The ITU‑R Recommendation P.833‑2 provides guidance on estimating radio‑wave attenuation caused by vegetation for frequencies between 30 MHz and 60 GHz. Because foliage conditions vary widely and experimental data are limited, the recommendation offers separate models for different frequency bands and path geometries. For a terrestrial link with one end inside a woodland, the extra loss is expressed using two parameters: the specific attenuation rate γ (dB / m) that describes short‑range scattering loss, and a maximum attenuation Am that caps the total excess loss due to additional mechanisms such as surface‑wave propagation and forward scattering. The excess attenuation for a path length d inside the vegetation is given by Aev = Am 1 – exp(–d γ / Am) » . This formulation allows engineers to calculate the additional loss when a transmitter or receiver is located within dense vegetation.
