Informal outdoor lore in the Ozarks often includes references to something called a thong tree.  These are trees that have been bent over and forced  to grow upright from the far end of the pushed-over stem.

 

Lore has it that these are deliberate signs created by native American and early explorers intended to point the way towards some objective such as campsite or mountain trail.  There are a number of reasons to suspect this kind of story.  There are no documented references to thong trees in the journals produced by early visitors to our area like Schoolcraft and Nuttall.  Moreover, there are so many examples of such bent over trees that it is hard to believe that the sparse distribution of early settlers would need to mark so many trails.  The single known reference to trees trimmed by explorers to mark the way comes from French traders in northern Canada where waterways were disorganized into a complex maze by past glacier activity and the landscape is covered by a monotonous spruce forest.  Branches would be pruned on spruce trees located on prominent points of land adjacent to portages or river tributaries as a way of marking these locations.  Because the marking was done by cutting branches to produce a distinctive “flagged” shape to the spruce, these became known as “lop trees”.

Yet another reason to doubt the lore behind the thong trees we see in the Ozarks is that it is easy to see how they could form by natural occurrences without any human help at all.  Because the forest in northwest Arkansas is now recovering from the damage inflicted by the infamous late winter 2009 ice storm, this is an especially good time to see thong trees in the making.  Young trees established in older forests usually lean to one side from the natural habit of growing towards small patches of sunlight that penetrate from above.  These supple but leaning trees are occasionally bent over and pinned to the ground when a large branch falls from above.  Those are rare events that require just the right conditions of branch fall and leaning sapling to produce a tree that is bent over and pinned to the ground.  However, relatively infrequent ice storms are especially effective in producing future thong trees in abundance.  This is a result of the unique conditions that trigger such storms.

When freezing rain falls on bare branches, the water mostly runs off before it has time to turn into ice.  It is only under rare conditions where raindrops have been falling through really cold air that  they have become super-cooled.  The drops are so cold that any jolt such as landing on a branch instantaneously turns the water to ice before it can drip away.

Ice storms damage trees in a way that is different from other storm damage where branches are ripped off or tree trunks get snapped above the ground (see Ozark Society book “Forest Forensics”).  The gradual load of ice in an ice storm bends the tree over so that the wood starts to splinter over an extended part of the stem.  As the bending occurs, the wood splinters on the top while the bark remains attached on the underside of the trunk.   In years that follow, the bent over top of the tree is kept alive by the strip of bark on the underside of the trunk.  A few branches start to grow upwards while the bent stem heals over.  In many cases, the top of the bent trunk develops a cavity and in other cases the wound heals over entirely.  Over time, the upper part of the tree becomes limited to one or two dominant upright stems that grow into mature trees in their own right situated at the end of a smoothly curved basal arch. 

Ten years after the ice storm, s a good time to see thong tree formation for yourself.  My illustration shows a white oak right next to the Wedington trail about a quarter mile in from the parking lot at the trail’s southern end on highway 16 west of Fayetteville where the road passes Lake Wedington.  You can see how the healing process has begun to allow the tree to survive with an arch for a lower trunk, while a combination of older branches with growth redirected upwards and newly sprouted branches are competing with each other for dominance.  A few more decades and this will be a classic thong tree ready to sprout its very own legend.  Daniel Boone must have been here!