Flatiron Lake Bog is a rare classic tamarack-ringed bog. It is an acid, kettle-hole bog that displays the classic ringed zonation of bog plant communities. Furthest out are the upland kame ridges surrounding Flatiron Lake that are covered by mature oak-maple forests. The forest zone grades into the next zone of a tall shrub community dominated by highbush blueberry. The tall shrub zone then grades into a tamarack woods, then a shrub zone and floating sphagnum mat and finally an open pool in the center.
The bog developed in a kettle hole that formed in the Kent end moraine when the Wisconsinan ice sheet retreated approximately 12,000 years ago, making the bog among the oldest kettle hole bogs in the country. The bog bears a striking resemblance to Canadian bogs some 300 miles further north.
The ecological significance of the bog was not recognized until 1980 when Dr. Barbara Andreas went there to investigate an area where tamaracks were reported to grow. The Nature Conservancy purchased a 77-acre tract near the bog in 1985. Additional acquisitions have increased the size of the preserve to 97 acres.
A few of the plants that are found there include: Tamarack, white beak-rush, pitcher-plant, two-scaped bladderwort, lesser bladderwort, Carolina yellow-eyed-grass, Howe’s sedge, white-fringed orchid, large & small cranberry, wild calla, leather-leaf and round-leaved sundew. Community types include tamarack-hardwood bog, tall shrub bog, and sphagnum bog.