Posts Tagged ‘Heggie’s Rock’

The Natural Environments of Georgia by Charles Wharton

March 23, 2011

The Natural Environments of Georgia by the late Charles Wharton is a book I remember reading between classes in the Augusta College library in 1986.  Then as now,  local ecology and natural history fascinated me.  For my recent 3 part blog series about the Okefenokee Swamp, I read a research paper that referenced this book and reminded me about it.   I knew this source would provide a great deal of fodder for my blog, so I began to search for it.  It’s out of print, and the only copy on sale at is a used one for $186 which is about 10 times what I’m willing to pay for it.  The east central Georgia library has 62 copies of the book, so I asked for an interlibrary loan.  Again no dice–it’s considered a reference book, and they don’t loan it out.  Finally, I went out of my way to the downtown library to look at it, but I only had an hour.  I had to cram the 200 page book into my brain instead of being able to digest the interesting details at my leisure.  Research shouldn’t be this hard.

Dr. Wharton lists 100 different types of natural environments in Georgia, but this is an arbitrary and somewhat redundant list.  A new version of this book (which was originally written in 1979) is due from the University of Georgia Press within the next 2 years, and they list 72 types.  The new version will be entitled A Guide to the Natural Environments of Georgia, and I expect it to be an expensive volume.

Many of the plant associations found in these myriads of environment types probably date back well into the Pleistocene and perhaps earlier.  Certainly, some Pleistocene plant associations no longer exist.  Part of north Florida once consisted of a forest of spruce, beech, and hickory, a combination of trees now found nowhere in the south, at least naturally.  A plant fossil site near Winder, Georgia known as Nodoroc suggests a forest of northern pines (red and white), southern pines (shortleaf), and oak along with hickory, chestnut, and fir, and interspersed with many grassy meadows–another environment not found today.  All forest types including the extinct Critchfield’s spruce as a component, of course, no longer exist.  Critchfield’s spruce was a temperate species once widespread in the southeast.

The composition of plants within an environment depends on many factors, chief among them is chance.  Many plant species have a wide tolerance for different climates and soil conditions.  Some compete better than others according to environmental conditions, but still dumb luck plays a big role in the distribution of different kinds of plants.  For example wind blows seeds of one plant in one direction creating a pure stand here, but it didn’t blow in the opposite direction making that plant absent there.  A series of annual freezes destroys the fruits of a tree, wiping out that species here, but not there on a sunny southern facing slope.  Fire burns up a forest transforming it into a meadow here, but leaves a stretch of wood there on the other side of a stream.  Animals consume all the acorns here allowing beech which can reproduce from sprouts to dominate, but over there a score of acorns go uneaten and a lot of oaks still grows.

I’ve already discussed open pine savannahs and cypress swamps in previous blog entries.  Here are a few other types of environments Charles Wharton catalogued in his book.  I’ve focused on common environments of central Georgia.

Alluvial River and Swamp Systems: Piedmont Region

Dr. Wharton states this type of environment made up about 9% of Georgia’s landmass.  Common trees included river birch, sycamore, sugarberry, green ash, red maple, box elder, water hickory, and oak.  Stands of water, cherrybark, overcup, and swamp chestnut oaks outnumbered stands of just water and willow oak.  Thick stands of giant river cane or bamboo forming impenetrable thickets occurred at the heads of creeks.  These were rich environments providing lots of forest mast and bamboo forage for the megafauna to eat.  Bison and mammoths could graze year round upon the cane which is a giant grass, and munch down on acorns in the fall and winter as well.  Early naturalist explorers such as William Bartram and John Lawson found canebrakes that stretched for miles.  The Indians maintained them with fire.  Now, canebrakes exist as small patches vanishing in the face of development and fire suppression.

Bluff and Ravine Forests with Northern Affinities

Disjunct populations of plant species that normally range in the north exist along the Mississippi River in southern Louisiana.  Ecologists theorize that during the last Ice Age cold meltwater from midwestern glaciers rushed down the mighty Mississippi and hit warm southerly fronts creating foggy moisture which got trapped in river valleys with steep bluffs.  These blufflands host beech, shumard, white, and chinkapin oaks, tulip, magnolia, elm, basswood, mulberry, Florida sugar maple, pignut and bitternut hickory, white ash, hackberry, sycamore, holly, spice bush, paw paw, hydrangea, silver bell, red bud, hop hornbeam, elderberry, giant bamboo cane, 11 species of fern, nettles, ginseng, and many other plants that prefer cool moist conditions.  Such bluff forests are also found on the Atlantic coastal plain as far south as north Florida suggesting a similar climatic explanation here as well, though no rivers in what is now Georgia drained directly from glacial meltwaters.

