On President’s Day I explored a section of woods which I’ll refer to as Killiansburg Woods. The name is derived from Killiansburg Cave, a rock overhang at the west end of the woods which residents of Sharpsburg used as a shelter during the Battle of Antietam. The woods extend east to Snyders Landing, along a north facing slope bordering a bend in the Potomac River. The C&O Canal forms the northern edge of these woods, where cliffs of Conocheague Limestone drop to the canal below. There are several small caves extending back into the cliffs. Some of the coves in the woods above appear to be sinkholes, forming perched valleys with flat bottoms and steep sides.
The underlying limestone results in rich soils and some species which are not particularly common in the state. Thuja occidentalis grows on the north facing cliffs, sometimes within arm’s reach of Juniperus virginiana, which grows on the crest of the cliffs. North facing limestone bluffs along the Potomac are the only locations I know of where Thuja grows in Maryland. Quercus muehlenbergii is another uncommon species that occurs here, but I only came across one or two of them. I would have expected to see Magnolia acuminata also, but did not encounter any. The woods don’t appear to be particularly old, although there were a few large older looking trees scattered about – the 13.6 cbh black oak being the most significant one. Civil War era maps show woods in the area, but the extents are unclear, and much of it could have been cut since then. A 1944 USGS map does clearly show most of the area being wooded and it does not appear there has been significant change since then.
The measurements I took are a sampling, and not a very full representation of the site. All of the trees measured were in the coves behind the cliffs, with the exception of the Thuja, which was on a cliff, and the Populus, which was at the edge of the canal, next to the towpath. The tall tulip was in a broad cove in an almost pure stand, with a few sycamores mixed in. I don’t think I got the tallest Thuja here, it probably tops out at around 50 feet.