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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.
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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.
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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.
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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.
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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.
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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.
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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.
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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.
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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.
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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.
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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.
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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.
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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.
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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.
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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.
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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.
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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.
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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.
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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.
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Ehoniyotan, Olayemi Ibukun, and Daniel Yomi Onemayin. "Studies on variation in morphological traits of mango trees (Mangifera indica) growing on Kogi State University campus, Anyigba, Kogi State, Nigeria." GSC Biological and Pharmaceutical Sciences 11, no. 1 (2020): 113–20. https://doi.org/10.5281/zenodo.4277010.
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Mango (<em>Mangifera indica</em>) is an economically important tropical fruit consumed all over the world due to its large fruit with a soft, sweet pulp. In this study, morphological characters of sixty (60) randomly selected mango trees growing on Kogi State University campus, Anyigba were examined. These characters were examined by comparison with those highlighted in mango descriptor by International Plant Genetic Resources Institute (IPGRI). The characters studied were crown shape, tree growth habit, leaf blade shape, leaf altitude in relation to branch, leaf apex shape, leaf margin, leaf base shape, and colour of fully developed leaf. Results revealed that 53.30% of the selected trees had broadly pyramidal crown shape; the highest percentage observed, none of the trees had spherical crown shape. There was no Drooping tree growth habit while spreading tree growth habit was the highest in 68.30% of the selected trees. Ovate, lanceolate and oblanceolate leaf blade shapes were not observed in any of the selected trees while oblong was the highest leaf blade shape observed in 50% of the selected trees. For leaf Apex Shape; Acuminate was observed in 65% of the selected trees, Acute in 35% and obtuse in none of the selected trees. Most of the trees had entire leaf margin with a percentage of 98.30% of the trees having the entire leaf margin. There were morphological variations among the selected trees for all the characters studied.
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Alves, Luciana F., and Flavio A. M. Santos. "Tree allometry and crown shape of four tree species in Atlantic rain forest, south-east Brazil." Journal of Tropical Ecology 18, no. 2 (2002): 245–60. http://dx.doi.org/10.1017/s026646740200216x.
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The allometry of crown shape and trunk diameter with tree height were analysed for four tree species in a tropical lowland rain forest, southeast Brazil. The dimensional relationships of a subcanopy species (Garcinia gardneriana) were contrasted with those of two canopy (Chrysophyllum flexuosum and Swartzia simplex) and one emergent species (Sloanea guianensis). For all trees ≥ 1 cm dbh, we recorded dbh, total height, branching height, crown area, crown width and crown length. Observed allometric relationships indicated interspecific variation in trunk diameter and crown shape with height. All species conformed to the elastic similarity model, except the emergent one that showed thicker trunks and a scaling exponent conforming to the constant stress model. The general allometric function used to describe the overall relationship (all sizes combined) did not specify exceptional variation in crown shape between species of contrasting adult stature (emergent vs. subcanopy species). However, when allometric relationships through ontogeny were considered, different strategies of growth, maintenance and expansion of crown became evident. Crown shapes were much more variable in canopy and emergent species than in the subcanopy one, suggesting that larger-statured species might be more flexible in the relative allocation of energy to height, diameter, and crown growth than smaller-statured ones. Notwithstanding, it is suggested that it is not possible adequately to predict allometric relationships only by adult stature/canopy position. Allometric variation may be also related to size-dependent changes in demographic traits and/or different responses to light availability among tree species.
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Chmura, Daniel J., Mark G. Tjoelker, and Timothy A. Martin. "Environmental and genetic effects on crown shape in young loblolly pine plantations." Canadian Journal of Forest Research 39, no. 3 (2009): 691–98. http://dx.doi.org/10.1139/x08-200.
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Tree crown shape is an important trait affecting the light environment in forest canopies. We examined genetic and environmental effects on outer crown shape of young single-family stands of loblolly pine ( Pinus taeda L.). Crown diameter profiles were measured after canopy closure at four experimental sites in the southeastern US. The two examined families of contrasting aboveground productivity differed in crown length but not in their outer crown shapes or crown shape ratios, defined as the ratio of crown diameter to crown length. Within each site, intensive silvicultural treatment, consisting of fertilization and control of competing vegetation, had little effect upon crown shape. A strongly significant effect of site on crown shape parameters was found in the family grown at all four experimental sites; however, density differences among the experimental series likely accounted for a part of the across-sites variation in crown shape. In contrast to other studies on crown shape in trees, and to findings at age 2 years in the same stands, we conclude that family effects on the outer crown shape were small compared with the environmental effects in these 5-year-old pine plantations, following canopy closure.
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Dai, Mingrui, and Guohua Li. "Soft Segmentation and Reconstruction of Tree Crown from Laser Scanning Data." Electronics 12, no. 10 (2023): 2300. http://dx.doi.org/10.3390/electronics12102300.
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Point cloud data obtained by laser scanning can be used for object shape modeling and analysis, including forest inventory. One of the inventory tasks is individual tree extraction and measurement. However, individual tree segmentation, especially tree crown segmentation, is challenging. In this paper, we present a novel soft segmentation algorithm to segment tree crowns in point clouds automatically and reconstruct the tree crown surface from the segmented crown point cloud. The soft segmentation algorithm mainly processes the overlapping region of the tree crown. The experimental results showed that the segmented crown was accurate, and the reconstructed crown looked natural. The reconstruction algorithm was highly efficient in calculating the time and memory cost aspects since the number of the extracted boundary points was small. With the reconstructed crown geometry, the crown attributes, including the width, height, superficial area, projecting ground area, and volume, could be estimated. The algorithm presented here is effective for tree crown segmentation.
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Gao, Huilin, Dongsheng Chen, Xiaomei Sun, and Shougong Zhang. "Responses of the Crown Shape of Larix kaempferi Plantations to Site Index in Subtropical Areas of China." Forests 14, no. 11 (2023): 2181. http://dx.doi.org/10.3390/f14112181.
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This study addresses how site index may affect crown shape by developing a crown shape regression model for the planted L. kaempferi at high altitudes in the subtropical climate of China. A total of 9241 branches from 78 trees, including 39 dominant trees and 39 intermediate trees, were measured in Hubei Province, southern China. The branch characteristics, including branch length, branch angle, and branch chord length of all living branches, were measured by felling trees. The models that showed good performance in crown shape modeling were used and compared in the present study. The goodness of fit statistics and stability of parameter estimation of the modified Kozak equation were better than those of the segmented polynomial equation. A nonlinear mixed-effect crown shape model was developed based on the modified Kozak equation. In addition to the tree level variables of diameter at the breast height (DBH), crown ratio (CR), and tree height-to-DBH ratio, an attempt was made to incorporate the site index into the crown shape model for the planted L. kaempferi. However, the site index was not a significant variable in the crown shape model. The purpose of our study was to lay the foundation for further study of the growth of the trees and the effects of crown morphology on stem growth in the future.
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Duchemin, Laurent, Christophe Eloy, Eric Badel, and Bruno Moulia. "Tree crowns grow into self-similar shapes controlled by gravity and light sensing." Journal of The Royal Society Interface 15, no. 142 (2018): 20170976. http://dx.doi.org/10.1098/rsif.2017.0976.
