Academic literature on the topic 'Tree crown shape'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the lists of relevant articles, books, theses, conference reports, and other scholarly sources on the topic 'Tree crown shape.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Journal articles on the topic "Tree crown shape"
1
Franceschi, Eleonora, Astrid Moser-Reischl, Mohammad A. Rahman, Stephan Pauleit, Hans Pretzsch, and Thomas Rötzer. "Crown Shapes of Urban Trees-Their Dependences on Tree Species, Tree Age and Local Environment, and Effects on Ecosystem Services." Forests 13, no. 5 (2022): 748. http://dx.doi.org/10.3390/f13050748.
Full textAbstract:
Crown shapes of common European urban tree species differ from tree species to tree species and are modified by the age of a tree and its local environment. A tree’s crown shape has a great influence on the crown volume and thus on the ecosystem service provision of a tree such as the shade area or the shade density. We used the data of 3852 tree individuals from eight German cities and the crown shape data of 528 trees for the species Acer platanoides, Acer pseudoplatanus, Aesculus hippocastanum, Fraxinus excelsior, Platanus × acerifolia, Robinia pseudoacacia and Tilia cordata to analyze tree structural dimensions and the crown volume and shade dependency on a tree’s crown shapes. Ovoid (57% of all tree individuals) and spherical (24%) crown shapes were mostly observed. However, columnar shape was observed for light-demanding R. pseudoacacia in close proximity of objects. The greatest shade areas were measured for spherical shape and the highest shade density for ovoid shape. Logistic regression analysis showed significant effects of age and distance to objects on crown shapes. Significant probability of crown shapes was found for different tree species, e.g., A. hippocastanum strongly showed half-ellipsoid crown shapes.
2
Shamim, Ahmed, and Pretzsch Hans. "TLidar-based crown shape indicates tree ring pattern in Norway spruce (Picea abies (L.) H. Karst) trees across competition gradients. A modeling and methodological approach." Ecological indicators 2023, no. 148 (2023): 110116. https://doi.org/10.5281/zenodo.7716499.
Full textAbstract:
Tree crowns and growth rings are physiologically and functionally connected through supporting and resource sharing. Management interventions may strongly influence tree growth by altering this linkage. However, conventional approaches have limited ability to characterize crown shape precisely, thus hindering our understanding of the relationship between crown shape and tree ring patterns. We, thus, aimed to test three hypotheses: (HI) Crown shape (regularity vs. irregularity) and ring patterns (regularity or irregularity) are significantly correlated and (HII) vary across density gradients; if so, (HIII) internal ring patterns could be predicted from external crown shape metrics. We, therefore, employed terrestrial laser scan-based crown shape and coring-based TRP metrics for Norway spruce (Picea abies (L.) H. Karst.) trees covering a range of density gradients to assess temporal changes of crown shape and tree ring patterns. We found a significant and positive influence of crown shape quantifying metrics on ring patterns, indicating crown regularity or irregularity strongly reflects tree ring regularity or irregularity (p < 0.05). Crown shape and ring patterns always showed comparable patterns across density gradients (e.g., trees from lower-density stands produced transgressive crown and ring growth) and significantly varied across competition level. Trees grown in lower-density stands are more likely to produce upper-reaching crowns (maximum crown radius expansion shifted to the mid- to upper-crown) than trees grown in competitive conditions, which result in lower-reaching crowns (maximum crown radius shifted to the crown base) with reduced crown shape and ring pattern parameters. Crown irregularities increased as density decreased through competition reduction, resulting in more regular ring patterns (stable growth). Since both crown shape and ring patterns are simultaneously impacted by stand density or competition, the relationship between crown shape and ring patterns is competition-neutral. When viewed separately, both patterns had a strong relationship with the competition index. Finally, our comparative model predictions showed that approaches ranging from simple linear models to complex machine learning techniques (e.g., random forest, neural network, support vector machine, etc.) were effective in predicting ring patterns using external TLidar-crown shape, indicating a potential method to evaluate the crown shape and ring pattern link. The relationship between the crown and growth ring and their synchronous patterns across competition gradients suggests that internal growth can be assessed from the external appearances of trees and recommends further consideration in forest modeling.
3
Li, Jian Ke, Jing Hui Yang, Yan Jun Liu, et al. "Growth and Development of Feijoa with Different Plant Shape and in Greenhouses Environment." Advanced Materials Research 886 (January 2014): 294–98. http://dx.doi.org/10.4028/www.scientific.net/amr.886.294.
Full textAbstract:
In order to explore the relation between tree crown shape and growth development and age of tree, flowering plants, fruiting plants, bearing plants, bearing branch and floweret, length of bearing branch were studied in greenhouse environments after tree corm shape were divided into three groups by live crown ratio of crown width to height and angle from the central leader to first scaffold branch. The result showed that the plants of upright crown shape were 83% at age one year among all plants, 45% at age two years and tree crown shapes, open tree increased to 25% at age of three years. The flowering trees increased from 5% at age of one year to 55% in age of three years and fruit set increased from 0 to 44% following increase of age tree. Open trees had more flowers with 10.6 in 2-year-old tree, 38.6 in 3-year-old tree. Open trees had more percentage of bearing plants with around 47%. The average length of bearing branches was 11.5 cm at open trees, which was more than other crown shapes at age of three years. Open trees had most fruit number per bearing tree (6.5, 8.5 apart). Therefore, creating open tree crown shape may increase flowering, fruiting and yield in greenhouse production of feijoa.
