Tree Canopy Research Articles

Canopy gaps facilitate establishment of invasive plants in a subtropical broadleaved forest of central Nepal

Plant invasions are major threats to the biodiversity and ecosystem function worldwide. In particular, forests are one of the highly affected ecosystems by invasive alien plant species (IAPS). In spite of several previous studies on plant invasion issues in forests, the role of tree canopy gaps in the establishment of IAPS is poorly understood, particularly in Nepal Himalaya. In this study, we examined the effect of tree canopy gaps on IAPS diversity and abundance in Shorea robusta dominated subtropical mixed broadleaved forest in central Nepal. Fifty pairs of plots (10 m × 10 m) were sampled, with a plot of a pair sampled in a canopy gap and its counterpart 20 m away into the forest interior within tree canopy. In every plot, the cover of the individual IAPS was estimated visually, and other environmental variables such as tree canopy, light intensity, slope, litter depth, tree basal area were measured. Higher number of IAPS (9 species) and their cover (31%) were measured in the canopy gaps than in the plots within tree canopy (6 species; 5% cover), suggesting that tree canopy in these forests provide moderate level of resistance to plant invasions. Moreover, the IAPS cover increased with increasing size of canopy gap. Similarly, IAPS richness increased with the age of gap but it was independent of the gap size. Non-metric multidimensional scaling revealed that the IAPS community within forest canopy was a subset of species found in forest gaps, suggesting that the canopy opening has facilitated establishment of IAPS in the studied forests. Therefore, monitoring forest gaps can be helpful in detecting IAPS in their early stage of invasion so that the effective control measures can be implemented before the IAPS are widespread and problematic at the landscape level.

Investigating the use of artificial nest boxes positioned at different heights on trees and in isolated positions by dormice (Muscardinus avellanarius): Implications for current survey guidelines

Abstract This research, carried out in two phases, is a response to questions raised regarding the validity of surveys based on artificial nest boxes, positioned at around 1.4 m from ground level, to determine the presence of dormice (Muscardinus avellanarius). This species is generally considered to be an arboreal mammal that visits the ground infrequently other than for winter hibernation. In Phase 1, artificial nest boxes were positioned high in the tree canopy and at standard height on the same tree. The presence of leaves and material from the woodland floor in nests informed the design of Phase 2 with the inclusion of a third box, on an isolated post with no arboreal connectivity, carried out on a different site. Results demonstrate the presence of dormice and their nests in artificial nest boxes positioned in the tree canopy, at conventional height and on isolated posts with no arboreal connectivity. This suggests that the current method of surveying for dormice using boxes at around 1.4 m from ground level may not result in robust ‘likely absence’ conclusions for surveys aimed at determining the presence of dormice on a site. Previous experience of long‐term surveys has indicated that use of artificial next boxes declines with age of box. This was confirmed over the 6 years of the second project reported here. While often taken to indicate decline in population alternative explanations are proposed and this is highlighted as requiring further investigation. The apparent decline of hazel dormice and the contraction of their range is evidenced by surveys carried out according to current ‘good practice’ guidance. The results of this research suggest that these should be reviewed and revised to ensure conservation objectives are being met.

Occurrence of Powdery Mildew Caused by Erysiphe corylacearum on Hazelnuts in Israel