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Plants have developed different tropisms: in particular, they reorient the growth of their branches towards the light (phototropism) or upwards (gravitropism). How these tropisms affect the shape of a tree crown remains unanswered. We address this question by developing a propagating front model of tree growth. Being length-free, this model leads to self-similar solutions after a long period of time, which are independent of the initial conditions. Varying the intensities of each tropism, different self-similar shapes emerge, including singular ones. Interestingly, these shapes bear similarities to existing tree species. It is concluded that the core of specific crown shapes in trees relies on the balance between tropisms.
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Hann, David W. "An Adjustable Predictor of Crown Profile for Stand-Grown Douglas-Fir Trees." Forest Science 45, no. 2 (1999): 217–25. http://dx.doi.org/10.1093/forestscience/45.2.217.
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Abstract This study developed a method for predicting the crown profile of stand-grown trees that can be adjusted to other populations of the same species by using either measurements or predictions of the largest crown width (LCW) for trees in the alternative population. The method should be of particular interest for tree species such as Douglas-fir that have exhibited variation in crown attributes across both their geographic range and genotypes. To model crown profile, the crown was divided into two segments: the portion of the crown above the point where LCW occurs, and the portion below that point. The equation for the upper portion predicted a crown profile that ranged in shape from nearly conic to parabolic, depending on position within the crown and the social status of the tree, as indicated by the ratio of total height divided by diameter at breast height for the tree. The equation for the lower portion predicted a crown profile with a cylindrical shape. This method explained nearly 94% of the variation in crown width when used with the felled tree measurement of LCW, 87% with a measurement of LCW taken while the tree was standing, and 83% with the use of a value for LCW that was predicted from an equation developed from an independent data set. For. Sci. 45(2):217-225.
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Polewski, P., J. Shelton, W. Yao, and M. Heurich. "SEGMENTATION OF SINGLE STANDING DEAD TREES IN HIGH-RESOLUTION AERIAL IMAGERY WITH GENERATIVE ADVERSARIAL NETWORK-BASED SHAPE PRIORS." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLIII-B2-2020 (August 12, 2020): 717–23. http://dx.doi.org/10.5194/isprs-archives-xliii-b2-2020-717-2020.
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Abstract. The use of multispectral imagery for monitoring biodiversity in ecosystems is becoming widespread. A key parameter of forest ecosystems is the distribution of dead wood. This work addresses the segmentation of individual dead tree crowns in nadir-view aerial infrared imagery. While dead vegetation produces a distinct spectral response in the near infrared band, separating adjacent trees within large swaths of dead stands remains a challenge. We tackle this problem by casting the segmentation task within the active contour framework, a mathematical formulation combining learned models of the object’s shape and appearance as prior information. We explore the use of a deep convolutional generative adversarial network (DCGAN) in the role of the shape model, replacing the original linear mixture-of-eigenshapes formulation. Also, we rely on probabilities obtained from a deep fully convolutional network (FCN) as the appearance prior. Experiments conducted on manually labeled reference polygons show that the DCGAN is able to learn a low-dimensional manifold of tree crown shapes, outperforming the eigenshape model with respect to the similarity of the reproduced and referenced shapes on about 45 % of the test samples. The DCGAN is successful mostly for less convex shapes, whereas the baseline remains superior for more regular tree crown polygons.
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Rudnicki, Mark, Victor J. Lieffers, and Uldis Silins. "Stand structure governs the crown collisions of lodgepole pine." Canadian Journal of Forest Research 33, no. 7 (2003): 1238–44. http://dx.doi.org/10.1139/x03-055.
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We investigated tree sway and crown collision behavior of even-aged lodgepole pine (Pinus contorta Dougl. ex Loud. var. latifolia Engelm.) stands of different structure in Alberta, Canada, to examine how these factors might affect loss of leaf area as stands mature. The Two Creeks stand (TC) had high density and slender trees, while the Chickadee stand (CH) had stout trees. The TC stand was then thinned (TCT) to reduce the stand density. For each stand, simultaneous tree sways of a group of 10 trees were monitored with biaxial clinometers during wind speed of 5 m/s (canopy top). Crown collisions were reconstructed by combining sway displacement of individual trees with their respective crown dimensions. Comparing the sway statistics between stands with contrasting mean bole slenderness (TC and CH) indicated that more slender trees have greater sway displacements, faster sway speeds, and a greater depth of collision. Disturbance by thinning increased sway displacements, sway speeds, and depth of collisions at TCT. Tree sway patterns were circular in shape and not aligned with wind direction, but patterns were elongated after thinning. This demonstrates the high frequency of crown collision experienced by stands with slender trees and supports the notion that crown collisions result in empty space between crowns of trees.
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Peterson, David L. "Crown scorch volume and scorch height: estimates of postfire tree condition." Canadian Journal of Forest Research 15, no. 3 (1985): 596–98. http://dx.doi.org/10.1139/x85-097.
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In salvage operations after wildfire, timber managers need to identify those trees most likely to die. Crown scorch volume and scorch height are commonly used to estimate damage to conifers after fire. Calculated crown scorch volume based on scorch height and tree dimensions was compared with observed crown scorch volume for four common conifer species of the northern Rocky Mountains. Calculated crown scorch volume was significantly greater than observed crown scorch volume for all species. The overestimates are the result of differences among species and trees of varying crown shape. When postfire tree condition was evaluated from observed crown scorch volume rather than from measured scorch height, crown damage was estimated with greater accuracy. Functions that estimate postfire tree mortality based on crown damage should be based on observed crown scorch volume rather than scorch height.
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Jacygrad, Ewelina, Maggi Kelly, Sean Hogan, John E. Preece, Deborah Golino, and Richard Michelmore. "Comparison between Field Measured and UAV-Derived Pistachio Tree Crown Characteristics throughout a Growing Season." Drones 6, no. 11 (2022): 343. http://dx.doi.org/10.3390/drones6110343.
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Monitoring individual tree crown characteristics is an important component of smart agriculture and is crucial for orchard management. We focused on understanding how UAV imagery taken across one growing season can help understand and predict the growth and development of pistachio trees grown from rootstock seedlings. Tree crown characteristics (i.e., height, size, shape, and mean normalized difference vegetation index (NDVI)) were derived using an object-based image analysis method with multispectral Uncrewed Aerial Vehicles (UAV) imagery flown seven times over 472 five-year-old pistachio trees in 2018. These imagery-derived metrics were compared with field-collected tree characteristics (tree height, trunk caliper, crown height, width and volume, and leaf development status) collected over two months in 2018. The UAV method captured seasonal development of tree crowns well. UAV-derived tree characteristics were better correlated with the field tree characteristics when recorded between May and November, with high overall correlations in November. The highest correlation (R2 = 0.774) was found between trunk caliper and June UAV crown size. The weakest correlations between UAV and field traits were found in March and December. Spring leaf development stage was most variable, and mean NDVI values were lowest in March, when leaf development starts. Mean NDVI increased orchard-wide by May, and was consistently high through November. This study showcased the benefits of timely, detailed drone imagery for orchard managers.
