Windbreak Effect Research Articles

Seasonal microclimate effect of Linpan settlements on the surrounding area in Chengdu Plain

Linpan settlements (abbreviated as Linpan) form an essential elementary unit of the villages scattered throughout the Chengdu Plain, Southwest China, where is the typical low radiation and calm wind area. Linpan is known for its multiple agroforestry ecosystem services. Building a comfortable microclimate in rural areas is one of its services. To identify the microclimatic effects of Linpan on the surrounding area, the microclimate conditions around 36 traditional Linpan, located in Sandaoyan town, Chengdu Plain, were measured during extreme seasons (i.e., summer and winter) of 2017 and 2018. Results indicate that Linpan exerted a cooling effect in summer and a warming effect in winter on the surrounding area. The mean cooling intensity (1.21 ± 0.49 °C) exceeded the mean warming intensity (0.76 ± 0.81 °C). It also provided decrease humidity (dehumidification), shading, and windbreak effects on the surrounding area. The largest influence distance (LID) of microclimatic variables are different, followed by the order of dehumidification distance (15 m) > cooling/warming distance (10 m) > windbreak distance (5 m in summer and 10 m in winter) > shading distance (5 m). Moreover, the intensities of shading and windbreak were also higher in summer than in winter. Tree canopy cover (TCC) of Linpan exerted a significant influence on the cooling effect in summer and the shading effect in winter. These findings are valuable for the understanding of rural heat stress in the low radiation and calm wind region. Several renewal strategies for Linpan were proposed to adjust the surrounding microclimate to improve the well-being of local inhabitants.

Effect of a Net-covered Windbreak on the Heat Loss from a Heated Greenhouse

Effect of a Net-covered Windbreak on the Heat Loss from a Heated Greenhouse

Sheltering effect of a multiple-row Tamarix windbreak – a field study in Niatak, Iran

The Sistan region in southeastern Iran is one of the country's main dust storm areas. To reduce the frequency and intensity of dust storms using efficient windbreaks is critical. In a field study the sheltering effect of a multiple-row windbreak (14 rows of Tamarix aphylla) in the Niatak area was evaluated by obtaining the vertical and horizontal values of Rc(x, z) (wind reduction coefficient) upwind (x=− 100), within (x=100 and 256) and downwind (x=448 and 560) of the windbreak. A slight deflection in the vertical profiles of the sheltering effect at a height ofz/h= 0.2–0.8, a significant increase in the Rc(x, z) values was observed within the windbreak that demonstrated the roughness influence of vegetation. The sheltering effect increased within the windbreak consistent with the increasing aerodynamic roughness length (z0). The greatest Rc(x, z) values was observed at the beginning of windbreak (x= 100), where the largest values of z0 occurred. At downwind distances of x=448 and 560 the values of Rc(x, z) were respectively greater and lower than upwind values, revealing the sheltering effect of the windbreak in an area 50 h beyond the vegetation. Significant sheltered areas (50 h beyond and 1.8 h above the windbreak) and reduced wind speeds (50% at x=100) by the windbreak and the location of minimum wind speed at the beginning of the windbreak demonstrates that the efficiency of the windbreak is optimum. This is mainly attributed to the optimal porosity (39%) and structure of the windbreak (multiple-row design).

Wind tunnel Assessment of Wind Environment and Dust Suppression Effect of Windbreak in Port Bulk Storage Yards

Windbreaks projects are constructed in order to reduce the dusting in port bulk storage yards. The assessment of wind environment and dust suppression effects are important in the planning or preliminary design of such projects. This paper takes a large port bulk storage yard with 853m x 966m area as an example, velocity measurement wind tunnel tests were carried out. The wind velocity reduction ratio and dust suppression rate were used to access the wind environment and the dust suppression effect. The influence of windbreak height was investigated. The comprehensive wind speed reduction rate and dust suppression rate vary with windbreak height nearly linearly. And combined with spraying system, the dust suppression rate can reach beyond 95%, which provides reference and assessment method for relative engineering applications.

Silvopastoral system with Eucalyptus as a strategy for mitigating the effects of climate change on Brazilian pasturelands.

The aim of the present study was to assess the effect of Eucalyptus trees in a silvopastoral system on the microclimate and the capacity of that to mitigate the effects of climate change on pasturelands. This study included an open pasture of Piatã palisadegrass and an adjacent pasture that contained both palisadegrass and East-to-West rows of Eucalyptus trees, with 15 m between rows, 2 m between trees within rows. The micrometeorological measurements were collected at several distances from the tree rows and in the open pasture. The silvopastoral system was associated with greater between-row shading when solar declination was high and greater near-tree shading when solar declination was around -22°. Both soil heat flux and temperature were influenced by solar radiation, wind speed, and the ability of tree canopies to reduce radiation losses. Wind speed was consistently lower in the silvopastoral system, owing to the windbreak effect of the Eucalyptus trees. The present study demonstrated that silvopastoral systems can be used to attenuate the effects of climate change, as trees can protect pastureland from intense solar radiation and wind, thereby reducing evapotranspiration and, consequently, improving soil water availability for the understory crop.

