Tree Characteristics Research Articles

Discovering and measuring giant trees through the integration of multi‐platform lidar data

Abstract Giant trees are pivotal in forest ecosystems, yet our current understanding of their significance is constrained primarily by the limited knowledge of their precise locations and structural characteristics. Amidst escalating human‐induced disturbances globally, there is an urgent need to devise a practical approach to discover and measure giant trees accurately and efficiently. Here, we propose a novel light detection and ranging (lidar)‐based framework designed for the discovery and measurement of giant trees. Our framework integrates cutting‐edge lidar platforms, including spaceborne, Unmanned Aerial Vehicle (UAV), and backpack lidar, to create an end‐to‐end workflow. The algorithm involved in the proposed framework was compiled into a code package and made available as open source. The method successfully identified the tallest trees in China, including the tallest tree in Asia, a Cupressus austrotibetica with a height of 102.3 m, discovered in Yarlung Zangbo Grand Canyon in May 2023. This finding has not only established a new record but also demonstrated the efficacy of our proposed framework. Utilising lidar data, we performed meticulous measurements at both individual and stand levels, revealing the unique characteristics of this giant tree. The new framework for the discovery and measurement of giant trees, encompassing detailed procedures and codes, is expected to facilitate the discovery and measurement of giant trees with high efficiency, thus fostering advancements in giant tree ecology.

Examining spatial and social characteristics of customary trees owned by villagers on public forestlands in Jharkhand, India

Tree ownership is typically tied to land ownership in many societies worldwide. Still, in India, tribal communities have customary ownership over trees in public forestlands, raising questions about what those trees are, where they are located, their characteristics, and whether socioeconomic factors influence their distribution and density. To address these questions, we conducted household interviews and a Global Positioning System (GPS) mapping in Sahritola, a village in the State of Jharkhand, India. We employed Kruskal Wallis, Spearman correlation, and Moran's Index to analyze the collected data. The villagers have been protecting and managing over 18,000 trees in public forestlands, including species such as asan (Terminalia tomentosa), sal (Shorea robusta), and mahua (Madhuca longifolia). Over 80 % of those trees are under individual ownership, while around 20 % are under shared ownership. Additionally, over 60 % of households owned between 100 and 500 trees. Customarily-owned tree species sharing similar characteristics (e.g., height, crown width, and diameter-at-breast-height) tend to cluster together. The number of customarily owned trees is influenced by their economic value and socioeconomic factors (e.g., religion, forestland, etc.). Additionally, the type of customary ownership (individual or shared) influences the characteristics of trees. This study could guide policymakers in potentially developing forest policies that consider the concept of customary tree ownership to promote sustainable management of forest resources in India and beyond.

Tree characteristics, drought and microtopography modulate the response of subtropical Cunninghamia lanceolata to drought

Tree characteristics, drought and microtopography modulate the response of subtropical Cunninghamia lanceolata to drought

The Effect of Organic and Amino Acid Biostimulants on Actinidia deliciosa ‘Hayward’ Cultivation: Evaluation of Growth, Metabolism, and Kiwifruit Postharvest Performance

The commercial value of kiwifruit is determined mostly by its nutritional composition and antioxidant content. The enrichment of these traits in an era where climate change affects kiwi growth conditions is worth investigating via the application of biostimulants that enhance plant growth. In this work, we evaluated the effects of three commercial biostimulants on the metabolism and growth characteristics of the Actinidia deliciosa cultivar ‘Hayward’: (I) a humic and fulvic-based biostimulant, (II) a glycine–betaine–proline-based biostimulant, and (III) a vegetal amino acid-based biostimulant. A biostimulant-free treatment was used as a control. In the two-year experiment (2022 and 2023), the growth characteristics of kiwi trees were measured, such as stem length, the number of leaves, leaf area, and fresh and dry biomass at the end of each growing season. The leaves’ total chlorophyll, total phenolics, and proline content were detected during the two seasons in order to obtain more insights into plant metabolism. Κiwifruit qualities and antioxidant traits, such as total soluble solids, titratable acidity, firmness, fresh and dry biomass, DPPH, and ascorbic acid (vitamin C), were recorded during the postharvest life for each season. Data analysis illustrated the beneficial impact of some biostimulants on several of the previously mentioned parameters, such as antioxidant kiwifruit traits, especially in the case of glycine–betaine–proline-based acid-based biostimulants.