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Parmar, Bhumikaben Maganbhai, C. R. Patel, Nikita Chandrakant Patel, and Hemangini M. Rathva. "Study on Morphological Tree Characteristics of Half-Sib Seedling Genotypes of Mango Hybrid Sonpari." International Journal of Plant & Soil Science 37, no. 4 (2025): 188–95. https://doi.org/10.9734/ijpss/2025/v37i45400.
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The present study was carried out at Agriculture Experimental Station, Navsari Agricultural University, Paria, Gujarat, India, during year 2023 & 2024 with 40 half sib seedling genotypes of mango hybrid variety Sonpari (Alphanso × Baneshan) which were evaluated and compared using morphological characters like tree height, trunk circumference, crown diameter, crown shape and descriptive statistics analysis was done. Mango hybrid Sonpari was taken as check variety. Among the half-sibs studied, genotypes SHS-61, SHS-123 and Sonpari were medium heighted (6.1-9.0 m) and remaining selected cultivars were short heighted ((≤6.0 m). Highest tree circumference (99.61 cm) and crown diameter (6.17 m) were recorded in genotypes SHS-46 and SHS-146 respectively. Among the selected half-sib genotypes, nineteen genotypes had oblong crown shape while semi-circular crown shape was observed in eight genotypes. The spherical crown shape was observed in eleven genotypes however three genotypes had broadly pyramidal crown shape. Thirty-two genotypes had spreading tree growth habit whereas, remaining nine genotypes had erect tree growth habit.
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Heisler, Gordon. "Energy Savings with Trees." Arboriculture & Urban Forestry 12, no. 5 (1986): 113–25. http://dx.doi.org/10.48044/jauf.1986.026.
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In conventional buildings, trees increase, decrease, or have little effect on energy use depending on general climate, building type, tree species, and tree location. Tree arrangements that save energy provide shade primarily for east and west walls and roofs and wind protection from the direction of prevailing winter winds. Particularly for buildings specially designed to use solar energy and those with solar collectors, it is important to place tree crowns so they do not block sun from collectors and south walls. But conventional houses also benefit from winter sun. Deciduous trees provide better year-round shade than conifers, but do reduce solar energy significantly even without leaves. In winter, reductions in solar energy on south walls by a deciduous tree may be greater than reductions by the same tree in summer. Hence, growth rate and crown shape are important criteria in selecting shade trees, and the placement of trees around the house is important. A summary of research data suggests that the maximum potential annual effect of trees on energy use in conventional houses is about 20 to 25% compared to the same house in the open.
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Wang, Jie, Chunjing Yao, Hongchao Ma, Junhao Xu, and Chen Qian. "Sample Plots Forestry Parameters Verification and Updating Using Airborne LiDAR Data." Remote Sensing 15, no. 12 (2023): 3060. http://dx.doi.org/10.3390/rs15123060.
Full textAbstract:
The rapid development of LiDAR technology has promoted great changes in forest resource surveys. The airborne LiDAR point cloud can provide the precise height and detailed structure of trees, and can estimate key forest resource indicators such as forest stock volume, diameter at breast height, and forest biomass at a large scale. By establishing relationship models between the forest parameters of sample plots and the calculated parameters of LiDAR, these developments may eventually expand the models to large-scale forest resource surveys of entire areas. In this study, eight sample plots in northeast China are used to verify and update the information using point cloud obtained by the LiDAR scanner riegl-vq-1560i. First, the tree crowns are segmented using the profile-rotating algorithm, and tree positions are registered based on dominant tree heights. Second, considering the correlation between crown shape and tree species, we use DBN classifier to identify species using features of crowns, which are extracted to 1D array. Third, when the tree species is known, parameters such as height, crown width, diameter at breast height, biomass, and stock volume can be extracted from trees, enabling accurate large-scale forest surveys based on LiDAR data. Finally, experiment results demonstrate that the F-score of the eight plots in the tree segmentation exceed 0.95, the accuracy of tree species correction exceeds 90%, and the R2 of tree height, east–west crown width, north–south crown width, diameter at breast height, aboveground biomass, and stock volume are 0.893, 0.757, 0.694, 0.840, 0.896 and 0.891, respectively. The above results indicate that the LiDAR-based survey is practical and can be widely applied in forest resource monitoring.
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Wan Mohd Jaafar, Wan, Iain Woodhouse, Carlos Silva, et al. "Improving Individual Tree Crown Delineation and Attributes Estimation of Tropical Forests Using Airborne LiDAR Data." Forests 9, no. 12 (2018): 759. http://dx.doi.org/10.3390/f9120759.
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Individual tree crown (ITC) segmentation is an approach to isolate individual tree from the background vegetation and delineate precisely the crown boundaries for forest management and inventory purposes. ITC detection and delineation have been commonly generated from canopy height model (CHM) derived from light detection and ranging (LiDAR) data. Existing ITC segmentation methods, however, are limited in their efficiency for characterizing closed canopies, especially in tropical forests, due to the overlapping structure and irregular shape of tree crowns. Furthermore, the potential of 3-dimensional (3D) LiDAR data is not fully realized by existing CHM-based methods. Thus, the aim of this study was to develop an efficient framework for ITC segmentation in tropical forests using LiDAR-derived CHM and 3D point cloud data in order to accurately estimate tree attributes such as the tree height, mean crown width and aboveground biomass (AGB). The proposed framework entails five major steps: (1) automatically identifying dominant tree crowns by implementing semi-variogram statistics and morphological analysis; (2) generating initial tree segments using a watershed algorithm based on mathematical morphology; (3) identifying “problematic” segments based on predetermined set of rules; (4) tuning the problematic segments using a modified distance-based algorithm (DBA); and (5) segmenting and counting the number of individual trees based on the 3D LiDAR point clouds within each of the identified segment. This approach was developed in a way such that the 3D LiDAR points were only examined on problematic segments identified for further evaluations. 209 reference trees with diameter at breast height (DBH) ≥ 10 cm were selected in the field in two study areas in order to validate ITC detection and delineation results of the proposed framework. We computed tree crown metrics (e.g., maximum crown height and mean crown width) to estimate aboveground biomass (AGB) at tree level using previously published allometric equations. Accuracy assessment was performed to calculate percentage of correctly detected trees, omission and commission errors. Our method correctly identified individual tree crowns with detection accuracy exceeding 80 percent at both forest sites. Also, our results showed high agreement (R2 > 0.64) in terms of AGB estimates using 3D LiDAR metrics and variables measured in the field, for both sites. The findings from our study demonstrate the efficacy of the proposed framework in delineating tree crowns, even in high canopy density areas such as tropical rainforests, where, usually the traditional algorithms are limited in their performances. Moreover, the high tree delineation accuracy in the two study areas emphasizes the potential robustness and transferability of our approach to other densely forested areas across the globe.
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Remphrey, W. R., C. G. Davidson, and M. J. Blouw. "A classification and analysis of crown form in green ash (Fraxinus pennsylvanica)." Canadian Journal of Botany 65, no. 11 (1987): 2188–95. http://dx.doi.org/10.1139/b87-301.
