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Journal articles on the topic 'Crown Height Model'

Author: Grafiati

Published: 2 June 2025

Last updated: 31 July 2025

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1

Seymour, Robert S., and David M. Smith. "A New Stocking Guide Formulation Applied to Eastern White Pine." Forest Science 33, no. 2 (1987): 469–84. http://dx.doi.org/10.1093/forestscience/33.2.469.

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Abstract A procedure is described for incorporating stand age, or stage in development, into the widely used stocking guides based on the crown competition factor (CCF). A simple model that predicts dbh of individual trees from crown projection area and total height is derived from a three-dimensional relationship between cumulative foliage production (crown volume) and total volume of the main stem. Procedures employed by previous researchers to prepare CCF-based stocking guides are then used to convert this individual-tree model to stand basal areas and numbers of trees per unit area at succ

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2

Dyer, Michael E., and Harold E. Burkhart. "Compatible crown ratio and crown height models." Canadian Journal of Forest Research 17, no. 6 (1987): 572–74. http://dx.doi.org/10.1139/x87-096.

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Several published crown ratio and crown height models were fitted to plantation loblolly pine tree data, but none were considered entirely adequate. A nonlinear model form that yields logical estimates is presented. Required inputs are stand age, tree diameter, and tree height. Both ordinary least squares and seemingly unrelated regression (SUR) were used to estimate model parameters. Cross equation constraints with the SUR procedure result in compatible estimates of crown ratio and crown height for a tree of given height.

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3

Antos, Joseph A., Roberta Parish, and Gordon D. Nigh. "Effects of neighbours on crown length of Abies lasiocarpa and Picea engelmannii in two old-growth stands in British Columbia." Canadian Journal of Forest Research 40, no. 4 (2010): 638–47. http://dx.doi.org/10.1139/x10-011.

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Crown length is a key aspect of vertical structure in multi-aged, multistrata, mixed-species forests. Crown length, defined as the distance from the tree top to the lowest live branch whorl, was determined for 3169 mapped trees ≥4.0 cm in diameter, in four 0.25 ha plots in each of two old-growth Abies lasiocarpa (Hook.) Nutt. – Picea engelmannii Parry ex Engelm. stands. We randomly selected half the trees to build models and half for validation. Crown length was modelled as a function of tree height, incorporating modifiers to account for neighbouring trees. The inclusion radius and height thr

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4

Zhu, Wancai, Zhaogang Liu, Weiwei Jia, and Dandan Li. "Modelling the Tree Height, Crown Base Height, and Effective Crown Height of Pinus koraiensis Plantations Based on Knot Analysis." Forests 12, no. 12 (2021): 1778. http://dx.doi.org/10.3390/f12121778.

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Taking 1735 Pinus koraiensis knots in Mengjiagang Forest Farm plantations in Jiamusi City, Heilongjiang Province as the research object, a dynamic tree height, effective crown height, and crown base height growth model was developed using 349 screened knots. The Richards equation was selected as the basic model to develop a crown base height and effective crown height nonlinear mixed-effects model considering random tree-level effects. Model parameters were estimated with the non-liner mixed effect model (NLMIXED) Statistical Analysis System (SAS) module. The akaike information criterion (AIC)

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5

Nasiri, Vahid, Ali A. Darvishsefat, Hossein Arefi, Marc Pierrot-Deseilligny, Manochehr Namiranian, and Arnaud Le Bris. "Unmanned aerial vehicles (UAV)-based canopy height modeling under leaf-on and leaf-off conditions for determining tree height and crown diameter (case study: Hyrcanian mixed forest)." Canadian Journal of Forest Research 51, no. 7 (2021): 962–71. http://dx.doi.org/10.1139/cjfr-2020-0125.

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Tree height and crown diameter are two common individual tree attributes that can be estimated from unmanned aerial vehicle (UAV) images thanks to photogrammetry and structure from motion. This research investigates the potential of low-cost UAV aerial images to estimate tree height and crown diameter. Two successful flights were carried out in two different seasons corresponding to leaf-off and leaf-on conditions to generate a digital terrain model and a digital surface model, which were further employed in calculation of a canopy height model (CHM). The CHM was used to estimate tree height u

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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.

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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 hillslop

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7

Valentine, H. T., and T. G. Gregoire. "A switching model of bole taper." Canadian Journal of Forest Research 31, no. 8 (2001): 1400–1409. http://dx.doi.org/10.1139/x01-061.

