Landscape History of the Serpentine Barrens

Literature Review

Summary:landscapehistoryoftheserpentineecosystemarticleimage.pngThe term "barrens" was used by English surveyors and settlers to refer to areas which were "bare of timber."  "... when the whites commenced settling here, they found no timber, hence they applied the term Barrens, a common appellation at that time, to such portions of the country, however fertile the soil."  Tree species, especially oaks, were present but open grown, with trunks too short for timber.  The landscape was predominantly oak savanna maintained by frequent autumnal fires ignited by Native Americans mainly for fire-hunting white-tailed deer.  Prior to settlement, beginning about 1750, the serpentine barrens covered expansive areas in Baltimore, Harford, and Carroll Counties of Maryland, and in adjacent York and Lancaster Counties of Pennsylvania.  Access to the barrens was provided by a system of Amerindian "highways," with a main artery called the Old Indian Road.  Native American fires ended about 1730 as American Indians succumbed to European diseases and other factors.  Livestock grazing quickly became widespread on the barrens, and Soldiers Delight was a favorite range for stock.  Barrens which were not grazed, burned, or cut by settlers soon developed trees with long trunks suitable for timber.  By 1800, timber was advertised in Annapolis and Baltimore newspapers as growing in the barrens, and all timber stands in Soldiers Delight were logged before 1914.  Also in the 1800s, chromite was mined from five shaft mines and from chromite-rich alluvial sand deposits (placers).  After 1930, the non-indigenous Virginia pine expanded rapidly across Soldiers Delight, in the absence of grazing and fire.  In just 50 years, Virginia pine dominated more than 50 % of areas which had been in native serpentine vegetation.  Ecological restoration of the serpentine ecosystem began in 1989 as a six-year research phase, and expanded in 1995 with the passage of a restoration and management plan.  By 2020, more than 500 acres had been manually cleared of pine and more than 100 acres burned at least once.  White-tailed deer management began on a limited basis in 2008 and fully expanded beginning in 2014.  Invasive species management began in the 1990s, after thousands of tree-of-Heaven (Ailanthis altissima) trees were discovered in Soldiers Delight.   A number of other invasive plants continue to be managed annually.


Pre-settlement Conditions

            Historical vegetative conditions on the barrens in Maryland and Pennsylvania have been described by Maryland historian William Bose Marye (1886-1979, pronounced Marie) (Marye 1920, 1955a, b, c).  Marye determined that the term "barrens" was used by English surveyors and settlers to refer to areas which were "bare of timber" (Marye 1955b). "... when the whites commenced settling here, they found no timber, hence they applied the term Barrens, a common appellation at that time, to such portions of the country, however fertile the soil."  The term barren was applied to individual exposures of serpentine as well as the vast serpentine-centric region which included areas of adjacent non-serpentine soils. 

            Prior to settlement of the barrens (beginning about 1750), they covered expansive areas in Baltimore, Harford, and Carroll Counties in Maryland, and in adjacent York and Lancaster Counties of Pennsylvania.  In 1722, the barrens of central Maryland were described in correspondence as "... a Vast Body of Barrens ... what is called so, because there is no wood [timber] on it; besides Vast Quantities of Rockey Barrens ...".  "... the Lands ... all along the west side of Baltimore Co[unty], are cut off & separated ... by large Barrens, many miles over..." (Marye 1955a).  Soldiers Delight was described as "... an immense barrens" circa 1730 (Marye 1920).  The following description occurred in a 1753 letter: "... about thirty miles from Navigable Water is a Range of barren dry Land without Timber about nine miles wide which keeps a Course about North East and South West parallel with the mountains thro this province Virginia & Pennsilvania..." (Marye 1955a).  In 1771, 620 acres in Baltimore County were described as "Verry poor bare Barrens"; "Barrense, hilly and stony"; "Poore hilly Barrance & much broke with stone & Verey scarce of Timber"; and "exceedingly poor & much broke with stone and Little or no Timber of any sort." (Marye 1955a).  Similar descriptions of other barrens in 1770 are provided in Marye (1955a).

            Barrens in Pennsylvania were noted by a Quaker in 1683 as extensive treeless spaces in the wilderness (Marye 1955a).  In 1737, they comprised about 130,000 acres, and their width at the Maryland border was reported to be 20 miles (Marye 1955b).  This historical estimate correlates well with the 23-mile strip of ultramafic bedrock mapped by Pearre and Heyl (1960). 

