Unshaded Area Research Articles

The tree cooling pond effect and its influential factors: A pilot study in Gold Coast, Australia

Residents were suffering from climatic issues resulting from global warming and urban heat islands (UHI). Researchers have explored ways of mitigating these issues. They have discovered several factors that adjust microclimate, including vegetation. Vegetation, especially trees, can significantly mitigate heat stress, often by providing canopied spaces. However, the temperature differences between various points under individual trees have rarely been investigated. The present study aimed to determine these temperature distribution patterns. A new concept, the tree cooling pond effect (TCP), was proposed and defined in a similar way to UHI. The level of TCP was represented by the mean radiant temperature (MRT) difference between four points in line with the direction of tree shade (A, next to the trunk; B, the midpoint between A & C; C, the margin of the shade; and D, 1 m away from C and in the sunshine). The MRT was measured and shown to increase slightly when moving from A to C, with a sharp increase between C and D. Physical characteristics of the trees, especially the tree crown diameter (TCD), impacted the incremental change (∆MRT) significantly. Through linear regression, it was found that ∆MRT was polynomially correlated with tree characteristics; e.g., TCD and distance from the trunk. For a tree with a TCD of 16.6 m, the ∆MRT between Point A and Point D was up to 18 °C; this result indicates that trees had insignificant cooling effects on the unshaded area (in the sunshine) despite neighbouring it. This study represents an initial effort; it visually illustrate tree cooling by identifying several critical points to delineate the pond, which has rarely been considered in previous studies.

The variation of temperature in parked car's cabin in the summer

This study aimed to investigate the inside temperature variation of two cars with different colours (black vs. white) in the conditions: doors fully closed vs. doors partially opened; sunny parking area vs. shaded parking area. Several temperature devices - Maxim Integrated DS1921 Hygrochron iButton were used to measure continuously and simultaneously both outdoor and indoor temperatures of the black and white cars. The results of this study showed that the temperature of a black car’s cabin was higher than that of white car’s cabin because the black colour absorbs sunlight more than the white colour. The results reported that the increase in temperature of the car’s cabin under the condition of closed doors and unshaded parking area was higher than that in other conditions. After 30 min (from 3:10 PM to 3:40 PM) of exposing to sunlight, the highest temperature of the black car’s cabin was 40.5 °C, meanwhile that of the white car’s cabin was 37.5 °C. Therefore, during the time of stationary, the automobile should be parked in shaded parking area in the summer.

AP Shadow Net: A Remote Sensing Shadow Removal Network Based on Atmospheric Transport and Poisson's Equation.

Shadow is one of the fundamental indicators of remote sensing image which could cause loss or interference of the target data. As a result, the detection and removal of shadow has already been the hotspot of current study because of the complicated background information. In the following passage, a model combining the Atmospheric Transport Model (hereinafter abbreviated as ATM) with the Poisson Equation, AP ShadowNet, is proposed for the shadow detection and removal of remote sensing images by unsupervised learning. This network based on a preprocessing network based on ATM, A Net, and a network based on the Poisson Equation, P Net. Firstly, corresponding mapping between shadow and unshaded area is generated by the ATM. The brightened image will then enter the Confrontation identification in the P Net. Lastly, the reconstructed image is optimized on color consistency and edge transition by Poisson Equation. At present, most shadow removal models based on neural networks are significantly data-driven. Fortunately, by the model in this passage, the unsupervised shadow detection and removal could be released from the data source restrictions from the remote sensing images themselves. By verifying the shadow removal on our model, the result shows a satisfying effect from a both qualitative and quantitative angle. From a qualitative point of view, our results have a prominent effect on tone consistency and removal of detailed shadows. From the quantitative point of view, we adopt the non-reference evaluation indicators: gradient structure similarity (NRSS) and Natural Image Quality Evaluator (NIQE). Combining various evaluation factors such as reasoning speed and memory occupation, it shows that it is outstanding among other current algorithms.

