# Effects of Wind Barrier Porosity and Inclination on Wind Speed Reduction
## 5 Conclusions  
In a wind tunnel experiment, we examined the simultaneous effect of wind barrier porosity and inclination on wind speed reduction. The key findings of this study were as follows:  
* The wind barriers tested in this study, which varied in porosity and inclination, exhibited different effects on wind speed reduction at various distances. This suggests that both the porosity and inclination of wind barriers play important roles in providing wind protection.
* All wind barriers provided up to six times more wind protection on the leeward side than on the windward side. However, the wind velocity reduction ratio varied at each distance for all wind barriers, indicating different levels of wind protection.  
* Among the evaluated wind barriers, a wind barrier with a porosity of 0% and an inclination of 90\({}^{\circ}\) demonstrated the highest reduction in wind velocity. However, this wind barrier had a very limited wind protection range and could potentially cause wind flow recirculation on the leeward side, posing a risk of sapling damage.
* In contrast, a wind barrier with a porosity of 50% and an inclination of 70\({}^{\circ}\) sufficiently decreased wind velocity and prevented the recirculation of wind flow, thereby improving sapling protection and reducing material costs.  
Our findings offer novel insights into the influence of wind barriers in terms of not only their porosity, which has been primarily examined as a key factor affecting wind speed reduction, but also their inclination. However, there are additional aspects that warrant further exploration beyond the scope of this study. Specifically, future investigations should explore the impact of wind barrier height, which was not evaluated in this study because of the limited size of the wind tunnel section. The height of wind barriers also plays a crucial role in determining shelter efficiency. Additionally, it is essential to investigate the integration of wind barriers with windbreak vegetative species (e.g., shrubs and trees), which exhibit diverse structural characteristics, porosities, and inclinations. Such comprehensive studies will facilitate the optimization of management strategies for vegetative windbreak forests under a range of environmental conditions.  
S.-H.L.: conceptualization, formal analysis, writing--original draft preparation, writing--review and editing, supervision, project administration, and funding acquisitions. H.K.: formal analysis, data duration, and writing--review and editing. H.M.: writing--review and editing. H.-S.K.: methodology, investigation, and writing--review and editing. S.-S.H.: writing--review and editing. S.J.: conceptualization, methodology, investigation, formal analysis, data curation, writing--original draft preparation, writing--review and editing, and visualization. All authors have read and agreed to the published version of the manuscript.  
This work was supported by the Forest Science & Technology Development Project funded by Korea Forest Service (grant number S111111L050130), and the research grant of the Gyeongsang National University in 2022.  
Not applicable.  
The data in this study are available on reasonable request from the corresponding author.  
The authors acknowledge the staff of the Korea Engineering Development Collaboratory Management Institute (KOCED) for their help in the set-up of wind barriers. We thank the editor and five anonymous reviewers for their constructive comments on the manuscript.  
The authors declare no conflict of interest.