4
Power, Hugues, Valerie LeMay, Frank Berninger, Derek Sattler, and Daniel Kneeshaw. "Differences in crown characteristics between black (Picea mariana) and white spruce (Picea glauca)." Canadian Journal of Forest Research 42, no. 9 (2012): 1733–43. http://dx.doi.org/10.1139/x2012-106.
Full textAbstract:
Black spruce ( Picea mariana (Mill.) Britton, Sterns & Poggenb.) and white spruce ( Picea glauca (Moench) Voss) are phylogenetically proximal species that differ in productivity. Crown characteristics of these two species have not been extensively studied, in spite of the importance of these two species to the Canadian boreal forest and the importance of tree crowns for understanding and modelling tree growth. In this paper, we characterize and compare the crown lengths, crown profiles (i.e., radii), shapes, and surface areas of these two species using 65 white spruce and 57 black spruce trees destructively sampled in the provinces of Alberta, Ontario, and Quebec, Canada. Crown length was measured on every sample tree, while crown profile was obtained by reconstructing crowns from branch measurements. Our results showed that crown lengths did not differ between these two species given the same tree size and growth conditions. However, these two species establish under different growth conditions resulting in crown length differences. Further, differences in crown radii and profiles were found even under the same growth conditions. White spruce trees had wider crown radii and profiles changed from a parabola to a cone shape under increased density. As a result, differences in crown surface areas were found.
5
Qian, Chen, Chunjing Yao, Hongchao Ma, Junhao Xu, and Jie Wang. "Tree Species Classification Using Airborne LiDAR Data Based on Individual Tree Segmentation and Shape Fitting." Remote Sensing 15, no. 2 (2023): 406. http://dx.doi.org/10.3390/rs15020406.
Full textAbstract:
Individual tree species classification is of strategic importance for forest monitoring, analysis, and management, which are critical for sustainable forestry development. In this regard, the paper proposes a method based on the profile of segmented individual tree laser scanning points to identify tree species. The proposed methodology mainly takes advantage of three-dimensional geometric features of a tree crown captured by a laser point cloud to identify tree species. Firstly, the Digital Terrain Model (DTM) and Digital Surface Model (DSM) are used for Crown Height Model (CHM) generation. Then, local maximum algorithms and improved rotating profile-based delineations are used to segment individual trees from the profile CHM point data. In the next step, parallel-line shape fitting is used to fit the tree crown shape. In particular, three basic geometric shapes, namely, triangle, rectangle, and arc are used to fit the tree crown shapes of different tree species. If the crown belongs to the same crown shape or shape combination, parameter classification is used, such as the ratio of crown width and crown height or the apex angle range of the triangles. The proposed method was tested by two real datasets which were acquired from two different sites located at Tiger and Leopard National Park in Northeast China. The experimental results indicate that the average tree classification accuracy is 90.9% and the optimal classification accuracy reached 95.9%, which meets the accuracy requirements for rapid forestry surveying.
6
Escoto-Rodríguez, Martín, José M. Facelli, and Jennifer R. Watling. "Do wide crowns in arid woodland trees reflect hydraulic limitation and reduction of self-shading?" Functional Plant Biology 41, no. 12 (2014): 1221. http://dx.doi.org/10.1071/fp14022.
Full textAbstract:
In arid regions many tree species develop broad crowns. A number of hypotheses involve trade-offs between growth in height and horizontal spreading, but there is no explanation for the switch from vertical to horizontal growth during development. Using Acacia papyrocarpa Benth as a model, we measured tree height and crown shape across different sites and topographic positions. We also measured δ13C of phyllodes from crown tops and lateral spreading branches. Trees were significantly taller at the base of a hill, where water availability is typically greater, than on the adjacent steep hillslope. In contrast, δ13C from the treetops was not significantly different across this topographic gradient, despite variation in tree height. In addition, δ13C was higher at treetops than in lower, lateral branches. These observations are consistent with hydraulic limitation to tree height. The shape of mature and young crowns in open environments was not symmetrical. At all sites, branches were shortest, but tree crowns tallest, on south-facing (i.e. shadiest) aspect of crowns. This suggests that light limitation may also affect crown development. If upper branches become water-limited and lower branches light-limited, then middle lateral branches become the less-stressed part of the crown and may grow more, producing a broad crown.
7
Dai, Mingrui, and Guohua Li. "Soft Segmentation of Terrestrial Laser Scanning Point Cloud of Forests." Applied Sciences 13, no. 10 (2023): 6228. http://dx.doi.org/10.3390/app13106228.