Analysis of the Species Composition of Wood and Shrubs Species, Their Role in the Structure of City Parks of Osh

In the city of Osh, one of the acute problems when using wood species in landscape design is the study of their ecological properties in relation to the environment. The planting of trees in urban parks, squares along streets and boulevards is influenced by various environmental factors. In such conditions, the study of the ecological state and viability of plants is relevant, since woody plants perform sanitary, hygienic and aesthetic functions in an urbanized environment. The main purpose of this scientific article is to identify in the conditions of the city of Osh, the peculiarities of the development of ornamental species of woody and shrubby plants, the ecological justification of their reconstruction, to improve the sanitary and hygienic condition and the development of practical recommendations in landscape works. The study of the characteristics of tree and shrub species and the results obtained to assess their role in the structure of urban parks in Osh will help to improve their decorative qualities, the correct choice of their placement, care and improvement of the urban environment. The results of the work can also be used in the construction and reconstruction of green spaces in parks in the city of Osh, as well as in the improvement of other public facilities in the city. The practical recommendations obtained from the results of the study initiate a large-scale reconstruction of planted species of trees and shrubs in parks, squares and along modern streets.

Assessing the factors affecting maple syrup yield in the US and predicting production potential in Kentucky

Maple syrup is an important part of the economy in various regions of the United States. Studies on maple syrup production potential mostly use climatic factors as determinants and, therefore, fail to account for non-climatic factors. In this study, we applied a stochastic production function framework to establish a relationship between maple syrup yield and a set of climatic (temperature and tapping season length) and non-climatic determining factors, such as the number of maple trees and utilization rate of the potential number of taps. Tree characteristics, climatic, and other factors had mixed effects on syrup yield. The number of maple trees, the number of taps, and the minimum temperature had marginal negative effects on average syrup yield, while the length of the season and the maximum temperature had positive effects. A predictive model was developed and used to estimate the potential production of maple syrup under low, medium and high utilization levels in Kentucky, a likely region for maple syrup production. This model could be useful for maple syrup research, education, and extension in maple-producing states.

Financial distress prediction using an improved particle swarm optimization wrapper feature selection method and tree boosting ensemble

Financial distress prediction (FDP) is a complex task involving both feature selection and model construction. While many studies have addressed these challenges individually, there is a lack of FDP models that integrate feature selection into the overall model building process. To address the issues of fast convergence and local optimization in particle swarm optimization (PSO), this study proposes a modified PSO algorithm with three improvement strategies. This improved PSO, known as IPSO, is embedded within state-of-the-art tree boosting ensemble models for feature selection. IPSO continuously evolves toward the optimal feature subset, preventing premature convergence and avoiding local optima. To construct the FDP model, four state-of-the-art tree boosting models are combined using an improved majority voting ensemble strategy. The integration of IPSO enhances the prediction performance of the model. Comparative experiments are conducted on samples of Chinese listed companies under short-term and long-term prediction scenarios to evaluate the proposed model. The results demonstrate that IPSO significantly improves the prediction performance, and the ensemble strategy enhances the robustness of the predictions.

Detecting branching rate heterogeneity in multifurcating trees with applications in lineage tracing data.

Understanding cellular birth rate differences is crucial for predicting cancer progression and interpreting tumor-derived genetic data. Lineage tracing experiments enable detailed reconstruction of cellular genealogies, offering new opportunities to measure branching rate heterogeneity. However, the lineage tracing process can introduce complex tree features that complicate this effort. Here, we examine tree characteristics in lineage tracing-derived genealogies and find that editing window placement leads to multifurcations at a tree's root or tips. We propose several ways in which existing tree topology-based metrics can be extended to test for rate heterogeneity on trees even in the presence of lineage-tracing associated distortions. Although these methods vary in power and robustness, a test based on the statistic effectively detects branching rate heterogeneity in simulated lineage tracing data. Tests based on other common statistics ( and the Sackin index) show interior performance to . We apply our validated methods to xenograft experimental data and find widespread rate heterogeneity across multiple study systems. Our results demonstrate the potential of tree topology statistics in analyzing lineage tracing data, and highlight the challenges associated with adapting phylogenetic methods to these systems.