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Numerical switches are employed to change the values of two exponents in a variable-form model of bole taper. The taper of a bole is modeled, with respect to height from the ground, by three connected geometric segments (i.e., a basal, middle, and top segment). The numerical switches provide for either graded or abrupt transition from the basal to the middle segment and from the middle to the top segment. The height of the base of the crown was assumed to be the point of transition between the middle and top segments. Crown height can be either measured or estimated with a simple submodel that

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8

Zheng, Yujie, Weiwei Jia, Qiang Wang, and Xu Huang. "Deriving Individual-Tree Biomass from Effective Crown Data Generated by Terrestrial Laser Scanning." Remote Sensing 11, no. 23 (2019): 2793. http://dx.doi.org/10.3390/rs11232793.

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Biomass reflects the state of forest management and is critical for assessing forest benefits and carbon storage. The effective crown is the region above the lower limit of the forest crown that includes the maximum vertical distribution density of branches and leaves; this component plays an important role in tree growth. Adding the effective crown to biomass equations can enhance the accuracy of the derived biomass. Six sample plots in a larch plantation (ranging in area from 0.06 ha to 0.12 ha and in number of trees from 63 to 96) at the Mengjiagang forest farm in Huanan County, Jiamusi Cit

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9

Short III, E. Austin, and Harold E. Burkhart. "Predicting Crown-Height Increment for Thinned and Unthinned Loblolly Pine Plantations." Forest Science 38, no. 3 (1992): 594–610. http://dx.doi.org/10.1093/forestscience/38.3.594.

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Abstract Several nonlinear, individual tree crown-height increment equations were tested for their ability to predict annual crown-height increment in thinned and unthinned loblolly pine plantations. The selected model contained tree height (HT), tree crown ratio (CR) raised to the one-half power, age (A), and a measure of competition. The distance-dependent and the distance-independent models were the same form; however, the competition index (CI) in the distance-dependent model was replaced by the ratio of quadratic mean diameter to tree dbh (DR) for the distance-independent model. The indiv

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10

Moraes, Sandra Lucia Dantas de, Fellippo Ramos Verri, Joel Ferreira Santiago Junior, Daniel Augusto de Faria Almeida, Caroline Cantieri de Mello, and Eduardo Piza Pellizzer. "A 3-D Finite Element Study of the Influence of Crown-Implant Ratio on Stress Distribution." Brazilian Dental Journal 24, no. 6 (2013): 635–41. http://dx.doi.org/10.1590/0103-6440201302287.

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The purpose of this study was to assess the influence of the crown height of external hexagon implants on the displacement and distribution of stress to the implant/bone system, using the three-dimensional finite element method. The InVesalius and Rhinoceros 4.0 softwares were used to generate the bone model by computed tomography. Each model was composed of a bone block with one implant (3.75x10.0 mm) with external hexagon connections and crowns with 10 mm, 12.5 mm and 15 mm in height. A 200 N axial and a 100 N oblique (45°) load were applied. The models were solved by the NeiNastran 9.0 and

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11

Maguire, Douglas A., and David W. Hann. "Constructing models for direct prediction of 5-year crown recession in southwestern Oregon Douglas-fir." Canadian Journal of Forest Research 20, no. 7 (1990): 1044–52. http://dx.doi.org/10.1139/x90-139.

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Crown recession rates were estimated by branch mortality dating on 357 sectioned Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) stems from temporary plots. Numerous nonlinear, logarithmic, and gamma-theory generalized linear models were developed for predicting 5-year crown recession across a range in tree, stand, and site conditions. Residual analyses and indices of fit demonstrated that a multiplicative model with lognormal errors was the most appropriate model form. The recommended logarithmic model predicts crown recession from current crown ratio, total height, breast height age, heigh

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Sporek, Monika, Kazimierz Sporek, and Martin Kučerka. "Verification of the Scots Pine (Pinus sylvestris L.) Crown Length Model." Applied Sciences 15, no. 6 (2025): 3124. https://doi.org/10.3390/app15063124.

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One of the key modeling procedures is model verification, which ensures its reliability and confidence. In many respects, the length of the crown is an interesting biophysical property. Precise determination of crown length can be one of the components used in estimating the mass of needles or leaf area index (LAI), and consequently the amount of transpiration or the amount of carbon dioxide bound, which is crucial in the context of climate change. The objective of this study was to calculate the length of the crown Pinus sylvestris using an allometric model and to compare these results with t

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Sharma, Ram, Zdeněk Vacek, and Stanislav Vacek. "Generalized Nonlinear Mixed-Effects Individual Tree Crown Ratio Models for Norway Spruce and European Beech." Forests 9, no. 9 (2018): 555. http://dx.doi.org/10.3390/f9090555.