Oak-Hickory-Pine Climax Forests

Soapstone outcropping in suburban Atlanta.  This land was never farmed because it was too rocky, and a good example of oak-hickory-pine climax forest grew here.  The Woodland Indian culture carved bowls into the stone before the development of ceramic pottery.  Picture from google images.

This type made up 50-75% of the Georgia piedmont before European settlement.  Dr. Wharton gave 2 examples: one in Elbert County and the other in Dekalb County.  The latter is known as Soapstone Ridge.  People from the Woodland Indian culture (3000-1500 BC) chipped bowls in the abundant soapstone located in this region which is right off the Atlanta bypass.  They heated stews by dropping hot rocks in the bowls.  The development of ceramic pottery put an end to this practice.  The chipped bowls are still visible in many rocks.  The rocky soils prevented the development of agriculture, but now a subdivision known as Soapstone Ridge (what else?) has fragmented the forest.  These forests hosted red, white, and black oaks, pignut, shagbark, and mockernut hickories,  shortleaf and loblolly pines, and red maples.  Formerly, before the blight decimated the species 100 years ago, chestnut was a common component.  Soils within this region containing high levels of iron and magnesium also host Oglethorpe oak, mulberry, basswood, and redbud.

Shortleaf-Loblolly Pine Climax Forest

Regions within the oak-pine-hickory climax type that are continuously burned become dominated by fire resistant pines.

Oak Savannahs and Woodlands

This is an extremely rare type within the oak-hickory-pine climax type that was probably more common during the Pleistocene when dry cycles of climate  created a landscape of widely spaced shortleaf pine, red, scarlet, post, and blackjack oaks, blueberry and haw bushes, and grass.  Today, this type of environment only occurs on thin soils.

Beaver Ponds

Photo by Karan Rawlins from google images.  This is a beaver pond somewhere in Georgia.

Without humans limiting their numbers, beavers dammed most of the abundant creeks in what is now central Georgia creating long chains of beaver ponds.  If beavers completely chewed down all the trees in a vicinity, they abandoned the area and sediment filled the ponds until the ponds transformed into a marsh.  After enough willow trees resprouted the beavers would return.  Treeless marshes were the preferred habitat of the extinct giant beaver.  Therefore, it’s reasonable to suppose that the present day beaver (Castor canadensis) created habitat favorable for the extinct giant beaver (Castor ohioensis).  Beavers don’t build dams on large rivers but instead live in riverside tunnels.  When trees grow scarce, they will dig canals connecting their home pond with distant woodlots.

Dr. Wharton’s book has a neat aerial photograph of a chain of beaver ponds along a tributary of the Flint River.  A hunter told him that one of these ponds alone held 1000 ducks.  King rails and Virginia rails, both of c0nservation concern in the state, live here.  Pickerel, buffalo fish, bowfin, and many other fish species swim in this pond–if it still exists.  Remember, the book is 30 years old.

Successional Forest Stages

An area in the piedmont stripped of its trees will soon become a grassy field with annual flowers.  If stripped of soil too, a stage where moss grows and soil builds will occur.  During the Pleistocene, megafauna foraging and fires probably prolonged the grassy meadow stage.  Next, perennials and pine tree and sweetgum seedlings, their seeds windborne, begin to take hold.  Berry bushes too, their seeds carried in bird turds, form colonies. Pine trees grow quickest and dominate while oaks try to catch up.  Eventually, oaks and hickories shade out the pines and they dominate.  Shade tolerant trees such as maples are the final colonists.  A mature piedmont forest was something beautiful and awe-inspiring, according to William Bartram who saw much of Georgia before Europeans ruined it. 

Granite outcroppings

1902 map of granite outcroppings in central Georgia.

Some rare plants live in shallow solution pits in this type, but mostly they’re just bare rock.  Below is a link to a virtual tour of Heggies’s Rock in Columbia County, Georgia.  In my opinion the surrounding woods are much more beautiful than the naked granite.   There are sandstone outcroppings in the coastal plain.