Hazelnut (Corylus avellana L) is an emerging crop in Israel, primarily cultivated as a host plant to establish truffle plantations through symbiosis with ectomycorrhizal fungi. A significant damage and yield reduction is caused by the prevalent occurrence of powdery mildew in hazelnut trees (Sezer et al., 2017). Until recently, Phyllactinia guttata was considered the primary pathogen in Western Asia, the Caucasus region, and Europe (Abasova et al. 2018; Arzanlou et al. 2018; Mezzalama et al. 2021). However, in the last years, a new destructive species Erysiphe corylacearum has been identified as the pathogen of powdery mildew on hazelnuts in these regions (Meparishvili et al. 2019; Mezzalama et al. 2021; Kalmár et al. 2022; Zajc et al. 2023). In May 2022, powdery mildew symptoms were observed on hazelnut plants in the Ein-Zivan truffle plantation, gardens of Merom-Golan, and the adjacent garden of the packing house Pri-Beresheet in the northern Golan region of Israel. Symptoms were observed on the abaxial and adaxial leaf surfaces, fruits, and husks. Disease incidence and severity ranged between 30-70% and 5-90%, respectively. Disease severity was significantly greater on the leaves of the offshoots compared to those on the tree canopy. Morphological characterization of leaf samples from ten different trees showed the following characteristics: hyphal appressoria were lobed, solitary, 1–4 μm in diameter; mycelium was amphigenous, hyaline, and septate; conidiophores vertically elevated from the mycelium 50– 80 μm long. Conidia (n= 30) on conidiophores were hyaline, ellipsoid to ovoid, 24 – 34 μm long and 15.5 – 23 μm wide. Chasmothecia in several maturation degrees appeared in October on both sides of the leaves. They were spherical (n= 30) 86 – 125 μm in diameter, with 7 - 14 aseptate straight appendages, 67 - 96 μm long, 4.9 - 7.1 μm wide, dichotomous branched at the end 42 - 56 μm wide. In each chasmothecia, there were 3-5 asci (n=30) with a width of 38 – 43 μm and a length of 48–64 μm of oval-ellipsoid shape. Asci contained 4-8 ascospores (n=30), 18 - 26 μm long and 11 - 15.5 μm wide. A pathogenicity test was conducted to fulfill Koсh’s postulates. Both detached leaves and plants of C. avellana were artificially infected by brushing conidia from infected leaves. Inoculated leaves in Petri dishes on 2% water agar (n= 5), and plants (n= 5) were incubated under 25°C and 12-h photoperiod/day. Untreated leaves and plants served as control. Typical symptoms appeared on the upper surface of the leaves within 7-10 days after inoculation. No symptoms were found on untreated control plants or detached leaves. The fungus isolated from the inoculated leaves was morphologically identical to the original isolates from natural diseased plants. DNA was extracted and the rDNA internal transcribed spacer region of five isolates originated from leaves of the tree canopy and offshoots was amplified using primers ITS1 and ITS4, and sequenced. BLAST analysis of 595 bp fragments (all identical and represented by isolate Cora1, GenBank Accession No. OR752437) showed 99% identity to ITS rDNA sequences of E. corylacearum from Georgia (MK157199) and 100% identity to isolates from Azerbaijan, Turkey and Italy (LC270863, KY082910 and MW045425, respectively) and only 83% similarity to P. guttata (accession number AB080558). To the best of my knowledge this is the first report on E. corylacearum causing powdery mildew in Israel. Future control measures to manage the disease on hazelnuts in truffle plantations in Israel should be considered.

A NIDILRR Traumatic Brain Injury Model Systems Investigation of Home Neighborhood Tree Canopy Coverage after Traumatic Brain Injury

A NIDILRR Traumatic Brain Injury Model Systems Investigation of Home Neighborhood Tree Canopy Coverage after Traumatic Brain Injury

Using ecological niche modelling to prioritise areas for conservation of the critically endangered Buffy-Headed marmoset (Callithrix flaviceps).

