Treefall gap

A treefall gap is a distinguishable hole in a forest with vertical sides extending through all levels down to an average height of two meters above ground. These holes occur as result of a falling tree or large limb. The ecologist who developed this definition used two meters because believed that "a regrowth height of 2 m was sufficient" for a gap to be considered closed, but not all scientists agreed. For example, Runkle believed that regrowth should be 10–20 meters above the ground. Alternatively, a treefall gap as "the smallest gap [that must] be readily distinguishable amid the complexity of forest structure."

There is no upper limit in gap size. However, it must be caused by a tree or a large limb. For example, a field would not be considered a treefall gap.

Tree falls are commonly caused by old age, natural disasters, or parasites (i.e. epiphytes).

Measurement

Scientists have not been able to come to a conclusion on one absolute method for measuring a treefall gap. However, there are two types of measurements that are commonly used: