Microclimate Data Research Articles

Microclimate Characteristics On Oil Palm (Elaeis guineensis Jacq.) And Agarwood (Aquilaria malaccensis Lamrk.) Agroforestry System


 In general, oil palm plants are cultivated using a monoculture system. The monoculture system is profitable from an economic perspective and harms the environment; one is the microclimate. One of the efforts to reduce the negative impact of the oil palm monoculture system is to apply the oil palm agroforestry system with agarwood. This research is conducted on smallholder oil palm plantations in Bukit Kemuning Village, Tapung Hulu Sub District, Kampar District, Riau Province. This research was conducted using a survey method, which was done by choosing a location intentionally. Determination of the research location using purposive sampling method, that is, on land found agroforestry systems of oil palm plants with agarwood and oil palm monoculture systems in the same location. Microclimate observations are carried out by measuring air temperature, air humidity, and sunlight intensity. Measurement of air temperature and humidity uses the Temperature and Humidity Data Logger, while the sunlight intensity measurement uses the Lux Meter Data Logger tool. Measurements are carried out one day a week for three months, for getting 12 times of data retrieval. The recording is carried out from 07.00 am to 05.00 pm, with 15 minutes intervals. Microclimate data on agroforestry and monoculture systems are analyzed in comparative descriptive analysis. Based on the results of the study, it is concluded that the microclimate in the agroforestry system of oil palm and agarwood was better than that of the oil palm monoculture system, where the light intensity and air temperature in the agroforestry system are lower than the monoculture system, and the humidity in the agroforestry system higher than the monoculture system.
 In general, oil palm plants are cultivated using a monoculture system. Monoculture system is profitable from an economic perspective, but also has a negative impact on the environment, one of which is the micro climate. One of the efforts to reduce the negative impact of the oil palm monoculture system is to apply the oil palm agroforestry system with gaharu. This research is conducted on smallholder oil palm plantations in Bukit Kemuning Village, Tapung Hulu Sub District, Kampar District, Riau Province. This research is conducted using a survey method. Determination of the research location using purposive sampling method, namely on land found agroforestry systems of oil palm plants with gaharu and oil palm monoculture systems in one stretch. Microclimate observations are carried out by measuring air temperature, air humidity, and sunlight intensity. Measurement of air temperature and humidity uses the Temperature and Humidity Data Logger, while the measurement of sunlight intensity uses the Lux Meter Data Logger tool. Measurements are carried out one day a week for 3 months, for getting 12 times of data retrieval. Recording is done at 07.00 am up to 05.00 pm with 15 minute intervals. Microclimate data on agroforestry and monoculture systems are analyzed in comparative descriptive analysis. Based on the results of the study, it is concluded that the microclimate in the agroforestry system of oil palm and gaharu was better than that of the oil palm monoculture system, where the light intensity and air temperature in the agroforestry system are lower than the monoculture system, and the humidity in the agroforestry system higher than the monoculture system

Fifteen emerging challenges and opportunities for vegetation science: A horizon scan by early career researchers

AbstractWith the aim to identify future challenges and opportunities in vegetation science, we brought together a group of 22 early career vegetation scientists from diverse backgrounds to perform a horizon scan. In this contribution, we present a selection of 15 topics that were ranked by participants as the most emergent and impactful for vegetation science in the face of global change. We highlight methodological tools that we expect will play a critical role in resolving emerging issues by providing ways to unveil new aspects of plant community dynamics and structure. These tools include next generation sequencing, plant spectral imaging, process‐based species distribution models, resurveying studies and permanent plots. Further, we stress the need to integrate long‐term monitoring, the study of novel ecosystems, below‐ground traits, pollination interactions and global networks of near‐surface microclimate data at fine spatio‐temporal resolutions to fully understand and predict the impacts of climate change on vegetation dynamics. We also emphasize the need to integrate traditional forms of knowledge and a diversity of stakeholders into research, teaching, management and policy‐making to advance the field of vegetation science. The conclusions reached by this horizon scan naturally reflect the background, expertise and interests of a representative pool of early career vegetation scientists, which should serve as basis for future developments in the field.

