San Felasco Sweetgum Seed Rain

A couple of cavers came down from Tennessee last weekend to relax in Florida’s warmer weather, so Bruce, JJ and I took them out to San Felasco Hammock State Park for some biking and hiking on Saturday. We took the Cellon Creek Loop (south) bike trail to the Tung Nut Loop bike trail through an overgrown field to Sanchez Prairie. At that point, the Tennesseans had to turn back due to one of them just not quite being over his recent head cold. Bruce, JJ and I abandoned the bikes at the edge of the prairie and continued on foot from there. We hiked first along the toe of the prairie’s western slope to the third tributary, then wandered westward along the edge of that little karst valley to its head, from which we hiked back to the bikes along the “highland rim” of the prairie and then biked back to the vehicles. My GPS recorded 7.5 miles of biking and another 3.0 miles of hiking – an easy day, for once! Well, it‘s easy if you’re not sick.

The layout of the karst valleys is interesting to me. Imagine three lines of sinkholes developing in impermeable sediments atop soft limestone, trending in fairly straight lines (lineaments) oriented roughly east to west. Give those lineaments a little geological time and a couple of things happen. First, the sinks expand until they coalesce, and second, new sinks form westward of the last ones. By this process, the valleys undergo headward erosion and extend into the uplands. Unfortunately, very little rock is exposed and no caves are apparent.

Seepage springs occur at the head of each valley and occasionally along the lower slopes of the valleys. These lateral seeps are heavily damaged by feral pigs, which root up anything edible to a pig and then wallow in the clayey spring run bottoms. Whatever ferneries might once have existed in these places are now reduced to a few sprigs here and there. I saw a group of feral pigs a few weeks ago in the third valley, and we saw a group there again on Saturday. Based on the number of pigs, their sizes and coloration, I suspect this is the same (family?) group I saw before. A predictable nuisance is a manageable nuisance. Is anyone from park management reading this?

We did not see any feral pigs in the prairie bottom, but then I didn’t see any feral pigs in that part of the bottom last time, either. Perhaps that area is part of the territory of the pigs in the third valley.

Upon returning to the bikes, Bruce and JJ noticed they were being “rained” upon by tiny objects. From my more sheltered location it sounded like they were being pelted by aphid honeydew, but when I went over to them it became immediately obvious what it was. Back in 1971, I was walking across the University of Florida campus at, well, probably exactly this same time of the year through a monocultural stand of small but mature sweetgum trees. As I stopped to look at something I have since forgotten, the faint sound of a light rain could be heard, but instead of tiny droplets on my sleeve there were tiny seeds from the sweetgums. Evidently, sweetgum seeds dehisce simultaneously and then fall in one or more episodes over a short period of time. That is what Bruce and JJ had noticed – a sweetgum seed rain! When looking at darker backdrops like a downed tree trunk we could readily see the seeds falling abundantly. What a pity that our cameras were unable to video the event. It was only the second time in my life that I have experienced a sweetgum seed rain, and was a first for Bruce and JJ.

Incidentally, sweetgum seeds contain shikimic acid, the starting ingredient for making antiviral drugs to combat bird flu.

Sanchez Prairie (Saturday's Serengeti)

I got an early start today, arriving at the San Felasco SP bicycle trailhead and scooted off about 0930, following Cellon Creek trail to the power line and southward. Always before I have passed the barn where the dairy used to be, but this time I veered west a little to check it out and the large sinkhole close by. The sink was dry and without any limestone showing, but they say there is a barn owl in the barn, and I spotted this 2m yellow rat snake on a log nearby:


I thanked the snake for letting me see it and warned it about the owl, and then headed on southward following a bike trail thru an old field growing up in young loblolly pines and sweetgums, and Spanish needles (Bidens pilosa) galore. My pants and shoes, and exposed socks, snagged quite a few of their centimeter-long, half-millimeter wide seeds that have two 3-mm retrorsely barbed spines on one end. The spines stick into clothing and then the barbs start ratcheting the needle deeper into the clothing when you move, and soon you are being jabbed by few little needles here and a few more there. You stop and pick the worst of them out, being thankful for the short rest, and then move on.