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Tree crowns are commonly measured to understand tree growth and stand dynamics. Crown ratio (CR—crown depth-to-total height ratio) is significantly affected by a number of tree- and stand-level characteristics and other factors as well. Generalized mixed-effects CR models were developed using a large dataset (measurements from 14,669 trees of Norway spruce (Picea abies (L.) Karst.) and European beech (Fagus sylvatica (L.)) acquired from permanent research plots in various parts of the Czech Republic. Among several tree- and stand-level variables evaluated, diameter at breast height, height to

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14

Lintunen, Anna, Risto Sievänen, Pekka Kaitaniemi, and Jari Perttunen. "Models of 3D crown structure for Scots pine (Pinus sylvestris) and silver birch (Betula pendula) grown in mixed forest." Canadian Journal of Forest Research 41, no. 9 (2011): 1779–94. http://dx.doi.org/10.1139/x11-092.

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The interplay between plant structure and functioning determines vital plant characteristics, such as the efficiency of light capture by the foliage, and thus continuous efforts have attempted to include plant architecture in plant growth models. We constructed two crown structure models enabling the generation of 3D trees using simple tree measurements as input for Scots pine ( Pinus sylvestris L.) and silver birch ( Betula pendula Roth.), boreal species growing in mixed stands. The data for the models were obtained from sample-based digitizing of 3D crown architecture accompanied by characte

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15

Lee, Sunjoo, Choongshik Woo, Sungyong Kim, Youngjin Lee, Chungeun Kwon, and Kyungwon Seo. "Drone-Image-Based Method of Estimating Forest-Fire Fuel Loads." Journal of the Korean Society of Hazard Mitigation 21, no. 5 (2021): 123–30. http://dx.doi.org/10.9798/kosham.2021.21.5.123.

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A method of estimating forest-fire fuel loads was developed using drones to collect information about the height and diameter-at-breast-height (DBH) of individual trees. It was conducted for forest fire prevention monitoring (Control, 20% thinned, and 40% thinned area) located in Goseong-gun, Gangwon-do. Object-based images and 3D-model red/green/blue band characteristics were superimposed to select and extract individual trees. A digital crown height model was developed based on the difference between the heights of digital surface and terrain models. In addition, the DBH was estimated based

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16

Zhou, Kuibin, and Albert Simeoni. "An analytical model for predicting the flame length of fire lines and tree crown scorching." International Journal of Wildland Fire 31, no. 3 (2022): 240–54. http://dx.doi.org/10.1071/wf21087.

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In forest fires, the fire plume can heat tree crowns and cause the mortality of live vegetation, even though the surface fire spread is of low burning intensity. A lot of empirical or semi-empirical correlations have been built to link the fire intensity and flame height to the crown scorch height. These correlations lack the basic physical processes of heat transfer and thermal response of needles and leaves. Besides the flame height, the fire plume temperature and velocity are also of great importance to quantify the heat transfer to the tree crown. Accordingly, an analytical model, derived

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17

Kim, K. M. "ESTIMATION OF STAND HEIGHT AND FOREST VOLUME USING HIGH RESOLUTION STEREO PHOTOGRAPHY AND FOREST TYPE MAP." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLI-B8 (June 23, 2016): 695–98. http://dx.doi.org/10.5194/isprs-archives-xli-b8-695-2016.

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Traditional field methods for measuring tree heights are often too costly and time consuming. An alternative remote sensing approach is to measure tree heights from digital stereo photographs which is more practical for forest managers and less expensive than LiDAR or synthetic aperture radar. This work proposes an estimation of stand height and forest volume(m<sup>3</sup>/ha) using normalized digital surface model (nDSM) from high resolution stereo photography (25cm resolution) and forest type map. The study area was located in Mt. Maehwa model forest in Hong Chun-Gun, South Korea

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Kim, K. M. "ESTIMATION OF STAND HEIGHT AND FOREST VOLUME USING HIGH RESOLUTION STEREO PHOTOGRAPHY AND FOREST TYPE MAP." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLI-B8 (June 23, 2016): 695–98. http://dx.doi.org/10.5194/isprsarchives-xli-b8-695-2016.

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Traditional field methods for measuring tree heights are often too costly and time consuming. An alternative remote sensing approach is to measure tree heights from digital stereo photographs which is more practical for forest managers and less expensive than LiDAR or synthetic aperture radar. This work proposes an estimation of stand height and forest volume(m&lt;sup&gt;3&lt;/sup&gt;/ha) using normalized digital surface model (nDSM) from high resolution stereo photography (25cm resolution) and forest type map. The study area was located in Mt. Maehwa model forest in Hong Chun-

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19

Raharjo, Jany T., and Ronggo Sadono. "Model Tajuk Jati (Tectona Grandis L.f) dari Berbagai Famili pada Uji Keturunan Umur 9 Tahun." Jurnal Ilmu Kehutanan 2, no. 2 (2008): 89. http://dx.doi.org/10.22146/jik.834.

