As an impressive number of people knew, the black markings on the yellow birch
were caused by fungi that create what is called “spalting” in trees. When the
temperature (70 � 90 degrees F.) and moiisture content (30%) of certain trees
(birch, beech and maple, most commonly) is just right, colonies of fungi infect
them. There are different forms of spalting � the pictured fine black lines are
referred to as “zone lines.” They are created when incompatible colonies of
fungi come into contact with each other and lay down barriers to separate their
territories. The presence of spalting indicates that the decay process has
begun. Spalted wood’s natural beauty is highly regarded by wood turners and is
held in contempt by the lumber industry (with time, the wood softens and weakens
as it decomposes). As the Ohio Dept. of Natural Resources so eloquently states,
“Spalted wood embodies all that is curious in the natural world. It is formed by
unseen organisms at a specific time and place that only it knows.” (Thanks to
John Gutowski for yesterday’s yellow birch mystery photo and the HobbitHouse for
the bowl photograph.)
