## 4 Discussion
Atmospheric effects (stratification and wind shear) can raise sound levels by 10-20 dB at significant distances from the road, potentially causing violations of environmental noise limits [65]. Meteorological phenomena, including temperature gradients, can lead to the refraction of sound waves--bending them either downward or upward depending on the type of temperature inversion [66]. Wind direction and speed also significantly influence sound propagation--observed changes in excessive attenuation strongly correlate with wind parameters [67]. Another important factor affecting sound propagation is topography and surface morphology, which causes reflection, absorption, and diffraction of sound waves as they interact with the ground, vegetation, buildings, and other objects. It has been demonstrated that sound intensity varies with terrain form. Sounds are perceived differently depending on slope and elevation due to complex interactions between sound waves and terrain features [68]. Perceived sounds vary with height differences: in flat terrain, sound propagates evenly in all directions, while variations in terrain act as obstacles that scatter sound, sometimes reducing propagation speed [69]. Complex or irregular geomorphological terrain is associated with increased sound attenuation, amplification, or shielding, depending on its shape and land cover. Vegetation is also a critical factor influencing noise propagation. Field measurements have shown that sound attenuation in forests averages approximately 7 dB per 30 m (about 100 feet), depending on vegetation type and terrain conditions [70]. However, attenuation effectiveness can vary with tree species, canopy density, and meteorological conditions. Coniferous stands reduce noise propagation in both summer and winter (by up to 18%), while deciduous trees exhibit such properties only during the growing season [71]. Ground surfaces, such as grass or snow, create complex reflection coefficients, altering the sound spectrum. Terrain morphology and surface cover type significantly affect sound propagation. The ground covered with grass and vegetation has a high sound absorption capacity, particularly at higher frequencies, due to its porous structure and moisture retention capacity [72]. In contrast, mineral soils and hard surfaces, such as asphalt, reflect acoustic waves across a wider range of frequencies. Hilly terrain can create shadow zones or multiple reflections. In sloped terrain, compared to flat ground, sound pressure levels can increase by up to 30 dB at elevated points. \begin{table}
\begin{tabular}{c c c c c c c c} \hline
**P1** & **r** & **P2** & **r** & **P3** & **r** & **P4** & **r** \\ \hline A & \(-\)0.982 & A & \(-\)0.998 & A & \(-\)0.914 & A & \(-  
Additionally, complex temperature profiles and atmospheric conditions further modify noise levels, resulting in fluctuations ranging from \(-3\) dB to \(+10\) dB compared to a homogeneous atmosphere. Theoretical analyses of sound propagation in natural environments, particularly in forest ecosystems, indicate complex interactions between acoustic waves and structural elements of vegetation. Trees, forest understory, and terrain morphology play significant roles in attenuating, scattering, and refracting sound waves. Understanding these processes is crucial for effective noise management in spatial planning and the protection of natural environments. The literature describes several primary acoustic mechanisms occurring in forest environments. Destructive interference results from the interaction between direct waves and those reflected from the ground surface, which is often acoustically soft due to the presence of forest litter. Scattering of acoustic waves by trunks, branches, and twigs leads to a loss of wave coherence, thereby increasing sound attenuation in the mid- and high-frequency ranges. Additionally, the density and morphology of leaves significantly influence sound absorption efficiency--empirical modeling demonstrates a relationship between leaf surface area and attenuation level [73].