Journal articles: 'Segment trees'

1

Blankenagel, G., and R. H. G�ting. "External segment trees." Algorithmica 12, no. 6 (December 1994): 498–532. http://dx.doi.org/10.1007/bf01188717.

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Easwarakumar, K. S., and T. Hema. "BITS-Tree -- An Efficient Data Structure for Segment Storage and Query Processing." INTERNATIONAL JOURNAL OF COMPUTERS & TECHNOLOGY 11, no. 10 (December 5, 2013): 3108–16. http://dx.doi.org/10.24297/ijct.v11i10.2980.

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In this paper, a new and novel data structure is proposed to dynamically insert and delete segments. Unlike the standard segment trees, the proposed data structure permits insertion of a segment with interval range beyond the interval range of the existing tree, which is the interval between minimum and maximum values of the end points of all the segments. Moreover, the number of nodes in the proposed tree is lesser as compared to the dynamic version of the standard segment trees, and is able to answer both stabbing and range queries practically much faster compared to the standard segment trees.

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Butterfield, R. P., R. P. Crook, R. Adams, and R. Morris. "Radial Variation in Wood Specific Gravity, Fibre Length and Vessel Area for Two Central American Hardwoods: Hyeronima Alchorneoides and Vochysia Guatemalensis: Natural and Plantation-Grown Trees." IAWA Journal 14, no. 2 (1993): 153–61. http://dx.doi.org/10.1163/22941932-90001310.

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Natural-grown and young (5.5 year old) plantation-grown trees were sampled for two Central American hardwood species: Hyeronima alchorneoides and Vochysia guatemalensis in the Atlantic lowlands of Costa Rica. Increment cores extracted at a height of 1.3 m from trees were divided into 1cm segments from pith to bark. Basic specific gravity was calculated for each segment. Using the same cores, fibre length was measured from macerations for five natural and plantation-grown trees of each species. Number of vessels/mm2 and vessel tangential diameter were measured from segment cross sections for five natural-grown trees of each species.

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4

Chang, Yeim-Kuan, and Yung-Chieh Lin. "Dynamic Segment Trees for Ranges and Prefixes." IEEE Transactions on Computers 56, no. 6 (June 2007): 769–84. http://dx.doi.org/10.1109/tc.2007.1037.

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5

van Kreveld, Marc J., and Mark H. Overmars. "Union-copy structures and dynamic segment trees." Journal of the ACM 40, no. 3 (July 1993): 635–52. http://dx.doi.org/10.1145/174130.174140.

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6

Noest, A. J. "Conservative trees have universal segment measure distributions." Mathematical Biosciences 80, no. 2 (August 1986): 173–86. http://dx.doi.org/10.1016/0025-5564(86)90043-x.

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7

Andriantiana, Eric Ould Dadah, Stephan Wagner, and Hua Wang. "Extremal problems for trees with given segment sequence." Discrete Applied Mathematics 220 (March 2017): 20–34. http://dx.doi.org/10.1016/j.dam.2016.12.009.

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8

Gerbessiotis, Alexandros V. "An architecture independent study of parallel segment trees." Journal of Discrete Algorithms 4, no. 1 (March 2006): 1–24. http://dx.doi.org/10.1016/j.jda.2005.01.001.

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Jiao, Jichao, and Zhongliang Deng. "Individual Building Rooftop and Tree Crown Segmentation from High-Resolution Urban Aerial Optical Images." Journal of Sensors 2016 (2016): 1–13. http://dx.doi.org/10.1155/2016/1795205.

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We segment buildings and trees from aerial photographs by using superpixels, and we estimate the tree’s parameters by using a cost function proposed in this paper. A method based on image complexity is proposed to refine superpixels boundaries. In order to classify buildings from ground and classify trees from grass, the salient feature vectors that include colors, Features from Accelerated Segment Test (FAST) corners, and Gabor edges are extracted from refined superpixels. The vectors are used to train the classifier based on Naive Bayes classifier. The trained classifier is used to classify refined superpixels as object or nonobject. The properties of a tree, including its locations and radius, are estimated by minimizing the cost function. The shadow is used to calculate the tree height using sun angle and the time when the image was taken. Our segmentation algorithm is compared with other two state-of-the-art segmentation algorithms, and the tree parameters obtained in this paper are compared to the ground truth data. Experiments show that the proposed method can segment trees and buildings appropriately, yielding higher precision and better recall rates, and the tree parameters are in good agreement with the ground truth data.

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Bloom, J. Z. "The use of neural networks and rule induction for customer segmentation and target market profiling." South African Journal of Economic and Management Sciences 5, no. 1 (March 31, 2002): 233–57. http://dx.doi.org/10.4102/sajems.v5i1.2673.

