Reconstruction of Tree Crown Shape from Scanned Data

2008 ◽  
pp. 745-756 ◽  
Author(s):  
Chao Zhu ◽  
Xiaopeng Zhang ◽  
Baogang Hu ◽  
Marc Jaeger
Keyword(s):  
Tree Crown ◽  
Crown Shape

scholarly journals Comparative performances of new and existing indices of crown asymmetry: an evaluation using tall trees of Eucalyptus pilularis (Smith)

2020 ◽  
Vol 32 (1) ◽  
pp. 43-65
Author(s):  
Fanlin Kong ◽  
Huiquan Bi ◽  
Michael McLean ◽  
Fengri Li
Keyword(s):  
Rank Order ◽  
Bilateral Symmetry ◽  
Tree Crown ◽  
Remotely Sensed Data ◽  
Individual Tree ◽  
True Value ◽  
Crown Shape ◽  
Crown Morphology ◽  
Eucalyptus Pilularis ◽  
Relative Scale

AbstractOver the past 50 years, crown asymmetry of forest trees has been evaluated through several indices constructed from the perspective of projected crown shape or displacement but often on an ad hoc basis to address specific objectives related to tree growth and competition, stand dynamics, stem form, crown structure and treefall risks. Although sharing some similarities, these indices are largely incoherent and non-comparable as they differ not only in the scale but also in the direction of their values in indicating the degree of crown asymmetry. As the first attempt at devising normative measures of crown asymmetry, we adopted a relative scale between 0 for perfect symmetry and 1 for extreme asymmetry. Five existing crown asymmetry indices (CAIs) were brought onto this relative scale after necessary modifications. Eight new CAIs were adapted from measures of circularity for digital images in computer graphics, indices of income inequality in economics, and a bilateral symmetry indicator in plant leaf morphology. The performances of the 13 CAIs were compared over different numbers of measured crown radii for 30 projected crowns of mature Eucalyptus pilularis trees through benchmarking statistics and rank order correlation analysis. For each CAI, the index value based on the full measurement of 36 evenly spaced radii of a projected crown was taken as the true value in the benchmarking process. The index (CAI13) adapted from the simple bilateral symmetry measure proved to be the least biased and most precise. Its performance was closely followed by that of three other CAIs. The minimum number of crown radii that is needed to provide at least an indicative measure of crown asymmetry is four. For more accurate and consistent measures, at least 6 or 8 crown radii are needed. The range of variability in crown morphology of the trees under investigation also needs to be taken into consideration. Although the CAIs are from projected crown radii, they can be readily extended to individual tree crown metrics that are now commonly extracted from LiDAR and other remotely sensed data. Adding a normative measure of crown asymmetry to individual tree crown metrics will facilitate the process of big data analytics and artificial intelligence in forestry wherever crown morphology is among the factors to be considered for decision making in forest management.

scholarly journals The Influence of Ecosystem and Phylogeny on Tropical Tree Crown Size and Shape

2019 ◽  
Author(s):  
Alexander Shenkin ◽  
Lisa Patrick Bentley ◽  
Imma Oliveras ◽  
Norma Salinas ◽  
Stephen Adu-Bredu ◽  
...  
Keyword(s):  
Spatial Scales ◽  
Tree Size ◽  
Phylogenetic Distance ◽  
Tree Crown ◽  
Tree Crowns ◽  
Size And Shape ◽  
Biogeochemical Models ◽  
Crown Shape ◽  
Crown Dimensions ◽  
Crown Size

1ABSTRACTThe sizes and shapes of tree crowns are of fundamental importance in ecology, yet understanding the forces that determine them remains elusive. A cardinal question facing ecologists is the degree to which general and non-specific versus ecological and context-dependent processes are responsible for shaping tree crowns. Here, we test this question for the first time across diverse tropical ecosystems. Using trees from 20 plots varying in elevation, precipitation, and ecosystem type (savanna-forest transitions) across the paleo- and neo-tropics, we test the relationship between crown dimensions and tree size. By analyzing these scaling relationships across environmental gradients, biogeographic regions, and phylogenetic distance, we extend Metabolic Scaling Theory (MST) predictions to include how local selective pressures shape variation in crown dimensions. Across all sites, we find strong agreement between mean trends and MST predictions for the scaling of crown size and shape, but large variation around the mean. While MST explained approximately half of the observed variation in tree crown dimensions, we find that local, ecosystem, and phylogenetic predictors account for the half of the residual variation. Crown scaling does not change significantly across regions, but does change across ecosystem types, where savanna tree crowns grow more quickly with tree size than forest tree crowns. Crowns of legumes were wider and larger than those of other taxa. Thus, while MST can accurately describe the central tendency of tree crown size, local ecological conditions and evolutionary history appear to modify the scaling of crown shape. Importantly, our extension of MST incorporating these differences accounts for the mechanisms driving variation in the scaling of crown dimensions across the tropics. These results are critical when scaling the function of individual trees to larger spatial scales or incorporating the size and shape of tree crowns in global biogeochemical models.

scholarly journals Data on annotated approximate bilaterally symmetric leaf-off trees based on particle flow simulation and predefined tree crown shape