Full textAbstract:
As the three-dimensional (3D) laser scanner is widely used for forest inventory, analyzing and processing point cloud data captured with a 3D laser scanner have become an important research topic in recent years. The extraction of single trees from point cloud data is essential for further investigation at the individual tree level, such as counting trees and trunk analysis, and many developments related to this topic have been published. However, constructing an accurate and automated method to obtain the tree crown silhouette from the point cloud data is challenging because the tree crowns often overlap between adjacent trees. A soft segmentation method that uses K-Nearest Neighbor (KNN) and contour shape constraints at the overlap region is proposed to solve this task. Experimental results show that the visual effect of the tree crown shape and the precision of point cloud segmentation have improved. It is concluded that the proposed method works well for tree crown segmentation and silhouette reconstruction from the terrestrial laser scanning point cloud data of the forest.
8
Muhairwe, Charles K. "Tree form and taper variation over time for interior lodgepole pine." Canadian Journal of Forest Research 24, no. 9 (1994): 1904–13. http://dx.doi.org/10.1139/x94-245.
Full textAbstract:
Changes in tree form and taper over time, as affected by changes in tree, stand, and site factors for interior lodgepole pine (Pinuscontorta var. latifolia Engelm.) were investigated using detailed stem analysis data from interior British Columbia. It was found that tree shape and taper change along the stem at one time and over time with changes in tree and stand factors, particularly the diameter at breast height to total tree height ratio, crown length, and crown ratio, and with predicted quadratic mean diameter at age 50 years, a stand density measure. At young ages, the trees were parabolic in shape from ground to top. However, as they increased in size over time, different portions of the stem took different shapes because of unequal growth in diameter along the stem. Changes in tree shape and taper over time were closely related to the crown size, which is related to stand density.
9
Aryal, Bimal, James Steenberg, and Peter Duinker. "The Effects of Residential Street Tree Spacing and Crown Interactions on Crown Dimensions and Canopy Cover." Arboriculture & Urban Forestry 47, no. 5 (2021): 183–95. http://dx.doi.org/10.48044/jauf.2021.017.
Full textAbstract:
Urban trees provide people with a range of ecosystem services. Trees planted along streets have been a large focus of urban forest research and practice, and municipalities invest significant resources in their survival. However, the optimal spacing of street trees is not addressed in the scientific literature, and existing municipal street tree spacing standards are highly variable and poorly enforced. In this study, we examine variability in crown shape and size for street trees to test for possible interaction effects at closer spacings. We measured variability in crown diameters both parallel and perpendicular to street tree rows to test whether changes in crown dimensions can be explained by interaction effects with neighbouring trees, and whether crown interactions lead to a reduction in total crown projection area (i.e., canopy cover). We measured the crown dimensions and diameter at breast height of 1,338 street trees in Halifax, Canada. We used two-way analysis of variance to test whether crown shape and crown projection area were affected by crown interactions and spacing. We found that the effect of narrower spacing and interactions (i.e., crowns touching/overlapping) among trees translated to crowns extending away from the direction of interaction. We also found that these changing crown dimensions were associated with increases in canopy cover. Urban forest ecosystems are a vital resource for the increasingly urban population. There is a need for empirical research on spacing standards and practices that investigate their influence on the supply of ecosystem services, such as stormwater retention, air pollution removal, and cooling.
10
Zeide, Boris, and Charles A. Gresham. "Fractal dimensions of tree crowns in three loblolly pine plantations of coastal South Carolina." Canadian Journal of Forest Research 21, no. 8 (1991): 1208–12. http://dx.doi.org/10.1139/x91-169.
Full textAbstract:
Because crown structure is closely associated with many aspects of tree growth, fractal dimension of the crown is likely to be a useful indicator of tree form as well as growth. This paper investigates the relationship between the fractal dimension of crowns and two growth-regulating factors, site quality and thinning intensity. The two-surface method allows one to calculate fractal dimension from the regression of foliage area (or mass) on the area (or volume) of the convex hull that envelopes the crown. The hull's volume can be computed from the length and width of a crown using an equation that accounts for the change in crown shape. Fractal dimensions of tree crowns were calculated for three loblolly pine (Pinustaeda L.) plantations of coastal South Carolina using detailed measurements of 72 dominant and intermediate trees. Analyses of data and the involved processes suggest that the fractal dimension of crown surface may change with site quality and thinning intensity.
Dissertations / Theses on the topic "Tree crown shape"
1
Sadeghinaeenifard, Fariba. "Automated Tree Crown Discrimination Using Three-Dimensional Shape Signatures Derived from LiDAR Point Clouds." Thesis, University of North Texas, 2018. https://digital.library.unt.edu/ark:/67531/metadc1157521/.