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Crown Model on Several Family of 9 years old of Teak (Tectona grandis L.f) Progeny TrialCrown plays an important role in regulating the rate of tree growth through the photosynthesis process. Furthermore it can be used to measure stand density and to determine the availability of growing space. Because of the difficulty and time consuming in direct crown measurement, the development of crown model is needed. The objectives of this study were to develop crown models of teak (Tectona grandis) of 9 years old from selected open pollinated families and to identifi) the variations of crown models am

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20

Batni, Sushmita, Vikram Shetty, Taher Manasawala, and Devashree Mujumdar. "Evaluation of torque expression with varied bracket positions and varying crown-root angles of maxillary central incisor – A 3 dimensional finite element study." IP Indian Journal of Orthodontics and Dentofacial Research 8, no. 4 (2022): 249–53. http://dx.doi.org/10.18231/j.ijodr.2022.043.

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To evaluate the torque expression of right permanent maxillary central incisor with varying bracket positions and to compare the torque expression of the same tooth with different crown-root angulations. Finite Element Models of Maxillary Central Incisor were used for simulation of torque expression with various crown-root angles. Three FEM models of a Maxillary Central Incisor with different crown-root angles (170˚,175˚,180˚, and 165°) were constructed with varying bracket heights and subjected to a 30° labial root torque and the resultant torque expressions were evaluated. The model with the

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de Assis Prado, Carlos Henrique Britto, and Dilma Maria de Brito Melo Trovão. "The woody crown network model incorporates maximum height." Ecological Modelling 481 (July 2023): 110345. http://dx.doi.org/10.1016/j.ecolmodel.2023.110345.

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22

Sporek, Monika, and Kazimierz Sporek. "Allometric Model of Crown Length for Pinus sylvestris L. Stands in South-Western Poland." Forests 14, no. 9 (2023): 1779. http://dx.doi.org/10.3390/f14091779.

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The growth of a tree depends on the size, shape, and functioning of the crown. The length of the crown is a somewhat subjective value because the base of the crown is often difficult to determine. The aim of this study was to develop an allometric model to calculate the crown length of Pinus sylvestris L., which might serve as an alternative to the current equations used especially for stands of variable density. The model used three predictive variables, i.e., diameter at breast height, tree height, and density. The developed crown length model showed high compatibility with empirical data wi

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Cohn, Gregory M., Russell A. Parsons, Emily K. Heyerdahl, Daniel G. Gavin, and Aquila Flower. "Simulated western spruce budworm defoliation reduces torching and crowning potential: a sensitivity analysis using a physics-based fire model." International Journal of Wildland Fire 23, no. 5 (2014): 709. http://dx.doi.org/10.1071/wf13074.

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The widespread, native defoliator western spruce budworm (Choristoneura occidentalis Freeman) reduces canopy fuels, which might affect the potential for surface fires to torch (ignite the crowns of individual trees) or crown (spread between tree crowns). However, the effects of defoliation on fire behaviour are poorly understood. We used a physics-based fire model to examine the effects of defoliation and three aspects of how the phenomenon is represented in the model (the spatial distribution of defoliation within tree crowns, potential branchwood drying and model resolution). Our simulations

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Stancioiu, Petru Tudor, and Kevin L. O'Hara. "Sapwood area leaf area relationships for coast redwood." Canadian Journal of Forest Research 35, no. 5 (2005): 1250–55. http://dx.doi.org/10.1139/x05-039.

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Coast redwood (Sequoia sempervirens (D. Don) Endl.) trees in different canopy strata and crown positions were sampled to develop relationships between sapwood cross-sectional area and projected leaf area. Sampling occurred during the summers of 2000 and 2001 and covered tree heights ranging from 7.7 to 45.2 m and diameters at breast height ranging from 9.4 to 92.7 cm. Foliage morphology varied greatly and was stratified into five types based on needle type (sun or shade) and twig color. A strong linear relationship existed between projected leaf area and sapwood area at breast height or sapwoo

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Nigh, Gordon D., and Bobby A. Love. "Predicting crown class in three western conifer species." Canadian Journal of Forest Research 34, no. 3 (2004): 592–99. http://dx.doi.org/10.1139/x03-220.