Chainsaw hollows carved into live trees provide well insulated supplementary shelters for wildlife during extreme heat

Context Supplementary shelters for hollow-dependent fauna, such as timber or plywood nest boxes, have much drier and less thermally insulated cavity microclimates than do natural tree hollows. Hollow-dependent endotherms can experience hyperthermia and dehydration when occupying poorly insulated nest boxes during extreme heat. Aims We investigated the effectiveness of three different types of artificial hollows in buffering hollow-dependent birds and mammals against hyperthermia and dehydration during extremely hot summer weather (ambient air temperatures >40°C). Methods We recorded microclimate (temperature and relative humidity) data inside (1) chainsaw hollows carved into live trees, (2) log hollows, and (3) plywood nest boxes, during extremely hot weather events in Australia in December 2019–January 2020 (austral summer). We quantified temporal variation in microclimates inside the different supplementary shelters relative to ambient conditions and used statistical models to evaluate the effects of different factors (wall thickness and solar exposure) on internal microclimates. Key results Microclimates inside chainsaw hollows were significantly different from those in log hollows and nest boxes, remaining >16°C cooler and 50 percentage points more humid than ambient conditions when daytime air temperatures reached 45°C. In comparison, nest boxes closely tracked ambient conditions throughout the day. Log hollows had an intermediate microclimate profile, getting warmer and drier than chainsaw hollows during the day, but remaining cooler and more humid than nest boxes. Conclusions Our results showed that artificial hollows more effectively mimic the stable microclimates inside naturally occurring hollows if placed inside the tree (e.g. carved into the tree trunk of live trees), rather than attached to the outside. Implications The chainsaw hollow design we tested could provide microclimate refugia that reduce the risks of hollow-dependent wildlife experiencing either hyperthermia in regions with hot summer climates, or hypothermia in areas with cold winters. We encourage managers to consider incorporating chainsaw hollows into existing nest box programs to provide fauna with well insulated microclimate refugia.

New records to the bryoflora of the E slope of Mt. Kenya

The first author studied the bryophyte communities on the East slope of Mt. Kenya through the forest belt between 1600 and 3000 m elevations. Seven sampling plots were selected at each 200 m altitudinal interval. At each sampling plot microclimate data measurements were carried out for six months between July and December 2020 using dataloggers and the composition of epiphyllous communities was studied in details with special reference to the host plants. Tamás Pócs and his team (Bence Együd, Judit Havasi and Mária Szegedi) joined to this research during the August of 2021, to help in further collection and identification work. The collected specimens are deposited in the herbaria of EA and EGR. Majority of the collections have already been identified. The discovery of the only mainland African occurrences of the Lemurian Microlejeunea inflata and Leptodon fuciformis are outstanding results. Other species are new for Kenya: Cololejeunea platyneura, Cyclodyction subbrevifolium, Diplasiolejeunea deslooveri, Fissidens intramarginatus and Telaranea coactilis. The last author visited the same sites 2004 with his late wife, Sarolta Czímer, guided by Min S.Chuah-Petiot from Nairobi University and from their collection Gemmabryum subapiculatum, Orthotrichum denticulatum, Lophocolea fragrans and Lophocolea muricata proved to be new to Kenya.

Estimating dead fine fuel moisture content of forest surface, based on wireless sensor network and back-propagation neural network

The dead fine fuel moisture content (FFMC) in forest affects the occurrence and spread of forest fires. Therefore, the estimation of surface dead FFMC plays an important role in forest fire behaviour, fire management and fire danger assessment. However, there are some challenges with current FFMC measurement methods. Modelling using meteorological variables may be a very potential method to achieve remote real-time FFMC estimation. A surface dead FFMC estimation method based on wireless sensor network (WSN) and back-propagation (BP) neural network was proposed. The WSN can realise the acquisition of microclimate data. The BP neural network can use these data to establish multiple FFMC estimation models for different terrain conditions and dead fuel types. The ability of these models to estimate FFMC at four different terrain sampling sites was evaluated. The results suggested that the dead FFMC can be estimated with some degree of accuracy. The correlation coefficients of the estimation results at the four sampling sites were all greater than 0.9, and the mean square errors were all less than 1. The method can be well applied to forest surface dead FFMC estimation and early fire danger assessment, which has practical significance for the rational allocation of fire fighting resources.