Full textAbstract:
Discrimination of different tree crowns based on their 3D shapes is essential for a wide range of forestry applications, and, due to its complexity, is a significant challenge. This study presents a modified 3D shape descriptor for the perception of different tree crown shapes in discrete-return LiDAR point clouds. The proposed methodology comprises of five main components, including definition of a local coordinate system, learning salient points, generation of simulated LiDAR point clouds with geometrical shapes, shape signature generation (from simulated LiDAR points as reference shape signature and actual LiDAR point clouds as evaluated shape signature), and finally, similarity assessment of shape signatures in order to extract the shape of a real tree. The first component represents a proposed strategy to define a local coordinate system relating to each tree to normalize 3D point clouds. In the second component, a learning approach is used to categorize all 3D point clouds into two ranks to identify interesting or salient points on each tree. The third component discusses generation of simulated LiDAR point clouds for two geometrical shapes, including a hemisphere and a half-ellipsoid. Then, the operator extracts 3D LiDAR point clouds of actual trees, either deciduous or evergreen. In the fourth component, a longitude-latitude transformation is applied to simulated and actual LiDAR point clouds to generate 3D shape signatures of tree crowns. A critical step is transformation of LiDAR points from their exact positions to their longitude and latitude positions using the longitude-latitude transformation, which is different from the geographic longitude and latitude coordinates, and labeled by their pre-assigned ranks. Then, natural neighbor interpolation converts the point maps to raster datasets. The generated shape signatures from simulated and actual LiDAR points are called reference and evaluated shape signatures, respectively. Lastly, the fifth component determines the similarity between evaluated and reference shape signatures to extract the shape of each examined tree. The entire process is automated by ArcGIS toolboxes through Python programming for further evaluation using more tree crowns in different study areas. Results from LiDAR points captured for 43 trees in the City of Surrey, British Columbia (Canada) suggest that the modified shape descriptor is a promising method for separating different shapes of tree crowns using LiDAR point cloud data. Experimental results also indicate that the modified longitude-latitude shape descriptor fulfills all desired properties of a suitable shape descriptor proposed in computer science along with leaf-off, leaf-on invariance, which makes this process autonomous from the acquisition date of LiDAR data. In summary, the modified longitude-latitude shape descriptor is a promising method for discriminating different shapes of tree crowns using LiDAR point cloud data.
Books on the topic "Tree crown shape"
1
Gunn, Steven. Principles and talents. Oxford University Press, 2017. http://dx.doi.org/10.1093/acprof:oso/9780199659838.003.0002.
Full textAbstract:
The talents and ideas of the new men can be elucidated using contemporary fiction and satire in verse and drama as well as their own writings, notably Edmund Dudley’s Tree of Commonwealth. They valued order and justice, the elevation of royal power, and the promotion of the common weal. Their attachment to the crown was shaped by the common law, their loyalty to the king by chivalry. They were quick to punish treason and to display the king’s badges on their possessions. They were efficient, persuasive, and shrewd. While they did not scorn what ancestry they had, they drew their status more from the positions the king gave them than from their blood. But contemporaries were alarmed by their rise and charged them with ruthless self-advancement and overweening pride.
Book chapters on the topic "Tree crown shape"
1
Zhu, Chao, Xiaopeng Zhang, Baogang Hu, and Marc Jaeger. "Reconstruction of Tree Crown Shape from Scanned Data." In Technologies for E-Learning and Digital Entertainment. Springer Berlin Heidelberg, 2008. http://dx.doi.org/10.1007/978-3-540-69736-7_79.
Full text
2
Lula, Mikolaj, Kjersti Holt Hanssen, Martin Goude, et al. "Regeneration." In Managing Forest Ecosystems. Springer Nature Switzerland, 2024. https://doi.org/10.1007/978-3-031-70484-0_3.
Full textAbstract:
Abstract In the context of continuous cover forestry (CCF), natural regeneration is the preferred form of regeneration, but it is a long-lasting and complex process. Shelter density has a large effect on the regeneration process and results. The selection system, particularly suited for shade-tolerant species like Norway spruce, relies on continuous regeneration and ingrowth into larger size classes. Regeneration and ingrowth rates vary significantly among stands, influenced by site and historical factors, with no clear relationship to current stand conditions. In the group system, edge trees influence regeneration by providing seeds, checking weed growth, and exerting competition. Regeneration in gaps is generally satisfactory for both Norway spruce and Scots pine. However, seedlings usually grow slower, especially close to the gap edges. The shelterwood system promotes regeneration through a successive, uniform opening of the canopy. Shelter trees provide seeds, and reduce seedling damage and competition from ground vegetation. On the other hand, the remaining overstorey shelter trees reduce seedling growth. Conversion to the selection system initiates regeneration in young stands, aiming for slow and steady regeneration. Given the rapid growth and crown closure in young stands, frequent manipulation of shelter density is essential during conversion, for example by opening small gaps.
3
Higgins, Richard, and Richard Higgins. "An Eye for Trees." In Thoreau and the Language of Trees. University of California Press, 2017. http://dx.doi.org/10.1525/california/9780520294042.003.0002.
Full textAbstract:
Thoreau observed the shape, color, texture and stance of trees. His eye took in all—root, trunk, bark, branch and crown, leaf, blossom and cone. He knew them all over Concord—birches, basswoods, hornbeams, pines and hemlocks in pastures and on hills. He loved big trees, like great pasture oaks and pines that rose like spires in the forest. But he loved small or common trees no less. His eye never tired of the details that differentiate one tree from another. “A tree seen against other trees is a mere dark mass, but against the sky it has parts, has symmetry and expression.” Examining those details was more than observation for him. It was an act of contemplation.