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Assessing the crown class (dominant, codominant, intermediate, suppressed) of a tree is a subjective procedure. Most definitions of crown class are based on the relative height of a tree and (or) the amount of light that is incident on the tree crown. With this research, we devised a classification scheme, based on easily measured tree variables, to assign a crown class to trees. Our data consisted of tree measurements, including crown class, from four stem-mapped 0.05-ha sample plots with buffers. The light model tRAYci was used to assess the light incident on each tree crown. These data gave

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26

Gillespie, Andrew R., and Harold W. Hocker Jr. "The influence of competition on individual white pine thinning response." Canadian Journal of Forest Research 16, no. 6 (1986): 1355–59. http://dx.doi.org/10.1139/x86-239.

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A model predicting white pine (Pinusstrobus L.) diameter growth after thinning included competition, initial diameter, and crown class as independent variables. Model coefficients indicated a decrease in percent 8-year diameter growth with increasing crown suppression, crown competition, or tree size class. Variables selected were superior to age, percent live crown, and prethinning growth. Equations predicting basal area and volume growth were similar in form to diameter growth. Height growth, however, was more closely correlated with crown characteristics and unaffected by competition. Annua

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Huang, Chenyu, Yuanyuan Zhang, Lu Chen, Liwen Zhuang, Yanliang Zhang, and Weiguo Sang. "Pipe Model Can Accurately Estimate Crown Biomass of Larch (Larix olgensis) Plantation Forest in Northeast China." Forests 14, no. 2 (2023): 400. http://dx.doi.org/10.3390/f14020400.

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The pipe model theory has been applied to estimate allometry of trees in many regions; however, its reliability and generality need more verification for estimating crown biomass in China. In the present study, the crown biomass of Larix olgensis plantations in four sites in northeast China was estimated using the pipe model, and the correlation efficiency index of larch crown biomass for pipe model estimation was 0.953. The crown biomass of larch plantations could be accurately estimated by the tree height, crown base height, and stem area at breast height. Meanwhile, the effects of site, sta

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So, Kangyu, Jenny Chau, Sean Rudd, et al. "Direct Estimation of Forest Aboveground Biomass from UAV LiDAR and RGB Observations in Forest Stands with Various Tree Densities." Remote Sensing 17, no. 12 (2025): 2091. https://doi.org/10.3390/rs17122091.

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Canada’s vast forests play a substantial role in the global carbon balance but require laborious and expensive forest inventory campaigns to monitor changes in aboveground biomass (AGB). Light detection and ranging (LiDAR) or reflectance observations onboard airborne or unoccupied aerial vehicles (UAVs) may address scalability limitations associated with traditional forest inventory but require simple forest structures or large sets of manually delineated crowns. Here, we introduce a deep learning approach for crown delineation and AGB estimation reproducible for complex forest structures with

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Bilgili, E., and IR Methven. "A Dynamic Fuel Model for Use in Managed Even-Aged Stands." International Journal of Wildland Fire 4, no. 3 (1994): 177. http://dx.doi.org/10.1071/wf9940177.

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A state-dependent dynamic crown fuel model is proposed. The model is a distance-dependent tree model. The model simulates crown characteristics such as foliage weight, crown base height, crown length and crown closure. The model is based on simplified dimensional growth relationships combined with photosynthesis and respiration. Preliminary tests of the model using coefficients derived from red pine, have shown that the model effectively simulates crown characteristics under a range of sites and silvicultural interventions.

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Xiong, Jingfeng, Hongda Zeng, Guo Cai, Yunfei Li, Jing M. Chen, and Guofang Miao. "Crown Information Extraction and Annual Growth Estimation of a Chinese Fir Plantation Based on Unmanned Aerial Vehicle–Light Detection and Ranging." Remote Sensing 15, no. 15 (2023): 3869. http://dx.doi.org/10.3390/rs15153869.

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Forest biomass dynamics are important indicators of forest productivity and carbon sinks, which are useful for evaluating forest ecological benefits and management options. Rapid and accurate methods for monitoring forest biomass would serve this purpose well. This study aimed at measuring aboveground biomass (AGB) and stand growth from tree crown parameters derived using unmanned aerial vehicle–light detection and ranging (UAV–LiDAR). We focused on 17-year-old Chinese fir plantations in a subtropical area in China and monitored them using UAV–LiDAR from February 2019 to February 2020. Two eff

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Andreu, Anne G., John I. Blake, and Stanley J. Zarnoch. "Estimating canopy fuel characteristics for predicting crown fire potential in common forest types of the Atlantic Coastal Plain, USA." International Journal of Wildland Fire 27, no. 11 (2018): 742. http://dx.doi.org/10.1071/wf18025.

