* limited to sites with higher soil calcium
Vascular plant nomenclature follows Rhoads and Block (2007). Bryophyte nomenclature follows Crum and Anderson (1981).

International Vegetation Classification Associations:

USNVC Crosswalk:

None

Representative Community Types:

Pitch Pine Rocky Summit (CEGL006116)

NatureServe Ecological Systems:

None

NatureServe Group Level:

Central Appalachian - Northeast Pine - Oak Rocky Woodland (G906)

Origin of Concept

Fike, J. 1999. Terrestrial and palustrine plant communities of Pennsylvania. Pennsylvania Natural Diversity Inventory. Pennsylvania Department of Conservation and Recreation, Bureau of Forestry, Harrisburg, PA. 86 pp.

Gawler, S. C. 2017. Pitch Pine Rocky Summit (CEGL006116). NatureServe Explorer [web application]. NatureServe, Arlington, Virginia. Available https://explorer.natureserve.org/. (Accessed: January 6, 2022).

Pennsylvania Community Code*

JP : Pitch Pine – Scrub Oak Woodland

*(DCNR 1999, Stone 2006)

Similar Ecological Communities

The Pitch Pine – Scrub Oak Woodland may occur alongside others in the Ridgetop Acidic Barrens Complex. The barrens types represent a group of communities with open-canopies found on high elevation ridgetops and summits (350m – 670m), where low soil moisture, shallow soils, high wind velocities, frequent fires, and usually a history of cutting have limited tree growth.

 

The Pitch Pine – Scrub Oak Woodland is most similar to the Dry Oak Heath Woodland. They differ in the cover of pitch pine or other conifers; the Dry Oak – Rocky Woodland has less than 25% cover of pitch pine or other conifers.

 

The tree and shrub species composition may be similar to the Pitch Pine – Mixed Oak Forest, however, forest types have a greater than 60% total tree canopy cover, while woodlands are less than 60%. The Low Heath Shrubland also has a similar species composition, but will have less than 10% tree canopy cover.

 

The Pitch Pine – Mixed Hardwood Woodland was previously recognized and has been combined with the Pitch Pine – Scrub Oak Woodland.

 

This community often co-occurs with several other types in the Ridgetop Acidic Barrens Complex:

 
• Dry Oak – Rocky Woodland 
    
• Red Spruce Rocky Summit (rare; confined to high elevations) 
   
• Scrub Oak Shrubland 
   
• Low Heath Bedrock Outcrop (confined to high elevation)  
 
• Little Bluestem – Pennsylvania Sedge Opening  
 
• Pitch Pine – Heath Woodland  
 
• Pitch Pine – Scrub Oak Woodland
 

 

The communities that create the Ridgetop Acidic Barrens Complex form a mosaic that are related by successional stage. The herbaceous types occur more sporadically throughout shrubland, woodland, and forest types based on time since fire, clearcutting, or other disturbance. The arrangement of different types within a site, and the pace of succession, is also determined by differences in environmental variables such as aspect, soil depth, elevation, exposure, and microclimate. In general, the physiognomy becomes more open at higher elevations and on southern exposures. Where fires are frequent, pitch pine will typically be present. In the absence of fire, other pines (white pine, Virginia pine, shortleaf pine, or Table Mountain pine) may accompany or replace pitch pine, or pine may be absent altogether. Frost pockets may play a role in maintaining open areas; this is especially true of the Little Bluestem – Pennsylvania Sedge Opening type. Long-term fire suppression may cause the distinctive vegetation of the herbaceous openings to give way to more mesic species typical of the surrounding forests at lower elevations.  

 

The forest types that most typically surround these communities are the Dry Oak – Heath Forest and Pitch Pine – Mixed Oak Forest.