Data in Brief ◽  
2022 ◽  
pp. 107806
Author(s):  
Štefan Kohek ◽  
Niko Lukač ◽  
Damjan Strnad ◽  
Ivana Kolingerova ◽  
Borut Žalik
Keyword(s):  
Flow Simulation ◽  
Particle Flow ◽  
Tree Crown ◽  
Crown Shape ◽  
Particle Flow Simulation

A spatial statistical analysis of cork oak competition in two Portuguese silvopastoral systems

2002 ◽  
Vol 32 (11) ◽  
pp. 1893-1903 ◽  
Author(s):  
M J Paulo ◽  
A Stein ◽  
M Tomé
Keyword(s):  
Shape Parameter ◽  
Quercus Suber ◽  
Cork Oak ◽  
Point Pattern ◽  
Spatial Point Pattern ◽  
Tree Crown ◽  
Spatial Statistical Analysis ◽  
Crown Shape ◽  
Crown Characteristics ◽  
Pattern Functions

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.

scholarly journals FULLY AUTOMATED GIS-BASED INDIVIDUAL TREE CROWN DELINEATION BASED ON CURVATURE VALUES FROM A LIDAR DERIVED CANOPY HEIGHT MODEL IN A CONIFEROUS PLANTATION

2016 ◽  
Vol XLI-B8 ◽  
pp. 563-569
Author(s):  
R. J. L. Argamosa ◽  
E. C. Paringit ◽  
K. R. Quinton ◽  
F. A. M. Tandoc ◽  
R. A. G. Faelga ◽  
...  
Keyword(s):  
Canopy Height ◽  
Tree Crown ◽  
M Cell ◽  
Individual Tree ◽  
Automated Method ◽  
Coniferous Plantation ◽  
Crown Shape ◽  
Canopy Height Model ◽  
Crown Delineation ◽  
Height Model

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.

scholarly journals FULLY AUTOMATED GIS-BASED INDIVIDUAL TREE CROWN DELINEATION BASED ON CURVATURE VALUES FROM A LIDAR DERIVED CANOPY HEIGHT MODEL IN A CONIFEROUS PLANTATION

2016 ◽  
Vol XLI-B8 ◽  
pp. 563-569
Author(s):  
R. J. L. Argamosa ◽  
E. C. Paringit ◽  
K. R. Quinton ◽  
F. A. M. Tandoc ◽  
R. A. G. Faelga ◽  
...  
Keyword(s):  
Canopy Height ◽  
Tree Crown ◽  
M Cell ◽  
Individual Tree ◽  
Automated Method ◽  
Coniferous Plantation ◽  
Crown Shape ◽  
Canopy Height Model ◽  
Crown Delineation ◽  
Height Model

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.

scholarly journals Single tree crown shape and volume models for Pinus nigra planted forests in Italy to support forest management strategies in artificial stands

2020 ◽  
Author(s):  
Umberto Di Salvatore ◽  
Maurizio Marchi ◽  
Paolo Cantiani
Keyword(s):  
Forest Management ◽  
Field Data ◽  
Light Transmittance ◽  
Black Pine ◽  
Tree Crown ◽  
Area Index ◽  
Additional Tool ◽  
Single Tree ◽  
Crown Volume ◽  
Crown Shape

Abstract Background Tree crown can be considered the engine of trees whose size is a key variable to understand the most important ecological and physiological processes that occur in forest ecosystem. The shape and dimension of single-tree crown are affected by a combination of multiple factors such as lateral competition, fertility as well as forest management practices. Anyway, few models are provided in literature to derive their shape and volume from sampled data except the light transmittance or light measurements under canopy closure (Photosynthetic Active Radiation or Leaf Area Index). The main goal of the study is to present a simple and effective method to predict crown shape and crown volume in artificial black pine plantations in Italy from simple field data. Two key parameters involved in crown volume calculation in literature were here modelled. Such parameters were the distance from the top where the crown expresses its the maximum radius (L 0 ) and the radius at crown base height (r cb ). The analysis of crown profile and volume is based on available knowledge we found in literature (Pretzsch 2009) and where the considered species was not included. Results The nonlinear equation results the most adequate for the fitting and able to characterise the ecological processes more properly. Even if just slightly different, the mean absolute error was lower and statistically significant and around 84 cm for L 0 and 36 cm for r cb . Then the use of a modelling procedure also allowed the calculation of confidence intervals and was more powerful than a single multiplier, which is the most common method available in literature. Once compared with field data collected during thinning harvesting, the calculated volumes were correlated with thinning intensities and able to characterise the number of trees removed in each treatment and the increased amount of PAR on the ground. Conclusions The proposed model results useful to evaluate the spatial structure of forest stand without sophisticated and time-consuming surveys and could be an additional tool to support the practical management of artificial black pine stands.

Growth and Development of Feijoa with Different Plant Shape and in Greenhouses Environment

2014 ◽  
Vol 886 ◽  
pp. 294-298
Author(s):  
Jian Ke Li ◽  
Jing Hui Yang ◽  
Yan Jun Liu ◽  
Jun Xun Huang ◽  
Chun Xia Wu ◽  
...  
Keyword(s):  
Growth And Development ◽  
Fruit Set ◽  
Average Length ◽  
Flowering Plants ◽  
Tree Crown ◽  
Greenhouse Production ◽  
Crown Width ◽  
Crown Shape ◽  
Growth Development ◽  
One Year

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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