Identifying microclimate tree seedling refugia in post-wildfire landscapes

High-severity wildfire in arid regions has caused ecological state change, transforming previously forested areas into shrublands. This dramatically alters the microclimatic conditions, which can exceed the climatic tolerance of tree seedlings, rendering the likelihood of returning post-wildlife landscapes to their previous state relatively low. Characterizing microclimatic variability across severely burned landscapes could allow for identifying locations where seedling survival is more likely. We used a combination of small unmanned aircraft system imagery, satellite data and in-situ microclimate data recordings, together with a machine learning approach, to model monthly near-ground minimum, mean and max temperature as well as relative humidity and vapor pressure deficit in a previously forested area, which is now dominated by two different shrub species. Spatially explicit models predicted recorded microclimate well (r = 0.73 to 0.97), and model projections highlight that at any given location in the hottest month, the solar buffering capacity of existing vegetation can alter the maximum temperature by ∼12 °C, increase relative humidity by ∼20% and reduced vapor pressure deficit by 0.3mbar relative to open areas. By harnessing these microclimate refugia, the success rate of reforestation efforts in post-wildfire landscapes could be substantially increased and mitigate seedlings from climate warming at local scales.

Impact of neighborhood spatial characteristics on the microclimate in a hot arid climate – A field based study

• Different neighborhood forms can create inter-neighborhood microclimate variability. • Local-specific characteristics affect microclimate differently across neighborhood area. • Influence of local-specific characteristics on microclimate vary across seasons. • Vegetation is more important in regulating microclimate in shallower than deeper canyon. Although neighborhood is the level where most local plans are realized, little research has been done to understand how neighborhood spatial characteristics can shape its microclimate. This study aims to understand the effect of neighborhood form on its microclimate in a hot arid city, in Egypt. Two neighborhoods with different layouts are selected- a low-density historic area and a modern high-density area. Each neighborhood form was analyzed according to seven spatial characteristics: aspect ratio, street orientation, street trees, green spaces, percentage of tree canopy and impervious surfaces at 20m radii, and sky view factor. Microclimate data was collected using mobile field measurements in summer and winter. In total air temperature, relative humidity and wind speed at 44 sites were measured. The statistical and spatial analysis reveal inter-neighborhood microclimate variation which is more observed in winter than in summer. Moreover, the local-specific spatial characteristics within each neighborhood have resulted in a variation in the microclimate across the neighborhoods. The study also found a seasonal effect on the overall microclimate and on the way local-specific characteristics influence the microclimate. Findings of this research can have implications for future (re)development and planning of climate resilient neighborhoods, in a hot arid context.

Caves, crevices and cooling capacity: Roost microclimate predicts heat tolerance in bats

Abstract The microsites that animals occupy during the rest phase of their circadian activity cycle influence their physiology and behaviour, but relatively few studies have examined correlations between interspecific variation in thermal physiology and roost microclimate. Among bats, there is some evidence that species exposed to high roost temperatures (Troost) possess greater heat tolerance and evaporative cooling capacity, but the small number of species for which both thermal physiology and roost microclimate data exist mean that the generality of this pattern remains unclear. Here, we test the hypothesis that bat heat tolerance and evaporative cooling capacity have co‐evolved with roost preferences. We predicted that species occupying roosts poorly buffered from high outside environmental temperature exhibit higher heat tolerance and evaporative cooling capacity compared to species inhabiting buffered roosts in which Troost remains well below outside conditions. We used flow‐through respirometry to investigate thermoregulation at air temperatures (Ta) approaching and exceeding normothermic body temperature (Tb) among six species with broadly similar body mass but differing in roost microclimate (hot vs. cool roosts). We combined these data with empirical measurements of Troost for each study population. Hot‐roosting species tolerated Ta ~4°C higher than cool‐roosting bats before the onset of loss of coordinated locomotion and non‐regulated hyperthermia. The evaporative scope (i.e. ratio of maximum evaporative water loss [EWL] to minimum thermoneutral EWL) of hot‐roosting species (16.1 ± 2.4) was substantially higher than that of cool‐roosting species (5.9 ± 2.4). Maximum evaporative cooling capacities (i.e. evaporative heat loss/metabolic heat production) of hot‐roosting species were >2, while the corresponding values for cool‐roosting species were ≤1. The greater heat tolerance and higher evaporative cooling capacity of hot‐roosting species compared with those occupying cooler roosts reveal variation in bat evaporative cooling capacity correlated with roost microclimate, supporting the hypothesis that thermal physiology has co‐evolved with roost preference. A free Plain Language Summary can be found within the Supporting Information of this article.