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We computed four stand-level canopy stratum variables important for crown fire modelling – canopy cover, stand height, canopy base height and canopy bulk density – from forest inventory data. We modelled the relationship between the canopy variables and a set of common inventory parameters – site index, stem density, basal area, stand age or stand height – and number of prescribed burns. We used a logistic model to estimate canopy cover, a linear model to estimate the other canopy variables, and the information theoretic approach for model selection. Coefficients of determination across five f

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Zhou, Zeyu, Liyong Fu, Chaofan Zhou, Ram P. Sharma, and Huiru Zhang. "Simultaneous Compatible System of Models of Height, Crown Length, and Height to Crown Base for Natural Secondary Forests of Northeast China." Forests 13, no. 2 (2022): 148. http://dx.doi.org/10.3390/f13020148.

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Individual trees are characterized by various sizes and forms, such as diameter at breast height, total height (H), height to crown base (HCB), crown length (CL), crown width, and crown and stem forms. Tree characteristics are strongly related to each other, and studying their relationships is very important. The knowledge of the compatibility and additivity properties of the major tree characteristics, such as H, CL, and HCB, is essential for informed decision-making in forestry. H can be used to represent site quality and CL represents biomass and photosynthesis of crown, which is the perfor

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Ma, Tianyu, Yanchuang Cao, Jun Liu, et al. "A multi-feature predicting model of crown evolution involving material properties." AIP Advances 12, no. 5 (2022): 055104. http://dx.doi.org/10.1063/5.0086420.

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We propose a new model for the crown evolution after a single drop impacts on a thin film. In contrast with the existing models that mainly focus on the status of well-developed crown or the bottom radius evolution, multiple features are provided in our model, including the temporal evolution of the crown radius, height, velocity, and the characteristic time when the crown reaches its maximum height. Both the fluid viscosity and surface tension are considered in this work rather than ignoring one or both of them as in previous studies, resulting in improved accuracy for crown development predi

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Ahmed, Naseer, Mohamad Syahrizal Halim, Ayesha Aslam, Zuryati Ab Ghani, Jawad Safdar, and Mohammad Khursheed Alam. "An Analysis of Maxillary Anterior Teeth Crown Width-Height Ratios: A Photographic, Three-Dimensional, and Standardized Plaster Model’s Study." BioMed Research International 2022 (February 7, 2022): 1–10. http://dx.doi.org/10.1155/2022/4695193.

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Objective. To analyze the width and height ratios of maxillary anterior teeth at different crown levels through photographs, 3D, and plaster dental model techniques in a subset of the Pakistani population. Material and Methods. This clinical study consisted of 230 participants. The maxillary impression, standardized photographs, and models were constructed for crown width and height analysis. The SPSS version 25 was used for statistical analysis. Descriptive statistics were carried out for mean, standard deviation, and percentage calculation of teeth width and height, gender, and age of partic

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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 f

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Štofko, Peter. "Aboveground parameters of spruce (Picea abies (L.) Karst.) stability in the light of discriminant analysis." Folia Forestalia Polonica, Series A - Forestry 54(3) (March 1, 2012): 153–58. https://doi.org/10.5281/zenodo.30868.

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In the locality Zemská (the Low Tatras Mts.) the following aboveground parameters were measured in windthrown and undamaged Norway spruce Picea abies (L.) Karst. trees: stem diameter at breast height, stem diameter measured 20cm from ground level, tree height, crown length, and crown width. The stem quotients, crown proportion index, height position of the green crown, and the height of the tree centre of gravity were calculated from these data. Our results agreed with the present understanding that a wide tree crown has a negative effect on spruce stability. Paradoxically, from the vie

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Hall, R. J., R. T. Morton, and R. N. Nesby. "A Comparison of Existing Models for DBH Estimation from Large-scale Photos." Forestry Chronicle 65, no. 2 (1989): 114–20. http://dx.doi.org/10.5558/tfc65114-2.

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The performance of 12 diameter prediction models suggested in the literature was studied in a controlled operational test. These models were linear and logarithmic transformations of tree height and/or crown area and were analyzed for white spruce, lodgepole pine, and trembling aspen and balsam poplar combined. Overall, all models were statistically significant, with differences due to variations in species and model form. Although simpler models may be adequate depending on operational objectives, two models emerged as deserving further investigation. It was unclear whether both tree height a

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Abdullah, Suzanah, Khairul Nizam Tahar, Mohd Fadzil Abdul Rashid, and Muhammad Ariffin Osoman. "ESTIMATING TREE HEIGHT BASED ON TREE CROWN FROM UAV IMAGERY." Malaysian Journal of Sustainable Environment 9, no. 1 (2022): 99. http://dx.doi.org/10.24191/myse.v9i1.17294.

