For decades, Engelmann Woods has been preserved as one of the last examples of the old-growth forests that once covered the uplands adjacent to the Missouri River. The area's earliest protection began with private landowners, mainly Mrs. Oscar Johnson, who donated the forest to the Missouri Botanical Garden in 1942.
The Missouri Department of Conservation purchased Engelmann Woods in the early 1980s. It was designated as a natural area in 1983.
Historic features at Englemann Woods include the remnants of an old road and a cellar that marks the location of an early water reservoir used to refill steam engines traveling on the nearby railroad. The reservoir was rumored to be the first such facility west of St. Louis.
The richer forest communities of the natural area occur on north and east facing slopes where loess deposits are several feet thick. Dominant trees include red oak, white oak, white ash, basswood, and sugar maple. Some of the larger trees are three feet in diameter, 100 feet tall, and approach an age of 200 years. Pawpaw and spicebush are common understory shrubs of the bottomland forest communities. Interesting herbaceous (non-woody) plants include celandine poppy, maidenhair fern, puttyroot orchid, and white trillium. The drier west and south facing slopes are dominated by chinquapin oak and sugar maple at the canopy level with flowering dogwood and young maples in the understory. There are several American beech trees growing near the parking lot that were planted and are not native to this part of Missouri.
The drier sites historically consisted of more open woodland (more open space between trees) due to the common occurance of wildfire. Some of these sites are in the process of being restored to historic conditions by thinning trees and conducting controlled burning. These activities will encourage many sensitive plants and animals to return to the site.
Wildlife found on the area include southern red-backed salamanders, white-tailed deer, pileated woodpeckers, migrating warblers and eastern chipmunks.