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Ecosystem models for landscaping

Four forest systems have been identified as dominating northeastern Pennsylvania counties, with more than 40 ecosystems as subsets of the group. Individual ecosystems may be found in more than one forest system where surface features are similar, and different forest systems may be found as close as opposite sides of a road or blurred over many hundreds of feet.

Four forces appear to impact the structure and arrangement of forest systems:

Repeated uplifting and folding of the landmass to create ridges and plateaus
Varied coverage by glaciers, most notably the Wisconsin glacier about 11,000 years ago
Erosion, particularly flowing water but also wind and frost action
Human habitation, especially in the context of agriculture and lumbering, but also in importation of biological materials including pests and diseases.

An alternative index of ecosystems, defined by general elevation characteristics rather than forest systems, may be helpful.

Major forest systems in the Poconos

Brief summaries of ecosystems are found below. For details about individual major systems with links to ecosystems in each:

Central Appalachian Dry Oak-Pine Forests

Northeastern Interior Dry-Mesic Oak Forests

Appalachian (Hemlock) Northern Hardwood Forests

Central Appalachian Pine-Oak Rocky Woodlands

Central Appalachian Dry Oak-Pine Forest System

White Pine - Oak Forest: Mid and lower slopes, mesic, acidic, nutrient-poor, sandy loam to sandy soils. Unglaciated plateau: rolling topography over sandstone. Glaciated areas: outwash plains, moraines, mid to lower slopes, ravines.
Dry Eastern Hemlock - Oak Forest: Steep northeastern to northwestern exposures. Sandy, stony soil.
Dry Chestnut Oak - Heath Forest: Upper slopes and ridgetops with thin, nutrient-poor, acidic soils.
Red Maple - Sweet Birch Hardwood Forest: Various slope and aspect positions, rarely on bouldery or rocky sites. Mesic, generally infertile sites that have been severely altered by logging and fires.
Mid-Atlantic Oak - Pine Successional Forest: Former agricultural lands and old fields that are no longer intensively mowed, plowed or managed, usually found on dry-mesic sites that are flat to gently rolling.
Allegheny Oak Forest: Found on sandy to rocky soil on dry upper slopes and terraces of shale and sandstone
Sugar Maple - Yellow Oak Forest: A dry, calcareous ecosystem found on wooded summits and upper slopes over limestone, dolomite or marble bedrock
Inland Pitch Pine - Oak Forest: Found in dry, well-drained soils from glacial outwash or till as well as shallow soils on ridges and south-facing slopes
Central Appalachian Chestnut Oak Forest: Found in dry, acidic, infertile soils on middle and upper slopes, dominated by chestnut oak.
Northeastern Dry Oak-Hickory Forest: Occurs on well-drained loamy sand of midslopes and is ecologically transitional between rich oak-hickory forests of high diversity and oak forests with sparse diversity.
Appalachian Low-Elevation Mixed Pine / Hillside Blueberry Forest: Shallow, infertile soils on steep slopes, narrow ridges and other exposed topographic positions, over shallow, infertile soils

Northeastern Interior Dry-Mesic Oak Forest System

Northeastern Dry Oak-Hickory Forest: Common on high to midslopes, steps-in-slope, and other dry-mesic sites. Extremely stony xeric soils. The sites may be gentle to steeply sloping and may contain scattered boulders and large rocks.
Oak - Hickory / Hophornbeam / Sedge Lawn Forest: Found on upper slopes and side slopes at lower elevations, usually with southeastern to western exposure and with well drained loams or sandy loams, typically circumneutral. Soil is stony, but exposed bedrock, boulders and cobbles are rare.
Red Maple - Sweet Birch Hardwood Forest: Various slope and aspect positions, rarely on bouldery or rocky sites. Mesic, generally infertile sites that have been severely altered by logging and fires.
Mid-Atlantic Oak - Pine Successional Forest: Former agricultural lands and old fields that are no longer intensively mowed, plowed or managed, usually found on dry-mesic sites that are flat to gently rolling.
Central Appalachian Dry-Mesic Chestnut Oak - Northern Red Oak Forest: Somewhat protected rocky slopes often at low and middle positions, generally with north to southeast aspects and cooler and moister climate
Dry, Rich Oak - Hickory Forest: Found on slightly acidic to circumneutral dry-mesic to dry upper and mid-levels slopes with sandy to well-drained loams
White Pine - Oak Forest: Mid and lower slopes, mesic, acidic, nutrient-poor, sandy loam to sandy soils. Unglaciated plateau: rolling topography over sandstone. Glaciated areas: outwash plains, moraines, mid to lower slopes, ravines.
Oak - Hickory / Hophornbeam / Sedge Lawn Forest: Found on upper slopes and side slopes at lower elevations, usually with southeastern to western exposure and with well drained loams or sandy loams, typically circumneutral. Soil is stony, but exposed bedrock, boulders and cobbles are rare.

