Earth Partnership for Schools



WOODLAND RESTORATION INTERACTIVE WORKSHOP > WOODLAND PLANT COMMUNITY MODELS

Before learning about specific woodland communities, please read the following to understand what a plant community is and how plant communities are classified.

What is a plant community?
How are plant communities classified?
How are northern Wisconsin plant communities separated from southern communities?
How does climate affect northern and southern Wisconsin?
Northern Woodland Communities
Link to photos of trees and plants organized by woodland

 

What is a plant community?

A plant community is a combination of different plants growing together. Each plant community has a unique structure and appearance, which is determined by the proportions of the species growing in it. The composition of a plant community type, such as a northern mesic forest, changes from place to place due to the physical environment. This is because each species has certain limits to where it will grow and survive. Those species that have similar limits often are found growing together, hence they become a loosely assembled plant community.

 

How are plant communities classified?

The woodland communities described in this workshop are based on The Vegetation of Wisconsin by John Curtis. John Curtis arranged plant communities along a soil moisture gradient or continuum. He divided the continuum into five segments dry (xeric), dry-mesic, mesic (medium), wet-mesic, and wet.

 

How are northern Wisconsin plant communities separated from southern communities?

Wisconsin vegetation is divided into two major regions or floristic provinces. The southern half of the state is called the prairie-forest province and the northern half is called the northern hardwoods province. These two provinces are separated by a narrow band, labeled the Tension Zone , that contains plants from each province. Click here to see a map of Wisconsin showing the distribution of major plant communities.

 

How does climate affect northern and southern Wisconsin?

The average annual temperatures in the north are 20° F below those of the south, based on average temperatures from weather stations (Curtis). The summers are usually shorter and cooler; winters are longer and often bitterly cold. As a result, very little precipitation is lost to evaporation. A deep layer of insulating snow cover keeps the ground from freezing, especially in the forests. This generally moist, cool climate is favorable for trees.

Annual precipitation is greater (31.5" vs. 30.1") and more variable south of the tension zone. However, evaporation is greater because of higher average temperatures and more days of sunshine. Snowfall is less in the south (41" vs. 51"), and the snow cover periodically melts. The alternate freezing and thawing brought about by the fluctuation of snow cover creates severe stress on plants, especially those in the seedling stage. Conifers are also stressed in the winter from lack of water availability in the frozen ground. Conifers keep their leaves, or needles, during the winter and continue to transpire water vapor through their stomata. Leaves exposed to sun and wind often become scorched and turn brown.

 

 

Northern Woodland Communities

Woodlands in the northern hardwood province contain hardwood trees including sugar maple, and soft wooded, coniferous trees, such as pine, hemlock, spruce, tamarack, cedar, and balsam fir. Coniferous trees are a common ingredient in northern forests, but within the tension zone many of these trees reach their southern limit and disappear from the forest. Northern woodlands occur on a full range of moisture and topographic sites, from very wet areas in extinct lakebeds to very dry areas with thin, rocky, soil. Original forested area was approximately 16,900,000 acres, or 48.3% of the land surface. The remainder of the land was comprised of open bracken grasslands, fens, sedge meadows, bogs, and savanna-like pine or scrub oak barrens.

 

Take a look at northern woodland types or models:

Definitions of terms used in the Woodland Plant Community Models

General Characteristics of Northern Dry and Northern Dry-mesic Forest
Northern Dry Forest Model
Northern Dry-mesic Forest Model
Northern Mesic Forest Model


General Characteristics of Northern Wet and Wet-mesic Forests
Northern Wet-mesic Forest Model
Northern Wet Forest Model
Boreal Forest Model

 

Southern Woodland Communities

Woodlands in the prairie-forest floristic province occur on a full range of moisture sites, from very wet areas along streams and lakes through areas with deep mesic soils to very dry, thin soils on exposed hills and bluffs. Original forested area was approximately 5,200,000 acres. An additional 7,250,000 acres were in closely associated oak savanna. There is no clear line between woodlands and savannas.

Frequent fires, started by lightning or by Native Americans, played a vital role in limiting woodland communities in southern Wisconsin. Areas frequented by fire developed as prairie, savanna, or open oak woodlands. Dense maple-basswood forests developed where fire breaks such as rivers, lakes and extreme topography prevented the spread of fires.

 

Take a look at southern woodland types or models:

Definitions of terms used in the Woodland Plant Community Models

General Characteristics of Southern Dry and Dry-mesic Forests
Southern Dry Forest Model
Southern Dry-mesic Forest Model
Southern Mesic Forest Model


General Characteristics of Southern Wet and Wet-mesic Forests
Southern Wet-mesic Forest Model
Southern Wet Forest Model

 

Link to photos of trees and plants organized by woodland

To see photos of trees and plants organized by the woodland (and other) ecosystems they inhabit, follow this link to the UW-Madison Botany Department's collection of Emeritus Professor Virginia Kline's Vegetation of Wisconsin teaching photos .