Full textAbstract:
Forty-five boulevard green ash (Fraxinus pennsylvanica var. subintegerrima (Vahl) Fern.), both male and female trees, were selected and numerous morphometric measurements were obtained. Multivariate and univariate techniques applied to the data suggested three crown shape classes based on the pattern of crown diameter changes. The crown shape classes were identified as broad and rounded (group C) to tall and conical (group A), with an intermediate category (group B). Although tree age was not significantly different, group C trees tended to be larger with larger crown areas and basal main-stem diameters compared with groups A and B, which were not different. A visual rating analysis of the woody frame revealed that group A trees tended to have an excurrent form, whereas group C trees were predominately decurrent. When comparing sexes, it was found that male trees were larger, with larger crown areas than females, and they had a greater ratio of crown area to basal stem diameter. The crowns of male trees were generally branchier, with more foliage per unit crown volume than females. It appears that, in terms of growth and form, male trees are probably better suited for use as boulevard trees than female trees. Differences among groups and between sexes are discussed in relation to factors like apical control and reproductive sinks.
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Bakhshaliyeva, N. "Evaluation of Genetic Diversity of Persimmon in Sheki-Zagatala Economic Region of Azerbaijan." Bulletin of Science and Practice 11, no. 3 (2025): 336–52. https://doi.org/10.33619/2414-2948/112/41.
Full textAbstract:
Persimmon is one of the main export crops in Azerbaijan. The aim of the study was to assess the genetic diversity of persimmon in Azerbaijan. The studies were conducted in June-July 2023. Persimmon plantations in the Sheki-Zagatala economic region were studied. 30 plants were selected that differed in morphological parameters and probably belonged to different varieties. During direct field work, each plant was described by the following parameters: tree height, crown shape, length, shape and color of leaves, color and size of flowers, monoecious or dioecious plant. Genetic material was extracted according to the Doyle & Doyle (1987) protocol, purified by electrophoresis and purity tested using a spectrophotometer. As a result, it was suggested that tall persimmon trees often have a pyramidal crown shape, while short trees have a wide oval shape. Also, trees with an oval crown often have oval or heart-shaped leaves, while trees with a pyramidal crown have elliptical leaves. Genetic analysis confirmed that all 30 persimmon samples probably belong to different varieties. 25 samples had contamination. The materials collected during this work will be used in the future to establish the genetic relationship of the persimmon varieties examined in Azerbaijan.
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Yan, Zhaojin, Rufei Liu, Liang Cheng, Xiao Zhou, Xiaoguang Ruan, and Yijia Xiao. "A Concave Hull Methodology for Calculating the Crown Volume of Individual Trees Based on Vehicle-Borne LiDAR Data." Remote Sensing 11, no. 6 (2019): 623. http://dx.doi.org/10.3390/rs11060623.
Full textAbstract:
Crown volume is an important tree factor used in forest surveys as a prerequisite for estimating biomass and carbon stocks. This study developed a method for accurately calculating the crown volume of individual trees from vehicle-borne laser scanning (VLS) data using a concave hull by slices method. CloudCompare, an open-source three-dimensional (3D) point cloud and mesh processing software package, was used with VLS data to segment individual trees from which single tree crowns were extracted by identifying the first branch point of the tree. The slice thickness and number to be fitted to the canopy point cloud were adaptively determined based on the change rate in area with height, with the area of each slice calculated using the concave hull algorithm with portions of the crown regarded as truncated cones. The overall volume was then calculated as the sum of all sub-volumes. The proposed method was experimentally validated on 30 urban trees by comparing the crown volumes calculated using the proposed method with those calculated using five existing methods (manual measurement, 3D convex hull, 3D alpha shape, convex hull by slices, and voxel-based). The proposed method produced the smallest average crown volume. Gaps and holes in the point cloud were regarded as part of the crown by the manual measurement, 3D convex hull, and convex hull by slices method, resulting in the calculated volume being higher than the true value; the proposed method reduced this effect. These results indicate that the concave hull by slices method can more effectively calculate the crown volume of a single tree from VLS data.
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Paulo, M. J., A. Stein, and M. Tomé. "A spatial statistical analysis of cork oak competition in two Portuguese silvopastoral systems." Canadian Journal of Forest Research 32, no. 11 (2002): 1893–903. http://dx.doi.org/10.1139/x02-107.
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This paper considers competition among cork oaks (Quercus suber L.) at three plots in two representative Portuguese stands. It uses spatial point pattern functions to describe densities and quantify differences among stands. Relations between cork oak characteristics and indices measuring intertree competition are modelled. Tree competition has a significant effect on tree crown characteristics. In particular, cork oaks with much competition have smaller and more elongated crowns. A standard model that relates crown diameter with diameter at breast height was improved. The R2 value increased from 0.53 to 0.63 by including a crown shape parameter and competition indices.
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Perles-Garcia, Maria D., Matthias Kunz, Andreas Fichtner, Nora Meyer, Werner Härdtle, and Goddert von Oheimb. "Neighbourhood Species Richness Reduces Crown Asymmetry of Subtropical Trees in Sloping Terrain." Remote Sensing 14, no. 6 (2022): 1441. http://dx.doi.org/10.3390/rs14061441.
Full textAbstract:
Reforestation in sloping terrain is an important measure for soil erosion control and sustainable watershed management. The mechanical stability of such reforested stands, however, can be low due to a strong asymmetric shape of tree crowns. We investigated how neighbourhood tree species richness, neighbourhood pressure, tree height, and slope inclination affect crown asymmetry in a large-scale plantation biodiversity-ecosystem functioning experiment in subtropical China (BEF-China) over eight years. We took the advantage of terrestrial laser scanning (TLS) measurements, which provide non-destructive, high-resolution data of tree structure without altering tree interactions. Neighbourhood species richness significantly reduced crown asymmetry, and this effect became stronger at steeper slopes. Our results suggest that tree diversity promotes the mechanical stability of forest stands in sloping terrain and highlight the importance of TLS-data for a comprehensive understanding of the role of tree diversity in modulating crown interactions in mixed-species forest plantations.
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Hess, André Felipe, Kemely Alves Atanazio, Geedre Adriano Borsoi, et al. "Crown Efficiency and Pine Cones Production for Brazilian Pine (Araucaria angustifolia (Bertol.) Kuntze) in South Brazil." Journal of Agricultural Science 11, no. 6 (2019): 247. http://dx.doi.org/10.5539/jas.v11n6p247.
Full textAbstract:
Crown efficiency is a relation of growth with the area tree occupies (available area efficiency). Efficiency is associated with the vertical and lateral expansion capacity of the tree and crown, increase, density and light absorption. Thus, our study aimed to evaluate crown efficiency with pine cones∙tree-1 production and dendro/morphometric variables of individual araucaria trees in three forest sites in south Brazil. In each site of each tree, dendrometric and morphometric variables were measured and increment rolls were taken at the breast height diameter level. Together with these data, the morphometric indexes, annual periodic increment in diameter of the last ten years (APId) and efficiency of the crown as a function of APId by the horizontal projection area of the crown (hpac) and number of pine cones∙tree-1 (np) by hpac were calculated. Crown efficiency was modeled as a function of the independent variables hpac, APId, crown length (cl), crown ratio (cr) and np. The accuracy of the adjustment was evaluated by the statistics of the deviance, Akaike&rsquo;s information criterion and graph of the residuals. The results show that the number of pine cones∙tree-1 increases with annual periodic increment in diameter and diameter. Crown efficiency decreases with increasing hpac, cl and cr, indicating silvicultural treatments should be performed with the removal of trees of larger diameter and crown size. A higher pine cones production and efficiency correlates with forest growth, shape, competition, sociological position (stratum tree occupies) and density.