The potential of natural shade provided by Brazilian savanna trees for thermal comfort and carbon sink

This study looked at the potential of thermal comfort provided to animals by four different Brazilian savanna (Cerrado) native trees, as well as their potential for carbon sink. The evaluations were carried out during the summer of 2020, which consisted of the collection of microclimate variables. The Mean Radiant Temperature (TMR, °C) was derived from the shaded and unshaded areas under the trees, and from that, the Radiant Heat Load (RHL, W m−2) was calculated as an index of thermal comfort. Solar radiation was estimated considering the sum of the direct, diffuse, and reflected components (W m−2), and carbon stock from trees biomass for CO2 sequestration was estimated from an allometric model applied to the native Cerrado tree species. The shade of the native trees reduced the meteorological variables such as dry bulb and black globe temperatures, to values considered adequate for the thermal comfort of animals, with an average reduction respectively equal to 1.3 °C and 6.4 °C. This represents a significant difference compared to the unshaded area as well as among tree species (P < 0.05), reflecting in lower values of TMR and RHL in the shaded area provided by each species. Carbon sequestration individually estimated by each native tree species was on average 8.85 Mg per tree. These results demonstrate the great potential for native tree species in the Cerrado biome to be used in agroforestry systems to provide higher levels of thermal comfort to animals and to combat climate change through their aptitude of CO2 sink.

Overheating in existing and renovated Danish single- and multi-family houses

This study compares the overheating risk of eight typical Danish residential buildings for today and future climate scenarios. The study includes four single-family and four multi-family houses, various renovation strategies, and two occupancy loads. Building performance simulation is employed to conduct 3012 simulations (using IDA-ICE), and the comparison of the overheating potential is conducted using the Indoor Overheating Degree (IOD). Results showed that the multi-family houses have a slightly higher overheating risk than the single-family houses. The building with the highest overheating risk was the one-story single-family house (1951–1960) characterised by a large unshaded glazed area. The most effective renovation strategy to reduce overheating resulted in being the window replacement. For the single-family houses, the renovation of the baseplate or the floor to an unheated basement was causing overheating. As for the multi-family houses, renovation of the external wall led to the largest increase in overheating in relation to the unrenovated case. The investigation of the future climates showed that overheating could increase with rising outdoor temperatures, whereby the interaction between temperature and solar radiation is a crucial factor.

Solar photovoltaic tree multi aspects analysis − a review

The generation of photovoltaic solar energy worldwide has increased significantly in recent years. This is mainly due to the growing demand of society for electricity, the need to reduce environmental impacts, and costs of such technology. The installation of a photovoltaic system with horizontally fixed panels requires a significant unshaded area, which has become increasingly scarce, especially in urban centers. The photovoltaic solar tree is a strategy used to increase the efficiency of photovoltaic systems by reducing the occupied area and optimizing the orientation angles of the panels. The originality of this work was that, through a literature review in different researches, seven relevant parameters related to solar photovoltaic trees were analyzed: (i) modeling and simulation, (ii) tree topology, (iii) orientation of the panels, (iv) constructive characteristics, (v) solar tracking, (vi) occupied area and (vii) site multiple uses. It was found that the photovoltaic solar tree is an interesting alternative to generate renewable energy for places without large enough areas, which can be used for other purposes, such as crop production and parking. Finally, it was concluded that, to date, there are no studies available in the literature on the optimization of photovoltaic generation per area for different topologies of known solar trees.

Dairy Heifer Motivation for Access to a Shaded Area.

Simple SummaryThe aim of this study was to determine the motivation of pasture housed dairy heifers to access shade during southern Brazil’s summer and autumn months, and if social rank affected shade use. Heifers valued shade and worked to access it, particularly on hot summer days. Heifers of higher social rank displaced other heifers more often and spent more time in the shaded areas, particularly in the area with trees plus a shade cloth, than the intermediate and subordinate heifers.We used an operant conditioning paradigm to test the motivation of non-pregnant dairy heifers to access shade during the summer and autumn months (January to June) in southern Brazil. Dairy heifers (n = 18) were trained to push a weighted gate to access either an experimental area containing both a shaded (simple tree shade and shade cloth) and unshaded area (WITH SHADE) or an experimental area with no shade (BARREN). The latency to push the weighted gate, and the maximum weight pushed by each heifer, were recorded in both the summer and the autumn. Temperature and humidity were recorded continuously for the duration of the study and were used to calculate the heat index. The maximum weight pushed to enter the WITH SHADE area was greater in summer than in autumn, and was inversely related to the latency to push the weighted gate. Heifers refused to work for access to the BARREN environment. As expected, both the maximum ambient temperatures and heat index were higher in summer than in autumn, and also higher in the non-shaded areas than under the shade in both seasons. Heifers of higher social rank displaced other heifers more often, and spent more time in the shaded areas, particularly in the area with trees plus a shade cloth, than the intermediate and subordinate heifers. We conclude that shade is an important and valued resource for heifers reared on pasture-based systems in sub-tropical environments, particularly during the hot summer months.