Distribution and Habitat Selection of Indian Flying Fox, Pteropus medius (Temminck, 1825) in Uttar Pradesh, India

The present study examines the distribution and habitat selection of Indian flying fox, Pteropus medius in Uttar Pradesh, India. A through field work conducted across six districts revealed 22 roosting locations with a total population of approximately 12,023 bats. These sites were located at rural (12), semi-urban (2), urban (1), agricultural (5), and industrial (2) areas, and a majority of roost sites observed close to human habitations. Pteropus medius preferred to roost on 20 species of trees which indicate wide-ranging habitat preferences. Although there were considerable differences in tree attributes across different species, such as tree height (ranging from 9.54 to 26.03 meters), canopy width (varying from 8.59 to 25.09 meters), crown height (ranging from 1.19 to 18.90 meters), circumference (ranging from 0.54 to 3.65 meters), and DBH (ranging from 0.17 to 3.73 meters), and there was no notable variation in bat occupancy per roost tree. The results of the regression analysis emphasized the significance of canopy width as a predictor of colony size, indicating its importance in identifying suitable roosting habitats for P. medius. ANOVA analysis indicated differences in tree characteristics across species, highlighting the necessity for through habitat evaluations. Subsequent post-hoc examination clarified distinct clusters of tree species with significant variations in roosting site features. These results underscore the intricate relationship between tree attributes and bat populations, emphasizing the significance of well-informed conservation approaches for the sustainable preservation of P. medius and the overall ecosystem well-being.

Changes in Water Utilization Characteristics of Trees in Forests across a Successional Gradient in Southern China

Elucidating the water utilization strategy of trees during forest succession is a prerequisite for predicting the direction of forest succession. However, the water utilization characteristics of trees in forests across a successional gradient remain unclear. Here, we utilized the hydrogen and oxygen stable isotopes combined with the Bayesian mixed model (MixSIAR) to analyze the water utilization of dominant trees (Pinus massoniana, Castanea henryi, and Schima superba) in forests along a successional gradient in the Dinghushan Biosphere Reserve of China. Furthermore, we determined the primary factor affecting the water utilization of various trees based on variation partitioning analysis and a random forest model. Our results illustrated that in the early-successional forest, the water utilization ratios from shallow soil layers by P. massoniana were significantly lower than that in the mid-successional forest (51.3%–61.7% vs. 75.3%–81.4%), while its water utilization ratios from deep soil layers exhibited the opposite pattern (26.1%–30.1% vs. 9.0%–15.0%). Similarly, the ratios of water utilization from shallow soil layers by C. henryi (18.9%–29.5% vs. 32.4%–45.9%) and S. superba (10.0%–25.7% vs. 29.2%–66.4%) in the mid-successional forest were relatively lower than in the late-successional forest, whereas their water utilization ratios from deep soil layers showed the contrary tendency. Moreover, our results demonstrated that the diverse water utilization of each tree in different successional forests was mainly attributed to their distinct plant properties. Our findings highlight the increased percentage of water utilization of trees from shallow soil layers with forest succession, providing new insights for predicting the direction of forest succession under changing environments.

Impacts of ash tree removals on summer daytime temperatures in Madison, Wisconsin

Maintaining and increasing canopy cover is frequently promoted as a strategy for mitigating excess heat in cities. However, the impact of changing tree cover on surrounding air temperatures is often unpredictable and can depend on tree species, size, shape, and location. In this study, we explore whether the removal of ash trees in one downtown neighborhood in Madison, Wisconsin affected surrounding air temperatures at small spatial scales (15 to 35 m). We used a bicycle-mounted temperature and radiation sensor to repeatedly record high-frequency observations along four transects. We observed no discernible difference between daytime air temperatures near locations surrounded by tree removals and temperatures at locations without any nearby tree removals. Overall, across the four clusters of streets that were monitored, proximity to mature ash trees did not correlate to reduced air temperatures. Attempts to model temperature as a function of surrounding land cover and street tree characteristics all had poor predictive power (R2 ranged from 0.01 to 0.54), and explanatory variables related to tree cover were never statistically significant. The finding that the removal of ash trees did not impact daytime air temperatures patterns at the neighborhood scale suggests that the most densely developed streets in Madison may not easily support sufficient canopy cover to experience tree-induced cooling, underscoring the importance of pursuing a variety of strategies to mitigate urban warming.