Urban cooling strategies as interaction opportunities in the public space: a methodological proposal

In the context of global warming, cities promote temporary or permanent public space designs based on the integration of various cooling techniques, hereafter called spatio-climatic devices, to locally cool down the atmosphere and preserve urban liveability. Such public spaces create interaction opportunities for citizens to seek thermal pleasure outdoors. To inform about the citizens’ thermal experience of these spaces, this paper explores fieldwork and data analysis methods at the crossroads of urban climatology, environmental psychology and urban design. Four spatio-climatic configurations are investigated in the ‘Extraordinary Garden’ in Nantes (France) through mobile microclimate measurements and ethnographic observations. By applying an ‘urban transect’ approach, preliminary selected microclimate, behavioural and activity observation data is displayed together with spatial information. This allows to highlight thermal situations induced by urban design and to link them to specific citizen-environment interactions. As a result, this approach contributes to a better characterization of urban cool spots as a strategy for more resilient public spaces.

Outdoor Thermal Comfort Optimization through Vegetation Parameterization: Species and Tree Layout

The optimization of outdoor thermal comfort has become the keystone to guarantee the healthy and comfortable use of outdoor spaces. This study aims to optimize the outdoor thermal comfort through vegetation parameterization in a boulevard located in Guelma city, Algeria during summertime. However, two main parameters were investigated, species and tree layout, through a numerical simulation. We first collected microclimate data of a sunny summer day. Second, we used real microclimate data in different simulations using the Envi-met atmospheric model. The findings reveal that Ficus Nitida is the most significant species to intercept solar radiation and provide shade over the day in Souidani Boudjemaa Boulevard, with a maximum reduction of Ta = 0.3 °C and UTCI = 2.6 °C at 13:00 p.m. Tree layout is a determining parameter in the creation of shaded paths, based on the quality of the shadows cast by the trees, namely, their size. Thereby, planting the washingtonia palm trees along the center of the boulevard is the best option to maximize the shaded area within the boulevard, with maximum reduction of Ta = 1.8 °C and UTCI = 3.5 °C at 16:00 p.m.

Resilience of spider communities affected by a range of silvicultural treatments in a temperate deciduous forest stand

To secure the ecosystem services forests provide, it is important to understand how different management practices impact various components of these ecosystems. We aimed to uncover how silvicultural treatments affected the ground-dwelling spider communities during the first five years of a forest ecological experiment. In an oak-hornbeam forest stand, five treatments, belonging to clear-cutting, shelterwood and continuous cover forestry systems, were implemented using randomised complete block design. Spiders were sampled by pitfall traps, and detailed vegetation, soil and microclimate data were collected throughout the experiment. In the treatment plots spider abundance and species richness increased marginally. Species composition changes were more pronounced and treatment specific, initially diverging from the control plots, but becoming more similar again by the fifth year. These changes were correlated mostly to treatment-related light intensity and humidity gradients. The patchy implementation of the treatments induced modest increase in both gamma and beta diversity of spiders in the stand. Overall, spiders gave a prompt and species specific response to treatments that was by the fifth year showing signs of relatively quick recovery to pre-treatment state. At the present fine scale of implementation the magnitude of changes was not different among forestry treatments, irrespective of their severity.

Developing a thermal suitability index to assess artificial turf applications for various site-weather and user-activity scenarios

