How does vegetation affect UHF and microwave signals?
Causes knife-edge diffraction, distorting voice peaks
Absorbs signals, leading to poor reception of weak signals✓Bonne réponse
Amplifies signals, improving reception of weak signals
Has no effect
Explication
Leaves and needles contain water, and at UHF and microwave frequencies the wavelength is short enough that foliage absorbs and scatters the signal instead of passing it. The loss grows with frequency and with the depth of vegetation, so weak signals suffer most.