The mixed mesophytic forest of Fort Hill.
Fort Hill: 1300 Acre Natural Area
Fort Hill is protected as much for its outstanding natural features as its archaeological ones. Fort Hill preserves one of the largest and oldest examples of native forest to be found in southern Ohio. Although the woodlands is not technically old-growth, scattered through Fort Hill are islands of fully mature forest, as well as giant specimens of individual trees (especially on the Fort wall), and an exceptionally tall canopy of oaks, tulip poplar, hickories, and ash.
The forest at Fort Hill is known to botanists as a "mixed mesophytic" woodlands, the richest type of forest community to be found in eastern United States. Mixed mesophytic forest communities are restricted to the central spine of the Appalachian Mountains and their western-flanked foothills, spanning a region from Ohio to Tennessee. They are the most protected forest-type in the East, being characterized as not too hot, not too dry, not too windy, nor too cold. Consequently, mixed mesophytic forests boast the highest number of tree species to be found in the America's Eastern temperate forest, with no one particular tree species dominating any of the others. Among naturalists who frequent southern Ohio destinations, the forests of Fort Hill is a memorable example of a nearly ecologically intact temperate forest. Some of the oldest forest islands in the park happen not to be accessed by the current trail system and in these remote forest glades, ancient trees grow in undisturbed, regal slumber, rising above thick carpets of rotting leaves and bedecked with hundreds of species of mushrooms and spring ephemeral flowers.
To appreciate the full range of Fort Hill's wildflower displays one should begin visiting the park in early spring. The floral show first begins in late March, when the spring daytime temperatures surmount the threshold of 50 degrees Fahrenheit for a few days in a row, accompanied by sunshine. At such times, a rare and diminutive lily bursts into bloom. It is known as Snow Trillium, or Trillium nivale, and it is the smallest of all the world's 47 species of trilliums. When first arising from the ground , often above the melting snow, the entire plant's diameter -- leaves, flower and all -- is no larger than a fifty cent piece. Although never common at Fort Hill, snow trilliums can be found by keen observers growing along the dolomite rocks lining the Gorge Trail.
In early April, warmer weather brings out carpets of rue anemones and false anemones (a regretful name for this lovely limestone-loving species), along with hepatica, bloodroot, twinleaf, Dutchman's breeches and harbinger-of-spring. By mid-month, thousands of Trillium grandiflorum grace the woods with the showiest displays of the year, highlighted with bright golden Celandine Wood Poppies, bluebells, and the delicate snowflake-wands of bishop's caps. In late April, as the forest continues to green and the fallen boulders become alive with moss, softened lichens and unfurling ferns, the last of the "spring carpet" comes into bloom: mayapples, jack-in-the-pulpits, columbines and wild geraniums. The best displays continue to be seen along the Gorge Trail.
But one of the rarest and most sublime flowers of spring waits to open when the other flowers are fading and the forest's leaf canopy is nearly covered over. It is the regal yellow lady slipper orchid, one of most impressive native orchid species. Rare now at the Fort Hill and absent from most of Ohio's forests, its seductive and unearthly beauty have contributed to its current scarcity. Today, the yellow ladyslipper must be carefully stewarded and protected -- a goddess of the forest to admire, but not to touch nor disturb. The plants require a distinct mychorhizzal root association with forest fungi in order to grow; and even in the best of environments, transplanting the flowers into different soils results in certain failure. Because Fort Hill is the home of these and other rare flowers, hikers are asked to stay strictly on the trail, walk lightly, and avoid disturbing any of Fort Hill's native vegetation. Hikers will be rewarded by being able to view one of the showiest wildflower displays to be found in the state, with flowers literally brushing one's ankles as you walk along the trails.
Fort Hill shares its eastern boundary with the 12,000 acre Pike State Forest and several smaller conservation lands purchased by the Arc of Appalachia, creating a large, contiguous block of forest that is critical habitat for neo-tropical breeding birds. One of the hallmark species of Fort Hill is the Cerulean warbler, a species in heavy decline across its home in America's Eastern temperate forest. Some of the Cerulean's best and last strongholds on the continent have been documented in southern Ohio forests having both a strong component of mature oak trees and an established understory. Other migrant species heard and seen in the spring and summer woodlands of Fort Hill include: Scarlet tanager, red-eyed vireo, ruby-throated hummingbird, yellow-billed cuckoo, hooded warbler, red-breasted grosbeak, Kentucky warbler, worm-eating warbler, and ovenbird. However, the hallmark of Fort Hill is not a migrant at all, but a year around resident and regular icon of Eastern old growth - the pileated woodpecker.
Lucy Braun - A Botanist's View of the Forest. Fort Hill’s extraordinary plant diversity was first promoted by the late Cincinnati botanist, Lucy Braun, who was the colorful matriarch of Ohio’s earliest nature preservation movement. In 1969 she published An Ecological Survey of the Vegetation of Fort Hill State Memorial for the Ohio Biological Survey, a slim romantic tome of natural history that inspired many a budding naturalist in the 20th century to walk in her footsteps. It is to her words that we turn to bring an naturalist's overview of Fort Hill to present day readers:
“Fort Hill lies at the northern end of the Knobs Border Area (a Mixed Mesophytic Forest region primarily found in Kentucky) and displays many of the botanical features of the Knobs. Control of underlying rock on the character of growing vegetation is pronounced, and results in a great diversity of plant communities throughout the park. The diversity is due in part to the presence of both calcareous and noncalcareous bedrock (dolomite, sandstone and shale), with the resultant differences in resistance to erosion, soil reaction, and direction of slope. The pH of soils in the park range from a high alkaline reading of 7.6 to a severely acid reading of 4.6. Topographical character has also contributed to the diversity of vegetation. Hilltops are approximately 1300 feet in elevation descending to a low of 820 feet on Baker Fork.
The many plant communities of Fort Hill State Memorial may be classified under seven major divisions: 1) bottomland flats of Baker Fork 2) calcareous dolomite cliffs, slopes, and promontories 3) lower slopes 4) acid Ohio shale slopes 5) upper slopes 6) summits , and 7) old field areas.”
Lucy Braun took note of some of the ancient trees growing along the fort wall that boasted breathtaking girths: Black gum at 41 inches in diameter, chestnut oak at 52 inches, and tulip tree at 30.5 inches. In 1969 her list of vascular plants in the region totaled 650 species. The list was later updated by Columbus naturalist John Watts, and rose to 675 species. In 2009, Ohio Heritage botanist Rick Gardner estimated that when botanical studies are completed at Fort Hill, the list will be close to 800 species. Because of the constant and responsible stewardship of the Ohio Historical Society since 1938, the giant trees first noted by Lucy Braun remain standing today. Many impressive specimens can be seen along the Fort Trail.