We propose that a tree with a spiral crown architecture featuring alternating rotational directions (Paper 1) functions as a hierarchical acoustic resonator with five coupled standing waves at different spatial scales. Alternating directions of nested spirals (right–left–right at trunk–major branch–minor branch–petiole levels) creates partial reflection of airflow at each level boundary. Standing pressure waves form between pairs of adjacent reflectors, with characteristic lengths from metres (trunk) to micrometres (stoma). All five levels are acoustically coupled: standing wave nodes at level N coincide with attachment points of level N+1 elements. Wind energy cascades from large to small scales. We analyse: self-resonance condition (Kármán vortices from the macro-spiral matching trunk standing wave natural frequency), broadband wind energy capture, modal selection in the hierarchical resonator, mechanoreceptor stomatal stimulation through resonant vibration, and acoustic tree health diagnostics from the resonance spectrum.
Bersimenko et al. (2026) studied this question.