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Tree crown delineation is a significant measurement for forest inventory and management purposes. The increasing availability of high-resolution Unmanned Aerial Vehicle (UAV) data makes it possible to delineate the tree crown of a single tree. Currently, with the advancement in technology UAV has become one of the emerging technologies that offers an affordable, cheaper, and faster technology in acquiring data for numerous applications. More importantly, this technology is embedded with efficient approaches for real-time acquisition of high resolution to produce three-dimensional (3D) informat

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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

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Ao, Mingrui, Miaocao Wang, and Fulong Zhu. "Investigation of the Turbulent Drag Reduction Mechanism of a Kind of Microstructure on Riblet Surface." Micromachines 12, no. 1 (2021): 59. http://dx.doi.org/10.3390/mi12010059.

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With the k-ε renormalization group turbulence model, the drag reduction mechanism of three- dimensional spherical crown microstructure of different protruding heights distributing on the groove surface was studied in this paper. These spherical crown microstructures were divided into two categories according to the positive and negative of protruding height. The positive spherical crown micro-structures can destroy a large number of vortexes on the groove surface, which increases relative friction between water flow and the groove surface. With decreasing the vertical height of the spherical c

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Hasenauer, Hubert, Robert A. Monserud, and Timothy G. Gregoire. "Using Simultaneous Regression Techniques with Individual-Tree Growth Models." Forest Science 44, no. 1 (1998): 87–95. http://dx.doi.org/10.1093/forestscience/44.1.87.

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Abstract Individual-tree growth models basically consist of a number of equations (e.g., diameter or basal area increment model, height increment model, crown ratio model) to update tree parameters over time. These equations commonly are assumed to be independent, with parameters of each equation estimated separately rather than simultaneously with linear or nonlinear regression. However, the opposite assumption of interdependence seems more reasonable. A tree is a highly organized system, and assimilation of tissues in the form of diameter increment, height increment, and crown size does not

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Loghin, Ana-Maria, Johannes Otepka-Schremmer, and Norbert Pfeifer. "Potential of Pléiades and WorldView-3 Tri-Stereo DSMs to Represent Heights of Small Isolated Objects." Sensors 20, no. 9 (2020): 2695. http://dx.doi.org/10.3390/s20092695.

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High-resolution stereo and multi-view imagery are used for digital surface model (DSM) derivation over large areas for numerous applications in topography, cartography, geomorphology, and 3D surface modelling. Dense image matching is a key component in 3D reconstruction and mapping, although the 3D reconstruction process encounters difficulties for water surfaces, areas with no texture or with a repetitive pattern appearance in the images, and for very small objects. This study investigates the capabilities and limitations of space-borne very high resolution imagery, specifically Pléiades (0.7

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Maguire, Douglas A., and David W. Hann. "Equations for predicting sapwood area at crown base in southwestern Oregon Douglas-fir." Canadian Journal of Forest Research 17, no. 3 (1987): 236–41. http://dx.doi.org/10.1139/x87-040.

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Two basic taper models were analyzed for their ability to predict sapwood area at crown base. Sapwood areas were estimated on stem cross sections by measuring sapwood radii on the longest and perpendicular to longest axes and by assuming conformity to an ellipse. These data were collected on 2 to 14 points along the stems of 72 Douglas-fir trees in southwestern Oregon. Across the range in diameter at breast height, total height, and height to crown base, quadratic–quadratic segmented polynomials (T. A. Max and H. E. Burkhart. 1976. For. Sci. 25: 283–289) provided more consistent monotonie tape

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Kozniewski, Marcin, Łukasz Kolendo, Szymon Chmur, and Marek Ksepko. "Impact of Parameters and Tree Stand Features on Accuracy of Watershed-Based Individual Tree Crown Detection Method Using ALS Data in Coniferous Forests from North-Eastern Poland." Remote Sensing 17, no. 4 (2025): 575. https://doi.org/10.3390/rs17040575.

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The accurate detection of individual tree crowns and estimation of tree density is essential for effective forest management, biodiversity assessment, and ecological monitoring. The precision of tree crown detection algorithms plays a critical role in providing reliable data for these applications, where even slight inaccuracies can lead to significant deviations in tree population estimates and ecological indicators. Various algorithmic parameters, such as pixel size and crown segmentation thresholds, can substantially impact tree crown detection accuracy. This study aims to explore the influ

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Parish, Roberta, Gordon D. Nigh, and Joseph A. Antos. "Allometry and size structure of trees in two ancient snow forests in coastal British Columbia." Canadian Journal of Forest Research 38, no. 2 (2008): 278–88. http://dx.doi.org/10.1139/x07-172.