4
Evans, Julian, and John W. Turnbull. "High pruning." In Plantation Forestry in the Tropics. Oxford University PressOxford, 2004. http://dx.doi.org/10.1093/oso/9780198529941.003.0017.
Full textAbstract:
Abstract In tropical tree plantations pruning is mainly carried out in two very different situations: to improve stem and wood quality in some industrial crops and as a tool in agroforestry and social forestry plantings, both to manipulate the trees to favour food crops, for example, in alley cropping, and to provide fodder, leaf mulch, fuel wood, smooth, snag-free poles, etc. Note that pruning in arboriculture and horticulture is to improve crown shape, stimulate flowering and fruiting, train branches, and sometimes simply for aesthetic purposes. This chapter primarily concerns high pruning in industrial plantations; Chapters 18, 20–21, and 23 make further reference to pruning practices in agroforestry and rural development forestry including pollarding.
5
Quevedo-Rojas, Ana, and Mauricio Jerez-Rico. "Mixed Forest Plantations with Native Species for Ecological Restoration in Cloud Forests of the Venezuelan Andes." In Silviculture [Working Title]. IntechOpen, 2020. http://dx.doi.org/10.5772/intechopen.95006.
Full textAbstract:
Tropical cloud forests play a fundamental role in the hydrological cycle of mountain watersheds having the largest biodiversity per unit area. In Venezuela, cloud forests are subject to intense deforestation and fragmentation by farming and cattle-ranching causing soil erosion, water cycle alteration, and biodiversity loss. Reforestation projects used exotic species as Pines and Eucalyptus, native species were rarely planted by lacking knowledge on species requirements and management. We report the performance of 25 native cloud forest species differing in shade-tolerance, planted in mixed assemblies on degraded areas. Tree survival and the individual tree variables: total height, root-collar diameter, tree-slenderness, and crown-ratio were evaluated at 1, 2, 4.5 and 7 years-old. Data was analyzed with a repeated measures analysis of variance mixed model considering species shade-tolerance, light intensity at planting and age as explanatory factors. Survival was over 80%. Shade-intolerant species displayed faster height and root-collar diameter growth. Shade-tolerant species had larger crown ratios due to persistence of lower branches; whereas, shade-intolerant showed signs of crown recession at age 7. Slenderness values from age 4.5 were indicative of good trees stability and health across treatments. The positive results have motivated landowners to establish native species plantations in critical areas with our support.
6
Hartman, John R., Thomas P. Pirone, and Mary Ann Sall. "The Value of Trees." In Pirone’s Tree Maintenance. Oxford University PressNew York, NY, 2000. http://dx.doi.org/10.1093/oso/9780195119916.003.0001.
Full textAbstract:
Abstract Almost everyone likes trees for one reason or another. They provide cool shade during hot summer days, and whether in the yard or the park, they offer a serene setting to relieve the tensions of modern life. They add to the beauty and value of property. The splendor of a springtime floral display and the pageantry of autumn coloration make trees a delight to the eyes (Fig. 1-1). Even in winter, tree crown silhouettes and textured bark details provide enjoyment (Fig. 1-2). Trees evoke sentiment perhaps because Grandpa planted them when he and Grandma moved into the neighbourhood many years before or because some historic event took place beneath their boughs. No matter what the reason-aesthetic, financial, or sentimental-a tree is a sound investment.
7
"Speculations on the Shapes of Tree Crowns." In Adaptive Geometry of Trees (MPB-3), Volume 3. Princeton University Press, 2020. http://dx.doi.org/10.2307/j.ctvx5w9x8.12.
Full text
8
Longino, John T. "Azteca Ants In Cecropia Trees: Taxonomy, Colony Structure, And Behaviour." In Ant-Plant Interactions. Oxford University PressOxford, 1991. http://dx.doi.org/10.1093/oso/9780198546399.003.0019.
Full textAbstract:
Abstract The most conspicuous ant-plant association in the wet neotropics is that of Aztecu ants and Cecropia trees. In most low-elevation, wet regions of the ncotropics, Cecropia is an ubiquitous and important invader of man-made clearings (Uhl et al. I 981; Brokaw 1987). The open, candelabra-shaped crowns of Cecropia often appear as the sole emergents over dense vine tangles in abandoned fields. The hollow internodes of these trees are almost always occupied by biting ants in the genus Azteca, each tree typically containing a single colony (Bequaert 1922; Wheeler 1942; Benson 1985).
9
Shettleworth, Sara J. "Cognition and the Study of Behavior." In Cognition, Evolution, and Behavior. Oxford University PressNew York, NY, 2009. http://dx.doi.org/10.1093/oso/9780195319842.003.0001.