Wind Condition Analysis of Japanese Rural Landscapes in the 19th Century: A Case Study of Kichijoji Village in Musashino Upland

Woodlands in the traditional rural landscape of Japan are thought to have a role as windbreaks, among various functions. However, in previous studies, the windbreak effect of woodlands in early-modern settlements has not been quantitatively analyzed. To perform a quantitative analysis, computational fluid dynamics was used with a 3D reconstruction of the early-modern rural landscape of Kichijoji village in a suburb of Tokyo. The landscape was reconstructed based on historical records. The analysis showed that the woodland in Kichijoji village effectively reduced the speed of northbound and southbound winds in the fields. The results are consistent with the actual prevailing wind direction in this area. The purpose of this study was to determine a method and model to quantify the windbreak effect of woodlands in early-modern settlements.

Soil water availability in a full sun pasture and in a silvopastoral system with eucalyptus

Silvopastoral system is becoming an important strategy to reduce the impacts of climate variability and change on animal production. However, such system interferes in the soil water availability for the pasture, which is not already very well understood. Based on that, the aim of this study was to assess two pastoral systems: a full sun pasture system of Piata palisadegrass and a silvopastoral system with the same pasture associated with Eucalyptus rows, and their influence on soil water availability (SWA). The tree rows were oriented near East–West, with 15 m spacing. The treatments comprised SWA measurements at 0.00, 3.75, 7.50 and 11.25 m from the trees of the North row, and under full sun. A capacitance probe was used to measure soil moisture. During dry periods, SWA until 1-m depth was higher at the inter-row than under the trees, which indicates a faster water uptake by the trees; however when the inter-row was shaded, SWA was lower at the open pasture than at the inter-row. It occurred as a consequence of the shading and windbreak effects on evapotranspiration. Soil water recharge, during rainy days, was higher close to the trees, as a result of large water interception by trees and its subsequent deposition into the soil, increasing the amount of SWA at this position.

Effect of windbreaks on particle concentrations from agricultural fields under a variety of wind conditions in the farming-pastoral ecotone of northern China

Wind erosion from agricultural fields contributes substantial amounts of particulate matter (PM) in the form of dust to the atmosphere, with significant impacts on air quality and human health. Vegetation barriers affect particle transport via altering air flow, yet the impact of windbreaks on PM concentrations from agricultural soil erosion is still unknown. This study describes brief campaigns to explore the effects of windbreaks on PM concentrations in Zhangbei County, Heibei Province, China. Measurements were made in arable lands with windbreaks, of which the dominant tree species was Populus, following dust events from April to May, when the trees were without leaves. We selected windbreaks with different structures and measured PM concentrations at the windward and the leeward sides of the windbreaks, using high time-resolution measurements. The effects of windbreaks were quantified by calculating the PM concentration ratios in front of and behind the windbreaks. During dust events, the average value of maximum PM10 emissions was 109.87 μg/m3, which was above the threshold established by the World Health Organization (WHO) for air quality. The PM10 emissions increased with air temperature and wind speed. The highest PM10 emission was observed at a relative air humidity of 20%. PM1 and PM2.5 concentrations were not lower behind the windbreak than in front of the windbreak in most of the events, while PM10 concentrations could be reduced by an average of 27%. A significant increase in PM2.5/PM10 by 56.86% behind the windbreak indicates the high efficiency of the windbreak to reduce PM10 levels. Simply planting trees can, in some cases, increase downwind PM concentrations. Vegetation configuration and avoiding locating residential areas in the immediate lee of windbreaks should be considered when planning windbreaks.

Three-dimensional numerical simulations of windbreak effects on pollen dispersal and cross-pollination

Based on the atmospheric turbulence diffusion model, a three-dimensional numerical model was applied for predicting the cross-pollination rate distribution in leeward area of windbreaks by considering actual weather observation data, daily fluctuation parameter of pollen release rate, pollen life during flowering period, etc. Several cases of cross-pollination effect of windbreak distributions in the field were simulated. It is demonstrated that windbreak nets and windbreaks plant or forest are effective in suppressing pollen dispersal and cross-pollination. By simulating pollen diffusion under actual weather conditions using this model, it is possible to evaluate the effect of cross-pollination by the windbreak facilities and give advises of how to set windbreaks for suppressing crossing.

Application of Boundary Layer Displacement Thickness in Wind Erosion Protection Evaluation: Case Study of a Salix psammophila Sand Barrier.