Screening of Cellulolytic Bacteria from Biological Education and Research Forest Floor Andalas University, Indonesia.

&lt;b&gt;Background and Objective:&lt;/b&gt; Organic waste dump is a problem that needs to be solved, one of which is by using microbe. Cellulolytic bacteria's ability to produce cellulase enzymes that can hydrolyze cellulose. Cellulose is the major component of the plant cell walls that are difficult to endure degradation naturally. This study aimed to find cellulolytic bacterial isolates on Biological Education and Research Forest floor Andalas University and characterize the cellulolytic bacteria found. Material and Methods: CMC (Carboxymethyl Cellulose) medium is used as a screening for bacteria isolate and this study used the survey method and also conducted catalase, glucose and lactose test for characterizations. &lt;b&gt;Results:&lt;/b&gt; We found 16 bacterial isolates on Biological Education and Research Forest floor where 9 isolates were in a shaded area and 7 isolates were in an unshaded area. There were 12 isolates from 16 isolates that have the positive cellulolytic ability with a variety of clear zone sizes, where there were 8 isolates with the large clear zone and 4 isolates producing very small clear zones. Characteristics of bacterial isolates with the large clear zone obtained were 2 gram-positive coccus isolates with positive catalase test, 3 gram-negative coccus isolates with positive glucose test and 3 gram-negative bacilli isolates with negative fructose test. &lt;b&gt;Conclusion:&lt;/b&gt; We identified 2 potential isolates with a cellulolytic index value greater than 2, isolate UCB 4 with a cellulolytic index value of 3.5 and UCB 6 with a cellulolytic index value of 2.2.

A Coupled Modelling Method for the Evaluation of the Impact of Pavement Solar Collector on Urban Air Temperature and Thermal Collection

The Urban Heat Island (UHI) effect is a phenomenon whereby urban areas become warmer than their surrounding rural areas, due to the replacement of vegetation and soil with surfaces such as asphalt and concrete. The asphalt pavement surfaces tend to absorb a large amount of heat through solar radiation and increase the air temperature, which affects the operation of building heating and cooling systems, causing environmental problems and thermal discomfort. However, this energy can be collected by water circulated through buried copper pipes to cool down temperatures and be stored for other usages. This work aims to develop a method for determining the optimum areas to locate pavement solar collector (PSC) systems and simulate the reduction of ambient air and surface temperature by using a coupled computational modelling approach. Discrete ordinate model and solar-ray tracing were utilised for solar radiation effect modelling in the 3D simulation. Furthermore, the PSC prototype was developed, and lab-scale experiments were carried out for validation. Based on the simulated conditions, in the unshaded area, the asphalt slab’s near-surface temperature was reduced by up to 10℃ and the outlet water temperature increased by about 5℃. At the pedestrian height level, the air temperature was reduced up to 4.6℃. This study further expands the investigation of the variation of outdoor conditions such as air temperature and solar radiation. The results showed that the proposed method could be used to optimise the pavement solar collector’s positioning to reduce urban surface and air temperature.