Full textAbstract:
Abstract Walnut trees shade the streets of Davis, California. They also provide food for the crows that roost near Davis. Crows crack walnuts by dropping them from heights of 5–10 meters or more onto sidewalks, roads, and parking lots. Occasionally they drop walnuts in front of approaching cars, as if using the cars to crush the nuts for them. Do crows intentionally use cars as nutcrackers? Some of the citizens of Davis, as well as some professional biologists (Maple 1974, in Cristol et al. 1997) were convinced that they do, at least until a team of young biologists at UC Davis put this anecdote to the test (Cristol et al. 1997). They reasoned that if crows were using cars as tools, the birds would be more likely to drop nuts onto the road when cars were coming than when the road was empty. Furthermore, if a crow was standing in the road with an uncracked walnut as a car approached, it should leave the nut in the road to be crushed rather than carry it away.
10
Gatrell, V. A. C. "Watching From Curiosity." In The Hanging Tree. Oxford University PressOxford, 1994. http://dx.doi.org/10.1093/oso/9780198204138.003.0009.
Full textAbstract:
Abstract Did Polite People Ever Feel An Unabashed Excitement And curiosity when they attended executions? Could they ever have attended without disgust or guilt overlaying those simpler feelings? Is it thinkable that readers of Pamela or Sense and sensibility were moved by the same impulses as the vulgar crowd? If so, what within their secret natures accounted for that ‘strange fascination’ and ‘dark and dreadful interest’ which Dickens discerned whenever the scaffold was in view? When did it cease to be permissible to contemplate executions in these open ways? The supposition which shapes our answers was stated in the last chapter. It is that fascination with what happened on the scaffold was primal. It was common to all people regardless of social standing. At its most self-regarding, the fascination spoke for pleasure that it was others who died, and it expressed an elemental curiosity about how they died. ‘I never saw a man hanged but I thought I could behave better than he did,’ James Boswell declared; or as a New Grub Street character admitted when he read of a Newgate hanging, ‘There’s a clear satisfaction in knowing that it is not oneself’ Provided that identification with the vic tim was checked, a fantasy about one’s own relative longevity might be savoured as the other’s fate was settled before one’s eyes. Add to that the gratification of watching a life extinguished which law or morality had defined as deserving of extinction, and add again the crowd’s self loving solidarity as it watched-and the ‘pleasures’ of witnessing become more intelligible, even to those who would prefer not to admit such proclivities in themselves or their fellow creatures.
Conference papers on the topic "Tree crown shape"
1
Chanika, H. K. P., N. Weerasinghe, and R. U. Halwatura. "Effect of urban vegetation cover on CO2 reduction in the city." In Civil Engineering Research Symposium 2024. Department of Civil Engineering, University of Moratuwa, 2024. http://dx.doi.org/10.31705/cers.2024.28.
Full textAbstract:
Rising urban carbon dioxide levels have emerged as a critical issue due to their adverse effects on public health and the environment. Trees are a natural and sustainable solution to mitigate urban carbon dioxide (CO2) concentrations, as they absorb CO2 from the atmosphere through photosynthesis. However, the specific relationship between tree density and CO2 concentration within cities is unclear. The main objectives of this research are to determine the relationship between tree density and CO2 concentration reduction in cities and to identify the optimum tree density to reduce the CO2 level in the city to obtain the required CO2 level. For this study, data were collected in the densely urbanized city of Colombo and various urban areas within the Hambantota district. Tree densities and CO2 concentration reduction data were collected from 300 sample plots, each with a fixed size of 50m x 50m, near roads in selected urban areas. When calculating tree density, it is important to calculate canopy volumes of trees. It depends on canopy height, crown diameter and canopy shape. The tree density of the sample plot was calculated by dividing the total canopy volume by the area of the sample plot. A digital portable CO2 meter was used to measure the CO2 level. First the CO2 concentration was measured at the centre of the road and then the CO2 concentration was measured at the centre of the sample plot. The reduction in CO2 level was calculated by the difference between these two readings. By analysing tree densities and CO2 concentration data collected through field data studies, a linear relationship was obtained between tree density and CO2 concentration reduction in urban areas. The plotted line got a R2 value of 0.8806 indicating a well-fitting model. Therefore, this linear plotted line can be described as a reasonable fitted line representing all collected data. Also, the data was classified based on the CO2 concentration in the centre of the road and the behaviour of the CO2 concentration reduction Vs tree density relationship was studied in each range. A linear relationship was obtained in each of those ranges. When all the collected data were classified as residential and non-residential based on the usage of the sample plots, the R2 values obtained from those graphs were higher than the R2 value of the graph drawn without classification. The R2 value of the graph for non-residential areas has increased relative to the value of the graph for residential areas. Accordingly, classifying in this manner led to an increase in the accuracy of the relationship. Using these relationships, the optimum tree density required to obtain the required CO2 reduction in urban areas can be identified. The results of this study will be valuable for policymakers and urban planners looking for ways to improve air quality and create more sustainable urban environments.
2
Li, Hongjun, Xiaopeng Zhang, and Yi-Kuan Zhang. "Modeling trees with crown shape constraints." In ACM SIGGRAPH ASIA 2010 Posters. ACM Press, 2010. http://dx.doi.org/10.1145/1900354.1900396.