Endemic to the Atlantic Forest in Southeastern Brazil, the critically endangered Buffy-Headed marmoset (Callithrix flaviceps) is lacking the required attention for effective conservation. We modelled its ecological niche with the main objectives of (1) defining suitable habitat and (2) prioritising areas for conservation and/or restoration. The current geographical range of Callithrix flaviceps in the Atlantic Forest of Southeast Brazil. We used Ensemble Species Distribution Modelling to define current habitat suitability considering four climate and two landscape variables. To identify areas to prioritise for conservation and/or restoration, we predicted future habitat suitability considering the intermediate (RCP4.5) and extreme (RCP8.5) climate change scenarios for the years 2050 and 2070. Among the variables included to predict current species distribution, tree canopy cover, precipitation seasonality and temperature seasonality were the most important whereas digital elevation model and precipitation during the wettest month were the least important. Callithrix flaviceps was most likely to occur in areas with tree canopy cover >80%, high precipitation seasonality and temperature seasonality between 21 and 23°C. From the future suitability prediction maps, the Caparaó National Park stands out as a likely key area for the preservation of the species. Furthermore, high climatic suitability but low landscape suitability suggests that habitat restoration in 'Serra das Torres' (South of the current distribution area) might be a useful strategy. However, creating ecological corridors on the west side of Caparaó would be necessary to improve connectivity. More surveys within and beyond the current geographical range are required to define more precisely the distribution of the species. Our results support the notion that seasonality is important for Callithrix flaviceps and that as a montane species, it prefers colder environments and higher altitudes. Within both climate change scenarios, Caparaó National Park was predicted to be highly suitable, with a high probability of presence.

High-resolution satellite images reveal the prevalent positive indirect impact of urbanization on urban tree canopy coverage in South America

Trees in urban areas act as carbon sinks and provide ecosystem services for residents. However, the impact of urbanization on tree coverage in South America remains poorly understood. Here, we make use of very high resolution satellite imagery to derive urban tree coverage for 882 cities in South America and developed a tree coverage impacted (TCI) coefficient to quantify the direct and indirect impacts of urbanization on urban tree canopy (UTC) coverage. The direct effect refers to the change in tree cover due to the rise in urban intensity compared to scenarios with extremely low levels of urbanization, while the indirect impact refers to the change in tree coverage resulting from human management practices and alterations in urban environments. Our study revealed the negative direct impacts and prevalent positive indirect impacts of urbanization on UTC coverage. In South America, 841 cities exhibit positive indirect impacts, while only 41 cities show negative indirect impacts. The prevalent positive indirect effects can offset approximately 48% of the direct loss of tree coverage due to increased urban intensity, with full offsets achieved in Argentinian and arid regions of South America. In addition, human activity factors play the most important role in determining the indirect effects of urbanization on UTC coverage, followed by climatic and geographic factors. These findings will help us understand the impact of urbanization on UTC coverage along the urban intensity gradient and formulate policies and strategies to promote sustainable urban development in South America.

丘陵山地果园单轨式防霜机的仿真与试验

In order to solve the problems of artificial operation, high labor intensity and low efficiency of frost prevention in hilly orchards, this study takes hilly orchards as the research object. Based on the agronomic requirements of frost prevention in hilly orchards, a smoke anti-frost machine based on the transport track of hilly orchards is designed. With the help of Fluent software, the spatial and temporal distribution characteristics of smoke mass concentration and temperature in the process of smoke diffusion are simulated and analyzed based on the discrete phase model. The results show that the smoke continues to erupt at a speed of 6 m / s, and the plume volume gradually increases. After 9 s, the smoke reaches a stable diffusion state. Based on the established smoke diffusion simulation model, the orthogonal test analysis of the working parameters at the smoke outlet of the frost-proof machine was carried out with the temperature increase near the canopy of the fruit tree as the index. The results showed that the best combination of working parameters at the smoke outlet of the frost-proof machine was the smoke outlet speed of 10 m / s, the smoke outlet angle of 60 °, and the smoke outlet diameter of 140 mm. The field test results show that the frost-proof machine can continuously operate for 0.5 h at a running speed of 0.6 m / s, and the temperature in the height range of 1.5 m to 4 m in the working area can be increased by about 1.7 ° C. This study is of great significance to reduce the frost disaster loss of hilly orchards and improve the economic benefits of hilly orchards.