Since the establishment of blown sand physics, surface roughness has been widely used in current research to indicate the ability of a surface to resist wind erosion and to evaluate the windproof effect of protective measures. However, since the calculation of surface roughness can result in different values and its applicability is poor, there are disadvantages to its use. Therefore, it is proposed that the boundary layer displacement thickness should be used rather than roughness as an indicator to solve such problems. To analyze the new indicator’s accuracy and applicability when evaluating the effect of protective measures, a wind tunnel simulation experiment on a typical mechanical protection measure commonly used for sand control in China was conducted. Indicators of roughness and boundary layer displacement thickness were compared in evaluating the windproof performance of a Salix psammophila sand barrier of differing heights, side lengths, and porosities. The wind speed acceleration rate and effective protection area, which can directly reflect the protective effect of a sand barrier, were analyzed as evaluation criteria. The results show that roughness can only reflect the influence of height on the windbreak effect of sand barriers, whereas the boundary layer displacement thickness accurately showed the influence of height, side length, and porosity on the windproof effect of the sand barriers. Compared with roughness, the boundary layer displacement thickness was more strongly correlated with the effective protection area. Therefore, the boundary layer displacement thickness, rather than roughness, should be used as a new indicator when evaluating the windproof effect of protective measures.

Effectiveness of Japanese larch windbreaks during spring cultivation season: testimonies in local history chronicles, Shari plain

Effectiveness of Japanese larch windbreaks during spring cultivation season: testimonies in local history chronicles, Shari plain

Effectiveness of Japanese larch windbreaks during spring cultivation season: evaluation in local history chronicles, Tokachi plain

Effectiveness of Japanese larch windbreaks during spring cultivation season: evaluation in local history chronicles, Tokachi plain

Effectiveness of Japanese larch windbreaks during spring cultivation season: evaluation in the pamphlet issued in１９９８ by Tokachi sub-prefecture, Hokkaido Prefecture Government

Effectiveness of Japanese larch windbreaks during spring cultivation season: evaluation in the pamphlet issued in１９９８ by Tokachi sub-prefecture, Hokkaido Prefecture Government

GIS approach to estimate windbreak crop yield effects in Kansas\u2013Nebraska

Windbreaks were originally promoted across the U.S. Great Plains to reduce wind erosion. A review paper published nearly 30 years ago showed yield increases for a variety of crops associated with windbreaks. However, with the widespread use of no-till cropping systems and advanced crop genetics, the question is “Do windbreaks still provide a yield benefit?” This study compared data from protected and unprotected fields over multiple years across Kansas and Nebraska looking at relative soybean (Glycine max L.) and winter wheat (Triticum aestivum L.) yield differences. Farmer’s pre-existing georeferenced data, generated by automated combine yield monitors, were analyzed with ArcGIS 10.3.1 to visualize windbreak interaction with crop yield. Statistics were conducted to determine if the yield in protected areas of the field was significantly different from the yield in unprotected areas. Also, yield loss was estimated from the windbreak footprint to assess if yield increases were enough to compensate for the area taken out of crop production. Results showed: soybeans (57 crop/years) presented the most positive response to windbreak effect with significant yield increases 46% of the time, with a 16% (283 kg ha−1) average yield increase. Wheat (44 crop/years) yield increases were significant 30% of the time, with a 10% (319 kg ha−1) average yield increase. Narrow windbreaks (1–2 tree rows, average width of 13 m) and those on the north edge of fields resulted in yield increases that compensated for the footprint of the windbreak more often (71%) than wider windbreaks on the south edges of fields (38%).

A Numerical Analysis on Windbreak Effect of the Uiseong Sachon Maeulsoop

The history of Korean traditional Maeulsoop seems to have begun in the 6th century. Maeulsoop is known to have been formed in the expectation for diverse ecosystems and improvement of the village environment in harmony with the natural surroundings, such as hills, mountains, waterways, and wind ways, regarding the residential environment in the unit of a village. So, the effects of Maeulsoop on wind field, a factor of external environment, were analyzed. For the analysis into the windbreaking effect, an analysis algorithm based on computational fluid dynamics was created, and the windbreaking effects of Maeulsoop were simulated and analyzed depending on the analysis conditions. As the result, the wind speed reduction effect at the height of 3 m (a one-storied house) from the ground level was 85% at maximum when the space volume penetration of Maeulsoop was 50%, and 95% at maximum when the space volume penetration of Maeulsoop was 25%. In addition, the maximum distance with more than 85% of wind speed reduction effect was respectively 632 m with 50% of penetration from Maeulsoop and 867 m with 25%. Therefore, as the research result, as one of the influences of Maeulsoop, it has been analyzed that it has a big impact on decreasing the effects of wind on the village. Keywords: Maeulsoop, Windbreak Forest, Uiseong Sachon, Road Side Forest, Windbreak Effect