            Between 1580 and 1652, serpentine in Maryland was within the hunting domain of the Susquehannock Indians (Marye 1955c).  Their villages were concentrated mostly on both sides of the lower Susquehannock River in York and Lancaster Counties, Pennsylvania, near the Maryland border (Cadzow 1936, Witthoft 1959).  (The Shenk's Ferry culture preceded the Susquehannocks in this region (Witthoft 1959)).  "Fire hunting" was the primary technique for harvesting wildlife on serpentine (Marye 1955b), as it was in a variety of habitats throughout the Southeast (Maxwell 1910, Swanton 1946).  The following quotations are from Marye's transcriptions of historical documents (Marye 1955b).  "It was the custome of the Indians in the autumn to set fire to and burn the barrens of York [Pennsylvania] and Baltimore [Maryland] Counties...".  "When the Indians no longer set their fires, trees began to creep back...".  Another source, in reference to the York Barrens of Pennsylvania, stated "...that the Indians for many years, and until 1730 or 1731, to improve this portion of their Great Park for the purpose of hunting, fired the copse or bushes as often as their convenience seemed to call for it...". 

            Between 1652 and 1730, hunting in the barrens was shared with other tribes (Marye 1955c). By 1675, the Susquehannocks had succumbed to European diseases and to warfare with both settlers and Iroquois Indians (Hunter 1959, Witthoft 1959).  They disappeared as a distinct group by 1680, and the last identifiable descendent was killed in 1763. 

            Access to the barrens was provided by a system of Indian "highways."   The Old Indian Road (Marye 1920), the main travel artery, passed through the barrens region and was within 3.5 miles of Soldiers Delight to the north, east, and west.  A resident of a Baltimore County plantation gave sworn testimony in 1697 that it was located "in the 'walks' which Indians usually take when they move to their hunting Quarters ..." (Marye 1955c).  The plantation "was situated on or very near a highway followed by Indians in going to or returning from certain hunting grounds or when travelling 'on the warpath'," and the "highway" was commonly referred to as the Indian Road or Old Indian Road in a "considerable number" of eighteenth-century records (Marye 1920).  Fire was probably used for other reasons such as communication and warfare (Moore 1972). 

            White-tailed deer were probably the primary object of fire-hunting, based on archaeological evidence and the widespread distribution of deer.  Donald Cadzow (1936) led archaeological excavations of Susquehannock sites along the Susquehanna River in 1930 and 1931.  He reported the contents of 31 food storage pits at the Schultz site, located in one of the largest Indian villages.  White-tailed deer bones were discovered in 61 % of the storage pits.  Elk bone were found in 32 % of the pits, and other bone included fish, black bear, beaver, raccoon, and turkey.  Buffalo bone was not found in storage or fire pits at the Schultz site and not reported from the other four sites studied.  At the Strickler site, Futer (1959) excavated a large midden-filled pit and found many bones of deer and bear.  The regional abundance of elk before settlement is uncertain (Mansueti 1950 and Paradiso 1969), and the presence of elk herds at Soldiers Delight was not reported in the historical literature. 

            Fire-hunting improved the harvest of low-density wildlife populations compared to other hunting techniques.  According to a review by Knox (1997), the white-tailed deer population prior to English arrival in 1607 was only about 8.0 – 10.9 deer/mi2 in neighboring and physiographically similar Virginia.  For comparison, in March 2008, a helicopter-mounted forward-looking infrared camera (FLIR) survey estimated a density of 93 deer/mi2 in Soldiers Delight (Helicopter Applications, Inc. 2008).

Post-settlement Conditions

            European settlement of the barrens region was delayed until the 1740s (Porter 1975, 1979).  Among factors causing this delay were the psychological effect of a vast barren landscape, scarcity of timber, and lack of an effective treaty with the Five Nations of Iroquois before 1744.  After Indian extirpation, barrens were used by settlers for livestock grazing (Marye 1955c).  In addition, "... lands which lay within easy distance of the Barrens, were considered to be more valuable on that account." (Marye 1955c).  For example, one parcel was advertised in the Maryland Gazette (1746) as "...convenient for stock, there being an outlet to the Barrens of Patapsco...".  Marye concluded that this outlet must have been by way of Soldiers Delight.  The name of "Graziers Delight", 892 acres, surveyed on Soldiers Delight in 1774 implied that the barrens of Soldiers Delight were a favorite range for stock (Marye 1955c).  The longevity of grazing as an ecological factor controlling woody plants has not been documented. Although the use of fire by settlers to maintain and create grazing land may have been widespread initially, the practice was "...largely abandoned..." by 1780 (Marye 1955b).  Grazing may still have been a factor in the 1800s and into the early 1900s, based indirectly on historical vegetation descriptions and photographs (Tyndall and Hull 1999).  However, information on grazing intensity and distribution have not been published. 

