Natural Heritage of Indiana

The Natural Heritage of Old Growth Forests in Indiana


Content adapted with permission from the Indiana Department of Natural Resources, a partner in the Natural Heritage of Indiana project. The original source of the information can be found here.

Of Indiana's original 20 million acres of forest, fewer than 2000 acres of old growth forests remain intact. Most of the sites that remain are now protected as nature preserves, and many have been selected as national natural landmarks.

Tall Trees

The first thing you notice when you enter an old growth woods is the sheer size of the trees. Giant hardwoods 3 and 4 feet across at the base soar more than 100 feet to the canopy above. The oldest trees are more than 250 years in age; many of Indiana's old growth oaks were producing acorns long before the American Revolution. Beneath the canopy, multiple layers of vegetation mark the descent to the forest floor. At 50 feet, younger trees wait in the shade of their parents for the openings that will allow them to attain canopy stature. Understory species such as dogwood, redbud and ironwood form a third layer of green at 20 to 30 feet. Lower still are the shrubs and herbs which occupy the forest floor.

Hollow trunks and treeholes in these woods provide habitat for squirrels, raccoons, bats, wood ducks, woodpeckers and a myriad of other birds and mammals. Dead trees and snags remain standing until a windstorm or other disturbance sends them crashing to the ground. Far from being a waste of wood, however, these fallen trunks now enter a new stage of the natural cycle. Each log becomes its own mini-ecosystem, complete with a teeming array of termites, ants, beetles, centipedes, millipedes and other invertebrates. These in turn become food for salamanders, shrews, mice and other denizen of the forest floor. The rotting wood is further broken down by fungi and bacteria. The wood is gradually converted to humus, replenishing the soil and completing the natural nutrient cycle.

A generation ago ecologists J.E. Potzger and Ray Friesner of Butler University described Indiana's old growth forests as "...monuments representative of the once massive eastern deciduous forest, to which generations of today and tomorrow might make their pilgrimage, to see in impressive miniature what pioneers of four score years tell us about the forest primeval which towered over the cabins of their boyhood days." These old growth forests are precious in ways that cannot be measured. There are over ten dedicated Nature Preserves in Indiana protecting old growth forest communities. More»



Content adapted with permission from the Indiana Historical Bureau, a partner in the Natural Heritage of Indiana Project. For more information about Indiana's state emblems, see here.

Well over a hundred species of trees were native to Indiana, and nearly half of these regularly reached one hundred feet in height. A few exceptional species, could reach 200 feet, and were among the tallest living things east of the Rockies. One type of tree which can grow exceptionally tall is the tulip tree (Liriodendron Tulipifera), or yellow poplar. It was adopted by the 1931 General Assembly (Indiana Code 1-2-7) as Indiana's official state tree. It attains great height and can be found throughout the state. The leaf is distinctive (it appears in the border of the state seal), and the lovely bell-shaped greenish-yellow flowers appear in May or June. The soft white wood has many uses.

Check out the Indiana State Museum's exhibit "Footprints" ISMWhat was the area like 10,000 to 11,000 years ago? Where did the big animals go? And what can we learn from our impact on the past that will make us better stewards of our environmental future?

With Footprints: Balancing Nature's Diversity, presented by Central Indiana Land Trust, the Indiana State Museum will trace our state's natural history from the Ice Age to today and beyond, considering how humans and environmental changes have affected ecological diversity and the world we live in. Drawing from the museum's collections, the exhibit answers questions about Indiana's past, shows the animals' overwhelming size and number, and suggests what it might have been like to walk among them.
Explore the online exhibit »

Our Hoosier State Beneath Us: Newspaper articles about a variety of topics related to Indiana's Natural Heritage Our Hoosier State Beneath UsThis series of 155 brief illustrated articles is part of a set of about 250 such articles produced by the Indiana Geological Survey between 1974 and 1984. The articles were distributed to and printed by newspapers all over Indiana. The topics range from coal to paleontology to people to geology. There is even a keyword search tool and a full table of contents. Browse Articles »

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