Lawns are highly recognized and indispensable elements in the urban landscape. Due to water-saving, low maintenance cost, and avoided health-environmental impacts of agrochemical usage, artificial turf (AT) has increasingly replaced some natural turf (NT) sports fields and recreational lawns. It remains controversial whether AT is a healthy alternative to NT. We asked the research question, “Where and for whom the AT is (or isn't) suitable regarding user thermal sensation partaking various activities?” We established a field experiment at adjoining AT and NT fields in humid-tropical Hong Kong. Detailed microclimatic data were recorded under sunny, cloudy and overcast weather conditions to calculate the modified physiological equivalent temperature (mPET) as a thermal comfort index. Activities covering a range of metabolic rates were selected to evaluate user thermal sensation. AT experienced considerably raised ground surface temperatures on sunny days with a consequential increase in near-ground ambient air temperatures and the environs. The inter-turf temperature difference was somewhat subdued under cloudy and overcast weather. A regression model allowed the successful development of a nine-point thermal suitability index (TSI) to assess AT applications and provide a simple rule-of-thumb for design practice. To avoid undue heat stress, AT use can only be recommended for certain site-weather and user-activity scenarios. The TSI can be applied to other climatic zones by gleaning on-site microclimatic data and enlisting the proposed regression-modelling method. A comprehensive AT assessment scheme can be developed by incorporating the TSI to inform future AT installation and use decisions.

Urohidrosis as an overlooked cooling mechanism in long-legged birds

Behavioural thermoregulation could buffer the impacts of climate warming on vertebrates. Specifically, the wetting of body surfaces and the resulting evaporation of body fluids serves as a cooling mechanism in a number of vertebrates coping with heat. Storks (Ciconiidae) frequently excrete onto their legs to prevent overheating, a phenomenon known as urohidrosis. Despite the increasingly recognised role of bare and highly vascularised body parts in heat exchange, the ecological and evolutionary determinants of urohidrosis have been largely ignored. We combine urohidrosis data from a scientifically curated media repository with microclimate and ecological data to investigate the determinants of urohidrosis in all extant stork species. Our phylogenetic generalised linear mixed models show that high temperature, humidity and solar radiation, and low wind speed, promote the use of urohidrosis across species. Moreover, species that typically forage in open landscapes exhibit a more pronounced use of urohidrosis than those mainly foraging in waterbodies. Substantial interspecific variation in temperature thresholds for urohidrosis prevalence points to different species vulnerabilities to high temperatures. This integrated approach that uses online data sources and methods to model microclimates should provide insight into animal thermoregulation and improve our capacity to make accurate predictions of climate change’s impact on biodiversity.

Modeling and Assessing Heat Transfer of Piglet Microclimates

High piglet pre-weaning mortality rates can be attributed to poor creep area microclimate resulting in negative productivity, welfare, and economic consequences. A piglet mechanistic steady-state thermal balance model was developed using previous models and expanded to assess (a) thermal interactions of multiple pigs and (b) conduction heat transfer. The piglet Effective Environment Temperature (EET) equation was also modified to incorporate piglet age (day 0 to 30) and a conduction heat transfer term. Model parameters were validated with empirical data consisting of the thermal component (dry-bulb temperature, Tdb; mean radiant temperature, TMR; airspeed, U; mat underside temperature, Tm) of the microclimate and dimension data of the piglets (i.e., body weight, length, height, width, and calculated surface area). Model results demonstrate that the common microclimate supplemental heat sources (heat mats and heat lamps; HL) can meet the needs of the piglets. The new EET was more consistent for a novel semi-enclosed heated microclimate (SEHM) in comparison to the HL. This demonstrates the benefit of precision technologies over manually adjusted supplemental heat sources. The experimental data and model results suggest further development of an ideal thermal index for piglet microclimates needs to account for variations of piglet health and body condition to be more applicable in industry.

Active surveillance of ticks in peri-domestic areas of Indiana, Midwest United States.

The incidence of Borreliosis, Anaplasmosis, Babesiosis and other tick-borne diseases acquired from private residential/peri-domestic areas has increased over the decades. However, tick activity and proportion of private residential properties with established tick populations remain unknown. The purpose of the current study was to determine the predictors of tick activity in peri-domestic areas. In a cross-sectional study design, we used snowball-sampling with cold-calling techniques to collect free-living ticks, sociodemographic, and microclimatic data from June to November 2018 from a total of 96 private residential areas in south-central Indiana, USA. Thirty-eight percent of peri-domestic areas sampled had tick activity, and of these, 50% had established tick populations. Nymphal ticks were the most abundant life stage. Self-reported TBD diagnosis was 16%. Amblyomma americanum [Linnaeus (lone star tick)] was the most abundant tick species collected. Other tick species identified include: Ixodes scapularis [Say (black-legged/deer tick)] and Dermacentor variabilis [Say (American dog tick)]. Increasing temperature was positively associated with tick activity, while elevation was negatively associated with tick abundance. Our study results reveal that the proportion of peri-domestic areas in Indiana with established tick populations is high. Amblyomma americanum tick is the most predominant tick species in peri-domestic areas of south-central Indiana. Active surveillance of ticks in peri-domestic areas is necessary for informing decisions by households and communities about where to target tick exposure and tick-borne disease prevention efforts.