Microclimate and soil and water loss in shaded and unshaded agroforestry coffee systems

The agroforestry systems are a potential pathway to improve soil quality and protect against extreme temperatures that negatively impact coffee growth. However, more studies about the effects of inclusion of tree elements in coffee systems soil and water loss dynamics are needed. This study aimed to understand how the inclusion of trees influences the microclimate and soil and water loss in shaded compared with unshaded coffee systems. Two pluviometers, one in shaded and the other in unshaded area, were installed to record hourly data from August 2009 to June 2010. Soil temperature and moisture were monitored by a system of sensors: air temperature, soil temperature at 10 cm depth, and soil moisture at 10, 30 and 100 cm depths, recording data at hourly intervals from August 2009 to June 2010. The surface water runoff and soil mass lost by laminar erosion were measured using collectors. Air temperature under shaded conditions had less variation than under unshaded conditions and lower maximum temperatures. Soil and water loss of both systems were small due to the high soil cover. Our results indicate that the water loss was higher in the unshaded area (338 L ha−1) during the study period compared with the shaded system (150 L ha−1). Soil temperature was lower under shaded conditions and there was water absorption complementarity between coffee and trees in shaded area. Soil moisture of shaded area was lower than unshaded area for all depths in all monitored period. Therefore, the shaded agroforestry coffee systems improve microclimate conditions and deep water drainage compared with unshaded coffee systems.

Characteristic Analysis of Water Quality Variation and Fish Impact Study of Fish-Lighting Complementary Photovoltaic Power Station

Fish-lighting complementary photovoltaic power station organically combines aquaculture and renewable energy. In this study we aimed to develop a solar photovoltaic that is not confined to land. We used a shade net to simulate photovoltaic panels, and studied the effects of different proportions of photovoltaic panels on water and fish. The results showed that the average light intensity of the unshaded area and the shaded area were 16,661.7 Lux and 2437.0 Lux. The average light intensity of the shaded area was 85.4% lower than that of the unshaded area. The effective range of the shaded area for the light intensity of the water layer was 0 cm~30 cm. The temperature and pH in the water body showed a linear decreasing trend with the increase of the photovoltaic deployment ratio, and the dissolved oxygen showed an inverted “U”-shaped change characteristic, but this effect was limited. When the photovoltaic deployment ratio was 25% to 75%, the dissolved oxygen in the water body increases by an average of 2.37% compared to the unshaded area. The appropriate proportion of photovoltaic deployment did not affect the dissolved oxygen content in the water body. When the photovoltaic deployment ratio reached 75%, the number of algae species and algae biomass was the largest, and the fish production was the highest at 8094.6 kg·acre−1, which is an increase of 166.2 kg·acre−1 compared to the average yield in unshaded areas. Therefore, photovoltaic layout will not affect the growth of fish, and the proportion of 75% is the best layout choice.

Microclimate and pasture area preferences by dairy cows under high biodiversity silvopastoral system in Southern Brazil.

The aim of this study was to evaluate the influence of microclimate on dairy cows' behaviors and their preferences for different pasture areas under high biodiversity silvopastoral system (SPSnuclei) in a subtropical climate. We surveyed three different pasture areas under SPSnuclei: shaded area around the nuclei (SAN), unshaded area around the nuclei (UAN), and all-day sunny area distant from the nuclei (SDN). In each area, the microclimatic variables were measured-air temperature (°C), relative humidity (%), illuminance (lux), wind speed (m/s), and soil surface temperature (°C). In addition, the diurnal behaviors of 39 Jersey dairy cows were evaluated. Grazing, standing rest, lying rest, standing rumination, and lying rumination were registered by scans every 10min; drinking water was observed continuously. Microclimate differed (p < 0.05) among the SPSnuclei areas. Areas around the nuclei provided better conditions of air temperature (SAN, 31.05°C; UAN, 31.92°C; SDN, 33.39°C), illuminance (SAN, 5665lx; UAN, 61,065lx; SDN, 75,380lx), and soil surface temperature (SAN, 27.35°C; UAN, 32.38°C; SDN, 35.87°C). The frequency of use of each SPSnuclei area by dairy cows was different (p < 0.01); the highest frequencies of the grazing (SAN, 12.6%; UAN, 4.8%; SDN, 11.1%), rumination (SAN, 21.7%; UAN, 3.1%; SDN, 1.9%), and rest (SAN, 35.6%; UAN, 5.4%; SDN, 3.7%) were registered in the areas around the nuclei. The microclimate of the high biodiversity silvopastoral system leads the animals to perform grazing, ruminating, and resting preferentially on the areas around the nuclei even with no shade.

