The Silver Bluff Audubon Center

I planned to visit the Moody Nature Preserve over Thanksgiving break, but I changed my mind because I hate driving.  Instead, I went to The Silver Bluff Audubon Center near Silver Bluff, South Carolina.  It was a 45 minute drive from my house vs. a 3 hour drive to the Moody Preserve.  The shorter distance beat sitting in a car half the day.

The SBAC is located in the boondocks.  Silver Bluff Road runs off Old Jackson Highway, an area of second growth forest, agricultural land, and factories.  The latter are located here to take advantage of the state’s anti-union oppression.  A large wheat field borders the bird sanctuary.  The last 2 miles of Silver Bluff Road consists of unpaved but well graded dirt.  The road leads to the Savannah River but to reach the hiking trails it’s only necessary to drive about half that distance.

Map of the SBAC. I hiked the Tanager Loop Trail.  It’s supposed to be about 2 miles, but I think it’s slightly longer than that.  The Tanager Trail is well marked and easy to follow.

This ancient dwelling is near the beginning of Tanager Trail.  It looks like an outhouse, but someone probably lived in it a long time ago.  Perhaps it was a hunting cabin.  It’s surrounded by overgrown chinaberry trees (I think).

Over 200 species of birds have been recorded at the SBAC, and I saw about 5 % of them in the hour I was there.  I suppose, if I could have stayed all day, I could have easily doubled that number.  I didn’t see any of the rare birds that make this preserve special–bald eagles, Cooper’s hawks, wood storks, Bachman’s sparrows, prairie warblers, Swainson’s warblers, and loggerhead shrikes.  All of these species breed here, but some are migrants.  I didn’t see the ponds where the water level is managed for the wood storks.  Wood storks require shallow water that supports an abundance of small aquatic vertebrates.  They nest close to shallow water, making it easy to feed their young.  I did see a wood stork last spring around the corner from my house as it flew over a wooded stream.

The 10 species of birds I did see were common–white breasted nuthatches, Le Conte’s sparrows, downy woodpeckers, rufous sided towhees, mourning doves, cardinals, crows, redwinged black birds, and turkey vultures.  This was the first time I’d ever noticed and identified the white breasted nuthatch, though I realize now I’ve seen them many times in the past.  They occur in pairs, and I did see 2 flying together.  The other hiking trail is actually named the White Breasted Nuthatch Trail.  On the way to this preserve I drove on bridges over Phinizy Swamp, Merry Brickyard Ponds, and the Savannah River, and I spotted 4 additional species–black vultures, common mergansers, great blue herons, and egrets.  None of the birds in the SBAC cooperated with my attempts to photograph them.  They kept flitting about and perching high in the trees.

There’s an open pine savannah with longleaf pine and wire grass alongside the unpaved road that leads to the trails, but I didn’t stop to photograph it.  I didn’t see any longleaf pine trees along the trail I hiked, though much of the forest is quite open there, and the fires they use to manage the savannah have undoubtedly spread here.

Much of the forest in the SBAC is open like this.  It consists of a few species of pine and many species of oak.  These are loblolly pine, I believe.  Shortleaf pine and loblolly pine hybridize and some of the trees showed characteristics of both.

Many of the pine tree trunks are charred, showing evidence of fires.  The fires used to manage the open pine savannah evidentally spread here.  Both pines and oaks are fire resistant.  Most pine and oak trees over 3 years old can survive light ground fires.  Some species of oak, however, are somewhat less fire resistant.  They may survive, but the fire damage makes them vulnerable to diseases which rot out the wood and create snags.

Here’s an oak tree that was wrecked by a storm, probably earlier this past summer.

Common trees along the Tanager Trail that I identified include loblolly pine, shortleaf pine, hybrid pines, water oak, laurel oak, Shumard’s oak, southern red oak, black or cherry bark oak (I can’t tell the difference), blackjack oak, swamp chestnut oak, post oak, overcup oak, sweetgum, hickory, beech, and tupelo.  The composition suggests what botanists might refer to as a mesophitic river terrace forest because most of the species prefer moist sites.  I had never noticed and identified Shumard’s oak before, though I’ve certainly seen it.  Shumard’s oak can grow to 100 feet tall.  It’s a valuable species utilized for reforesting bottomlands due to its fast growth rate.  Swamp chestnut oak occurs here as well.  It’s also known as cow oak because its acorns are palatable enough for cows to eat.

Spanish moss grows on most of the hardwoods here.

