Excess attenuation increases with frequency in vegetated habitats
Evidence
The limit in field experiments of the AAH by playback procedures results in part from the unknown level of impedance of trees, rocks, grasses, water, and so on. The excess of attenuation (EA) that measures the amount of energy captured by the medium outside the limit of the inverse square law is linked to frequency by a positive correlation. Higher frequencies are reflected more by leaves and branches in forests than low frequencies, but local conditions can create different conditions for sound transmission. — Almo Farina, Soundscape Ecology, 418
Categorization
- DEFINE: Defines excess attenuation (EA) as medium capture of energy beyond the inverse-square limit — the key technical measure used in habitat playback tests.
- XREF: connects to: Reverberation favors low-frequency slow trills over fast high-frequency ones for long-range communication — Almo Farina, Soundscape Ecology: Principles,…, 443; Trunk scatter cannot alone explain forest high-frequency sound attenuation — Margaret A. Price, Keith Attenborough, and Nicholas W. Heap, Sound Attenuation through Trees:…, 87; Woodland attenuation shows a characteristic peak-dip-rise spectral shape — Margaret A. Price, Keith Attenborough, and Nicholas W. Heap, Sound Attenuation through Trees:…, 105 (+7 more)
Broader Connections
- Sound degradation has three measurable concurrent aspects en route through habitat
#expands(0.75) — Almo Farina, Soundscape Ecology, 662 - Vegetation substrate type shapes the spectral character of wind noise
#qualifies(0.72) — Almo Farina, Soundscape Ecology, 1255 - Each habitat has a distinctive ambient noise spectral profile
#qualifies(0.70) — Almo Farina, Soundscape Ecology, 1256