On Some Distance Spectral Characteristics of Trees

Graham and Pollack in 1971 presented applications of eigenvalues of the distance matrix in addressing problems in data communication systems. Spectral graph theory employs tools from linear algebra to retrieve the properties of a graph from the spectrum of graph-theoretic matrices. The study of graphs with “few eigenvalues” is a contemporary problem in spectral graph theory. This paper studies graphs with few distinct distance eigenvalues. After mentioning the classification of graphs with one and two distinct distance eigenvalues, we mainly focus on graphs with three distinct distance eigenvalues. Characterizing graphs with three distinct distance eigenvalues is “highly” non-trivial. In this paper, we classify all trees whose distance matrix has precisely three distinct eigenvalues. Our proof is different from earlier existing proof of the result as our proof is extendable to other similar families such as unicyclic and bicyclic graphs. The main tools which we employ include interlacing and equitable partitions. We also list all the connected graphs on ν ≤ 6 vertices and compute their distance spectra. Importantly, all these graphs on ν ≤ 6 vertices are determined from their distance spectra. We deliver a distance cospectral pair of order 7, thus making it a distance cospectral pair of the smallest order. This paper is concluded with some future directions.

Water-use characteristics of Populus euphratica trees in response to flood and groundwater depth in desert oasis

Populus euphratica, as the dominant species in arid desert area, plays an important role in maintaining the stability of desert ecosystem. However, P. euphratica water-use characteristics at different sizes and the effects of flooding and groundwater depth on water use remain unclear. In this study, the hydrogen and oxygen isotope compositions of xylem water, soil water, and floods were measured and coupled with the MixSIAR model to investigate the water-use patterns of P. euphratica at different sizes, flood periods (before, during, and after floods), and groundwater depths in the Taklimakan Desert hinterland. The carbon isotope composition of P. euphratica leaves was determined to investigate the water-use efficiency (WUE) of P. euphratica. The water-use patterns of P. euphratica at different sizes were consistent because of its reproductive mode (aswxual root tiller reproduction). P. euphratica showed a greater degree of ecological plasticity during different flood periods. Before the flood, the main water sources for P. euphratica were deep-soil-layer (140–220 cm) and near-groundwater-layer (220–300 cm). During the flood, it could absorb the flood directly, reducing water absorption from deep-soil-layer and near-groundwater-layer. After the flood, it resumed water absorption from deep-soil-layer and near-groundwater-layer. P. euphratica water absorption patterns differed at different groundwater depths. In the shallow and middle groundwater depth sample plots, the water sources were the deep-soil and near-groundwater layers, and the population of P. euphratica grew well. In the deep sample plot, water absorption was mainly near the groundwater layer, and the P. euphratica population showed a decreasing trend, further explaining the degradation of P. euphratica in terms of water-use patterns. WUE is related to the growth stage of P. euphratica and the water conditions of the living environment; the more mature the P. euphratica, the more deficit the water conditions, and the higher the WUE. This study provides a basis for maintaining the stability of P. euphratica forests in arid deserts and for water allocation.

Short Communication: Habitat preferences of epiphytic orchids and potential pollinators in Sumber Pawon Forest, Kediri District, East Java, Indonesia

Abstract. Putra SRT, Trisnawati I. 2024. Short Communication: Habitat preferences of epiphytic orchids and potential pollinators in Sumber Pawon Forest, Kediri District, East Java, Indonesia. Biodiversitas 25: 2780-2787. Sumber Pawon Forest, a unique and biodiverse ecosystem in Kediri, Indonesia, is home to approximately 30,000 orchids (family Orchidaceae), which can grow terrestrial or as epiphytes. A diversity of different taxa has been recorded as orchid pollinators. The distribution of epiphytic orchids in this forest is determined by habitat preferences including vertical distribution zone and host tree's characteristics. This research, conducted in the captivating Sumber Pawon Forest, aims to determine habitat preferences influencing the abundance of epiphytic orchids and provide a review of potential epiphytic orchid pollinators. The data were collected by systematic sampling method. Analysis of epiphytic orchids' habitat preferences was done using the ordination method. The study found 3 epiphytic orchids and 5 species of host trees, revealing new insights into their distribution. Epiphytic orchids include Cymbidium sp., Dendrobium crumenatum, and Rhynchostylis retusa. The host trees include Alstonia scholaris, Artocarpus elasticus, Bischofia javanica, Ficus elastica, and Samanea saman. Epiphytic orchids were mainly found in zone 4 rather than in zone 5. The characteristics of host trees, which are preferentially selected by epiphytic orchids, include tree height (ranging from 28.65 to 33.65 m), large DBH (ranging from 165.61 to 175.80 m), and closed canopy cover (ranging from 51 to 75%). One of the pollinator taxa (named Hymenoptera) was found to pollinate epiphytic orchid species, adding to our understanding of their ecological interactions.