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Deleuze, Christine, Jean-Christophe Hervé, Francis Colin, and Luc Ribeyrolles. "Modelling crown shape of Piceaabies: spacing effects." Canadian Journal of Forest Research 26, no. 11 (1996): 1957–66. http://dx.doi.org/10.1139/x26-221.
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A model of branch length increment and inclination was developed for Piceaabies (L.) Karst. to describe the dynamics of crown shape. Four trees belonging to the provenance Istebna, from Poland, were sampled in an experimental plot where density varied continuously from 200 to 10 000 stems/ha. Sampling along the density gradient enabled us to study the effect of spacing on tree morphology and development. The model of branch extension is based on height growth and on the year of elongation of the branch. A second model describes the change in branch inclination. Branch spread increased with between-tree spacing, whereas branch inclination was affected by crown contact; competition was then divided into two components: (i) direct mechanical contact and (ii) global resource depletion. The sample trees were young (26 years), so height growth was mainly linear and the effect of apical control could not be tested. This study provides a simple model of crown shape development that can be used in a more detailed process-based model. Simulations are presented based only on height growth. For wood quality purposes, the relationship between branch diameter and branch length is provided to give access to the knottiness of the stem. The limitations of the sample are discussed in view of a more general use of these models.
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Minařík, Robert, Jakub Langhammer, and Theodora Lendzioch. "Automatic Tree Crown Extraction from UAS Multispectral Imagery for the Detection of Bark Beetle Disturbance in Mixed Forests." Remote Sensing 12, no. 24 (2020): 4081. http://dx.doi.org/10.3390/rs12244081.
Full textAbstract:
Multispectral imaging using unmanned aerial systems (UAS) enables rapid and accurate detection of pest insect infestations, which are an increasing threat to midlatitude natural forests. Pest detection at the level of an individual tree is of particular importance in mixed forests, where it enables a sensible forest management approach. In this study, we propose a method for individual tree crown delineation (ITCD) followed by feature extraction to detect a bark beetle disturbance in a mixed urban forest using a photogrammetric point cloud (PPC) and a multispectral orthomosaic. An excess green index (ExG) threshold mask was applied before the ITCD to separate targeted coniferous trees from deciduous trees and backgrounds. The individual crowns of conifer trees were automatically delineated as (i) a full tree crown using marker-controlled watershed segmentation (MCWS), Dalponte2016 (DAL), and Li 2012 (LI) region growing algorithms or (ii) a buffer (BUFFER) around a treetop from the masked PPC. We statistically compared selected spectral and elevation features extracted from automatically delineated crowns (ADCs) of each method to reference tree crowns (RTC) to distinguish between the forest disturbance classes and two tree species. Moreover, the effect of PPC density on the ITCD accuracy and feature extraction was investigated. The ExG threshold mask application resulted in the excellent separability of targeted conifer trees and the increasing shape similarity of ADCs compared to RTC. The results revealed a strong effect of PPC density on treetop detection and ITCD. If the PPC density is sufficient (>10 points/m2), the ADCs produced by DAL, MCWS, and LI methods are comparable, and the extracted feature statistics of ADCs insignificantly differ from RTC. The BUFFER method is less suitable for detecting a bark beetle disturbance in the mixed forest because of the simplicity of crown delineation. It caused significant differences in extracted feature statistics compared to RTC. Therefore, the point density was found to be more significant than the algorithm used. We conclude that automatic ITCD methods may constitute a substitute for the time-consuming manual tree crown delineation in tree-based bark beetle disturbance detection and sanitation of individual infested trees using the suggested methodology and high-density (>20 points/m2, 10 points/m2 minimum) PPC.
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Davidson, Campbell G., and William R. Remphrey. "An analysis of architectural parameters of male and female Fraxinus pennsylvanica in relation to crown shape and crown location." Canadian Journal of Botany 68, no. 9 (1990): 2035–43. http://dx.doi.org/10.1139/b90-266.
Full textAbstract:
Architectural variables from male and female green ash (Fraxinus pennsylvanica var. subintergerrima (Vahl) Fern.) comprising three different crown-shape classes were analyzed at four different crown levels to determine which variables influenced crown shape. The narrow conical shape class had the largest mid shoot diameters and the smallest shoot tip abortion frequencies. The broad to round shape class had greater abortion frequency overall. In addition, there was less difference in shoot length between the top and bottom of the crown. The more oval shape class was intermediate for both shoot diameters and abortion frequency. Parent and daughter shoot lengths were longer, midshoot diameters larger, and elevation angles greater with increasing sampling height in the tree. Male trees had shorter shoot lengths and shorter and fewer daughter lateral shoots than female trees. Principal component analysis was used to identify shoot lengths, elevation angles, and abortion frequencies as potentially key variables in understanding crown shape in green ash. Interrelationships of many of the architectural variables suggest that a significant change in one may lead to changes in others, which ultimately would lead to changes in overall crown shape.
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Polewski, P., W. Yao, M. Heurich, P. Krzystek, and U. Stilla. "DETECTION OF SINGLE STANDING DEAD TREES FROM AERIAL COLOR INFRARED IMAGERY BY SEGMENTATION WITH SHAPE AND INTENSITY PRIORS." ISPRS Annals of Photogrammetry, Remote Sensing and Spatial Information Sciences II-3/W4 (March 11, 2015): 181–88. http://dx.doi.org/10.5194/isprsannals-ii-3-w4-181-2015.
Full textAbstract:
Standing dead trees, known as snags, are an essential factor in maintaining biodiversity in forest ecosystems. Combined with their role as carbon sinks, this makes for a compelling reason to study their spatial distribution. This paper presents an integrated method to detect and delineate individual dead tree crowns from color infrared aerial imagery. Our approach consists of two steps which incorporate statistical information about prior distributions of both the image intensities and the shapes of the target objects. In the first step, we perform a Gaussian Mixture Model clustering in the pixel color space with priors on the cluster means, obtaining up to 3 components corresponding to dead trees, living trees, and shadows. We then refine the dead tree regions using a level set segmentation method enriched with a generative model of the dead trees’ shape distribution as well as a discriminative model of their pixel intensity distribution. The iterative application of the statistical shape template yields the set of delineated dead crowns. The prior information enforces the consistency of the template’s shape variation with the shape manifold defined by manually labeled training examples, which makes it possible to separate crowns located in close proximity and prevents the formation of large crown clusters. Also, the statistical information built into the segmentation gives rise to an implicit detection scheme, because the shape template evolves towards an empty contour if not enough evidence for the object is present in the image. We test our method on 3 sample plots from the Bavarian Forest National Park with reference data obtained by manually marking individual dead tree polygons in the images. Our results are scenario-dependent and range from a correctness/completeness of 0.71/0.81 up to 0.77/1, with an average center-of-gravity displacement of 3-5 pixels between the detected and reference polygons.