Criticism of the Effect of Green Cover Change on Air Quality with i-Tree Canopy (Bursa-Osmangazi Region Sample)

Anything that reflects the ethnicity of a society that has aesthetic and visual textures transferred from past generations to the present day, that is universally accepted, that contains abstract and concrete concepts, and that is intended to be preserved and transferred to future generations is called "cultural heritage". Today's urbanism continues to develop around the settlements of ancient civilisations, which are accepted as cultural heritage. Today, migration from villages to cities has increased and population density in cities has shown a rapid upward trend. The destruction of green areas due to rapid urbanisation has increased visibly and has made smart cities with green areas obligatory. In smart urbanisation, practical methods are sought to quickly identify green areas and determine the benefits provided by these areas. The most widely used software for measuring tree canopy cover is i-Tree Canopy, which allows urban planners to quantify the ecosystem services and benefits of tree communities and forests at multiple scales, including pollution reduction, carbon sequestration and storage, and runoff reduction. Within the scope of the study, the changes on green areas such as urbanisation, industrialisation, increase in transportation networks brought about by population growth in the historical city centre of Bursa and the negative and positive effects of these changes were examined. In the study, the time-dependent changes of green areas in urban heritage and urban planning were determined with GIS (Geographical Information Systems) techniques, and suggestions were developed for existing and new green areas to be planned in the city.

Harsh environmental conditions promote cooperative behavior in an epiphytic fern

ABSTRACT Harsh, unpredictable environments are known to favor cooperative groups in animals. Whether plants exhibit similar relationships is unknown. Staghorn ferns (Platycerium bifurcatum, Polypodiaceae) are epiphytes that form cooperative groups which build communal water and nutrient ‘nests’ at the tops of trees, a habitat characterized by water and nutrient stress. We conducted field observations to test whether staghorn ferns continue to live in large, reproductively active groups after they become dislodged from the canopy and fall to the forest floor, where they are less limited by water and nutrient deprivation. To rule out the potentially confounding effects of light limitation on the forest floor, we also conducted a multi-year glasshouse experiment where we transplanted individual plants into soil and onto vertically oriented boards under standardized light conditions. Results from field observations showed that dislodged colonies formed smaller groups that reproduced less than epiphytic colonies. Results from the glasshouse experiment showed that even when growing in full sun, terrestrial individuals tended to remain solitary, while epiphytic individuals tended to recruit new individuals into colonies. Results also showed that plants growing in potting soil and exposed to full sunlight sporulated more heavily than plants growing epiphytically. However, localities that are characterized by both elevated soil and light resources are generally not available to staghorn ferns in the wild, perhaps with the exception of large, epiphytic colonies with well-developed nests at the top of tree canopies. Overall results indicate that the harsh environmental conditions at the tops of trees trigger the formation of colonies in staghorn ferns, similarly to group living animals.

The Combination of High-Light Efficiency Pruning and Mulching Improves Fruit Quality and Uneven Maturation at Harvest in Camellia oleifera

Camellia oleifera Abel is rich in oil, which is beneficial to human health. Seasonal drought and uneven canopy microclimate distributions result in low yields and picking efficiencies. To reveal the features of fruit development in the canopy and evaluate the impact of pruning on the canopy microclimate and fruit parameters, a field experiment was carried out in Zhuzhou, Hunan. The C. oleifera tree canopy was divided into four positions: inside the upper canopy (UI); inside the lower canopy (LI); outside the upper canopy (UO); and outside the lower canopy (LO). A combination of high-light efficiency tree pruning and mulching with camellia shells and weedproof film (CPM) was tested and compared with mulching (M). Compared with temperature and humidity, canopy light intensity is a key climate factor that affects the development of Camellia oleifera fruits. CPM improved the canopy light distribution and increased the light intensity inside the canopy of C. oleifera. There was no significant difference in the fruit cracking rate among the four canopy positions in the CPM treatment, which indicated that the fruit maturation period tended to be consistent across the canopy positions. Treatment with CPM resulted in 24.14% and 4.11% greater yield and oil content ratios, respectively, than the treatment with M. The fresh weight of the fruits from LO was the lowest, and the fatty acid accumulation was the lowest due to the poor light availability. CMP increased fruit quality, particularly in LI, which was 41.92%, 36.36%, 13.21%, and 12.79% greater in terms of fresh weight, yield, fresh seed rate, and oil content, respectively, than M. Unfortunately, there was no discernible difference in fatty acid components between CPM and M. Our research suggested that pruning combined with the mulching of organic material is an effective way to alleviate seasonal drought and uneven fruit maturation in C. oleifera trees, further increasing yield and fruit quality.