Fike Crosswalk

Pitch Pine – Scrub Oak Woodland and Pitch Pine – Mixed Hardwood Woodland (no longer recognized)

Conservation Value

Acidic barrens communities can host a number of rare plant species and an exceptional diversity of rare butterflies, moths, and other insects. Barrens communities can arise as a result of a variety of human-induced and natural disturbances; many have their origin in the 19th or 20th century, while others have persisted longer through a combination of periodic human-induced disturbance dating to pre-settlement times and edaphic factors (Copenheaver et al., 2000; Kurczewski, 1999; Latham, 2003; Motzkin & Foster, 2002). Latham (2003) suggests that the diversity and presence of rare plant species in barrens is correlated with the overall age of the barrens, with newer barrens less likely to host rare plants. Animal diversity appears to be less sensitive to age; perhaps because many of these species are highly mobile. Both plant and lepidopteran species can be sensitive to successional stage and time since disturbance; some require very open, grassy areas, while others can also inhabit shrublands and woodlands with partial shade. The species of conservation value are not necessarily indicator species for the community type, and may also occupy other types of habitathabitats, but barrens sites are one of the habitats importantof particular impotance for their conservation. Species of great conservation value that are associated with barrens include many species of Lepidoptera (moths and butterflies) which have barrens plants as hosts, plants that can withstand the acidic, thin soils, and vertebrate species who thrive with hot, dry conditions. Examples of invertebrates that can be found in barrens include waxed sallow moth (Chaetaglaea cerata; G3G4/S2S3), twilight moth (Lycia rachelae; G5/S2?), and flypoison borer moth (Papaipema sp. 1; G2G3/S2S3). The timber rattlesnake (Crotalus horridus; G4/S2S3) and eastern hognose snake (Heterodon platirhinos; G5/S3S4) can utilize barrens. A few plant species that are associated with barrens include variable sedge (Carex polymorpha; G3/S2), dwarf iris (Iris verna; G5/S1), and sand blackberry (Rubus cuneifolius; G5/S1).

Threats

The primary threats to acidic barrens communities are succession and fire suppression. Many of the unique species that inhabit these barrens are most successful in the early stages of succession, such as grasslands and open shrublands, and are therefore particularly vulnerable to the effects of succession over the long-term. Pitch pine are known to not germinate and establish well without fire. Spongy moth (Lymantria dispar) outbreaks also threaten barrens, which often have a strong component of oak species in the tree and shrub layers. However, spongy moth control agents can also threaten the unique butterfly and moth species that inhabit barrens.

 

Studies across a number of sites in New England and Pennsylvania demonstrate that many barrens are disturbance-dependent ecosystems that, in the absence of disturbance, move through succession to forest rapidly (Copenheaver et al., 2000; Kurczewski, 1999; Latham, 2003; Motzkin & Foster, 2002). These studies have observed similar patterns of barrens succession to forest, sometimes even mesic forest, in recent decades.

 

Changes in land use and fire suppression over the last century are at the root of these patterns of succession. Through meticulous efforts to identify historic land use and changes in vegetation over time, researchers have documented that barrens are correlated with areas that burned frequently, primarily from Native American use of fire. Fires occurred primarily during the dormant season, presumably in the

 

fall and early spring (Stambaugh et al. 2018). Wildfires caused by later anthropogenic activity, such as railroads, would have also contributed to the maintenance of barrens vegetation. The cessation of these land use practices, and the advent of widespread, long-term fire suppression, is correlated with succession of grasslands and open shrublands to dense shrub thickets and forests. Charcoal production retards vegetation such that former heaths resemble barrens, but it appears the mechanism is a more profound and persistent alteration of soil chemistry.