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Hosingholizade, Ali, Yousef Erfanifard, Seyed Kazem Alavipanah, et al. "Assessment of Pine Tree Crown Delineation Algorithms on UAV Data: From K-Means Clustering to CNN Segmentation." Forests 16, no. 2 (2025): 228. https://doi.org/10.3390/f16020228.
Full textAbstract:
The crown area is a critical metric for evaluating tree growth and supporting various ecological and forestry analyses. This study compares three approaches, i.e., unsupervised clustering, region-based, and deep learning, to estimate the crown area of Pinus eldarica Medw. using UAV-acquired RGB imagery (2 cm ground sampling distance) and high-density point clouds (1.27 points/cm3). The first approach applied unsupervised clustering techniques, such as Mean-shift and K-means, to directly estimate crown areas, bypassing tree top detection. The second employed a region-based approach, using Template Matching and Local Maxima (LM) for tree top identification, followed by Marker-Controlled Watershed (MCW) and Seeded Region Growing for crown delineation. The third approach utilized a Convolutional Neural Network (CNN) that integrated Digital Surface Model layers with the Visible Atmospheric Resistance Index for enhanced segmentation. The results were compared against field measurements and manual digitization. The findings reveal that CNN and MCW with LM were the most effective, particularly for small and large trees, though performance decreased for medium-sized crowns. CNN provided the most accurate results overall, with a relative root mean square error (RRMSE) of 8.85%, a Nash–Sutcliffe Efficiency (NSE) of 0.97, and a bias score (BS) of 1.00. The CNN crown area estimates showed strong correlations (R2 = 0.83, 0.62, and 0.94 for small, medium, and large trees, respectively) with manually digitized references. This study underscores the value of advanced CNN techniques for precise crown area and shape estimation, highlighting the need for future research to refine algorithms for improved handling of crown size variability.
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Long, Jie, and Michael D. Jones. "Reconstructing 3D Tree Models Using Motion Capture and Particle Flow." International Journal of Computer Games Technology 2013 (2013): 1–11. http://dx.doi.org/10.1155/2013/363160.
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Recovering tree shape from motion capture data is a first step toward efficient and accurate animation of trees in wind using motion capture data. Existing algorithms for generating models of tree branching structures for image synthesis in computer graphics are not adapted to the unique data set provided by motion capture. We present a method for tree shape reconstruction using particle flow on input data obtained from a passive optical motion capture system. Initial branch tip positions are estimated from averaged and smoothed motion capture data. Branch tips, as particles, are also generated within a bounding space defined by a stack of bounding boxes or a convex hull. The particle flow, starting at branch tips within the bounding volume under forces, creates tree branches. The forces are composed of gravity, internal force, and external force. The resulting shapes are realistic and similar to the original tree crown shape. Several tunable parameters provide control over branch shape and arrangement.
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Argamosa, R. J. L., E. C. Paringit, K. R. Quinton, et al. "FULLY AUTOMATED GIS-BASED INDIVIDUAL TREE CROWN DELINEATION BASED ON CURVATURE VALUES FROM A LIDAR DERIVED CANOPY HEIGHT MODEL IN A CONIFEROUS PLANTATION." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLI-B8 (June 23, 2016): 563–69. http://dx.doi.org/10.5194/isprs-archives-xli-b8-563-2016.
Full textAbstract:
The generation of high resolution canopy height model (CHM) from LiDAR makes it possible to delineate individual tree crown by means of a fully-automated method using the CHM’s curvature through its slope. The local maxima are obtained by taking the maximum raster value in a 3 m x 3 m cell. These values are assumed as tree tops and therefore considered as individual trees. Based on the assumptions, thiessen polygons were generated to serve as buffers for the canopy extent. The negative profile curvature is then measured from the slope of the CHM. The results show that the aggregated points from a negative profile curvature raster provide the most realistic crown shape. The absence of field data regarding tree crown dimensions require accurate visual assessment after the appended delineated tree crown polygon was superimposed to the hill shaded CHM.
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Argamosa, R. J. L., E. C. Paringit, K. R. Quinton, et al. "FULLY AUTOMATED GIS-BASED INDIVIDUAL TREE CROWN DELINEATION BASED ON CURVATURE VALUES FROM A LIDAR DERIVED CANOPY HEIGHT MODEL IN A CONIFEROUS PLANTATION." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLI-B8 (June 23, 2016): 563–69. http://dx.doi.org/10.5194/isprsarchives-xli-b8-563-2016.
Full textAbstract:
The generation of high resolution canopy height model (CHM) from LiDAR makes it possible to delineate individual tree crown by means of a fully-automated method using the CHM’s curvature through its slope. The local maxima are obtained by taking the maximum raster value in a 3 m x 3 m cell. These values are assumed as tree tops and therefore considered as individual trees. Based on the assumptions, thiessen polygons were generated to serve as buffers for the canopy extent. The negative profile curvature is then measured from the slope of the CHM. The results show that the aggregated points from a negative profile curvature raster provide the most realistic crown shape. The absence of field data regarding tree crown dimensions require accurate visual assessment after the appended delineated tree crown polygon was superimposed to the hill shaded CHM.
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Wang, Z., J. Wu, Y. Wang, et al. "CROWN-LEVEL TREE SPECIES CLASSIFICATION USING INTEGRATED AIRBORNE HYPERSPECTRAL AND LIDAR REMOTE SENSING DATA." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLII-3 (May 2, 2018): 2629–34. http://dx.doi.org/10.5194/isprs-archives-xlii-3-2629-2018.
Full textAbstract:
Mapping tree species is essential for sustainable planning as well as to improve our understanding of the role of different trees as different ecological service. However, crown-level tree species automatic classification is a challenging task due to the spectral similarity among diversified tree species, fine-scale spatial variation, shadow, and underlying objects within a crown. Advanced remote sensing data such as airborne Light Detection and Ranging (LiDAR) and hyperspectral imagery offer a great potential opportunity to derive crown spectral, structure and canopy physiological information at the individual crown scale, which can be useful for mapping tree species. In this paper, an innovative approach was developed for tree species classification at the crown level. The method utilized LiDAR data for individual tree crown delineation and morphological structure extraction, and Compact Airborne Spectrographic Imager (CASI) hyperspectral imagery for pure crown-scale spectral extraction. Specifically, four steps were include: 1) A weighted mean filtering method was developed to improve the accuracy of the smoothed Canopy Height Model (CHM) derived from LiDAR data; 2) The marker-controlled watershed segmentation algorithm was, therefore, also employed to delineate the tree-level canopy from the CHM image in this study, and then individual tree height and tree crown were calculated according to the delineated crown; 3) Spectral features within 3&amp;thinsp;&amp;times;&amp;thinsp;3 neighborhood regions centered on the treetops detected by the treetop detection algorithm were derived from the spectrally normalized CASI imagery; 4) The shape characteristics related to their crown diameters and heights were established, and different crown-level tree species were classified using the combination of spectral and shape characteristics. Analysis of results suggests that the developed classification strategy in this paper (OA&amp;thinsp;=&amp;thinsp;85.12&amp;thinsp;%, Kc&amp;thinsp;=&amp;thinsp;0.90) performed better than LiDAR-metrics method (OA&amp;thinsp;=&amp;thinsp;79.86&amp;thinsp;%, Kc&amp;thinsp;=&amp;thinsp;0.81) and spectral-metircs method (OA&amp;thinsp;=&amp;thinsp;71.26, Kc&amp;thinsp;=&amp;thinsp;0.69) in terms of classification accuracy, which indicated that the advanced method of data processing and sensitive feature selection are critical for improving the accuracy of crown-level tree species classification.