Exploring Urban Greenery: A Case Study of Roadside Trees in Pokhara Metropolitan City

Roadside trees play a crucial role as important components of urban greenery, significantly enhancing the overall quality of cities and ultimately contributing to the quality of life for residents and visitors alike. This study examines the condition, maintenance, and proximity of roadside trees to electric wire corridors in Pokhara Metropolitan City, Nepal. This study employs field surveys, categorization based on tree attributes, and mapping techniques to analyze the distribution and characteristics of roadside trees. Out of approximately 1500 trees initially collected, 1435 were processed for further analysis. Trees were classified by species, height, condition, and the presence of fencing or resting structures (Chautaro), with proximity to electric wire corridors also assessed. Findings reveal a significant presence of trees in good condition, predominantly Dhupi, Kapur and Ashoka species, with a notable percentage requiring maintenance. A substantial number of trees were found in close proximity to electric wires, posing potential hazards. Mapping techniques facilitated visualizing the spatial distribution of trees, aiding in urban planning and management strategies. The study underscores the importance of sustainable urban greening practices and the need for proactive measures to address challenges related to tree maintenance and safety in urban environments like Pokhara Metropolitan City. This study emphasizes the pivotal role of roadside trees in enhancing the aesthetic appeal and quality of city life, positioning them as decisive factors in shaping urban environments and fostering a welcoming atmosphere for residents and visitors.

Quaking Aspen in a High-Use Recreation Area: Challenges of People, Ungulates, and Sodium on Landscape Resilience

Quaking aspen (Populus tremuloides Michx.) landscapes are valued for their biodiversity, water retention, fire mitigation, aesthetics, and recreation opportunities. Across North America, some aspen populations are experiencing population declines as they face uninhibited ungulate browsing, drought, fire suppression, insects, disease, and inappropriate management. Increased human development and recreational use within aspen landscapes can serve as additive stressors, though there is a dearth of literature examining these elements. At a popular recreational area in Utah, USA, identifying the cause of apparent decline within a larger aspen community is complicated by development upstream and recreation-related activities. We sought to (1) assess the overall condition of the aspen at the site, (2) understand key variables that influence aspen conditions, and (3) elucidate how aspen fitness varies across the site. We collected data from forty-five plots using established aspen sampling methods, including ungulate presence, tree characteristics, soil chemistry, and environmental descriptors. Results suggest that a combination of higher levels of browsing and elevated soil sodium may be causing premature mortality and limiting aspen recruitment in a portion of the study area. These findings will inform future management at this site, as well as similar recreational forest settings experiencing compound stressors.

Experimental investigation on vibration characteristics of sympodial tree

Sympodial trees are prevalent in tropical and subtropical urban areas while suffering the threat of wind storms every year, which leads to unpredictable economic losses and secondary hazards. However, the research on the dynamics of sympodial tree, which exhibits extremely complex structures, is limited. Therefore, this study conducts wind tunnel tests to systematically investigate vibration characteristics for trees with different crown configurations. Results show that as the scaled Cauchy number increases, the base overturning moment coefficient (CM) gradually reduces, yet its reduction rate decreases. Subsequently, a higher spectral peak and narrower bandwidth of CM is observed with the extent of pruning severity. Finally, an energy coefficient (CE) is developed to depict the wind energy absorption ability of trees. It is revealed that CE displays a declining trend with an increase in LAI1 (leave area / ground area) and LAI2 (leaf area / frontal area). Furthermore, it is found that trees characterized by robust and squat trunks along with dense foliage possess an enhanced capacity for wind energy dissipation.