Spatial Heterogeneity of the Respiratory Health Impacts of Wildfire Smoke PM2.5 in California.

Wildfire smoke fine particles (PM2.5) are a growing public health threat as wildfire events become more common and intense under climate change, especially in the Western United States. Studies assessing the association between wildfire PM2.5 exposure and health typically summarize the effects over the study area. However, health responses to wildfire PM2.5 may vary spatially. We evaluated spatially-varying respiratory acute care utilization risks associated with short-term exposure to wildfire PM2.5 and explored community characteristics possibly driving spatial heterogeneity. Using ensemble-modeled daily wildfire PM2.5, we defined a wildfire smoke day to have wildfire-specific PM2.5 concentration ≥15μg/m3. We included daily respiratory emergency department visits and unplanned hospitalizations in 1,396 California ZIP Code Tabulation Areas (ZCTAs) and 15 census-derived community characteristics. Employing a case-crossover design and conditional logistic regression, we observed increased odds of respiratory acute care utilization on wildfire smoke days at the state level (odds ratio [OR]=1.06, 95% confidence interval [CI]: 1.05, 1.07). Across air basins, ORs ranged from 0.88 to 1.57, with the highest effect estimate in San Diego. A within-community matching design and spatial Bayesian hierarchical model also revealed spatial heterogeneity in ZCTA-level rate differences. For example, communities with a higher percentage of Black or Pacific Islander residents had stronger wildfire PM2.5-outcome relationships, while more air conditioning and tree canopy attenuated associations. We found an important heterogeneity in wildfire smoke-related health impacts across air basins, counties, and ZCTAs, and we identified characteristics of vulnerable communities, providing evidence to guide policy development and resource allocation.

Potential of Nature-Based Solutions to Diminish Urban Heat Island Effects and Improve Outdoor Thermal Comfort in Summer: Case Study of Matadero Madrid

Urban heat island effects and climate change are climatic phenomena responsible for periods of extreme heat in summer which severely impact citizens’ well-being and health. In this alarming context which questions the livability of our cities, Nature-Based Solutions (NBSs) are considered an unavoidable component of the complex strategy in diminishing urban temperatures. The present work aims to show the relevance of NBSs in urban temperature regulation through the estimation of their potential to improve outdoor thermal comfort of the heritage site Matadero Madrid. To this end, this article evaluates the effects of a scenario combining different solutions including NBSs and identifies which solutions are the most effective. The results show that this scenario has an impact on direct solar radiation and wind speed but does not affect air temperature and relative humidity. Furthermore, even if this scenario combining a fabric canopy, tree canopy, and green area significantly improves thermal conditions, it does not allow us to reach an optimal level of thermal comfort for visitors. To consider the implementation of more meaningful interventions, existing legal, administrative, and cultural limitations of the case study should be omitted. This would enable us to identify which restrictions could be adapted, thus unlocking the adaptation potential of Matadero Madrid.