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Inadequate market segmentation and clustering problems could cause an enterprise to either miss a strategic marketing opportunity or not cash in on a tactical campaign. The need for in-depth knowledge of customer segments and to overcome the limitations of non-linear problems require a different approach. The objectives of the research are (1) to consider the use of self-organising feature (SOM) neural networks for segmenting tourist markets and (2) to assess the use of inducing decision trees to obtain rules for profiling existing and classifying new respondents. The findings of the SOM neural network modelling indicate three definitive natural clusters. The induction of rules from decision trees were used to obtain a broad indication of a segment profile on the basis of a rule set and also enables the segment classification of customers from follow-up surveys.

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Hoxie, Irene, and John J. Dennehy. "Rotavirus A Genome Segments Show Distinct Segregation and Codon Usage Patterns." Viruses 13, no. 8 (July 27, 2021): 1460. http://dx.doi.org/10.3390/v13081460.

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Reassortment of the Rotavirus A (RVA) 11-segment dsRNA genome may generate new genome constellations that allow RVA to expand its host range or evade immune responses. Reassortment may also produce phylogenetic incongruities and weakly linked evolutionary histories across the 11 segments, obscuring reassortment-specific epistasis and changes in substitution rates. To determine the co-segregation patterns of RVA segments, we generated time-scaled phylogenetic trees for each of the 11 segments of 789 complete RVA genomes isolated from mammalian hosts and compared the segments’ geodesic distances. We found that segments 4 (VP4) and 9 (VP7) occupied significantly different tree spaces from each other and from the rest of the genome. By contrast, segments 10 and 11 (NSP4 and NSP5/6) occupied nearly indistinguishable tree spaces, suggesting strong co-segregation. Host-species barriers appeared to vary by segment, with segment 9 (VP7) presenting the weakest association with host species. Bayesian Skyride plots were generated for each segment to compare relative genetic diversity among segments over time. All segments showed a dramatic decrease in diversity around 2007 coinciding with the introduction of RVA vaccines. To assess selection pressures, codon adaptation indices and relative codon deoptimization indices were calculated with respect to different host genomes. Codon usage varied by segment with segment 11 (NSP5) exhibiting significantly higher adaptation to host genomes. Furthermore, RVA codon usage patterns appeared optimized for expression in humans and birds relative to the other hosts examined, suggesting that translational efficiency is not a barrier in RVA zoonosis.

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Valenti, Michael A., and Quang V. Cao. "Use of crown ratio to improve loblolly pine taper equations." Canadian Journal of Forest Research 16, no. 5 (October 1, 1986): 1141–45. http://dx.doi.org/10.1139/x86-201.

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Data from 278 trees felled in a loblolly pine (Pinustaeda L.) plantation were used to include crown ratio as a measure of tree form in a taper equation. The data were divided into 10 crown ratio classes. A segmented taper equation was fitted to each of the 10 classes to detect trends in the coefficients. Coefficients were then expressed as functions of crown ratio. The resulting three-segment taper equation with crown ratio as an additional independent variable was more flexible and provided more accurate predictions of upper stem diameters. Similar techniques were used to include crown ratio in a two-segment taper equation. The three-segment equation fitted the data better than the two-segment equation and provided superior taper predictions for the test data set.

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Nouën, Cyril Le, Gaëlle Rivallan, Didier Toquin, Pierre Darlu, Yannick Morin, Véronique Beven, Claire de Boisseson, et al. "Very virulent infectious bursal disease virus: reduced pathogenicity in a rare natural segment-B-reassorted isolate." Journal of General Virology 87, no. 1 (January 1, 2006): 209–16. http://dx.doi.org/10.1099/vir.0.81184-0.

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The purpose of this study was to compare the molecular epidemiology of infectious bursal disease virus (IBDV) segments A and B of 50 natural or vaccine IBDV strains that were isolated or produced between 1972 and 2002 in 17 countries from four continents, with phenotypes ranging from attenuated to very virulent (vv). These strains were subjected to sequence and phylogenetic analysis based on partial sequences of genome segments A and B. Although there is co-evolution of the two genome segments (70 % of strains kept the same genetic relatives in the segment A- and B-defined consensus trees), several strains (26 %) were identified with the incongruence length difference test as exhibiting a significantly different phylogenetic relationship depending on which segment was analysed. This suggested that natural reassortment could have occurred. One of the possible naturally occurring reassortant strains, which exhibited a segment A related to the vvIBDV cluster whereas its segment B was not, was thoroughly sequenced (coding sequence of both segments) and submitted to a standardized experimental characterization of its acute pathogenicity. This strain induced significantly less mortality than typical vvIBDVs; however, the mechanisms for this reduced pathogenicity remain unknown, as no significant difference in the bursal lesions, post-infectious antibody response or virus production in the bursa was observed in challenged chickens.