Full text
3
Lele, Anna, Inga Straupe, and Solveiga Luguza. "The vitality of Taxus Baccata L. in forest stands in Slitere National Park, Latvia." In Research for Rural Development 2023 : annual 29th international scientific conference proceedings. Latvia University of Life Sciences and Technologies, 2023. http://dx.doi.org/10.22616/rrd.29.2023.003.
Full textAbstract:
Taxus baccata L., a relic of the Atlantic flora, is fourth of Latvia’s coniferous tree species, and it is endangered with a limited utilization because of its rare distribution. Evaluation of species condition, tree vitality and unfavourable factors influencing tree growth is crucial to improve species status. Measurements of forest stands with T. baccata autochthon and anthropogenic populations were collected, crown condition was rated, damages of trees were assessed, and projective cover of vegetation (canopy closure, shrub and herbaceous layer) was evaluated to determine the effect on T. baccata populations in Slitere National Park, Latvia. Main results show that factors strongly influencing the vitality of T. baccata are soil reaction and light conditions. Mostly the light conditions were determined by the canopy closure. Major conditions of shade negatively influenced the vitality and distribution of T. baccata.
4
Jawaharlal, Mariappan, Gustavo Vargas, and Lorenzo Gutierrez. "The Plant Kingdom in Engineering Design: Learning to Design From Trees." In ASME 2017 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/imece2017-72497.
Full textAbstract:
A tree may be the earliest multifunctional structure, and wood is the oldest known engineering material. Yet, trees have no place in engineering education. If we view a tree from merely a mechanical or civil engineering perspective, engineering mechanics can be learned from the tree’s example. Trees have survived by adapting to the most difficult circumstances: heavy winds, rains, floods, droughts, earthquakes, mammal damage, human intervention, etc. The root system must be strong and flexible enough to support the tree’s entire structure from varying load conditions and to provide food storage and nutrient transfer. The stem system provides structural support for the tree’s above-the-ground parts and transfers water and nutrients from the roots through the network of thick-walled cells to other parts of the tree. Leaves produce food and form the surface area surrounding the tree. Leaves come in a variety of shapes and sizes. The tree’s crown, comprising branches, leaves, and reproductive elements, help the tree to catch more sunlight. It moves upward and outward to expose more of its leaves to direct sunlight for photosynthesis while maintaining physical balance on the earth. A tree’s lifecycle can span hundreds of years, despite its vulnerability to constantly changing loads throughout the day and throughout its life. In monsoon and windy seasons, trees endure extremely difficult fatigue-loading. Various parts of the tree and its stem are subjected to combined loading conditions: tension, compression, shear, bending, and torsion. Trees develop and adapt stress management strategies by adjusting their shapes to the type or level of stress they endure: they add more mass where more strength is needed, allows material to easily break off (or physiologically inactive) from locations where it is not necessary, design optimum shapes, and create variable notch radii for reducing stress concentration. But a tree is much more than a structural member. It provides food and shelter for wildlife. It absorbs atmospheric carbon dioxide and produces oxygen. It lowers air temperature and facilitates the water cycle. Structural analysis of a tree can benefit engineering students and practicing engineers alike. Furthermore, a deeper understanding of trees can help us to create multifunctional designs that are in a symbiotic relationship with other members in the system. In short, studying tree mechanics can help us to become better engineers. This paper presents our efforts to integrate trees into engineering curricula to teach mechanics ranging from equilibrium study to stress analysis. Students of statics, dynamics, the strength of materials, stress analysis, material science, design, etc., can benefit from learning about trees. This approach enables students to understand the complexities of real-world living systems, appreciate the genius of nature’s design, and develop methods for creating sustainable designs.
5
Amar, Haddad, Rached-Kanouni Malika, Badri Boukous, Mokhtar Adjadj, and Walid Medjoub. "STUDY OF THE VIABILITY OF ALEPPO PINE TREES BY USING PHF INDEX." In GEOLINKS Conference Proceedings. Saima Consult Ltd, 2021. http://dx.doi.org/10.32008/geolinks2021/b2/v3/24.
Full textAbstract:
This work, which was conducted in the Chettaba forest about the viability of the stands can be given by the PHF index, a three-digit index that gives a judgment of the position of the tree (in relation to the others and thus indicating the dominance and the stage of competition or exposure to the dominant stage), of the general shape of the crowns, and of the shape of the shafts, it allows a more detailed silvicultural interpretation to predict the future of the stand and ultimately deduce the viability of the stands. Thus, there is an essential need for a study to be conducted in this regard to understand the existing problems and to bring about proposals on the appropriate intervention in logged surface. The slenderness coefficient of a tree is defined as the ratio of the total height (H) to the diameter at 1.3 m above ground level (d). For the stand level, the slenderness coefficient is calculated using the root mean square diameter and the average tree height as (H/D). It is well known that there is a direct relationship between the stand slenderness coefficient and the risk of stem breakage. It is well known that there is a direct relationship between the stand slenderness coefficient and the risk of stem breakage or tree fall due to abiotic factors such as wind or snow. Sustainability monitoring is crucial to the credibility, validation, value of the options implemented and should be considered early on in the planning process this allows us to say that these stands are stable in the forest and always in the 6 plots studied. Analyses results show a mid-viability for the forest and more of individual listed present instability which is indicated by a medium stability of forests stand’s quality (PHF = 123) and a slenderness coefficient (H/D = 34.47).
