Natural Community Systems -- Photo Guide

Appalachian oak - pine forest system

Appalachian - oak - pine forest system at Dumplingtown Hill (photo by Ben Kimball for the NH Natural Heritage Bureau)
Appalachian - oak - pine forest system at Dumplingtown Hill in Raymond (photo by Ben Kimball)

 

Description:  Appalachian oak – pine forest systems are found mostly below 900 ft. elevation in southern New Hampshire south of and at lower elevations than the hemlock – hardwood – pine forest system.  The southernmost portions of the state are associated with the warmer and drier climatic conditions and apparently more fire-influenced landscapes that prevail south of New Hampshire in lower New England.  Much of the area of these forests corresponds to nutrient-poor, dry to mesic, sandy glacial tills, and some large areas of sand plain or shallow-to-bedrock tills, particularly in the seacoast and lower Merrimack and Connecticut River valleys.  Sand plains in these areas that have a frequent fire history correspond to pitch pine sand plains; those with a less-frequent fire regime (i.e., more than 50100 years) are classified as oak – pine forest or sometimes hemlock – hardwood – pine forest systems depending on the composition of trees.  More isolated patches of oak – pine forest systems are found to the north in central NH associated with dry rocky ridges or sand plains with a historic fire regime.

This forest system is marked by the appearance of oaks other than red oak, hickories, and numerous other southern plant species that are found in the Appalachian states and reach their northern limit in or near southern New Hampshire.  It is also coincident with the decreased abundance and frequency of Tsuga canadensis (hemlock) and Fagus grandifolia (American beech), species that are more prominent in hemlock – hardwood – pine forests, although both are still commonly present here, particularly in dry-mesic or mesic sites.  Sugar maple and yellow birch are found in low abundance and are restricted to more mesic sites such as along drainages or patches of mesic Appalachian oak - hickory forest found on lower slopes or silt soils.  Southern species characteristic of Appalachian oak – pine forests (see below) are diagnostic of the system even in relatively low abundance (i.e., 15% cover for trees) as long as they are relatively consistent and well distributed in the forested area (e.g., not single individuals across many acres). 

The natural communities of this system are restricted to the southeastern part of the state and low elevations of the lower Connecticut and Merrimack River watersheds.  The dominant forest types are mesic Appalachian oak - hickory forests on dry-mesic to mesic soils, and dry Appalachian oak forest on dry soil.  Patches of more mesic or finer-textured soils mix with the more dominant coarser till and outwash soils along drainages, slope-bases, on silty soils of river terraces, and on marine deposits in the seacoast area.  These areas often correspond to mesic Appalachian oak - hickory forests, which can be locally abundant in some landscapes.  Overall, dry-mesic conditions are probably the most common in the landscape, which generally corresponds to the dry-mesic variant of mesic Appalachian oak - hickory forest. This community is essentially the southern counterpart to hemlock - beech - oak - pine forests that dominate central NH.  In some areas of southwest New Hampshire, oak - mountain laurel forest can be abundant.  On soils that are weakly enriched, semi-rich oak - sugar maple forest can be present.  On shallow rocky till sites, pitch pine - Appalachian oak - heath forest and chestnut oak forest/woodland can intersperse with the dominant dry Appalachian oak forest.


Diagnostic natural communities:

      • Dry Appalachian oak forest (S1S3)

      • Mesic Appalachian oak - hickory forest (S2S3)

      • Oak - mountain laurel forest (S3)

      • Semi-rich oak - sugar maple forest (S2S3)

Peripheral or occasional natural communities:

      • Pitch pine - Appalachian oak - heath forest (S1)

      • Chestnut oak forest/woodland (S1S2)

      • Dry river bluff (S3)


Landscape settings: hills, valleys, and lowland flats

Soils: loose and firm glacial till, glacio-fluvial soils (e.g., river and kame terraces, outwash), marine silts and clays

Spatial pattern: large patch to matrix (<10–100+ acres); irregular and linear zonation of component communities

Physiognomy: forest

Distribution: below 900 ft. elevation in southern NH; disjunct into south-central NH on steep, south-facing hills


Characteristic species:
   Southern species diagnostic of Appalachian oak – pine forest systems:
   (many species of hemlock – hardwood – pine forest systems may also be present)
      
Quercus alba (white oak)
      Quercus velutina (black oak)
      Quercus coccinea (scarlet oak)
      Quercus alba (white oak)
      Quercus prinus (chestnut oak)
      Carya spp. (hickories)
      Pinus rigida (pitch pine)
      Sassafras albidum (sassafras)
      Kalmia latifolia (mountain laurel)
      Desmodium spp. (tick-trefoils)
      Cornus florida (flowering dogwood)
      Cornus rugosa (flowering and round-leaved dogwoods)
      Solidago odora (sweet goldenrod)
      Aureolaria spp. (foxgloves)
      Baptisia tinctoria (wild indigo)


Associated natural community systems:  At more northern locations or towards more mesic or higher elevation locations, this forest system is transitional to hemlock – hardwood – pine forest system.  It transitions to pitch pine sand plain systems in more fire-prone settings, and to temperate ridge - cliff - talus systems in shallow-to-bedrock landscapes of lower elevations and southern parts of the state.


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