Is this a dried out Carolina Bay?  I took this photo while standing on a boardwalk, but last summer must have been so dry the water here completely evaporated.  Tupelo trees grow here.  They normally grow partially submerged.  I think this might be a Carolina Bay.

There’s lots of snags in these woods.

The tree on the right is a beech.  I’m always excited to find this northern species in Georgia.  I couldn’t identify the tree on the left because the leaves had all fallen off, but there were a lot of hickory leaves on the ground around the trunk.

Note the woodpecker hole at the very top of the debarked tree.  Did the woodpeckers debark their nesting tree?

A windstorm knocked this tree precariously over the trail.  Several other trees were knocked over in a neat row.  Tornado or downburst?

Photo of the trunk of the leaning tree in the previous photo.  The base is cracked.

The trail goes through a planted pine plantation.  I couldn’t believe the trail sign pointed this way.  I thought some practical joker had twisted the sign because a trail criscrossed this one.  Luckily, I did follow the sign.  Trees are harvested here, but for the most part the management is beneficial for the birds.  This was the dullest part of the trail, though a big flock of redwinged blackbirds flew over us here.

I saw deer tracks and heard a squirrel barking–the only mammal life I detected here.  Surrounding this deer track are fallen leaves from laurel oak, water oak, and overcup oak.

If I would have had more time I would have walked down the unpaved road to the river.  I hiker can easily get over 5 miles of enjoyable walking here on the trails and unpaved road.  On the Friday after Thanksgiving there were only 2 other cars parked here, so it’s not at all crowded.

 

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The Congaree National Park, Home of the Giants

The Congaree National Park in South Carolina still held some surprises for me, even though I traversed this biggest last stand of bottomland forest in 1988.  Then, it was just a National Monument but in 2003 was upgraded to National Park status.  The park hosts 17 national and/or state record trees, including an 156 foot tall loblolly pine; and record shumard, southern red, and overcup oaks; as well as champion water hickory, Carolina ash, holly, box elder, persimmon, and paw paw.

Loblolly Pine–Pinus taeda

Loblolly pine.  The state record tree located in this park has a circumference of 16 feet.  This one looks to be at about 9 or 10.

The tree on the right is the loblolly pine from the previous photo.  The tree to the left is a red maple.  Some of the stands of loblolly pine in the park were found to be 227 years old.  The same study found that this species sprouts following hurricanes which open up the forest canopy.  The ages of stands corresponded with the history of hurricanes. (I took all the photos for this blog entry.)

This species is also known as old field pine because it reseeds so easily in lots devoid of other trees.  It has become a dominant tree throughout the southeast since much of the cotton and corn fields and horse pastures, which 100 years ago made up the face of the southern lands, were abandoned and went fallow.  Before European settlement it was merely a common component, but today it grows in pure stands as well as mixed with other species.  Therefore, it’s sometimes given the name bull pine due to its predominance.  Not only does it grow in upland locations, but it reaches prodigious size in wet areas from whence it gets its name, loblolly, which means mud puddle.  In the Congaree they grow in wet mud.

Sweetgum–Liquidamber styraciflua

Forked sweetgum trunk.

Another surprise for me.  I didn’t know this species could grow with its root system submerged in water, but I saw plenty of individuals in the Congaree growing in 6-12 inches of water.  Some had roots spread in structures similar to those of cypress and tupelo, enabling them to balance without tipping over in muddy soils.  Sweetgums, like loblolly pines, reseed readily in fields and are a common tree in upland sites.  But they’re adaptible enough to thrive in low muddy land as well.

Cypress–Taxodium distichum and Tupelo– Nyssa sp.

Cypress tree trunk.

Look at all of these cypress knees.  Scientists are unsure whether the cypress knees, which are part of the root system, grow for respiration or balance.

Up close view of a cypress knee.  Cypress trees are closely related to California red woods.

There are a lot of interesting microhabitats within a cypress-tupelo swamp.  Areas flooded in shallow water provide homes for fish, reptiles, amphibians, crayfish, and aquatic insects and spiders.

Flooded land in the cypress-tupelo swamp.

Fallen hollow logs and standing snags provide dens from everything from bats and possums to snakes and birds.

This hollow log is a possum mansion.

This standing snag could be hiding bats or flying squirrels.

When the water recedes lush grass and bamboo cane grow.  I can just imagine such Pleistocene mammals as long-horned bison, horses, and mammoths feeding in these grassy glades which often come about when a mighty old tree topples over allowing more light to reach the forest floor.

Note the grassy glade in the background.  There is plenty of grass and cane for a small population of bison and horses in the Congaree.  Too bad they’ve been extirpated.  The only big game left is deer and feral hogs.

