Forest floor clutter and roughness are treated as distinct acoustic variables from canopy structure.

Evidence

Site 3 is called “cluttered pine,” and contained a mix of deciduous and pine trees with substantial ground clutter including branches and stumps on the ground [Fig. 1(c)]. The ground surface was also very uneven and rough, with a mix of leaves, cones, and needles on the surface. — Donald G. Albert, Michelle E. Swearingen, Frank E. Perron, and David L. Carbee, Low Frequency Acoustic Pulse…, 39

Categorization

• QUESTION: Does ground clutter scatter sound the way a rough impedance boundary would, or does it mainly absorb?