Soundscape categories shape recreational responses across independently characterized bamboo forest settings: a two-phase audio– visual experiment

<title>Abstract</title> <p>Bamboo forests provide ecological, production, and recreational functions, yet the quality of their cultural ecosystem services may depend on both stand structure and acoustic conditions. Visual context can influence soundscape evaluation but is often insufficiently characterized in controlled audio–visual experiments. We used a two-phase design with independent participant samples to compare responses to natural sounds (NAT), human-activity sounds (HUM), and traffic noise (TRA) across independently characterized bamboo-space visual contexts. Phase 1 derived block-level visual restorative potential, vertical stratification, and groundcover coverage from 50 matched photograph–plot units. In Phase 2, 113 adults completed six 50-s exposures, yielding 678 observations across 10 visual blocks and 18 soundtracks. Outcomes were relaxation, pleasure, preference, and EEG Δ(β/α). Mixed-effects models adjusted for trial position and visual context, with sensitivity analyses addressing alternative visual specifications, stimulus omission, soundtrack reuse, participant heterogeneity, bootstrap inference, and participant-clustered CR2 inference. Subjective responses decreased from NAT to HUM to TRA, whereas EEG showed the reverse ordering. Relative to NAT, HUM reduced relaxation, pleasure, and preference by 17.47, 18.14, and 22.36 points, while TRA reduced them by 41.52, 41.51, and 46.64 points; EEG contrasts were 0.318 for HUM–NAT and 0.494 for TRA–NAT. All eight contrasts remained significant after Holm adjustment. Joint adjustment for pleasantness and annoyance attenuated HUM–NAT contrasts by 95.2%–99.6% and TRA–NAT contrasts by 81.3%–90.0%. EEG–subjective correspondence was weak, and neither age nor pre-exposure STAI-S showed multiplicity-adjusted evidence of moderation. These findings indicate that acoustic conditions represent a distinct component of recreational quality in bamboo forests and should be considered alongside stand structure in the assessment and management of forest cultural ecosystem services.</p>