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Shade-tolerant trees that start in the understory but ultimately reach the canopy persist through different microhabitat conditions during their ontogeny. We evaluate how the height to diameter ratio and the crown ratio (crown length/tree height) change during development and differ among four coniferous species ( Abies amabilis (Dougl. ex Loud.) Dougl. ex J. Forbes, Chamaecyparis nootkatensis (D. Don) Spach, Tsuga mertensiana (Bong.) Carrière, and Tsuga heterophylla (Ref.) Sarg.) in ancient forests. At two sites, we measured diameter, height, and height to the base of live crown for trees ≥4.

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Liu, Yongchao, and Baoguo Ma. "The mathematical model of crown height in hedgerow orchard on southern hill slope." World Journal of Engineering 11, no. 1 (2014): 71–76. http://dx.doi.org/10.1260/1708-5284.11.1.71.

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In the hedgerow orchard of hilly land, the crown height changes with ground slope so as to meet the condition of the sun light. Using astronomical trigonometric formulas, this paper calculates solar position of the 40° north latitude in vernal equinox and autumnal equinox. At the same time, it calculates the shadow length of tree body, determines the shadow length coefficient y and drafts the chart of shadow top contour based on the solar azimuth angle A and the coefficient of shadow length γ. According to the design of the north-south direction, we take two lines of the hedge with the changin

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Li, Yao, Wei Wang, Weisheng Zeng, Jianjun Wang, and Jinghui Meng. "Development of Crown Ratio and Height to Crown Base Models for Masson Pine in Southern China." Forests 11, no. 11 (2020): 1216. http://dx.doi.org/10.3390/f11111216.

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Crown ratio (CR) and height to crown base (HCB) are important crown characteristics influencing the behavior of forest canopy fires. However, the labor-intensive and costly measurement of CR and HCB have hindered their wide application to forest fire management. Here, we use 301 sample trees collected in 11 provinces in China to produce predictive models of CR and HCB for Masson pine forests (Pinus massoniana Lamb.), which are vulnerable to forest canopy fires. We first identified the best basic model that used only diameter at breast height (DBH) and height (H) as independent variables to pre

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Xu, Jie, Minbin Su, Yuxuan Sun, et al. "Tree Crown Segmentation and Diameter at Breast Height Prediction Based on BlendMask in Unmanned Aerial Vehicle Imagery." Remote Sensing 16, no. 2 (2024): 368. http://dx.doi.org/10.3390/rs16020368.

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The surveying of forestry resources has recently shifted toward precision and real-time monitoring. This study utilized the BlendMask algorithm for accurately outlining tree crowns and introduced a Bayesian neural network to create a model linking individual tree crown size with diameter at breast height (DBH). BlendMask accurately outlines tree crown shapes and contours, outperforming traditional watershed algorithms in segmentation accuracy while preserving edge details across different scales. Subsequently, the Bayesian neural network constructs a model predicting DBH from the measured crow

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Raptis, Dimitrios, Vassiliki Kazana, Angelos Kazaklis, and Christos Stamatiou. "A Crown Width-Diameter Model for Natural Even-Aged Black Pine Forest Management." Forests 9, no. 10 (2018): 610. http://dx.doi.org/10.3390/f9100610.

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Crown size estimations are of vital importance in forest management practice. This paper presents nonlinear models that were developed for crown width prediction of Black pine (Pinus nigra Arn.) natural, pure, even-aged stands in Olympus Mountain, central Greece. Using a number of measured characteristics at tree and plot level from 66 sample plots as independent variables, an attempt was made to predict crown width accurately, initially based on Least Square Analysis. At the second stage, nonlinear mixed effect modeling was performed in order to increase the fitting ability of the proposed mo

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Hynynen, Jari. "Predicting tree crown ratio for unthinned and thinned Scots pine stands." Canadian Journal of Forest Research 25, no. 1 (1995): 57–62. http://dx.doi.org/10.1139/x95-007.

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A nonlinear model that yields logical predictions for tree crown ratio is presented. The model is based on data from permanent experimental plots located in even-aged Scots pine (Pinussylvestris L.) stands in southern and central Finland. Regressor variables in the model are stand dominant height, stand basal area, tree diameter, and tree height. The effect of thinning on tree crown ratio is modelled by incorporating a thinning response variable into the model. Thinning effect is dependent on thinning intensity and time elapsed from thinning, the latter of which is represented by the differenc

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