Urban Sustainability and Climate Issues: The Effect of Physical Parameters of Streetscape on the Thermal Comfort in Urban Public Spaces; Case Study: Karimkhan-e-Zand Street, Shiraz, Iran

One of the most important issues in urban studies relating to climate and environmental sustainability is the analysis of the thermal conditions of urban public spaces, especially urban streets, since this issue seems to affect the comfort of citizens using such spaces. Thus, the main aim of the present study is to investigate the effect of streetscape parameters on the thermal comfort of citizens using urban streets in a hot summer and in a hot semi-arid climate. For this purpose, Karimkhan-e-Zand Street in Shiraz, Iran, was selected as the case study. The selected street is a historical and popular public space of Shiraz. In the present study, using physical and micro-climatic data analyzed in ENVI-met v4 software, the thermal comfort conditions of Karimkhan-e-Zand in Shiraz on 10 July were simulated during the hottest day of the year. Furthermore, the relationships between physical street parameters and micro-climatic parameters and their effects on the thermal comfort index (PMV) were investigated through running a set of regressions in STATA 14 and analysis of ENVI-met v4 output maps. The results of the present study show that the thermal comfort of the citizens, which is determined by the PMV index values, is in very poor condition in almost all the studied hours, and the air temperature has the greatest effect compared to other micro-climatic parameters on the PMV index. The results of present study also show a significant relationship between the sky view factor and mean radiant temperature, as well as between the surface albedo and relative humidity. Furthermore, the type of vegetation and the aspect ratio of the street affect the level of increase in thermal comfort on the street.

Influence of Scale Effect of Canopy Projection on Understory Microclimate in Three Subtropical Urban Broad-Leaved Forests

The canopy is the direct receiver and receptor of external environmental variations, and affects the microclimate and energy exchange between the understory and external environment. After autumn leaf fall, the canopy structure of different forests shows remarkable variation, causes changes in the microclimate and is essential for understory vegetation growth. Moreover, the microclimate is influenced by the scale effect of the canopy. However, the difference in influence between different forests remains unclear on a small scale. In this study, we aimed to analyze the influence of the scale effect of canopy projection on understory microclimate in three subtropical broad-leaved forests. Three urban forests: evergreen broad-leaved forest (EBF), deciduous broad-leaved forest (DBF), and mixed evergreen and deciduous broad-leaved forest (MBF) were selected for this study. Sensors for environmental monitoring were used to capture the microclimate data (temperature (T), relative humidity (RH), and light intensity (LI)) for each forest. Terrestrial laser scanning was employed to obtain the canopy projection intensity (CPI) at each sensor location. The results indicate that the influence range of canopy projection on the microclimate was different from stand to stand (5.5, 5, and 3 m). Moreover, there was a strong negative correlation between T and RH, and the time for T and LI to reach a significant correlation in different urban forests was different, as well as the time for RH and LI during the day. Finally, the correlation between CPI and the microclimate showed that canopy projection had the greatest effect on T and RH in MBF, followed by DBF and EBF. In conclusion, our findings confirm that canopy projection can significantly affect understory microclimate. This study provides a reference for the conservation of environmentally sensitive organisms for urban forest management.