 

The Pitch Pine – Heath Woodland is also threatened by the southern pine beetle (Dendroctonus frontalis). The southern pine beetle is a native beetle of the southeastern United States that feeds primarily on pines such as pitch, shortleaf, Virginia, and white. Outbreaks occur every 6-12 years and can last for 2-3 years. The southern pine beetle feeds on phloem in the inner bark, which ultimately girdles and kills the tree (Liu, n.d.). Additionally, the southern pine beetle has experienced an unprecedented northward expansion in recent years due to mild winters and climate models predict the range to expand to almost the entirety of Pennsylvania (aside from much of the Northern Allegheny Plateau) by 2050, and north into Canada by 2080 (Lesk et al., 2017). The southern pine beetle does not currently overlap with the native range of this community type, however it is considered a serious long-term threat. This community type may also be impacted by the spotted lanternfly (Lycorma delicatula). The spotted lanternfly is newly established in Pennsylvania and has been found to lay eggs and feed on a number of common hardwood trees, vines, and shrubs in Pennsylvania (Barringer & Ciafré, 2020). This invasive pest may weaken hardwood associate trees in this type but may only represent a small threat since hardwood trees are not dominant. However, the black sooty mold which proliferates on honeydew produced by spotted lanternfly may pose a severe threat to native flora under/around mass-feeding sites.

 

Other threats include loss of this community due to development of cell phone towers, wind turbines, and utility lines, or trampling by visitors on ATVs.

Management

It is important to develop a site-wide management plan at acidic barrens to maintain multiple successional stages. Appropriately applied prescribed fireis the optimal tool for barrens management. Where it is not feasible to use fire as a management tool, a combination of cutting and soil scarification can be used to mimic its effects.

 

Plans should also consider specific needs of barrens indicator species and rare species. To avoid severe reduction of lepidopteran populations, prescribed burning should not be undertaken across an entire site at once. In a given year, unburned areas should be left as refugia for these species.

 

Spongy moth control programs should balance maintenance of oaks and lepidopterans, using control agents specific to the spongy moth where possible, or leaving some untreated areas as refugia for native lepidopteran populations.

Range Map

Pennsylvania Range

The Pitch Pine – Scrub Oak Woodland is found in the following USEPA Level III (Level IV) Ecoregions: Northern Allegheny Plateau (60), North Central Appalachians (62), Blue Ridge (66), Ridge and Valley (67) and Central Appalachians (69).

Global Distribution

Connecticut, Massachusetts, Maryland, Maine, New Hampshire, New Jersey, New York, Pennsylvania, Rhode Island

Barringer, L., & Ciafré, C. M. (2020). Worldwide feeding host plants of spotted lanternfly, with significant additions from North America. Environmental Entomology, 49(5), 999-1011.

Copenheaver, C. A., White, A. S., & William A. Patterson III. (2000). Vegetation Development in a Southern Maine Pitch Pine-Scrub Oak Barren. Journal of the Torrey Botanical Society, 127(1), 19-32.

Illick, J. S., and Aughanbaugh, J. E. 1930. Pitch pine in Pennsylvania. Pa. Dept. Forests and Waters Res. Bul. 2.

Kurczewski, F. E. (1999). Historic and Prehistoric Changes in the Rome, New York Pine Barrens. Northeastern Naturalist, 6(4), 327-340.

Latham, R. E. (2003). Shrubland longevity and rare plant species in the northeastern United States. Forest Ecology and Management, 185(1-2), 21-39. https://doi.org/10.1016/S0378-1127(03)00244-5

Lesk, C., Coffel, E., D'Amato, A. W., Dodds, K., & Horton, R. (2017). Threats to North American forests from southern pine beetle with warming winters. Nature Climate Change, 7, 713-717. https://doi.org/10.1038/nclimate3375

Liu, H. (n.d.). Southern Pine Beetle: Forest Insects& Diseases Fact Sheet. Pennsylvania Department of Conservation and Natural Resources, Bureau of Forestry, Division of Forest Health.

Motzkin, G., & Foster, D. R. (2002). Grasslands, heathlands and shrublands in coastal New England: Historical interpretations and approaches to conservation. Journal of Biogeography, 29(10-11), 1569-1590.

Ordnorff, S., & Patten, T. (Eds.). (2007). Management Guidelines for Barrens Communities in Pennsylvania (p. 208). The Nature Conservancy.

Schweitzer, D.F. & Rawinski, T.J. (1987) Northeastern pitch pine ⁄ scrub oak barrens. Eastern heritage task force. The Nature Conservancy, Boston, MA.