# Numerical Study on Tree Belt Impact on Wind Shear on Agricultural Land
## 1 Introduction
The results of the studies in [36; 37; 38; 39; 40] indicated that the tree belts reduce the wind speed behind them and create accelerated airflow zones above their height. The analysis in [41] showed a model that investigates how the trees bend under wind forces, revealing that this reduces their zone of protection and changes the air movement around them. According to the findings in [14], these zones can be used strategically to protect crops and optimize the placement of wind turbines. More detailed studies in [42] showed that the structure of tree belts--density, height, and orientation relative to prevailing winds--has a significant influence on wind shear and agricultural conditions. The denser belts create strong turbulence, which can reduce erosion but harm some crops. From an energy point of view, the combined windbreaks in [43] (vegetated and artificial barriers) are more effective, arguing that there are plant species that significantly outperform natural plants at high wind speeds. Analysis through CFD and RANS simulations in [44; 45; 46; 47; 48; 49] revealed optimal protection through a row of artificially planted bushes and highlighted the diversity in performance of different prediction models. Only one of the models in the study accurately predicted turbulence behind single-row barriers. The study in [50] provided valuable information on the interaction of airflow with vegetation shelterbts using CFD simulations with a k-\(\varepsilon\) model that successfully predicts flow characteristics but underlines the need to overcome limitations related to the accuracy of complex interactions. In [51], the challenges of modeling airflow in forest clear-cutswere highlighted, noticing the non-necessity of specific measures, such as increased wind turbine hub height to minimize turbulence and shear layers. The study in [52] evaluated the spectral tensor model of rapid distortion theory (RDT), which showed high accuracy in forested terrains under stable atmospheric conditions but struggled under unstable stratification. The analysis in [53] examined the performance of windbreaks through numerical simulations, highlighting the importance of parameters such as porosity and planting distance as optimal conditions for significant reduction of wind speed and erosion. In [54], a strategic combination of vegetation for sensible dryland management was investigated, but the study was limited to a specific geography and short observation period, which limits its applicability. The study in [17] analyzed the geometrical parameters of the shelter belts, showing that increasing the width and length improved the shelter effect, but increased the turbulence, while the presence of openings reduced the shelter area. The study in [55] proposed innovative indices to measure the performance of vegetated windbreaks using 3D CFD simulations that define optimal configurations for dry regions to reduce wind erosion and manage airflows. The studies cited in [56; 57; 58; 59; 60] indicated that sparse tree belts promote a more uniform airflow, which is favorable for the installation of wind turbines. The study in [61] investigated the influence of turbulence spectral parameters on turbine loads, highlighting the significant influence of the anisotropy and the turbulence scale. The turbulence generated by tree belts is a key factor for wind turbine design in agricultural areas, as it significantly affects the load and lifetime of the turbines. The research in [62] has shown that turbulence zones extending up to 1.5-2 times the height of the belts result in increased rotor loading, requiring strategic placement of turbines to optimize performance and reduce maintenance costs. Although the study in [63] analyzed the airflow characterization in different boundary layers, there was insufficient attention to seasonal changes and flow dynamics in real conditions.