Appalachian (Hemlock) Northern Hardwood Forest System

Eastern Hemlock-Northern Hardwood Forest: Cool, dry-mesic to mesic sites and acidic soils, often on rocky, north-facing slopes. Soils can have a thick, poorly decomposed duff layer over sandy loams.
Northern Hardwood Forest: Middle of gentle to moderately steep slopes with a northern, or occasionally eastern, aspect. Soils are usually channery silt loams to gravelly sand loams with rock outcrops common.
Eastern White Pine Forest: Moderate to steep sloping sites or in sheltered ravines. Soils are moderately to extremely well-drained (dry-mesic to mesic), loamy sands and sandy loams, often sandy, stony, or bouldery. Coniferous forests on moderate to steep slopes with dry-mesic to mesic loamy sands and sandy loams, often stony or boulder and dominated by white pine and Canada hemlock.
Northern Red Oak - Mixed Hardwood Forest: Northern and eastern facing midslopes and coves. Deep, moist to well-drained loams and silt loams. Soils may be rocky, and slopes may be steep. Often found on moist north and east-facing slopes, coves and well-drained flats. Soils are somewhat fertile but slightly to strongly acidic.
Tuliptree - Beech - Maple Forest: Gentle to slightly steep low and midslopes often on toeslopes, in coves. Soils vary from sandy loam on higher floodplain terraces to gravelly and channery loams and silt loams at higher elevations (midslopes of ridges).
Red Maple - Sweet Birch Hardwood Forest: Various slope and aspect positions, rarely on bouldery or rocky sites. Mesic, generally infertile sites that have been severely altered by logging and fires.
Mid-Atlantic Oak - Pine Successional Forest: Former agricultural lands and old fields that are no longer intensively mowed, plowed or managed, usually found on dry-mesic sites that are flat to gently rolling.
Northern Hardwood - White Pine Forest: Mixed hardwood-white pine forests on acidic, well-drained, acidic, gravelly and sandy soil over glacial till, usually a less mesic setting than northern hardwood forests where white pine is absent.
Central Appalachian White Pine - Eastern Hemlock Forest: Occurs on middle slope dry-mesic sites with infertile, sandy soils in the Central Appalachians and Allegheny Plateau.
Central Appalachian Northern Hardwood Forest: Found on acidic to circumneutral, moderate to deep loams or loamy sands, mesic to wet-mesic and nutrient-rich soils, on gentle to moderate slopes
Hemlock - Beech - Oak Forest: Found on usually stony, sandy loams that are nutrient-poor, well drained and dry to dry-mesic, commonly over acidic bedrock.
Hemlock - Northern Hardwood Forest: Often on north-facing, rocky slopes, the system occurs on cool mesic to dry-mesic, acidic soils with a thick, partially decomposed duff layer over sandy loam.
Red Oak - Northern Hardwood Forest: Found on well-drained, loamy, sometimes rocky and slightly acidic soils of varied fertility on midslopes and in coves in glaciated areas of the region
Golden-saxifrage Forested Seep: Small and scattered herbaceous areas in the vicinity of seeps, usually overtopped by trees and shrubs from the adjacent forest ecosystem.
Central Appalachian Hemlock - Northern Hardwood Forest: Found in rocky ravines or moderate to steep slopes of any aspect, sometimes in flats and on stream terraces on sandy, mesic acidic loams and loams from glacial till or sandstone.
Semi-rich Northern Hardwood Forest: Occurs at moderate elevations, ridgetops and slopes on slightly enriched soils, often silt loams derived from slates and shales or other subacidic bedrock.
Northern Hardwood Forest: Middle of gentle to moderately steep slopes with a northern, or occasionally eastern, aspect. Soils are usually channery silt loams to gravelly sand loams with rock outcrops common.
Tuliptree - Beech - Maple Forest: Gentle to slightly steep low and midslopes often on toeslopes, in coves. Soils vary from sandy loam on higher floodplain terraces to gravelly and channery loams and silt loams at higher elevations (midslopes of ridges). Found on middle to lower slopes on deeper soils that are circumneutral to slightly acidic.
Mid-Atlantic Oak - Pine Successional Forest: Former agricultural lands and old fields that are no longer intensively mowed, plowed or managed, usually found on dry-mesic sites that are flat to gently rolling.
Northern Calcareous Talus Slope Forest: Found on shallow rocky soils or slopes of rocks and boulders overlying calcareous or circumneutral bedrock.
High-Elevation Hemlock - Yellow Birch Seepage Swamp: Scattered high-elevation wetlands in shallow valleys, stream headwaters or groundwater-saturated flats along streams, sometimes in slight basins impacted by seasonally perched groundwater but without flowing streams.

Central Appalachian Pine-Oak Rocky Woodland System

Blueberry Granite Barrens: Rocky ridges, summits and outcrops. Patches of shrub dominance and areas of bedrock-dominated sparse vegetation grow on soils described as shallow, well-drained, dry, acidic, coarse sands
Central Appalachian Blueberry Shrubland: Higher-elevation acidic rock outcrops or summits. Sometimes found in depressions on level outwash plains or valley floor frost pockets. Soils are shallow accumulations of organic material on bedrock habitats, or rapidly drained and nutrient-poor sands on outwash plains
Ridgetop Scrub Oak Barrens: Extremely shallow, stable acidic soils over bedrock, typically on ridges. Open bedrock is common.
Pitch Pine - Mixed Hardwood Rocky Summit: Dry rocky ridges and summits of low to moderate elevations. Soils are derived from acidic bedrock and are typically shallow, well- to excessively drained, coarse sands or gravels that develop in pockets of the exposed bedrock expanses.
Red Oak - Heath Woodland / Rocky Summit: Found on rocky, low to mid-elevation summits and south-facing upper slopes, this dry, acidic oak woodland, soils are composed of nutrient poor gravels and coarse sands, commonly with exposed bedrock.
Oak - Hickory / Hophornbeam / Sedge Lawn Forest: Found on upper slopes and side slopes at lower elevations, usually with southeastern to western exposure and with well drained loams or sandy loams, typically circumneutral. Soil is stony, but exposed bedrock, boulders and cobbles are rare.
Temperate Shale Cliffs and Talus: Restricted by heat and lack of soil, the system is sparse, mostly herbaceous vegetation on steep, unstable shale talus and cliffs.
Little Bluestem - Poverty Grass Low- to Mid-Elevation Outcrop Opening: Grassy openings found on flat summits and rock outcrops, plateaus and southwest-facing upper slopes. Exposed acidic sandstone and conglomerates can often make up a large part of the cover

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