Influence of Light Intensity on Leaf Photosynthetic Traits and Alkaloid Content of Kiasahan (Tetracera scandens L.)

Kiasahan (Tetracera scandens L.) is one of the plants that people use as atraditional medicine for various diseases. This study was conducted to determine the characteristics of anatomy, morphology, chlorophyll content, and alkaloids of Kiasahaan leaf (T. scandens) based on differences in light intensity in the Pananjung Pangandaran Nature Reserve. The survey method was used to determine the location of sampling. The location was determined based on the existence of T. scandens plant. The shaded and unshaded area had the light intensity of 5516 and 922,000 lux, respectively. Leaf samples were taken as many as three strands of three different individuals on the shaded and unshaded areas. Parameters measured were the thickness of leaf, leaf area, stomatal density, chlorophyll, and alkaloid content. Measurement of chlorophyll and alkaloids used chlorophyll meter and Mayer’s reagent method, respectively. The results showed that the average leaf thickness, leaf area, stomatal density, chlorophyll content in theshaded area were 0.048 mm, 7.086 cm2, 50.958 cells / mm2, 15.38 CCI, respectively whereas in the unshaded area were 0.076mm, 6.496 cm2, 62.678 cells / mm2, 8.86 CCI, respectively. Alkaloid content of T. scandens leaves in the unshaded area was higher than in the shaded area.

Impact of tree shading on the microclimate of a coffee plantation: a case study from the Peruvian Amazon

L’agroforesterie est considérée comme l’une des stratégies agricoles pouvant contribuer à l’adaptation des cultures au changement climatique. La présente étude de cas visait à comparer les conditions microclimatiques d’une parcelle de Coffea arabica cultivée sous ombrage, principalement Inga spp., et celles d’une parcelle de C. arabica menée en monoculture sans ombrage dans la même plantation de café, dans la région de Pasco au Pérou. La température et l’humidité de l’air, la température du sol et la disponibilité en eau du sol ont été mesurées pendant trois ans. Les résultats indiquent que l’ombrage des arbres réduit la température moyenne de l’air de 0,4 ± 0,04 °C et la température du sol de 1,7 ± 0,3 °C, et augmente l’humidité de l’air de 3,9 ± 0,4 % par rapport à la zone sans ombrage. Cependant, la moyenne mensuelle des températures de l’air dans la zone non ombragée, et même la température maximale, ne dépassent pas outre mesure la limite permettant la photosynthèse (seuil 34 °C). De plus, les températures minimales mensuelles diffèrent peu entre les zones ombragées et non ombragées, alors que la fluctuation des températures du sol est plus marquée dans la zone non ombragée. Un des principaux constats de cette étude concerne la sécheresse plus marquée des sols dans la zone ombragée, surtout au début et à la fin de la saison sèche. Ceci s’explique probablement par l’augmentation de la transpiration totale par celle des arbres d’ombrage. L’absorption d’eau plus importante en agroforesterie pourrait ainsi avoir un impact négatif sur la croissance des caféiers dans les situations où la disponibilité en eau est un facteur limitatif.

Experimental Investigation of Thermal Performance in a Vehicle Cabin Test Setup With Pcm in the Roof

Heat flow from the roof with radiation through glass windows obviously high level that contributes to the total heat gained of a vehicle cabin. The cabin temperature of closed stationary vehicles in direct sunlight can quickly rise to a very level that may damage property and harm children or pets left in the vehicle. The problem that is faced by many car users today is very hot interior after certain minutes or hours of parking in open or un-shaded parking area. The heat accumulated inside the vehicle with undesired temperature rise would cause the parts of the car’s interior to degrade. Even the passengers are affected with the thermal condition inside the vehicle itself. The passenger has to wait for a certain time before getting into the car to cool down the interior condition either by lowering down the window or switching on the air conditioner at high speed that really affect the fuel consumption. A new roofing structure to improve its total thermal resistance is developed. Its uses phase change material properties to trap the heat from solar radiation and then release it back to the outer atmosphere by external convection when the vehicle is in use or during the nocturnal cycle. Phase change material, which has become an attractive means to store. Thermal energy, which has a wide range of applications, has been used. Phase change material has a high heat of fusion which is able to store and release large amount of energy. This PCM has been insulated in the roof of the vehicle to arrest the heat entering into the vehicle cabin. Experimental and numerical analyses have been conducted to compare the thermal performance of the new roofing structure and the normal roofing. By this experiment, the cooling process of the cabin could be much lower. The experimental investigation revealed that, on a hot day, the interior temperature of the vehicles cabin was approximately 22ºCe higher than the ambient temperature. The results show that the new roofing structure could effectively reduce the inlet of heat from the roof into the cabin. As a result, the interior temperature of the cabin could be much lower.

