominate most conifer Michigan's wetland acreage has swamps in northern Michigan, Like most wetlands, swamps been lost since 1800. Swamps, although balsam fir, eastern hem- are ever changing systems. conifer swamps in particular, com- lock, and white pine may also be Depending on the surrounding important components. Found landscape, swamps are often a mostly in northern Lower Michigan transitional step in the natural and the Upper Peninsula, conifer process from water to dry upland. swamps are situated along All swamps start out as a lake, moraines, lake beds, outwash pond, stream, or other body of plains, and other glacial shallow slow moving water. drainage. Associated with Water-loving trees and shrubs peatlands, conifer swamps may take root in the warm, relative- be rich or poor in minerals. ly stable wetland. As plants Sunlight penetration to the decay, their material accumu- ground is usually poor. This lates and adds to the topsoil until reduces the amount of the water depth decreases and ground cover and gives supports more dense vegetation. some conifer swamps a Continued succession will result in dark, mysterious appear- very little surface water, and a ance. The soil of these swamps buildup of organic soils, which sup- is typically acid, but it may also be neutral or even alkaline if it is influ- Combinations of shrubs such as enced by groundwater input. tag alder, buttonbush, willow, and Alkaline sites tend to be cedar- dogwood often dominate shrub dominated and offer greater plant swamps. Alder-willow swamps diversity. In slightly less water-sat- are most commonly found along urated conditions in northern streams and lake margins in north- Michigan or along northern flood- ern Lower Michigan and the Upper plains, mixed conifer-hardwood Peninsula. Buttonbush-willow swamps are more common. swamps appear mostly in the southern Lower Peninsula. In Hardwood swamps are 1800, about one percent, or some those dominated by ash, elm, and 43,000 acres, of Michigan was cov- buttonbush red maple but may also include sil- ered with some kind of shrub One management option, ver maple, cottonwood, and black swamp, mostly in the Upper therefore, may be to leave the willow. Pin oak and swamp white Peninsula. Today, about 730,000 swamp alone and allow it to mature oak are included in southern Lower acres are thought to exist naturally, especially if the tract is Michigan and quaking aspen, big- statewide. The increase is due to large (200 acres or more). Old- tooth aspen, and balsam poplar extensive logging of conifer growth forest left intact, for exam- can be found throughout northern swamps and to the network of road ple, will favor area-sensitive birds Michigan swamps. In 1800, hard- construction. like the red-shouldered hawk, the wood swamps comprised about five cerulean warbler, and the pro- percent (1.7 million acres) of the Management thonotary warbler. Do not frag- state's land base, and most were Considerations ment the swamp by making roads, found in southern Lower Michigan. and trails. Create a buffer strip of Today, many of the conifer swamps Swamp management for grass, shrubs or trees at least 100 have been converted to hardwood wildlife can be as simple as doing feet wide around the swamp. swamps. This is due to the exten- nothing or it can be very complex Remove invasive species like garlic sive logging of conifer swamps and and involve the manipulation of mustard, glossy buckthorn, and changes in hydrology. Much of this wildlife habitat. Swamps that have purple loosestrife that may be has occurred in the northern Lower a steady, stable supply of water growing in the swamp or around it. Peninsula and the Upper Peninsula. year round function naturally. Many southern Michigan counties Usually they can best be managed Swamps that have been frag- hardwood swamp areas have by protecting the water source and mented can be regenerated by decreased by as much as 50 per- enhancing the adjacent uplands. planting tree and shrub species cent. Many hardwood swamps are suited to the sites, but the process located along lower river reaches Water is the key to swamp takes a long time and may not be that flood in spring and fall. maintenance, even though water successful. The slow growth of Southern Michigan lowlands tend levels fluctuate throughout the many swamp-loving trees and the to be very diverse and support year. Additional water over several exacting conditions required to many plants commonly found in years or many years of drought can restore them are good reasons for states farther south. impact the condition of the site. maintaining what already exists. In Draining adjacent uplands into the many cases, little or no timber har- swamp, for example, can lead to a vest is needed to increase the value higher water table, which may to wildlife. prompt conversion of the swamp to a marsh of cattails. By altering If timber harvest is part of your watetables, soils could dry out, overall plan, however, take no more leading to succession and a conver- than 25 percent of the trees at one sion to upland vegetation. time and space harvests 10 to 20 years apart. Removing one to four swamp white oak trees in a group is the best way to SWAMPS mimic natural disturbances such as some wildlife species such as deer, lightning strikes and severe storms rabbit, wild turkey, grouse, and that topple trees. This method of woodcock. Opening the canopy by uneven-aged management (also careful timber harvest to allow sun- called selective cutting) promotes a light to reach the ground may stim- swamp of mixed-aged, young and ulate the growth of vegetation that old trees and is the best timber these species prefer. However, harvesting strategy as it creates where stands exist on poorly the least amount of disturbance to drained muck soils or on sites with white cedar the swamp. Uuneven-aged man- a high water table, the results of agement can retain benefits to a the timber harvest are far less pre- seed sources for regeneration. variety of wildlife species that dictable. The species composition require mix-aged forests. However, of the resulting stand may not be at Shrub swamps with a ratio of it is not the best harvesting method all like the parent stand. Consider, 40 to 60 percent open water can for many edge-loving wildlife for example, that full-crowned provide habitat for a variety of species. swamps release up to 1/4 inch of wildlife such as beaver, muskrat, soil moisture into the air each day waterfowl, and numerous reptiles When conducting timber har- through the process of evaporation and amphibians. If your shrub vesting, retain a good mix of tree and transpiration. The higher swamp contains more than 60 per- species, including swamp white water table and seasonal flooding, cent woody vegetation, consider oak, basswood, and hackberry, which could result from extensive creating openings 30 feet by 30 while managing for structural diver- logging, may completely change feet or 30-foot-wide strips from sity--a mixture of ages, diameters, the vegetation composition. Also, edge to edge. Make the openings crown sizes, and shapes of trees. success in regenerating conifer in winter by cutting willow, button- Leave old logs, large standing swamps can be poor, especially if bush and other woody plants at ice snags, and den trees because they white cedar is the target species. level with a chainsaw, loppers, or provide food and habitat for inver- White cedar is often promoted as backblade pulled by a tractor. This tebrates, amphibians, woodpeck- critical to deer management practice works best after a dry fall ers, and other cavity-nesting birds. because it provides both quality because spring flooding over the See the Timber Harvesting chap- food and cover. However, once cut stems during the next growing ter in the Forest Management sec- cedar is cut, white spruce and bal- season will eliminate or reduce tion for more harvest strategies. sam fir usually regenerate the site regrowth for several years. because deer browse the nourish- Because swamps are often ing shoots of white cedar. For Wildlife professionals do not devoid of young trees and an more information see the chapter usually recommend building water- understory of shrubs, they don't on Lowland Conifers. control devices in swamps because provide high quality habitat for of the difficulty in duplicating and Minimize harvest activities in enhancing the natural wetland spring when water levels are high processes. However, if dikes or and flood events are likely. Do any other means of water retension selective cutting in late summer, already exist, waterfowl and shore- and only when soils are dry and birds may benefit by drawing down firm. Some swamps freeze, allow- the water level to only a few inches ing for a winter harvest. Be careful in spring to allow preferred plants not to disturb the soil any more such as smartweed, wild millet, than is necessary and avoid making arrowhead, bulrushes, and sedges permanent logging roads, which to grow on exposed mud flats. The will alter the flow of water. Do not spring draw-down also provides log where deer browsing is severe. waterbirds with improved access to Locate skid trails and any roads on insects, crayfish, and other inver- the upland edge of the cut, and tebrates. Once the plants have leave clumps of scattered trees as produced seed in late summer or SWAMPS