Down the Tung Nut Depot trail, I rode thru a beautiful deciduous hardwood bluff forest to the north edge of Sanchez Prairie west of the powerline and stashed the bike. Now for the real fun - moseying. I walked pretty slowly counter-clockwise along the edge of the big wetland polje, with the bluff forest on my right. Coming to the northwest corner of the ponded water, I walked to within less than 10 meters of a nearly 3-meter alligator because I didn’t see it. I was looking upward at a flock of migratory yellow-rumped warblers that were being scolded by local Carolina wrens and Carolina chickadees, and I guess the big ‘gator figured it wasn’t in too much danger, for it only slowly did a U-turn in its muddy slide and languidly slithered into the water under a floating mat of frogbit. There are times when I’m glad we don’t have top carnivores like lions and hyenas around here. I thanked the ‘gator and moved on.

I explored the uplands to the west of Sanchez Prairie. Boring young pines and such, they are, and the patch of Spanish needles of the world! Oh, man, I came out the other side with major needles stuck below the belt. They were burrowing thru two layers of socks into my ankles, so I had to take 20 to pull them off. Mr. GPS then logged more sinkholes and ravines while walking back to the prairie’s southwest corner. There was a family of feral pigs, a sow and 6 young ‘uns just uphill of the prairie in a moist ravine. Check out this hog wallow in a seepage spring creek:


I am in awe over the huge amount of wildlife I saw today. I am going to list it and you aren’t going to believe it. There were two yellow rat snakes and two alligators. This smaller ‘gator is only about 2 meters long:


I ran across 4 or 5 (they backtrack and confuse me) families of feral pigs, each having 5 – 7 members. They forage mostly on moist to wet ground around the prairie’s perimeter and up the centers of larger tributary ravines. Here is a photo of the edge of a pond within the prairie:


Notice a couple of things here, first the countless pig tracks in the mud just up from the water’s edge. Second, there is a meter-wide open waterway between the mud and floating frogbit. Can you see the alligator track on the left, moving away from the camera and then cutting left into the vegetation? That waterway at the water’s edge is maintained by alligators slowly moving around at the water’s edge. You know what they say? “Don’t turn your back to the water!”

Along the edge of the pond where numerous small tree trunks <15 cm diameter emerge thru the stagnant, duckweed-covered tannic waters there were wood ducks. I don’t know if I was just flushing the same few repeatedly, like egrets flush while you’re canoeing down a river only to land a few hundred meters downstream where they will just flush again, and again, as you continue to float down. Otherwise, I might have seen 75 – 100 wood ducks in the space of a half-hour. Then the dickey birds were everywhere, and blackbirds were massing in an open-canopy part of the wetland forest where 3 destructive hurricanes came thru here several years ago. This picture will give you some idea of the damage the ‘canes did:


I doubt I have ever seen so many whitetail deer in a single day in my life. Did I see 50? Did I see 100? I never did start counting, but here are 3, there are 5, around the next bend are two groups of 4 and 5, and on and on. You know what you get when you don’t hunt big animals? You get deer all over the place, and they are sort of tame, too. If my path took me directly toward one, it would casually bound a few steps to the side and then stop, chow down on something green and then flick its ears at me, but they were not afraid. I just walked on by them, pointedly not making eye contact.

You also get pigs all over the place when there’s no hunting. The pigs would snort and stampede when they caught wind of me a few meters away, but when I neither chased nor shot at them they would stop, turn and face me, and watch as I walked on by. They never mess with me, pigs. Smile for me the next time you hear a beerbelly counting coup about how a hawg attacked him with “tushes THIS BIG!”

Oh, I almost forgot: Do you know why there was so much wildlife out there today? Acorns. Everywhere around and within Sanchez Prairie above the waterline is dominated by oaks, mostly diamondleaf oak (Quercus laurifolia), but also shumard oak, swamp chestnut oak, water oak and live oak. The bluff forest also has abundant pignut hickories that are dropping a moderate hickory nut crop this year. Wood ducks, feral pigs and whitetail deer depend heavily on mast (nuts) this time of the year. It is a seasonal crop, and perhaps they come from all around the nearby countryside to harvest the bounty that Sanchez Prairie has to offer. I know I do, thank you.