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Lin, Xiaodan, Shaohui Ma, and Junjie Liu. "Extraction of Fruit Tree Canopy Images Based on Machine Vision." Applied Science and Innovative Research 9, no. 1 (2025): p248. https://doi.org/10.22158/asir.v9n1p248.
Full textAbstract:
With the rapid development of machine vision technology and the help of smart agriculture, machine vision technology has developed from medical, military, national defense and other fields to the agricultural field and achieved remarkable results. Such as: fruit and vegetable picking robot, fruit quality classification, weed pest monitoring and so on. In this paper, machine vision technology is used to complete the segmentation of fruit tree crown image, which is complicated due to the influence of fruit tree shape, planting mode and growth environment. For pear trees in orchards, OpenCV software and image processing method are used in this paper to propose a tree crown image segmentation algorithm to provide reference for the subsequent prediction of fruit tree crown volume and accurate spraying.
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HD, Japheth, Vange T, and Amonum JI. "Crown bole diameter linear equation for Daniellia oliverii (Rolfe) Hutch and Daviz and its application to stand density control in natural stands." MOJ Ecology & Environmental Sciences 6, no. 1 (2021): 22–26. http://dx.doi.org/10.15406/mojes.2021.06.00209.
Full textAbstract:
At present, no adequate information on the application of crown-bole diameter model to stand density and stock control for Daniellia oliverii (Rolfe) Hutch and Daviz open grown trees for sustainable forest management in the study area. The species numbers are threatened, because farmers and foresters do not actively plant this tree species. Livestock, fire, and anthropogenic activities are few factors that limit the success of natural regeneration of the species; and is facing regeneration problem. These have led to the species declining in the natural forest areas and the loss of biological values (genetic hereditary). A total of nine blocks as sample plots sizes 100x100 meters were randomly laid. Simple random sampling was used to collect data on tree diameter at breast height (dbh). Dbh was used to estimate crown diameter using a developed simple linear crown-bole diameter model. Based on this finding, dbh distribution was more (42 tree stands) concentrated at the lower diameter class (10 to 30cm) than at the upper diameter class distribution (31 and above). This could be that such tree stands might have been exploited as timber in the ecosystem. Nowadays, trees of smaller dimension are generally logged immediately they are discovered, especially the most economic and desirable species. The status of the tree species was a reversed “J” shaped distribution curve. The reverse ‘J-shape’ diameter distribution indicated healthy recruitment potentials; the lower class diameter tree stands could develop into mature trees and replace the old ones in the future if proper conservation efforts are sustained. Thus, this structure is typical of a natural forest. This finding estimated limiting stocking and stand density required for producing a complete canopy without effect of competition. D. oliverii with diameter 48.7cm would require a stocking of 168 trees per hectare in terms of total occupancy by tree crowns; stand density of 0.00001863m2ha-1 would be needed. Also, tree stands of 80cm dbh would have 73 tree stands limiting stocking, covering a stand density of 0.00005027m2/ha. Linear crown-bole diameter model could simply be used in forest inventory operations for determining the forest stock with less cost and time consuming. More research is needed with a greater variety of site and stand conditions in addition to a greater variety of tree sizes and ages.
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Efthimiou, Georgios, Athanasios Papadopoulos, Manthos Trichias, and Eleni Andrianopoulou. "Ecological Evaluation and Sustainable Management of the Riparian Forest in Central Greece." Environmental Research, Engineering and Management 78, no. 4 (2022): 66–76. http://dx.doi.org/10.5755/j01.erem.78.4.31174.
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The aim of this research is the ecological evaluation of the trees of a riparian peri-urban park, with measurement, inventory and processing of qualitative and quantitative variables of trees (Dendometry) in the riparian forest of the river Karpenissiotis in Central Greece. Each tree is recorded in relation to its species (structural elements) including the diameter at breast height (DBH), the height (H), the ruggedness coefficient (H/D), the height of the crown (Hk), the length of the crown (Lk), the diameter of the crown (Dk), the order of the crown, the order of vitality, the tendency of evolution, the position of the trunk, the shape of the crown, the problems in the space of the roots, the crown, pruning, insect infestations, fungi, and runoff. From the statistical analysis and processing of the measurements, assessment was made of the condition of their health and stability; and necessary measures are proposed in order to significantly improve the ecological conditions of a riparian forest. Thus, the main problems presented by the forest species of trees concerned mainly the sloping, crooked and serpentine trunks, asymmetrical crown shape, insect and fungal infestations. The riparian peri-urban plane forest studied is dominated by trees, which are classified as remaining, normally growing with long asymmetrical crowns with a moderate health status and moderate stability. For the sustainable management and sustainable development of the riparian forest, measures are proposed which are necessary for the forest protection of the trees including their health and safe growth.
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Osawa, Akira. "Inverse relationship of crown fractal dimension to self-thinning exponent of tree populations: a hypothesis." Canadian Journal of Forest Research 25, no. 10 (1995): 1608–17. http://dx.doi.org/10.1139/x95-175.
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The self-thinning rule describes in overcrowded even-aged plant monocultures a consistent relationship of mean mass to the approximately −3/2 power of plant density. Recent analyses revealed cases of statistically significant departures of the exponent from −3/2, confirming earlier suggestions. Shade tolerance, crown structure, and stand conditions have been suggested to influence variation in the self-thinning exponent; however, quantitative relationships of the species' traits to thinning exponent have been unclear. I examined patterns of crown fractal dimension, a quantitative measure of crown structure, and their relationship to the self-thinning exponent in four tree species, Nothofagussolandri var. cliffortioides (Hook. f.) Poole, Pinusbanksiana Lamb., Pinusdensiflora Sieb. et Zucc., and Cryptomeriajaponica (Linn. fil.) D. Don. Only stands at maximum crowding were used for analysis. Crown fractal dimension of monocultures is hypothesized to be a factor determining the species-specific variation in the self-thinning exponent of tree populations and is inversely proportional to the thinning exponent. Species-specific change in foliage packing through development of overcrowded populations is suggested to be closely related to variation in crown fractal dimension and the self-thinning exponent. Implications to possible effects of leaf shape and structural characteristics of crowns to crown fractal dimensions are discussed.
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Verma, Niva Kiran, and David W. Lamb. "The use of shadows in high spatial resolution, remotely sensed, imagery to estimate the height of individual Eucalyptus trees on undulating land." Rangeland Journal 37, no. 5 (2015): 467. http://dx.doi.org/10.1071/rj15021.