Analysis of Heat and Mass Distribution in a Single- and Multi-Span Greenhouse Microclimate

Recently, heat and mass distributions within a greenhouse were assumed to be homogeneous. Heat is gained or lost in absolute terms, and crop contribution in a greenhouse or its effect is not considered. In this study, statistical analyses were conducted to establish the significance of heat and mass variation at sensor nodes in two single-span and multi-span greenhouses. Three greenhouses were used in this study, 168 m2 floor area a single-layered (SLG), double-layered (DLG) single-span gothic roof type greenhouses, and 7572.6 m2 floor area multi-span greenhouse (MSG). The microclimatic parameters investigated were temperature (T), relative humidity (RH), solar radiation (SR), carbon dioxide (CO2), and vapor pressure deficit (VPD). To check their horizontal distribution, all microclimate data collected from each sensor node in each greenhouse were subjected to descriptive statistics and Tukey honestly significant difference (HSD) test. The lowest minimum temperatures of 2.93 °C, 3.33 °C and 10.50 °C were recorded at sensor points in SLG, DLG, and MSG, respectively, whereas the highest maximum temperatures of 29.17 °C, 29.07 °C and 27.20 °C were recorded at sensor point, in SLG, DLG, and MSG, respectively. The difference between the center and the side into the single-span was approximately 0.88–1.0 °C and in the MSG was approximately 1.03 °C. Significant variation was observed in the horizontal distribution of T, RH, SR, and VPD within SLG, DLG, and MSG. Also significant was CO2 in the MSG. Estimating the energy demand of greenhouses should be done based on the distribution rather than assuming microclimatic parameters homogeneity, especially for T, with VPD as a control parameter. Such estimation should also be done using a crop model that considers instant changes in air and crop temperature.

Compensation for the Lack of Measured Data on Decisive Cultivation Conditions in Diversified Territories without Losing Correct Information

Sustainable precision agriculture requires site-specific management procedures. This needs appropriate information combining traditional measured data and mapped conditions, models, and specific interpretation. It is impossible to cover the entire variety of sites in the territory with measuring devices, and therefore the measured data are insufficient for a detailed description of changing conditions on each geographical unit. However, detailed data on the morphology and pedologic conditions are usually available, and their synthesis creates the basis for detailed interpolation of the entire area’s measured data and mapping. This article presents a procedure for the synthesis of morphometric and soil indices resulting in the definition and mapping of morpho-pedotops, the interpretation of their thermal–moisture condition, and, consequently, the comparison of these conditions with the condition on the sites with installed sensor stations. This procedure enables reasonable logic interpolation of the measured microclimatic data by sensor stations to the whole study area. The result is the definition of the thermal–moisture condition of the whole territory in comparison to the measured sites. Therefore, the results provide the basis for interpolation for the forecast of climatic events developed for the sites of sensor stations to the whole study area and the forecast of temporal disease events, and thus the basis for precise site-specific field management interventions, even in the case of the lack of the whole area covering measured data.

Frost‐driven lower treelines in Angola and their implications for tropical forest–grassland mosaics

AbstractQuestionsForest–grassland boundaries in the tropics are primarily interpreted as driven by fire and herbivory. So far, frost has received little attention as driver of tropical vegetation boundaries. Here, we study mid‐altitudes in south‐central Africa and ask the following questions: (a) is there a lower treeline between grasslands and forests on the Angolan Plateau; (b) if so, do topoclimatic differences play a role in it; and (c) what do our results imply for tropical highlands globally?LocationThe Angolan Plateau (10°–16°S and 13°–21° E).MethodsWe mapped vegetation by applying a supervised support vector machine‐based classification on a Landsat satellite image. We used a 1,000‐m spaced point grid to extract the mean vertical distribution of the vegetation units from a digital elevation model. The topographic position of each point was calculated using a channel network approach. Microclimatic data were collected across topographic gradients at two sites along the Plateau. Analyses focussed on the number of nights where temperature dropped below 0℃, median and minimum temperatures, and diurnal temperature ranges.ResultsLower treelines separate Miombo forests from geoxyle grasslands in all major valley systems. Treelines are located 150–200 m below the headwater divides. Nocturnal outgoing net long‐wave radiation and resulting cold‐air pooling cause frequent frosts in the valleys during the dry season. Topography controls frost patterns, with minima of down to −7.5℃ and diurnal temperature amplitudes up to 40℃.ConclusionsThe results show that vegetation patterns in central Angola are shaped by frost. The processes causing frost depend on air humidity. Drier atmosphere and lower global temperatures indicate a longer frost season, lower minima and frost extending to lower elevations and latitudes for the Pleistocene. Pleistocene forest fragmentations and the rise of endemism‐rich grasslands in comparable tropical highlands worldwide may be explained by crossing thermic thresholds via increasing seasonal aridity.