Navigation system for orchard spraying robot based on 3D LiDAR SLAM with NDT_ICP point cloud registration

Autonomous navigation of orchard spraying robots can effectively improve operational efficiency and reduce workload. The conventional robot navigation solutions based on the Global Navigation Satellite System (GNSS) are susceptible to signal loss in orchards due to interference from the canopy of fruit trees. In this paper, an autonomous navigation scheme for orchard spraying robots based on multi-sensor devices and the three-dimensional (3D) LiDAR Simultaneous Localization and Mapping (SLAM) technology. The initial step of the scheme involved the construction of a 3D point cloud map of the orchard using the 3D LiDAR SLAM algorithm. Subsequently, a designed point cloud map transformation algorithm was used to convert the 3D point cloud map of the orchard into a two-dimensional (2D) grid map containing key feature information of the orchard. To enhance the mapping accuracy of the orchard point cloud, a point cloud registration algorithm combining Iterative Closet Point (ICP) and Normal Distributions Transform (NDT) was proposed. This algorithm initially utilized the NDT algorithm for coarse point cloud registration to obtain transformation parameters. Then, the ICP algorithm was applied in conjunction with the obtained parameters for fine registration. Regarding obstacle avoidance, a cooperative obstacle avoidance algorithm based on the Robot Operating System (ROS) multithreaded communication mechanism was introduced. Experimental trials conducted in a standardized spindle-shaped peach orchard validated the successful completion of the SLAM mapping trajectory, which was achieved through the utilization of the proposed NDT_ICP point cloud registration algorithm. The average absolute pose error between the mapped trajectory and the reference trajectory was 1.173 m, with a standard deviation of 0.498 m. The robot's positioning and navigation errors increased with higher speeds, with the largest positioning deviation observed at 1.2 m/s speed, with a maximum lateral positioning error of 7.04 cm. The robot's average lateral navigation error did not exceed 16 cm, and the average heading deviation was less than 8° at different speeds of 0.4, 0.8 and 1.2 m/s. Both the positioning and navigation accuracies of the robot were sufficient to meet the autonomous operational requirements of orchard spraying robots.

Natural shading vs. artificial shading: A comparative analysis of their cooling efficacy in extreme hot weather

Shading, comprising both natural and artificial coverings, is an efficient and effective strategy to reduce heat stress in outdoor environments. Despite its recognized efficiency, there is limited comparative insight into the cooling performance of natural and artificial shading. This study examined the cooling efficacy of two covered walkways and two tree canopies, concerning microclimate conditions by various variables and thermal stress quantified by four thermal indices. Our findings highlight three key points: Firstly, the average cooling effects provided by natural and artificial shading were comparable, including reductions in air temperature (1.42 °C vs. 1.31 °C), mean radiant temperature (15.93 °C vs. 13.71 °C), and Physiological Equivalent Temperature (PET) (9.06 °C vs. 9.70 °C), Universal Thermal Climate Index (UTCI) (4.71 °C vs. 5.08 °C), and Hong Kong Heat Index (HKHI) (2.36 °C vs. 2.50 °C). Secondly, it is inconsistent which shading solution is better for microclimate improvement and heat stress alleviation, which is affected by canopy materials, configurations, and tree species. Thirdly, the four indices presented an inconsistent pattern in heat stress assessment. Notably, PET and UTCI showed similar patterns, while HKHI and modified PET presented lower sensitivity to high heat stress. This study offers valuable insights for urban designers to create sustainable shaded communities and also initiates a discourse for revising local heat warning systems, considering various thermal stress indices.

The metabolic fingerprint of Scots pine-root and needle metabolites show different patterns in dying trees.

The loss of leaves and needles in tree crowns and tree mortality are increasing worldwide, mostly as a result of more frequent and severe drought stress. Scots pine (Pinus sylvestris L.) is a tree species that is strongly affected by these developments in many regions of Europe and Asia. So far, changes in metabolic pathways and metabolite profiles in needles and roots on the trajectory toward mortality are unknown, although they could contribute to a better understanding of the mortality mechanisms. Therefore, we linked long-term observations of canopy defoliation and tree mortality with the characterization of the primary metabolite profile in needles and fine roots of Scots pines from a forest site in the Swiss Rhone valley. Our results show that Scots pines are able to maintain metabolic homeostasis in needles over a wide range of canopy defoliation levels. However, there is a metabolic tipping point at around 80-85% needle loss. Above this threshold, many stress-related metabolites (particularly osmoprotectants, defense compounds and antioxidants) increase in the needles, whereas they decrease in the fine roots. If this defoliation tipping point is exceeded, the trees are very likely to die within a few years. The different patterns between needles and roots indicate that mainly belowground carbon starvation impairs key functions for tree survival and suggest that this is an important factor explaining the increasing mortality of Scots pines.