6
Komura, Ryotaro, and Ken-ichiro Muramoto. "Classification of forest stand considering shapes and sizes of tree crown calculated from high spatial resolution satellite image." In 2007 IEEE International Geoscience and Remote Sensing Symposium. IEEE, 2007. http://dx.doi.org/10.1109/igarss.2007.4423817.
Full text
7
Griffin, Alidair A., Barbara Doyle Prestwich, and Eoin P. Lettice. "UCC Open Arboretum Project: Trees as a teaching and outreach tool for environmental and plant education." In Learning Connections 2019: Spaces, People, Practice. University College Cork||National Forum for the Enhancement of Teaching and Learning in Higher Education, 2019. http://dx.doi.org/10.33178/lc2019.25.
Full textAbstract:
The University College Cork (UCC) Open Arboretum Project aims to re-imagine the original purpose of the University’s tree collection – as a teaching tool. The arboretum represents a unique on-campus learning space which has been under-utilised for teaching in recent times. The arboretum has the capacity to engage students, staff and visitors in a tangible way with important global issues (e.g. the climate emergency and biodiversity loss). It is also an opportunity to combat ‘plant blindness’, i.e. the ambivalence shown to plants in our environment compared to often charismatic animal species. Wandersee and Schussler (1999) coined the term “plant blindness” to describe the preference for animals rather than plants that they saw in their own biology students. Knapp (2019) has argued that, in fact, humans are less ‘plant blind’ and more ‘everything-but-vertebrates-blind’ with school curricula and television programming over-emphasising the role of vertebrates at the expense of other groups of organisms. Botanic gardens and arboreta have long been used for educational purposes. Sellman and Bogner (2012) have shown that learning about climate change in a botanic garden led to a significant shortterm and long-term knowledge gain for high-school students compared to students who learned in a classroom setting. There is also evidence that learning outside as part of a science curriculum results in higher levels of overall motivation in the students and a greater feeling of competency (Dettweiler et al., 2017). The trees in the UCC collection, like other urban trees also provide a range of benefits outside of the educational sphere. Large, mature trees, with well-developed crowns and large leaf surface area have the capacity to store more carbon than smaller trees. They provide shade as well as food and habitats for animal species as well providing ‘symbolic, religious and historic’ value in public common spaces. Such benefits have recently been summarised by Cavender and Donnolly (2019) and aligned with Sustainable Development Goal 11, Sustainable Cities and Communities by Turner-Skoff and Cavender (2019). A stakeholder survey has been conducted to evaluate how the tree collection is currently used and a tour of the most significant trees in the collection has been developed. The tour encourages participants to explore the benefits of plants through many lenses including recreation, medicine and commemoration. The open arboretum project brings learning beyond the classroom and acts as an entry point for learning in a variety of disciplines, not least plant science and environmental education generally.
8
Oshio, Haruki, Takashi Asawa, Akira Hoyano, and Satoshi Miyasaka. "Detailed reproduction of three-dimensional crown shape and foliage distribution of trees in an urban area using high-resolution airborne LiDAR." In IGARSS 2012 - 2012 IEEE International Geoscience and Remote Sensing Symposium. IEEE, 2012. http://dx.doi.org/10.1109/igarss.2012.6352081.
Full text
9
Peroni, Marco, Nicolò Minguzzi, and Enrico Favi. ""Unstable Branch" Footbridge in Borgo Rivola (RA), Italy." In Footbridge 2022 (Madrid): Creating Experience. Asociación Española de Ingeniería Estructural, 2022. http://dx.doi.org/10.24904/footbridge2022.219.
Full textAbstract:
<p>A new pedestrian walkway has to be built across the Senio River, in Borgo Rivola (RA), after the damages caused by an overflow to the existing one.</p><p>The project involves the construction of a new steel cable-stayed footbridge (in order to make intermediate pylons unnecessary). The walkway is precambered not only for structural purposes, but also to allow future overflows of the river causing no more structural damage. The name “unstable branch” was chosen because the shape of the steel pylon’s body, which supports the footbridge, is inspired to a tree branch whipped by the wind. It is inclined, but its stability is provided by the cables fixed to the ground on one side and connected to the footbridge on the other. The conformation of the pylon should blend and harmonize in the surrounding nature arousing the curiosity and attention of tourists, amazed by the lightness and the complicated interweaving of ropes that keeps the bridge in balance.</p><p>In the following pages, its static and dynamic behavior will be analysed, together with the description of the structure and how it will be constructed. Furthermore, a simple intervention to prevent the new footbridge to resonate with a crowd on will be proposed.</p>