The Hills Are Alive with Oaks

Beginning of the IP Track in Copenhagen Hills Reserve

Copenhagen Hills Preserve is an ecological gem.  With its unique calcium-rich soils, it hosts a plethora of plant communities, ranging from pine forests and prairies to bottomlands and swamps.  This cornucopia of habitats is home to many rare and indigenous plants, such as purple cone flower (Echinacea purpurea), three-flowered hawthorn (Crataegus triflora), and, of course, a variety of uncommon oak species.

My journey to Copenhagen began as a trip to sample both delta post oak (Quercus similis) and Durand oak (Q. sinuata).  To find these beauties, I enlisted the help of Dr. Lowell Urbatsch of Louisiana State University.  Together we began a three-hour trip from Baton Rouge to Caldwell Parish in northern Louisiana.   The preserve itself encompasses the Copenhagen Prairie and Ouachita Hills in the north and the Bayou Dan bottoms in the south.  The area stretches over 1,000 acres that are owned and maintained by The Nature Conservancy.  The property

Quercus similis (click on images to enlarge)

contains a high level of biodiversity and is home to at least 26 rare species.  Up to 12 of these species have not been recorded anywhere else in the state.  The various habitats of the preserve are diverse as well, including ridgetops, prairies, bottomlands, and swamps near the Ouachita River.    

We began our journey driving to the northern portion of the preserve to an area called L’s Prairie, just west of the Ouachita River.  The path, known as the IP Track, took us through roughly a mile of mixed pine and hardwood forest running alongside an open area of prairie and shrub.  Along the road, campers and trailers reminded us that we were to tread cautiously through the forest where local hunters had been looking for wild turkeys earlier that morning.  As such, we had access to the preserve from only 10 a.m. till 3 p.m. 

The first leg of our hike began through prairie grassland mixed with a tangle of beauty berry (Callicapra americana).  The appropriately-named elegant blazing star (Liatris elegans) stood out amongst the grasses in a delicate spike of lavender.  Other fall wildflowers, such as partridge pea (Chamaecrista fasciculata), false foxglove (Agalinis sp.), and many species of goldenrod (Solidago sp.) dotted the pathway, with colorful butterflies flitting in between.  It was quite difficult not to stop and survey the surrounding beauty of the prairie, especially when accompanied by Lowell, an expert on Solidago.

Gray hairstreak (Strymon melinus) on goldenrod (Solidago sp.) Quercus sinuata

 

Eventually the prairie gave way to stands of shortleaf (Pinus echinata) and loblolly pine (P. tadea) mixed with blackjack oak (Q. marilandica).  Although these are common species throughout Louisiana, we stopped for a few

Quercus marilandica acorns

photos of a nearby tree brimming with acorns.  Soon the woods transitioned into a mixed hardwood of hickory, maple, dogwood, ash, and additional oak species.  Along the way, we spotted southern red oak (Q. falcata), post oak (Q. stellata), Shumard oak (Q. shumardii), and white oak (Q. alba).  Swamp chestnut oak (Q. michauxii) and cherrybark oak (Q. pagoda) are also known to occur on the preserve, although we didn’t catch a glimpse of any around. 

Continuing along, the path began to slope downhill where eroding soil uncovered seashells – remnants of an ancient sea bed.  These marine relics provide the preserve with rich calcium, creating the unique calcareous forest and calcareous prairie habitats for which Copenhagen Hills is well known.  For this reason, the preserve has also served as an important site for geologists and paleontologists studying the geological history of Louisiana.  Digs have uncovered shells, shark teeth, and fossilized corals from the Upper Eocene.  Scientists at the University of Louisiana have even unearthed ancient whale bones that are estimated to be between 36 and 40 million years old.  

As we continued our trek downhill, we hit a hard bend in the path. There, standing like a noble guidepost, was a young Durand oak (Q. sinuata) – my first prize.  Although there were no acorns to be seen, a few low hanging branches provided me a good look at this oak’s puzzling leaves.  This species is often misidentified as a hybrid

Elegant blazing star (Liatris elegans)

due to the appearance of its leaves, which are sporadically lobed – or often unlobed.  Beside the tree, a small footpath led to a more mature Durand oak, stretching high into the canopy.   After a half-hour’s struggle, we managed to snip off one branch to find most of its leaves, sadly, riddled with holes.      

Undeterred, we ventured further down the track into yet another ecosystem, a bottomland forest.  Although the forest was dry, cypress knees peeking out between grassy patches reminded us that this forest floor had been covered in water earlier that spring.  Towering above our heads stood my second prize, a much-anticipated delta post oak (Q. similis).  Moss and lichen clambered up the sides of its scaly bark giving it a shaggy, ancient appearance.  Around us, we noticed there were other oaks well at home in the bottomlands.  In the distance, my binoculars found what appeared to be a laurel oak (Q. laurifolia), although the preserve is also home to willow oak (Q. phellos).  Closer by, a large overcup oak (Q. lyrata) dug its roots into the side of a high creek bank.    

The path then led onto a wooden bridge over the creek.  I would have loved to venture further into the wood, but our time was running short so we began our trek back up the ridge.  However, the local vegetation beckoned me to stay as I nearly backed into the devilishly barbed bark of a

Quercus muehlenbergii

Hercules’ club (Zanthoxylum clava-herculis).  After a few photographs of the ostentatious plant, we resumed our walk on towards the prairie.  At the calcareous hardwood forest along the way, we encountered yet another distraction, a beautiful chinkapin oak (Q. muehlenbergii).  This time our tarrying was rewarded with a climb on its strong branches and a sighting of a few shiny black acorns. 

Unfortunately, we ran out of time to catch a glimpse of Oglethorpe oak (Q. oglethorpensis) and cherrybark oak (Q. pagoda) present on land used by the nearby International Paper Company.  These two species are currently being managed by The Nature Conservancy in agreement with the paper company.  Perhaps a future private tour will allow me to catch a glimpse of these trees and the other rare beauties the preserve harbors. Have I convinced any of you to start planning your own trip?    

All photos © Rebecca Dellinger-Johnston

 

Sources:  

Smith, Latimore. Copenhagen Prairie/Ouachita Hills Abbreviated Conservation Area Description. July 2005.
The Nature Conservancy. http://www.nature.org/ourinitiatives/regions/northamerica/unitedstates/louisiana/placesweprotect/copenhagen-hills-preserve.xml . Accessed 7 Feb 2017.