UAV-RGB-image-based aboveground biomass equation for planted forest in semi-arid Inner Mongolia, China

The acquisition of high-resolution aboveground biomass (AGB) data cost-effectively and expeditiously represents a formidable challenge within the domain of current ecosystem surveillance. Plot-based inventory, the conventional approach for estimating and validating remote sensing data, is nonetheless costly and constrained in terms of spatial coverage. The expeditious advancements in unmanned-aerial-vehicle (UAV) technology furnish the potential to devise AGB equations that transcend traditional diameter-height-based equations alongside techniques for quantifying forest structural parameters through standard RGB aerial imagery. Since the canopy diameter (CD) and tree height (H) can be directly ascertained from UAV-derived datasets, biomass equations parameterized by CD and H may be more valuable. In the present investigation, we established AGB equations predicated on data procured from a UAV outfitted with a high-resolution RGB camera, specifically for planted sparsely Pinus sylvestris forest in central Inner Mongolia, China. Utilizing the aerial imagery, we generated the digital terrain model (DTM), digital surface model (DSM) and the digital orthophoto image (DOM). Then, the canopy height model (CHM) was obtained by subtracting DSM from DTM to extract the H and CD of individual trees. This methodology's CD (R2 = 0.85, RMSE = 0.203 m) and H (R2 = 0.77 and RMSE = 0.671 m) obtained closely mirrored the in-situ measurements. Six prospective AGB equations were constructed for the Pinus sylvestris forest, taking H and CD extracted from UAV aerial survey datasets as the dependent variables. The accuracy of the AGB estimation was appraised by employing extant allometric growth equations, which were parameterized using the ground-measured tree diameter at breast height (DBH) and H. The most efficacious biomass equation, predicated on H and CD data extracted from UAV aerial surveys, was delineated as W=2.3442CD∗H0.9057(R2 = 0.731, RMSE = 2.46 kg), thus presenting a convenient tool for estimating the AGB of sparse Pinus sylvestris forests in semi-arid locales.

Drone-mounted remote-controlled arm for monitoring and precision spraying coconut rhinoceros beetle infestations

This paper presents a low-cost (locally-assembled) drone system with a sprayer arm and a remote control for monitoring and precisely applying pesticides to coconut trees infested by the Rhinoceros Beetle. A modified RGB IP camera continuously monitors potential coconut beetle infestation points, capturing real-time spray images, and displaying the results through a smartphone interface. The system provides real-time monitoring, allowing immediate remote control of the spray operation from the ground upon detecting beetle infestations. The drone-mounted sprayer arm is controlled in response to the ground-based signals, to accurately extend or contract while effectively dispensing spray chemicals onto the target areas at the upper canopy of coconut trees. In our tests using Nam-Hom coconut trees, which averaged a height of 10.4 m, the system operated at a speed of 1.25 km/h, achieving a spraying flow rate of 0.333 l/h and a working capacity of 0.352 ha/h. The controlled spraying setup emits a solid jet, ensuring precision and effective atomization of chemicals within a distance range of 1.0 to 4.0 m from the target. The spray quality attributes (droplet size, pattern, and coverage) were not significantly affected by the wind speed. The system could potentially reduce labor costs, chemical usage, and health risks associated with pesticide application.