Effect of time and weather on preference, frequency, and duration of shade use by horses.

The Federation of Animal Science Societies (FASS) recommends providing access to shade for horses in hot, sunny weather at equine facilities. Previously, we found that healthy, mature domestic horses use shade with behavioral and physiological benefits during those weather conditions. The objective of this study was to characterize preference, frequency, and duration of shade use by healthy, mature horses in a Bureau of Land Management (BLM) holding facility during hot, sunny weather. The study took place at the BLM's Palomino Valley Wild Horse and Burro Center in Reno, NV, from Aug. 10 to Oct. 1, 2014. Freestanding shade structures were constructed in each of 2 drylot pens with shade cloth covering the top that blocked 98% of UV radiation. A group of 4 mares was placed in each of the 2 pens. After a 2-d acclimation period, data were recorded for 5 d, the horses were moved to the opposite pen, and data collected for an additional 5 d. This schedule was repeated for a total of 4 consecutive trials and 32 horses. Footage from time-lapse cameras was viewed at 10 s intervals between 0930 and 1700 h to record each horse's position relative to shade. Dosimeters secured to horses' halters recorded UV exposure. Automated weather stations recorded daytime ambient temperature (mean 25.9°C [SD 5.8]), relative humidity (mean 25.4% [SD 17.1]), black globe temperature (mean 29.3°C [SD 6.5] in shade and 35.8°C [SD 8.0] in unshaded area), and solar radiation (mean 595 W/m [SD 235]). Horses spent 10.9% more time in shade than by chance ( < 0.0001) within the drylots across all 40 study days. Mean daily time spent in shade was 107.9 min/horse (SD 66.9), comprising 17.1 bouts (SD 12.1) with an average bout length of 6.3 min (SD 3.4). The mean daily UV Index experienced by horses in these partially shaded drylots was 1.52 (SD 0.58) compared with 3.4 (SD 1.5) for a control instrument in the sun. Horses used shade more on the sunniest days and greater than just by chance at all hours of the day, with greatest use in the morning before peak ambient temperature. This study supports the FASS recommendation for provision of shade and may be useful in management and facility design for both domestic and captive wild horses.

Implementation of Open Source GIS Tools to Identify Bright Rooftops for Solar Photovoltaic Applications – A Case Study of Creek Lanes, DHA, Karachi

The mega city of Karachi is still mainly dependent on conventional sources of energy to cater its daily electricity requirements. Dependence on conventional sources of energy for power production results in environmental degradation and depletion of fossil fuel resources. In particular, it also highlights an immense need of alternate sustainable solution for current electricity generation scenario. In this research work, an innovative methodology has been proposed to identify bright rooftops using open source geographic information system (GIS) tools which may be utilized for sustainable power generation in Karachi metropolis. First, bright rooftops have been extracted using open source Quantum GIS (QGIS) software. Edge extraction technique using gradient filter; an open source algorithm of QGIS has been utilized. Furthermore, image processing techniques have been used to extract and refine building rooftops. Then, rooftops have been polygonized and their area has been calculated using Measure Area function of QGIS. To assess the accuracy of the extracted rooftops, field validation work has been performed and sample rooftops have been physically measured. A comparison of extracted and physically measured sample rooftops yielded 90.45% accuracy. Reduction in total roof area has been made considering different roof uses and shading effect from nearby trees and buildings. Then, unshaded bright rooftops area of 4,626 m2 has been calculated which can be used for solar photovoltaic (PV) applications in Creek Lanes, DHA Phase 7 Karachi. An annual energy output of 2.1 MWh has been estimated using Crystalline Silicon (c-Si) solar PV panel and available rooftop area. The methodology adopted can be extrapolated to macro-scale as well. However, challenges and limitations for extrapolation of methodology have also been highlighted. Solar radiation studies that demonstrate the use of open source GIS tools for sustainable power generation for this region have been scarce. Thus, this study is a preliminary research work to highlight an immense solar electricity potential that exists for Karachi metropolis.