            Barrens which were not grazed, burned, or cut by settlers soon developed trees with long trunks suitable for timber.  By 1800, timber was advertised in Annapolis and Baltimore newspapers as growing in the barrens (Marye 1955a).  Before settlement, the landscape was described as "... acres upon acres overgrown with nothing but saplings; other considerable areas, with bushes only; still others, denuded and bare." (Marye 1955a).  After settlement, "... the sapling lands produced timber trees, hardwood seedlings sprang up on the bushey grounds, and the Barrens vanished..." (Marye 1955a).  Rapid timber development within a barren was probably from tree species already in place on deeper silt loam soils ("sapling lands"); i.e., not from afforestation by oaks from surrounding non-serpentine areas.  "Bushey" may have referred to stunted oaks on shallower silt loam or deeper gravelly sandy loam, and "denuded and bare" to gravelly sandy loam too shallow for woody plant root systems.  However, the definition of these terms was not provided in Marye (1920, 1955a, b, c).  Referring to the "York Barrens of Pennsylvania," one source stated "Portion of the country that were sixty or seventy years ago [1775-1785] without timber are now [1845] thickly covered with sturdy oaks and large hickories." (Marye 1955b).  Since hickories do not grow on serpentine, this quote apparently includes non-serpentine areas adjacent to serpentine barrens. 

            In 1910, Shreve et al. reported that the "Barrens ... in the Soldiers Delight area ... have an open park-like stand of trees ... The Black Jack Oak and Post Oak are often the sole trees on the thinnest soil, or they may be accompanied by Red Cedar."  In a corresponding photograph, Virginia pine is not evident nor is red cedar (first reported by Knox [1984]).  Oak trees are scattered or absent on ridges of various aspect.  In 1914, the State Forester (Besley 1914) did not identify seedlings or stands of Virginia pine in Soldiers Delight.  Only stands of "culled hardwoods" were mapped indicating that all hardwood forests had been logged.  In 1929, "The desolation of the serpentine barrens around Soldiers Delight, with its rocky soil and stunted vegetation of cedar and meagre grass..." was reported by the Maryland Geological Survey.  And also, "... characterized by a scanty vegetation of pine and cedar growing in a thin grey soil mantled in spring with the purple ground pink ...".  In 1937, during an automobile drive along Deer Park Road, Bowen states, "All about us are small ridges and steep barren slopes ... The road winds along the barren hillsides, through occasional clumps of bushes ... The scrub oaks grow with gnarled trunks and have very glossy dark green leaves.  Sassafras bushes dot the hills in little communities in spite of the very thin covering of soil...".   

            Mining for chromite could have contributed to treeless conditions in small localized areas, but widespread surface mining was not employed due to the nature of chromite deposits.  Merchantable quantities of chromite were found in perennial stream beds, at five primary upland locations, and in scattered small shallow pits.  Mining of chromite-rich alluvial sand deposits ("placers") in Soldiers Delight began between 1810 and 1820 (Pearre and Heyl 1960), and some level of production continued into the early 1920s (Johnsson 2017).  Placer mining consisted of hand-digging chromite-rich sand deposits in streambeds and banks, and manually removing much of the sand with a screen mesh (Singewald 1928).  The sifted material was then carried to a troughlike wooden structure, called a buddle, for final separation of chromite grains.  Buddles were about 12 feet long and a foot wide positioned along the stream with a small dam to provide for water flow down the buddle.  The lighter chromite grains would concentrate at the end of the buddle, and repeated washing would increase the concentration. 

            Woody plant growth could also have been impacted in the vicinity of the five shaft mines for lode chromite.  Records support the beginning of Choate Mine ore production soon after 1825 (Johnsson 2017).  Operation of each mine ended by about 1880, with the exception of an aborted restart of the Choate Mine in 1917-1918 (Johnsson 2017, Pearre and Heyl 1960).  Peak periods of activity at the Choate Mine were the 1830s and 1865 - 1875 (Pearre and Heyl 1960).  The number of mine shafts at each mine ranged from one to four, and three mines had concentrating mills and other structures (Johnsson 2017, Singewald 1928).  