Assessing the magnitude of soil carbon enhancement under canopy in an arboretum environment

Soil organic carbon (C) is a larger and more stable C storage pool than terrestrial biomass. Some trees are very effective in transferring C from the atmosphere to the soil, particularly soil under canopy. As a consequence, in environments containing a variety of trees, the distribution of soil organic C is patchy at the 1–10 m scale making it challenging to quantify at the larger scales relevant for C sequestration accounting. The aim of this study was to develop and test a process for assessing soil organic C in such environments. An initial set of 53 soil cores was collected in open spaces across the Waite Arboretum in Adelaide, Australia, which contains over 800 different tree species across 27 ha of parkland. Conventional soil organic C analysis indicated variation in organic C concentration of the 0–10 cm soil layer through the 2–5% range with an average soil organic C concentration of 3.19%. A reliable model to predict soil organic C concentration from mid-infrared (MIR) spectra from further soils collected in the Waite Arboretum was developed using partial least squares regression (PLSR). Follow-up sampling targeted 144 soils collected in a radial pattern under and close to tree canopies and the soil organic C values obtained from MIR-PLSR prediction of these soils confirmed the open-space average (3.19%) is a substantial underestimate, with higher average values at half canopy (7.47%) canopy edge (5.10%) and twice-canopy distance (3.84%) for twelve selected trees of different species. Importantly, the elevation in under-canopy organic C concentration varied substantially from tree to tree. This study highlights the challenge posed in assessing soil organic C in urban forest environments, confirms soil organic C storage varies with tree species and demonstrates the value of using mid-infrared prediction in tandem with traditional chemical analyses for assessing soil organic C.

Spatial Analysis of Bike-Sharing Ridership for Sustainable Transportation in Houston, Texas

This study aims to analyze bike-sharing information and related urban factors to promote bike-sharing utilization in Houston, Texas. The research was initiated with a descriptive analysis, where the hourly and daily variations in bike demand are investigated, thereby revealing the time-related patterns of bike tours. The models included data on socio-demographics, public transportation availability, land use patterns, tree canopy coverage, bike routes, and job density within 0.25-mile and 0.5-mile buffer zones around each bike-sharing station. Stepwise regression was utilized to examine the effects of urban factors on bike-sharing ridership, and the explanatory power of the model was enhanced by selecting meaningful variables. The analysis found that tree canopy coverage was a significant factor in influencing bike-sharing ridership. Expansion of tree coverage can help make biking a sustainable mode of transportation. These findings have the potential to guide the development of practical policies that aim to promote sustainable urban mobility through bike-sharing programs.

Seeking shade equity: Tree canopy coverage in public schools in Austin, TX.

Tree canopies have dermatologic and environmental benefits, especially on school campuses. However, inequities likely exist, and tree planting initiatives may further exacerbate disparities. We sought to identify any relationship between tree canopy shade on public school campuses in Austin, TX and the socioeconomic makeup of the student population, as well as whether current initiatives appropriately address any inequities. In this cross-sectional study, we used ArcGIS, a publicly available geographic information system (GIS), to calculate the percentage of tree canopy on campuses within the Austin Independent School District (AISD) for the years 2006 and 2022. We compared this with the percentage of students eligible for free and reduced meals (FRM) at each school. The percentages of FRM-eligible students were also compared for "low priority" versus "high priority" neighborhoods, as assigned by Austin's Tree Priority Map. Among 112 schools analyzed, schools with minority FRM-eligible students had significantly more tree canopy compared to schools with majority FRM-eligible students (19.9% vs. 12.4%, p < .001). When comparing tree priorities, there was a significant difference between the percentage of FRM-eligible students in "low priority" schools compared to "high priority" schools (23.8% vs. 62.2%, p < .001). Additional work is needed to rectify inequities in tree canopy access for public school students. Designations such as those used in Austin's Tree Priority Map would likely help direct such efforts. We hope this study encourages future research with GIS by both dermatologists and other health care professionals to promote interdisciplinary work with urban planners.