Deciduous Forests of Eastern North America

Braun 1950:

– A tree-dominated vegetation type in which most of the woody taxa are winter deciduous.

Mixed mesophytic association

(MM, WM, OC of Braun)

Fagus, Liriodendron, Acer saccharum, Tilia, Aesculus, Castanaea, Betula, Quercus, Fraxinus

Sugar maple association

(BM, MB of Braun)

Acer saccharum, Fagus, Tilia,

Dry sites: Quercus, Carya

Wet sites: Fraxinus, Ulmus, Acer rubrum

Oak Hickory Association

Quercus, Carya

Varies from dense closed canopy to woodland and savanna

Oak Pine Hickory Association

Quercus margaretta, Q. marilandica, Juniperus virginiana

Poorer soils dominated by Pinus taeda, P. echinata, Quercus stellata (post oak), Q. Marilandica (black jack oak)

Eastern Deciduous Forest Characteristics

Typical forest canopy reaches 30 m and is closed.

May be multi-layered

Sub-canopy

One or two shrub layers

Well-developed herb layer

Boundaries

Evergreen dicot trees occur in canopy at southern edge.

Evergreen conifers dominate northern edge.

To west, forest becomes shorter, floristically poorer, and grades into savanna.

Geology

Geology is mixed: sedimentary, igneous and metamorphic rocks

Widespread calcareous outcrops

Glacially derived materials to north

Occurs on two landforms

Platform areas that are flat

Foldbelts with pronounced relief (0-1600 m)

Climate

Climate is humid

Warm summers

Cold winters in north with shortening cold periods as you move south

Restoration

Boerner, R. E., A.T. Coates, D.A. Yaussy and T.A. Waldrop. 2008. Assessing ecosystem restoration alternatives in eastern deciduous forests: the view from belowground. Restoration Ecology 16(3): 425-434

History

Some Appalachian mountain forests have been managed for 2000 y.

• Fire has been common for 4000y

• Fire return interval was stable until Native American decline after European contact.

After European contact, fire, harvest and small-holding agriculture were common through the early 20^th century.

Fire return interval of around ten years was common.

Government mandated fire suppression began in 30’s and was successful.

Denser forests, more detrital biomass

Some species composition changes

Historic soils were N-limited

Landscape was dominated by trees dependent upon ectomycorrhizae.

Common in low N soil with lots of recalcitrant OM

Industrialization of the east coast has resulted in chronic atmospheric deposition of N and S

Some parts of Appalachians are now N-saturated

This study looked at fire (functional restoration) and thinning (structural restoration).

Would these treatments lower N and result in more recalcitrant OM?

Treatments reduced soil OM, but not N; effects were short-lived.

They recommended regular thinning and burning.

Flinn, K.M. and M. Velland. 2005. Recovery of forest plant communities in post-agricultural landscapes. Front Ecol Environ 3(5):243-250

History:

– Phases of forest clearance for agriculture were followed by agricultural abandonment and forest regrowth.

– Forests on former agricultural land differ in vegetation and soils from uncleared forest.

• Even 2000 y after reforestation.

Herbaceous species

– The majority of forest plant diversity comes from herbaceous component.

– After abandonment, old fields are colonized by open-habitat herbaceous spp.

– A thicket of shrubs and trees takes 30-40 y

– Closed tree canopy takes 60-80 y

Problems for herbs that evolved in stable, spatially continuous habitat:

– Short-distance seed dispersal

– Short seed dormancy

– Low seedling recruitment

– Long reproductive cycles

Seeding and planting of live plants have both proven to be effective restoration methods.

Deer density has increased

– They graze more

– The can also disperse seeds