Blues Trace

Yesterday, I returned to San Felasco State Park with Bruce for a 10.3 mile bike and hike to nail down some karst features that are impossible to locate from topo maps and aerial imagery, and to have some fun. Blues Creek heads up just north of Millhopper Road in Gainesville, FL near the SE corner of the park. It drains surface waters during wet seasons and is kept wet by discharge from seepage springs during most of North Florida’s dry seasons (spring and fall). Blues Creek travels north from its origin through a moderately steep ravine dominated by a mature forest composed of mixed, semi-evergreen hardwoods. Shade from the forest canopy that the creek is embedded within is so dense that most of these woods have little brush, giving a park-like ambiance to the area.

Parallel to Blues Creek for a short distance is a karst valley that I will call Blues Trace until I learn what FDEP calls it. The valley is really a ragged line of deep, steep sinkholes that pond water up in serious or quickly-repeated storm events. This is one of the longer and deeper sinks, with Bruce for scale:


Blues Creek travels northward until it reaches a swamp forest, where it then flows within a wider, shallower, braided channel clockwise around the south side of the swamp. There are at least two blind valleys that extend to the south and west off the creek channel beside the swamp. The eastern blind valley has walls that are steep but climbable if you are healthy, and a floor of wet sand and mud, and logs galore. Blues Creek today runs through the western blind valley and sumps into a series of crevices at the base of the valley’s limestone walls that are too small to enter. Here is a portion of this very beautiful karst valley:


When it come to Florida karst scenery, it doesn’t get any better than that. We saw a 3ft long cottonmouth the last time we were here. Of course, the moccasin never threatened us. I have also seen downy nestling vultures hiding among these rocks several times over the years, and Florida tree fern (Ctenitis sloanei) maintains a small, possibly its northernmost Florida population in this valley (the USDA has records only as far north as Hillsborough County although I have seen it well north of that occasionally). The terminus of the valley has walls that are too steep and clay-slick to climb, and we didn’t want to do that anyway due to its splendid fern cover. You have to backtrack to get out of there. The only other people I have ever seen wandering around waaaay off-trail in the park were a couple of fellow naturalists at this spot. The place is a subtle magnet to my kind.

A major lineament (bedrock fracture) connects Alachua Sink in Payne’s Prairie to Hornsby Spring. Dye tracing has proven that several stream swallets only a mile or two north of this lineament connect to Hornsby Spring via underground conduits. These include Cellon Creek Swallet at the head of the San Felasco bike trailhead, Mill Creek Sink (an NSS-owned cave diving site) and another sink I don’t know the name of that used to channel the General Electric battery plant’s acid waste into the Floridan Aquifer. Sanchez Prairie almost certainly drains into that system – its swallet is almost dead-on the lineament. Blues Creek Swallet almost certainly feeds into that lineament too, as it is also only about a mile north of the lineament. Furthermore, Blues Creek Swallet may make the connection to the lineament via Blues Trace. Unfortunately, the known caves in this part of the lineament’s cave system have ceilings at 190ft to 220ft below the aquifer’s water level and there is plenty of overburden available to plug any solution pipe that might open up along Blues Trace, so it will take a dye trace to answer that question.

San Felasco and Gum Slough

The San Felasco Hammock Preserve State Park was the choice for Friday’s bike and hike. Bruce was recouperating from a bout with the flu, so we got a late start and only wandered about 9.5 miles that day. Using the GPS, existing bike and horse trails, and a variety of maps (topo, Google Earth, park trail maps), we were able to fill in some more of the puzzle (to me) that is the karst valley that ends in Sanchez Prairie. San Felasco is a special place that I never tire of exploring. It may be the closest thing around here to a large area of mature, natural vegetation spread across the transition zone between the impervious Northern Highlands and the karstic Newberry Plain. San Felasco also has small pockets of true “Old Growth Forest” if you know where to look. I know some of them, and continue to look for others.