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The shadows cast by 180 individual Eucalyptus trees, of varying canopy condition, on undulating land in south-eastern Australia were used to infer their heights from 50-cm spatial resolution, multispectral aerial imagery (blue = 0.4–0.5 μm; green = 0.5–0.6 μm; red = 0.6–0.7 μm; near infrared = 0.7–1 μm). A geometrical shadow model was developed incorporating the local slope and aspect of the ground from a digital elevation model at each tree location. A method of deriving ‘local tree time’ to infer the solar elevation angle, in situations where the image acquisition time is not available, was also developed. Based on a measurement of the shadow length from the geometric centre of the tree crowns, and ignoring the role of the crown periphery in distorting the shadow shape, the tree heights were estimated with a root mean square error of ±5.6 m (~±27%) with some overestimated by as much as 50%. A geometric correction for shadow distortion assuming spherical crown geometry provided an improved estimate with a root mean square error of ±4.8 m (~±23%).
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Tomșa, Vlăduț Remus, Alexandru Lucian Curtu, and Mihai Daniel Niță. "Tree Shape Variability in a Mixed Oak Forest Using Terrestrial Laser Technology: Implications for Mating System Analysis." Forests 12, no. 2 (2021): 253. http://dx.doi.org/10.3390/f12020253.
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The accuracy of the description regarding tree architecture is crucial for data processing. LiDAR technology is an efficient solution for capturing the characteristics of individual trees. The aim of the present study was to analyze tree shape variability in a mixed oak forest consisting of four European white oak species: Quercus petraea, Q. frainetto, Q. pubescens, and Q. robur. Moreover, we tested for association between tree shape and individual heterozygosity and whether oak trees identified as pollen donors in a previous genetic study have a larger size in terms of crown and trunk characteristics than non-donors. The woody structure of a tree was defined by the quantitative structure model (QSM) providing information about topology (branching structure), geometry, and volume. For extracting the 3D point clouds a high-speed 3D scanner (FARO FocusS 70) was used. The crown variables were strongly correlated to each other, the branch volume being influenced by branch length, maximum branch order, and the number of branches but not influenced by diameter at breast height (DBH), trunk length, trunk volume, or tree height. There was no relationship between the individual heterozygosity based on nuclear microsatellite genetic markers and crown and trunk characteristics, respectively. Branch volume, total area, DBH, trunk volume, and the total volume of tree were significantly larger in pollen donors compared to non-donor Q. petraea trees. Thus, the mean branch volume was more than three times higher. Pollen donors had nearly two and half times larger total area in comparison to non-donor individuals. Our results suggest that a thorough characterization of tree phenotype using terrestrial laser scanning may contribute to a better understanding of mating system patterns in oak forests.
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Rahmania, Farhani Nurshafa, Bayu Agung Prahardika, and Rony Irawanto. "Tree Architecture Models of the Syzigium Genus Collection at the Purwodadi Botanical Gardens." Journal of Tropical Biodiversity and Biotechnology 10, no. 2 (2025): jtbb12144. https://doi.org/10.22146/jtbb.12144.
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There are many species of plants in the genus Syzygium. This genus is distinguished by its strong root system, evergreen, sprawling and complex tree crowns and a powerful branching system on the trunk. The vertical structure of Syzygium trees is distinguished by branching a large crown. Based on its characteristics, the genus Syzygium has a great potential in supporting the sustainability of ecosystem balance. The diversity of tree architecture possessed by the genus Syzygium allows Syzygium species to play an active role in soil and water conservation efforts. The aim of this study is to identify various architectural models of trees Syzygium species in the collection of Purwodadi Botanical Garden in order to assess their role in the ecosystem. The method used in this study was to measure the physical characteristics of trees, such as tree height, trunk diameter, and crown area, and to observe the shape of trees, such as stem growth patterns, branching patterns, and direction of branch development. As the result, of the 17 Syzygium tree species selected and in accordance with the research criteria, 7 of them have the Stone model, 3 species have the Scarrone model, 2 species have the Attims model, 2 species have the Petit model, and 1 species each has the Koriba, Massart, and Troll models. Each variation of tree architecture model has different functions to the ecosystem.
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Harja, Degi, Grégoire Vincent, Rachmat Mulia, and Meine van Noordwijk. "Tree shape plasticity in relation to crown exposure." Trees 26, no. 4 (2012): 1275–85. http://dx.doi.org/10.1007/s00468-012-0703-x.
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Wang, Chao, Shu Ying Zhang, Wei Lin Meng, and Hui Si. "Recursion for Capturing Leaf Mass." Applied Mechanics and Materials 295-298 (February 2013): 2300–2307. http://dx.doi.org/10.4028/www.scientific.net/amm.295-298.2300.
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By using the recursive method, the total mass of the leaves for the whole tree is determined by the small parts of the trees. On the basis of summarizing the growth law of the tree, and assuming the shapes, branches and leaves of the tree follow its growth law, the mass measurement model is established, and the mass of the leaves in the highest-level branch is estimated by establishing the mass equations of the leaves. The variables in this model are the crown width, the crown height, the branch angle and the number of branches on each level per unit length. The parameters of this model are easy to obtain, and the extension of this model will push the establishment of database for various relative parameters. Moreover, it is found that there exists a certain relationship between tree shape index and leaf index, thus a new leaf classification method is proposed, and its description is carried out.
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Cameron, Ian R., Roberta Parish, James W. Goudie, and Catherine A. Bealle Statland. "Modelling the Crown Profile of Western Hemlock (Tsuga heterophylla) with a Combination of Component and Aggregate Measures of Crown Size." Forests 11, no. 3 (2020): 281. http://dx.doi.org/10.3390/f11030281.
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Research Highlights: We present statistical methods for using crown measurement data from multiple destructive sampling studies to model crown profiles in the Tree and Stand Simulator (TASS) and evaluate it using component (branch-level) and aggregate (tree-level) predictions. Combining data collected under different sampling protocols offered unique challenges. Background and Objectives: The approach to modelling crown profiles was based on Mitchell’s monograph on Douglas-fir growth and simulated dynamics. The functional form defines the potential crown size and shape and governs the rate of crown expansion. With the availability of additional data, we are able to update these functions as part of ongoing TASS development and demonstrate the formulation and fitting of new crown profile equations for stand-grown western hemlock (Tsuga heterophylla (Raf.) Sarg. Materials and Methods: Detailed measurements on 1616 branches from 153 trees were collected for TASS development over a 40-year period. Data were collected under two different sampling protocols and the methods were designed to allow the use of data from both protocols. Data collected on all branches were then introduced through the application of the ratio of length of each of the selected branches to the largest branch in the internode (RL). Results: A mixed-effects model with two random effects, which accounted for tree-level variation, provided the best fit. From that, a model that expressed one parameter as a function of another with one random effect was developed to complement the structure of the Tree and Stand Simulator (TASS). The models generally over-estimated crown size when compared to the projected crown area recorded from field measurements, and a scalar adjustment factor of 0.89 was applied that minimised mean-squared error of the differences. The new model is fit from direct measures of crown radius and predicts narrower crown shapes than previous functions used in TASS.