Friday, December 21, 2007

More Boundary Lines

With over 15,000 acres in Four Holes Swamp, the Audubon Center at the Francis Beidler Forest has many miles of boundary lines to maintain. Yesterday was to be a cool and sunny day, so plans were made to locate an abandoned interal line and make it the new northern boundary of the sanctuary (no hunting, no fishing) portion of Audubon South Carolina's (ASC) holdings within Four Holes Swamp. Alas, this was easier said than done.

The former Georgia Pacific property had obviously been heavily logged at some point prior to its aquistion by ASC in 1988. Apparently, there were few if any trees near the property line on which to chop blazes. The line across the swamp is almost two miles long. There are some iron rebars driven into the swamp to mark the slight changes in direction of the line, but after almost 20 years they have rusted or become buried. Yesterday, we had no luck finding the line. However, we had hiked over 1.5 miles with a gallon of red paint per person, so we were going to paint something!

We began painting the outside boundary along our path back to the truck (see yellow highlighted section in image). At every turn in the boundary line there is a iron pipe or rebar marking the spot in addition to triple blazes on nearby trees witnessing the spot. Where the boundary line passes near trees on the left or the right, two blazes are chopped as witnesses facing the line. That's plenty of painting. By the end of the day, we were each down to less than 1/2 gallon of paint (some of it on our finest swamp clothing).

With the promise that today's rain would let up by noon, we headed out to the corner with a cheap compass and a metal detector to try and find the elusive boundary line. The high-speed surveyor's compass was in a staff member's truck in Summerville. The red line shows the corner markers at each side of the swamp (and line). We began at the western corner and shot a bearing with our less-than-precise classroom compass. We measured out 169' with the tape and began searching the area with the metal detector. We soon had a squeal signifying iron lay beneath the muck. It was then that we noticed the three blazes hidden beneath a lush green carpet of moss on a nearby tree. Those would be the last blazes we found. Probing the muck with the machete produced the rusted off tip of rebar complete with a old piece of pink surveyor tape. We had our first corner and a line on which to follow into the swamp.

Using our crude compass and eyeball estimates, we flagged a path into the swamp and captured the coordinates of those points with a Global Positioning System (GPS) unit. We dumped the captured waypoints into the computer when we returned the center and generated the next image. Due to the available satellites when were in the swamp, we were not able to get very accurate coordinates. However, since blazes were not available on trees to assure us that we were on the correct line to the corner on the opposite side of the swamp, we simply wanted the waypoints to show that we were moving in the right direction. A few of the points are obviously inaccurate, but the general pattern matches the red line that connects the two corners. Therefore, we can assume that our straight line of flagging in the swamp is indeed heading to the far corner.

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