Spatial pattern of windbreak effects on maize growth evaluated by an unmanned aerial vehicle in Hokkaido, northern Japan

Effects of tree windbreaks on crop production vary from field to field. However, considerable labor is required to evaluate the effects of windbreaks by conducting yield surveys in multiple fields. The present study aimed to clarify whether the spatial pattern of windbreak effects on maize growth can be evaluated using an unmanned aerial vehicle (UAV) in a field with a windbreak in Hokkaido, northern Japan. We mapped normalized difference vegetation index (NDVI) distribution in the field using a UAV and conducted micrometeorological observation and survey of growth and yield. We found that the windbreak positively affected maize growth by increasing soil temperature at 3–5 H (H = windbreak height) and negatively by shading at approximately 1 H. NDVI estimated using the UAV was high in June and low in September, suggesting that the growth rate of maize at 3–5 H was higher than that at 6–12 H. NDVI was significantly correlated to dry matter content of maize, although the area shaded by the windbreak during observation could not be used for analysis. These results indicate that a UAV was successful to grasp spatial pattern of windbreak effects on maize growth. This study shows the potential of a UAV to be useful for saving time and money when we evaluate the effects of windbreaks on crop growth.

Shrub-induced snowpack variability alters wintertime soil respiration across a simulated tundra landscape

ABSTRACTAcross the arctic tundra, the expansion of tall shrubs is expected to alter soil microbial activity in winter through shrub effects on snow redistribution. Tall shrubs act as a windbreak, trapping deep snowdrifts that insulate the ground from extreme cold and elevate soil respiration within shrub patches. However, this windbreak effect may reduce both snow cover and soil respiration in open tundra areas outside shrub patches. The net impact of increasing shrub cover on soil respiration across landscapes with heterogeneous vegetation cover and snow depths remains unknown. Here, I use a set of tundra landscape simulations to address this knowledge gap. The simulations vary shrub cover, mean snow depth and the strength of shrub windbreak effect. I show that for mean snowfall depths 40 cm or greater, increasing shrub cover usually reduced landscape-level soil respiration due to greater heterogeneity in snow depth. These simulations suggest that there is no overarching positive relationship between shr...

Sonic anemometry and sediment traps to evaluate the effectiveness of windbreaks in preventing wind erosion

The present work analyzes the effectiveness of windbreaks against wind erosion through the study of streamline patterns and turbulent flow by means of sonic anemometry and sediment traps. To this end, windbreaks composed of plastic meshes (7.5 m long and 0.7 m tall) were used. Windbreaks are a good means to reduce wind erosion, as they produce a positive effect on the characteristics of air currents that are related to wind erosion processes. Due to their ease of installation and dismantling, plastic meshes are widely used in areas where they are not required permanently. In our study, the use of a mesh of 13 × 30 threads cm−2 and 39 % porosity resulted in an average reduction of 85 % in face velocity at a height of 0.4 m and a distance of 1 m from the windbreak. The turbulence intensity i increased behind the windbreak because the reduction of mean of air speed on the leeside caused by the flow of air through the windbreak. Fluctuation levels, however, remained stable. The mean values of turbulence kinetic energy k decreased by 65 % to 86 % at a distance of 1 m from the windbreak and at a height of 0.4 m. The windbreak reduces erosion and sediment transportation 2 m downwind (2.9 times the windbreak height). Nevertheless, sediment transportation was not reduced at a height of 1.0 m and the effect of the windbreak was not observed at a distance of 6 m downwind (8.6 m times the windbreak height).

Numerical analysis of wind microclimatic effects on a plastic greenhouse protected by a windbreak in different seasonal periods

Windbreaks are frequently used to protect greenhouses. Agricultural plastic nets are widely used for the construction of such windbreaks replacing the traditional natural windbreaks formed by trees. When installed against the dominant wind direction at an optimized distance from the greenhouse side walls, windbreaks may reduce wind loads. An additional effect of the provided protection against strong cold winds is the reduction of heat losses during the winter period. However, the effect of windbreaks in situations when cooling is necessary, particularly in cases of low wind speeds during summer period, has not been investigated so far. The present work aims to analyse the energy efficiency and the wind flow around and through an arched-roof greenhouse with two side and one roof opening (windows) in two extreme cases, namely a) a high velocity cold wind causing important heat losses on the greenhouse (closed windows), and b) a low velocity wind speed resulting to buoyancy-driven ventilation in the greenhouse (open windows). In the first case the reduction of heat losses due to the windbreak are explored. In the second case, the possible dissipation of the ventilation airflow and the corresponding temperature variations by the windbreak is investigated. Computational Fluid Dynamics (CFD) numerical simulations are used in the present work.

Effect of Windbreaks and some Design Factors on Performance of Sprinkler Irrigation System

Effect of Windbreaks and some Design Factors on Performance of Sprinkler Irrigation System