Models for estimating the diameter at breast height as a function of the diameter of the stump Pinus taeda L.

The study addressed the use of models to estimate dendrometric variables in a commercial plantation of Pinus taeda L. Allometric relationships were applied to estimate diameter at breast height (DBH) based on stump diameter (SD), providing a mathematical approach to relate these two variables. Additionally, a "conventional" measurement exclusively of DBH was conducted to compare the values obtained with traditional approach to the results of the proposed modeling. The study also explored hypsometric relationships to estimate tree height as a function of DBH, enabling an efficient and economical assessment of tree characteristics in the forest stand. Furthermore, a forest census was conducted in the area, allowing a comprehensive comparison between the methods used and the actual data from the forest stand, reinforcing the importance of these approaches for effective forest resource management. The results showed that the models were effective in estimating volume, basal area, and the number of trees per hectare, with consistent results compared to the forest census. Therefore, the study concludes that stump inventory methods are effective in estimating dendrometric data in Pinus taeda L. plantations, even after forest cutting events, thereby supporting forestry experts in conducting precise assessments in areas with completed timber harvesting and in making informed decisions. This contributes to the effective and sustainable management of forest resources and the enforcement of laws in cases of environmental or economic damage.

Predicting the boron removal of reverse osmosis membranes using machine learning

Reverse osmosis (RO) is a key technology for seawater desalination, but boron removal remains challenging due to the relatively low and varying boron rejection of RO membranes. This study explored the use of machine learning (ML) to develop predictive models for boron removal of RO membranes. Data of 11 features encompassing membrane properties, testing conditions and membrane performance were collected from journal articles. Missing data were recovered using data imputation algorithms. The predictive models were developed using five regression algorithms: linear, ridge, decision tree, random forest and XGBoost regressors, and the tree-based XGBoost regressor performed the best (R2 = 0.84). Feature importance analysis and tree diagrams revealed that membrane type, feed pH and NaCl rejection as key factors in influencing boron rejection, while membrane surface properties showed minimal impact. Partial dependence plots were generated to further analyze each feature. High NaCl rejection of >99.6 % is highly desirable for SWRO membranes to achieve high boron rejection. For BWRO membranes at pH >9, a looser structure with a NaCl rejection >95 % could be applied. The study successfully applied ML to a dataset with large portion of missing values, and the results provide valuable insights for future membrane design and boron removal processes.

Contrasting effects of urban trees on air quality: From the aerodynamic effects in streets to impacts of biogenic emissions in cities

Urban trees are often not considered in air-quality models although they can significantly impact the concentrations of pollutants. Gas and particles can deposit on leaf surfaces, lowering their concentrations, but the tree crown aerodynamic effect is antagonist, limiting the dispersion of pollutants in streets. Furthermore, trees emit Biogenic Volatile Organic Compounds (BVOCs) that react with other compounds to form ozone and secondary organic aerosols. This study aims to quantify the impacts of these three tree effects (dry deposition, aerodynamic effect and BVOC emissions) on air quality from the regional to the street scale over Paris city. Each tree effect is added in the model chain CHIMERE/MUNICH/SSH-aerosol. The tree location and characteristics are determined using the Paris tree inventory, combined with allometric equations. The air-quality simulations are performed over June and July 2022. The results show that the aerodynamic tree effect increases the concentrations of gas and particles emitted in streets, such as NOx (+4.6 % on average in streets with trees and up to +37 % for NO2). This effect increases with the tree Leaf Area Index and it is more important in streets with high traffic, suggesting to limit the planting of trees with large crowns on high-traffic streets. The effect of dry deposition of gas and particles on leaves is very limited, reducing the concentrations of O3 concentrations by −0.6 % on average and at most −2.5 %. Tree biogenic emissions largely increase the isoprene and monoterpene concentrations, bringing the simulated concentrations closer to observations. Over the two-week sensitivity analysis, biogenic emissions induce an increase of O3, organic particles and PM2.5 street concentrations by respectively +1.1, +2.4 and + 0.5 % on average over all streets. This concentration increase may reach locally +3.5, +12.3 and + 2.9 % respectively for O3, organic particles and PM2.5, suggesting to prefer the plantation of low-emitting VOC species in cities.