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14

Hema, T., and K. S. Easwarakumar. "An Efficient Kinetic Range Query for One Dimensional Axis Parallel Segments." International Journal of Intelligent Information Technologies 14, no. 1 (January 2018): 48–62. http://dx.doi.org/10.4018/ijiit.2018010104.

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We present a kinetic data structure named Kinetic Interval Graph (KI-Graph) for performing efficient range search on moving one dimensional axis-parallel segments. This finds applications in Artificial Intelligence such as robotic motion. The structure requires O(n) storage. The time taken per update when a critical event occurs is O (1) thereby improving responsiveness when compared to the kinetic segment trees, while the overall updates across all segments at a time instance is at most n/2. Also, range query is performed efficiently in θ (k) time, where k segments are reported.

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Lukashev, Alexander N. "Evidence for recombination in Crimean-Congo hemorrhagic fever virus." Journal of General Virology 86, no. 8 (August 1, 2005): 2333–38. http://dx.doi.org/10.1099/vir.0.80974-0.

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Crimean-Congo hemorrhagic fever (CCHF) virus has attracted considerable attention recently and a number of phylogenetic studies have been published, based mostly on partial sequences of S and M RNA segments. In this study, available full-length S, M and L segment sequences of CCHF virus were checked for recombination. Similarity plots and bootscan analysis of the S segment suggested multiple recombination events between southern European, Asian and African CCHF virus strains, with additional evidence provided by phylogenetic trees, the hidden Markov model and probabilistic divergence measures methods. No unambiguous signs of recombination were observed for M and L segments; however, the results did not exclude the possibility of this. These findings, coupled with a recent report on reassortment in CCHF virus, suggest caution when assessing CCHF virus phylogeny based on short sequence fragments.

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Godoy, Marcos, Daniel A. Medina, Rudy Suarez, Sandro Valenzuela, Jaime Romero, Molly Kibenge, Yingwei Wang, and Frederick Kibenge. "Extensive Phylogenetic Analysis of Piscine Orthoreovirus Genomic Sequences Shows the Robustness of Subgenotype Classification." Pathogens 10, no. 1 (January 7, 2021): 41. http://dx.doi.org/10.3390/pathogens10010041.

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Piscine orthoreovirus (PRV) belongs to the family Reoviridae and has been described mainly in association with salmonid infections. The genome of PRV consists of about 23,600 bp, with 10 segments of double-stranded RNA, classified as small (S1 to S4), medium (M1, M2 and M3) and large (L1, L2 and L3); these range approximately from 1000 bp (segment S4) to 4000 bp (segment L1). How the genetic variation among PRV strains affects the virulence for salmonids is still poorly understood. The aim of this study was to describe the molecular phylogeny of PRV based on an extensive sequence analysis of the S1 and M2 segments of PRV available in the GenBank database to date (May 2020). The analysis was extended to include new PRV sequences for S1 and M2 segments. In addition, subgenotype classifications were assigned to previously published unclassified sequences. It was concluded that the phylogenetic trees are consistent with the original classification using the PRV genomic segment S1, which differentiates PRV into two major genotypes, I and II, and each of these into two subgenotypes, designated as Ia and Ib, and IIa and IIb, respectively. Moreover, some clusters of country- and host-specific PRV subgenotypes were observed in the subset of sequences used. This work strengthens the subgenotype classification of PRV based on the S1 segment and can be used to enhance research on the virulence of PRV.

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17

Mound, Laurence A., and Gerald Moritz. "Corroboreethrips, a new genus of minute apterous thrips (Insecta : Thysanoptera : Phlaeothripinae) from the bark of Australian Acacia trees." Invertebrate Systematics 14, no. 5 (2000): 709. http://dx.doi.org/10.1071/it00002.

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Six new species are described in the new genus Corroboreethrips: C. kallus, sp. nov., C. siagonus, sp. nov., C. stomius, sp. nov., C. subsolanus, sp. nov., C. suspectus, sp. nov. and C. zophus, sp. nov. They all live in cavities beneath thin, split bark of slender branches on particular Acacia tree species in arid parts of Australia, and two species-pairs show a vicariant distribution between Queensland and Western Australia. In life, adults of these minute black, wingless thrips are remarkable in appearance, decorated with irregular rows of tiny white dots, the product of numerous short, stout dorsal setae coated with a white waxy substance. The structure of the antennae of these species is unique within the Phlaeothripidae, with segments VII and VIII short and forming a small style that is closely joined to segment VI, segment III produced basally into a sleeve around the pedicel, and segment II strongly asymmetric. The mouth cone varies in length among the six species more than in any other known thrips genus. In two species it is relatively short, extending to the fore coxae, but in two others it extends as far as the hind coxae and is thus relatively longer than in any other phlaeothripid.