Extinction debt of a common shrub in a fragmented landscape

Fil: Gonzalez Varo, Juan P.. Consejo Superior de Investigaciones Cientificas. Estacion Biologica de Donana; Espana

Effects of urban parks on the local urban thermal environment

Air temperatures in and outside of 60 parks in Taipei city were surveyed to study the effect of different urban parks on their surrounding thermal gradients. Results suggest that the factors governing the temperature of park surroundings are not identical to those of park interiors. Air-temperature gradients surrounding urban parks are influenced by both the horizontal transport of cool or warm air mass above parks and the evapotranspirative air-parcels from trees, creating a cool island larger than the boundaries of cool-island parks, a heat-island larger than the boundaries of strong heat-island parks, and a cool-ring outside weak heat-island parks. Such horizontal air movement is not easily detected using remotely sensed data. During daytime, the thermal environment within a park is dominated by the amount of solar input absorbed by unshaded paved area, which, when strong, can overflow to increase the temperatures of park surroundings; at night, despite park trees causing a warming effect inside parks, park surroundings are cooled by horizontal flow of evapotranspirative air-parcels from park trees. In business and other districts used mostly during daytime, it is recommended that parks and other open spaces be designed with less than 50% paved area and at least 30% trees, shrubs, and other shadings. In residential districts that are used mostly during nighttime, parks and other open spaces are recommended to be designed with more trees. Night irrigation, a measure commonly recommended for the conservation of water, is also recommended to further enhance this nighttime cooling.

Myxomycetes on Palm Trees: Species on &amp;lt;i&amp;gt;Attalea speciosa&amp;lt;/i&amp;gt; Mart. ex Spreng

Attalea speciosa Mart. ex Spreng (baba?u) is a palm tree of considerable economic importance in Brazil, especially in the northeast portion of the country. The myxobiota of baba?u was studied by examining living and dead trunks, leaves, inflorescences and fallen fruits on the ground during the wet season at the Teresina Park, Piauí State, Brazil. Taxonomic diversity, species diversity, frequency of occurrence, abundance and constancy of each species were determined in two areas of deciduous mixed forest. The taxonomic diversity of the myxobiota was similar, with values of 1.5 and 1.6 for the two areas. The highest frequency of occurrence value was recorded for the spathe (50% -54%), followed by the petiole (18% -19%) and leaf sheath (4% -19%). Myxomycetes were absent on fallen fruits and rare on the leaf blade (6%) and dead (9%) or living (2%) trunks. Hemitrichia serpula (Scop.) Rostaf. ex Lister, Perichaena depressa Lib., Arcyria cinerea (Bull.) Pers. and H. calyculata (Speg.) M. L. Farr were the species characterized by the highest levels of constancy, abundance and frequency. Cribraria microcarpa (Schrad.) Pers. and Stemonitopsis typhina (F. H. Wigg.) Nann.-Bremek. were occasionally present. Ceratiomyxa fruticulosa (Mull.) T. Macbr., Clastoderma debaryanum A. Blytt, Craterium aureum (Schumach.) Rostaf. and Physarum melleum (Berk. & Broome) Massee were infrequently encountered. Other species recorded were Arcyria denudata (L.) Wettst., Cribraria cancellata (Batsch.) Nann.-Bremek., C. violacea Rex, Lycogala exiguum Morgan, Metatrichia vesparia (Batsch) Nann.-Bremek. ex G. W. Martin, Physarum bogoriense Racib., P. nucleatum Rex, P. pusillum (Berk. & M. A. Curtis) G. Lister and Stemonitis axifera (Bull.) T. Macbr. The myxobiota of the shaded study area was characterized by a higher diversity (6.10) than the unshaded area (2.10), and the incidence of myxomycetes on the A. speciosa trees selected for study was appreciably higher (100% and 40%, respectively).