            After 1930, Virginia pine invasion and expansion rapidly ensued (Tyndall 1992a, b).  In 1937-1938 aerial photographs of the U.S. Department of Agriculture, pines are widely scattered in upland areas of Soldiers Delight. But in just 50 years, Virginia pine dominated more than 50 % of areas which had been in grassland or oak savanna vegetation.  Pines became established first in the deeper and wetter soils of steep ravines and floodplains and then spread into shallow ravines and upper and lower ends of ridges.  Virginia pine usually invaded the midsection of south-facing slopes last as they were hotter and drier than other habitats, leaving a landscape impression of scattered "openings" surrounded by pine. 

            The origin of invading Virginia pine is not known.  Preliminary study of a single sediment core from a small depression of unknown origin in serpentine near the perimeter of Soldiers Delight suggested that Virginia pine was present in small numbers as early as 1810 (Hilgartner et al. 2009).  Regardless of the source(s), the absence of fire, grazing, mining, and other disturbance activities, in conjunction with abundant bare mineral soil coverage which is favorable to pine seedling establishment, allowed Virginia pine to expand rapidly as a non-indigenous invasive species.   

Recent Conditions at Soldiers Delight

            Ecological restoration of the serpentine ecosystem began in 1989 as a six-year research phase.  Three research areas were selected to verify predicted indigenous vegetation response to the clearing and fall burning of Virginia pine invaded areas.  Spring burning was not tested since historical fires were autumnal (Marye 1955).  Results for 1989–1992 were presented in Tyndall (1994), while permanent-plot sampling continued in 1993 and 1994 and reported in Tyndall (2020).  Research results were consistently positive and warranted implementation of a restoration and management plan in 1995 for the entire Natural Environment Area.  Based on research results, the strategy was the manual removal of pines during winter followed by prescribed burning in fall.  Spring burning was also implemented in greenbrier-dense areas.  By 2020, more than 500 acres had been cleared of pine and more than 100 acres burned at least once.  Vegetation response to clearing and burning was robust as predicted by research results and the scientific literature.  The rate of prescribed burning lagged behind clearing mainly because of smoke management limitations in a rapidly developing landscape.

            White-tailed deer began to be conspicuous in 1994 during daylight hours, and excessive deer herbivory became a serious problem.  By 2007, nearly 100% of oak seedlings were being browsed, and herbaceous flowers were noticeably uncommon.  Most plants of gray goldenrod (Solidago nemoralis) and serpentine aster (Symphyotrichum depauperatum), a serpentine endemic and State Endangered species (Gustafson and Latham 2005, Maryland Department of Natural Resources 2019), were consumed to a height of only a few inches aboveground.  In March 2008, a helicopter-mounted forward-looking infrared camera (FLIR) survey estimated a density of 93 deer/mi2 (36 deer/km2) (Helicopter Applications, Inc. 2008).  In an attempt to reduce deer density, a two-day managed firearm hunt was conducted in January 2008 and continued annually through 2016.  Since signs of herbivory continued to be extreme, a four-night sharpshooter harvest was conducted during March 2014 (USDA 2014), and State regulated public hunting was expanded beginning with the September 2014–January 2015 hunting season.  This expanded public hunting program has continued annually (Maryland Department of Natural Resources 2020).

            In 2019 serpentine aster had recovered to within about 50% of 1994 levels, thanks to the sharpshooter harvest in conjunction with regulated public hunting (Tyndall 2020).  In addition, a resurgence of oak seedling and sapling growth was evident.  Although showing abundance in some areas in 2020, gray goldenrod may be slow to recover in areas where seed banks were exhausted by deer.  

            Invasive species management began with tree-of-Heaven (Ailanthis altissima) in the 1990s, after thousands of trees were discovered in Soldiers Delight.  The largest trees had been planted on-site decades earlier and provided abundant seed for rapid spread.  Other seed sources were large trees on adjacent properties.  Over 10,000 individuals were killed, and this invasive is now in the early detection-rapid response level of management.  Mile-a-minute-vine (Persicaria perfoliata), once a major problem like tree-of-Heaven, has been reduced to a minor problem thanks to assertive management in conjunction with the spread of two biocontrol weevils from off-site introductions by the Maryland Department of Agriculture.  During 2018 - 2020, Japanese barberry (Berberis thunbergii), sericea lespedeza (Lespedeza cuneata), and autumn-olive (Eleagnus umbellata) required the most management effort, followed by miscanthus (Miscanthus sinensis), wavyleaf basketgrass (Oplismenus hirtellus ), thistles (Carduus nutans, Cirsium arvense, Cirsium vulgare), callery pear (Pyrus calleryana), and beefsteak-plant (Perilla frutescens).


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