40 acres ally inappropriate for the north. Furthermore, government permits will be needed for most activities in HS a swamp. aspen upland & SS hardwoods Existing features birch Beaver dams often create com- bination marshes and swamps. M Road Although many individuals are House tempted to eliminate the beaver M Marsh & open water grassland LB Lowland brush upland and its dam and replace it with an SS Shrub swamp hardwoods conifer earthen dam, this is extremely HS Hardwood swamp swamp costly and difficult due to soil con- Beaver dam hardwoods ditions. If you have a beaver dam Habitat projects on your land, realize its importance Tree and shrub plant ing to the landscape and enjoy the nat- cropland Small group timber ural engineering abilities of the harvest beaver. cropland In summary, swamps occur SS LB throughout Michigan and are important havens for many wildlife This map is an example that demonstrates the many management options discussed species. Determining the water throughout this chapter. The option(s) you choose should depend not only on your source and evaluating the condition goals, but the location, condition, and present use of your land. of the swamp and adjacent uplands will help you decide on manage- ment options. Simply protecting the swamp and its water source as early fall, reflood the area with six large number of mast-producing it now exists will often be the most inches of water to attract herons, trees such as oak, red maple, wil- effective management decision. rails, red-winged blackbirds, and low, and ash. When considering harvest of waterfowl. Throughout the fall you swamp timber, carefully consider can increase the depth to 12 inch- Before creating dikes, earthen the various possible outcomes as es to enable migrants to reach dams, or other water-control struc- these are highly complex environ- acorns and other food. Because ice tures, consult with a professional to ments. action during the winter and early see if the management goal is spring can cause significant dam- desirable and realistic in terms of age to trees, it is important to draw the site's potential. Water control down the area in late fall to water structures are helpful in maintain- depths less than twelve inches. ing vegetation growth and FOR ADDITIONAL This practice of flooding and draw- regrowth. Unfortunately, they can CHAPTERS CONTACT: down is best conducted in dormant be costly to install and maintain, Michigan United Conservation Clubs swamps that have a dependable and may alter the natural process- PO Box 30235 water supply and heavy soil to help es of the area. Remember that Lansing, MI 48909 retain the water. They should be at wildlife-flooding practices used in 517/371-1041 least one acre in size and contain a the southern United States are usu

Private Land Partnerships: This partnership was formed between both private and public organizations in order to address private lands wildlife issues. Individuals share resources, information, and expertise. This landowner’s guide has been a combined effort between these groups working towards one goal: Natural Resources Education. We hope this manual provides you with the knowledge and the motivation to make positive changes for our environment.

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