San Felasco is pretty big for day trip explorations on foot, horseback or bicycle (no overnighters allowed - but maybe along the Florida Trail here?). The karst valley we are trying to tie down is smack in the middle between the north and south entrances to the park, there are no roads to it, the only trails to it are horse trails that bicyclists aren’t supposed to use, and the topography has a lot of ups and downs. In a nutshell, it is an aerobic little adventure to get there and another to come back, but they’re good ones. IMO, the trails are as challenging as the trails of the nationally renowned Santos Bike Trails Area, but are more scenic at San Felasco and are paths less traveled. The trails at Santos are on severely impacted property supporting raggedy early successional pine and hardwood forests plus old abandoned barge canal segments plus spoil piles and borrow pits and the like. It’s a great place to ride on red trails, though, and certainly more appropriate than San Felasco for ambitious, healthy mountain bikers who are not naturalists. Some of the trails at San Felasco are within early successional forests, too, but most of San Felasco’s trails run through mature hardwood forests or even older growth climax hardwood forests. Plus, the slope forests along the northern edge of Sanchez Prairie have that oak-beech look without the beech, but we can imagine…

On Saturday, Bruce, Brack and I did a bike and short hike trip at the Half Moon Wildlife Management Area in Sumter County, FL. The property encompasses 9,480 acres in the southeast corner of the confluence of the southern Withlacoochee River and Gum Slough. We got a late start on this 12.4-mile ride due to first attending an environmental expo in The Villages. We biked the main limerock road from the parking area at the northern end of CR 247 northward about 4 miles to Davies Road, intending to ultimately stand at the edge of Gum Slough Creek. There is a dirt road through the woods between and roughly paralleling the main road and the river-slough floodplain that would take us back to the parking area. We had intended to return via that route, but at that late hour it would have resulting in a death march along an unkempt road through hordes of ‘skeeters after dark. Nope. Didn’t.

Along Davies Road, we found a relatively easy route down into the Gum Slough floodplain where we stashed our bikes and hoofed it downhill. We almost made it to an eastern braid of the stream, but elected to keep our feet dry. This floodplain is not very level, but rather is crisscrossed with flood channels, natural streamside levees and natural rounded and elongated hillocks. Wet areas closer to the stream braids are dominated by mostly deciduous hardwoods like red maple and swamp tupelo, but we saw at least one pretty large sweetbay (Magnolia virginiana) almost 3 ft in diameter. The higher elevations supported a mature mid-successional mesic hardwood forest while intermediate elevations were dominated by a semi-evergreen hardwood forest dominated by live oak (Quercus virginiana). The latter habitat is also called “low hammock,” and is my favorite woods that we visited that day.

This low hammock is dominated by “too much” live oak, if there is such a thing. I say the former because it might compose over 50% of the overstory canopy, and I say the latter because live oak is a special tree. Driving down the highway you can see scads of live oaks out in Florida’s horse pastures. Their enormous 6-, 8- and 10-ft diameter trunks rise about a dozen feet off the ground and then multiple brontosaurian-necked limbs soar up and out and swoop down and spread out to form a hemisphere of photosynthesis a hundred feet in diameter and half that in height. Their limbs and trunks will be partially coated with resurrection fern and Spanish moss will cascade from their branches. If abandoned, that pasture will grow up into a forest dominated by those hemisphaerical, “open-grown” elders. You walk through that forest and think you are in an ancient copse because of the mightiness of their trunks, but in many cases they are less than a hundred years old, so don’t be fooled! The next step in the successional trend of the forest is exemplified by the low hammock habitat along Gum Slough, which you can see behind the below-pictured live oak:


Look at the form of that tree. Obviously, it is not a hemisphaerical, open-grown tree. That trunk rises almost straight up for about 45 feet before it first branches, and the trunk at that height is about 3 ft in diameter. This is a forest-grown tree, one that got its start in a small clearing that was created by a tree dying there long ago, allowing sunlight to reach the mature second-growth forest floor to energize the live oak of today. Notice the trunk is covered near the ground by bryophytes (true mosses). If you could see the limbwork high over Bruce’s and Brack’s heads, you could observe that resurrection fern and Spanish moss have been joined by several more epiphytes like ball moss, Bartram’s moss and several other Tillandsias, plus two orchids, the green-fly orchid (Epidendrum conopseum) and Tampa butterfly orchid (Encyclia tampensis). In truly old-growth live oak forests, there are more species of trees in the overstory and live oaks have a much higher density of epiphytes, at least in low hammocks.

The next time I visit Half Moon, and I certainly intend to, I will take the woods road and go looking for karst outcrops along the river and slough floodplain and its edge. Let me know if you want to go.