Saturday, October 9, 2004

Plant of the Day: Eastern sycamore, Platanus occidentalis

Eastern sycamore is one of the stateliest trees of the floodplain forest. Its massive size and white and tan mottled, peeling bark make it a conspicuous tree, visible for miles along waterways in the East. Although it is most abundant in the moist soils along streams, it also colonizes abandoned fields. It grows quickly, reaching heights above 70’ in less than 20 years. Its tiny seeds are clustered into tan pendant fruits, sometimes called “buttonballs”. Flowing water below the tree disperses seeds, depositing them in ideal germination sites on moist bars and mudflats downstream. Sycamore twigs are eaten by deer and muskrats, and many animals make their home in large cavities located in the trunk, including wood ducks, opossums, and raccoons.

Today was our last day of the ride! We only had a short trip from Dawsonville, Maryland into the Grand Finale ceremonies on the Ellipse in the heart of Washington, D.C. Shortly after we left Dawsonville, we dropped south to the Potomac River, and we followed that most of the way into the nation’s capital. We went right by the Chesapeake and Ohio Canal National Historical Park, situated along the Potomac. The canal runs 185 miles from the mouth of Rock Creek in Washington, D.C. to Cumberland, Maryland. The canal climbs from around sea level to 605’ elevation near Cumberland, through a series of 74 locks. It was initially built to provide transportation between the Midwest and the industrialized East; but thanks to repeated floods, use of the canal ceased in 1924. A towpath runs along the canal for part of its length, making this a popular recreation corridor for cyclists, hikers, and boaters.

A little closer to Washington, D.C., we went by Great Falls Park, part of the George Washington Memorial Parkway. Great Falls, where the Potomac descends the Fall Line, is one of the steepest and most spectacular Fall Line rapids on any river in the East—a fitting way to end our journey.

Photo taken by Avery Drake, Jr., USGS

Washington, D.C. is just one of many southeastern cities that developed on the Fall Line between the Piedmont and the Coastal Plain early in our country’s history. Many streams tumble down scenic falls and cascades as they make their way from the Piedmont, with its resistant crystalline rocks, onto the more easily eroded sediments of the Coastal Plain. Such falls terminated upstream travel as settlers pushed towards the western frontier; here they had to unload boats and travel over land to continue their journey. Settlements grew up at many of these points. The waterfalls also provided waterpower for mills and factories, which were often located adjacent to the rapids. Other Fall Line cities include Baltimore, Maryland, and in Georgia—Macon, Columbus, and Augusta,. At Great Falls, the Potomac River narrows from a width of nearly 1000’ wide to only 60-100’ as it cuts through Mather Gorge. It drops 76’ in less than a mile through a spectacular series of cascades and rapids, as the water rushes around jagged metamorphic rocks that have resisted the river’s erosive powers over the millennia.

It's been a wonderful journey. I hope you have enjoyed sharing it with me!