A stand of cane.

When the mighty behemonths do topple over, their roots rip caverns in the forest floor.  Those often fill with water forming deep pools that are free of fish.  Amphibians can breed here without fish preying on their eggs and tadpoles.

Upturned tree root.

Pool formed in a hole from where a tree toppled over.

Beech–Fagus grandifolia

Beech tree canopy

Beech grows on sites that are near water but normally stay high and dry.  I love beech, and I wish I lived in a forest of these beautiful trees.  Their bark is white, the leaves turn a lovely yellow in fall, and they produce delicious little nuts.  Beech trees were common in the south during certain climatic stages of the Pleistocene, and as I mentioned in my blog entry “Pleistocene Passenger Pigeon Populations,” I think it’s a clue that passenger pigeon populations skyrocketed when beech was common because beech can grow and spread from sprouts.  The absence of passenger pigeons feeding allows more oak acorns to survive, and oaks outcompete beech.

The Congaree Swamp is probably as old as the Okefenokee Swamp

No studies on the age of the Congaree Swamp have been conducted as far as I know, but I assume it formed about the same time as the Okefenokee which became a swamp between 7,000-8,000 years ago following the final dissolution of the Canadian glacial Lake Agassiz when the water table rose all across the continent.  Throughout much of the Pleistocene, the region around the Congaree River was likely a mixture of upland oak and pine forests and savannahs with only scattered marshes perhaps near creeks and beaver ponds.  Particularly dry climatic stages even hosted oak scrub and sand dune environments.  It’s possible this region has repeatedly converted and re-converted to swamps with every full blown interglacial.

A comparison between my 1988 trip to the Congaree with my experience in 2011

The park system has considerably upgraded the facilities since I was here last in 1988.  Then, there was a gravel parking lot, and nothing else other than some gray paint marks on trees to demarcate the trails.  I hiked by myself in late July and was impressed with the giant trees.  This was before 1989 when Hurricane Hugo flattened many of the trees, but even then there were quite a few felled trees.  I saw a deer resting on a log, a scarlet king snake, and about a billion orb-weaving spiders that built webs across the entire trail at about 1 foot intervals.  After about 5 hours of enjoying nature, I became paranoid that I didn’t know what trail I was on, and I began jogging because I didn’t want to get lost in the park after dark–I feared the potential threat from feral hogs and rabid raccoons.  I didn’t see a single person while I was there until I got back to my car and met a park ranger.

Today, the Harry Hampton Visitor center is located at the entrance of the park.  It’s an air conditioned haven with clean lavatories.  Though the park is still not crowded, we did cross paths with many people.  Moreover, there is a pleasant 2.4 mile boardwalk which made the park accessible for us because my wife is wheelchair bound.

The lower boardwalk goes through a cypress-tupelo swamp.  The upper boardwalk goes through a bottomland forest dominated by sweetgum, loblolly pine, red maple, river birch, and ash.  I only saw a few oaks here–water, swamp chestnut, and willow; though in other areas of the park they’re more common.  Holly trees are common in the understory, and there are occasional patches of palmetto.  I saw no paw paw trees here, but I remember there were many on the trails.

The trails are now color coded, so there is little danger of becoming confused as to which trail one is on as I did 23 years ago.  The paint marks are on trees for the hiker to follow.

The Geological and Ecological History of the Okefenokee Swamp (part three)

Common and Interesting Plants Found in the Okefenokee Swamp

Most of the aquatic  plants that dominate the present day landscape of the Okefenokee Swamp were restricted to small scale marshes alongside the reduced number of rivers and streams that still incised the Okefenokee basin during the arid milleniums of the Ice Age when the water table fell and the swamp dried up between 36,000 BP and 7,000 BP.  The rest of the basin during this time period probably consisted of grassy pine savannah and scrub oak.  Nevertheless, these relic aquatic remnants provided the nucleus of the population that eventually re-established itself as the primary vegetation of the region.  Here are some interesting floral components of this environment.

Bald Cypress (Taxodium distichum)–Eight-hundred year old giants still stand in a few coastal swamps near Georgia’s coast.  One-hundred years ago, when loggers decimated much of these ancient bottomland forests, they skipped over the biggest cypress trees because they were too large and hollow, and therefore too much trouble to economically harvest.  One of these gigantic cypress trees is located in the Townsend Wildlife Management Area in McIntosh County.  It’s 44 feet in circumference.  Imagine 7 men, all at least 6 feet tall, laying end-to-end in a circle around the tree and they still wouldn’t completely encircle it.  It’s understandable but not generally known that cypress trees are relatives of the famous Californian redwoods.  They sure have great size and long life in common.

For more about Georgia’s big cypress trees see this following link  http://savannahnow.com/news/2010-08-30/700-year-old-cypress-tell-story-survival

I took this photo of a cypress tree in autumn foilage at Phinizy Swamp in Augusta, Georgia.  Unlike most coniferous trees, cypress trees lose their foilage in the winter, like deciduous broad-leafed trees.

Unlike most coniferous trees, cypress trees are not evergreen, and they shed their needles in the winter.  They usually live in flooded swamps. They have mysterious knees–wooden knobs that grow above water.  Scientists are uncertain whether these aid in respiration or simply balance the trees in the watery muck where they grow.

Water tupelo (Nyssa aquatica)–Cypress trees hollow out and provide roosting habitat for bats and homes for other animals, but tupelo trees become hollow more frequently.  Matt Clement, a grad student at UGA, found 97 roosts of Rafinesque’s bats along the Altamaha River, and most of them were in hollow tupelo trees.

Water shield or dollar pad (Brasenia schreberi), Floating Heart (Nymphoides sp.), and White Water Lilly (Nymphaea odorata)–These are three completely unrelated plants, but their leaves look similar.  In fact, I can’t really tell their leaves apart.  It’s an example of convergent evolution when different species evolve similar structures to solve the same ecological problems.  All three are what people think of as the lilly pads so commonly seen floating on the surface of the open water habitats in the Okefenokee Swamp that are often confusingly referred to as prairie because they’re treeless.  All three species have round floating leaves attached via long stems to underwater roots.

Panic grass (Panicum sp.) Saber-tooths and jaguars lurked hidden in patches of this tall cane-like grass, stalking the long-horned bison and horses that fed upon it during the Pleistocene.  The large fauna are gone but the flora remains.

Photo of some panic grass also known as maiden cane that I took at Phinzy Swamp, Augusta, Georgia.  There was another patch on the other side of the path that was 12 feet tall.  I wish I would’ve taken a photo of that.

Spanish Moss (Tillandsia usneoides)–Oddly enough, Spanish Moss is related to pineapple–both are Bromeliads or air plants.  Wind and birds spread seeds and fragments.  The seeds and fragments of the Spanish Moss lodge in other tree branches.  The Spanish Moss then grows (both from seed and vegetatively).  The plant survives by extracting nutrients from air and rain water, not from the trees upon which they land, thus they’re considered epiphytes, not parasites.  Birds, bats, spiders, and snakes live in and about the moss.

Spanish Moss hanging from either a water or laurel oak at Phinizy Swamp, Augusta, Georgia.  Spanish Moss is quite common in the lowlands of the Augusta area, but I’ve never seen any in hilly sections.

Bladderwort (Utricularia sp.)–Like strange creatures from a low budget horror film, carnivorous plants thrive in the Okefenokee Swamp.  Bladderwort is an underwater plant with no roots.  The bladder-shaped structure on the plant works like a trap door, a suction-on-contact action captures fish fry, mosquito larvae, tadpoles, and protozoa.

Pitcher plants (Sarracenia flava, Sarracenia mino, Sarracenia psittacaea)–There are three species of pitcher plants found in the Okefenokee–the hooded, the parrot, and the golden.  A sweet rotten odor emanating from the plants attracts insects which get trapped in tubular stems.  Backward hairs block insects from being able to escape, and eventually, they tire and fall into the toxic water at the bottom of the tube.  Bacteria in the water digests the insects, releasing nitrogen that the pitcher plant is able to absorb.

Round-leafed Sundew (Drosera rotundifolia)–The sticky hairs on this plant work just like flypaper, trapping hapless insects.

Burreed (Sparanium sp.)–Fossil mastodon dung discovered in the Aucilla River, Florida contains many types of aquatic plants, including most discussed here.  Cypress was the most common item in their diet, but the beasts ate nympoides, nymphaea, and this one–burreed.  Burreed is an important plant in the second stage of forest succession that occurs when islands develop within the swamp.

The five stages of forest succession in the Okefenokee Swamp

1.  Sphagnum moss floats to the surface of open water and soil begins to accumulate on it forming an island.  Beakrush takes root.

2. Burreed, panic grass, and redroot are the second stage of plants to colonize the island.

3. Sedges take over.

4. Bushes and saplings colonize the island.

5. Trees such as cypress, tupelo, water oak, and pond pine form the final components of island forest succession in the Okefenokee Swamp.