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18

VANVEEN, M., and J. VANPELT. "Terminal and intermediate segment lengths in neuronal trees with finite length." Bulletin of Mathematical Biology 55, no. 2 (March 1993): 277–94. http://dx.doi.org/10.1016/s0092-8240(05)80266-6.

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19

Zhang, Jie, Hua Wang, and Xiao-Dong Zhang. "The Steiner Wiener index of trees with a given segment sequence." Applied Mathematics and Computation 344-345 (March 2019): 20–29. http://dx.doi.org/10.1016/j.amc.2018.10.007.

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van Veen, Mark P., and Jaap van Pelt. "Terminal and intermediate segment lenghts in neuronal trees with finite length." Bulletin of Mathematical Biology 55, no. 2 (March 1993): 277–94. http://dx.doi.org/10.1007/bf02460884.

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21

Noureen, Sadia, Akhlaq Ahmad Bhatti, and Akbar Ali. "A Note on the Minimum Wiener Polarity Index of Trees with a Given Number of Vertices and Segments or Branching Vertices." Discrete Dynamics in Nature and Society 2021 (January 22, 2021): 1–5. http://dx.doi.org/10.1155/2021/1052927.

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The Wiener polarity index of a graph G , usually denoted by W p G , is defined as the number of unordered pairs of those vertices of G that are at distance 3. A vertex of a tree with degree at least 3 is called a branching vertex. A segment of a tree T is a nontrivial path S whose end-vertices have degrees different from 2 in T and every other vertex (if exists) of S has degree 2 in T . In this note, the best possible sharp lower bounds on the Wiener polarity index W p are derived for the trees of fixed order and with a given number of branching vertices or segments, and all the trees attaining this lower bound are characterized.

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KIM, DAE-NYEON, HOANG-HON TRINH, and KANG-HYUN JO. "OBJECTS SEGMENTATION USING MULTIPLE FEATURES FOR ROBOT NAVIGATION ON OUTDOOR ENVIRONMENT." International Journal of Information Acquisition 06, no. 02 (June 2009): 99–108. http://dx.doi.org/10.1142/s0219878909001862.

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This paper presents the method to recognize objects for autonomous robot navigation in outdoor environment. The proposition of the method segments from an image taken by a moving robot in an outdoor environment. The method begins with object segmentation, which uses multiple features to obtain the object of segmented region. Multiple features are color, context information, line segments, edge, Hue Co-occurrence Matrix (HCM), Principal Components (PCs) and Vanishing Points (VPs). We model the objects of outdoor environment that define their characteristics individually. We segment the region as a mixture using the proposed features and methods. Objects can be detected when we combine predefined multiple features. Next, the stage classifies the object into natural and artificial ones. We detect sky and trees of natural objects. And we detect building of artificial objects. The last stage shows the combination of appearance and context information. We implement the result of object segmentation using multiple features through experiments.

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Khalid, Sohaib, and Akbar Ali. "On the zeroth-order general Randić index, variable sum exdeg index and trees having vertices with prescribed degree." Discrete Mathematics, Algorithms and Applications 10, no. 02 (April 2018): 1850015. http://dx.doi.org/10.1142/s1793830918500155.

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The zeroth-order general Randić index (usually denoted by [Formula: see text]) and variable sum exdeg index (denoted by [Formula: see text]) of a graph [Formula: see text] are defined as [Formula: see text] and [Formula: see text], respectively, where [Formula: see text] is degree of the vertex [Formula: see text], [Formula: see text] is a positive real number different from 1 and [Formula: see text] is a real number other than [Formula: see text] and [Formula: see text]. A segment of a tree is a path [Formula: see text], whose terminal vertices are branching or/and pendent, and all non-terminal vertices (if exist) of [Formula: see text] have degree 2. For [Formula: see text], let [Formula: see text], [Formula: see text], [Formula: see text] be the collections of all [Formula: see text]-vertex trees having [Formula: see text] pendent vertices, [Formula: see text] segments, [Formula: see text] branching vertices, respectively. In this paper, all the trees with extremum (maximum and minimum) zeroth-order general Randić index and variable sum exdeg index are determined from the collections [Formula: see text], [Formula: see text], [Formula: see text]. The obtained extremal trees for the collection [Formula: see text] are also extremal trees for the collection of all [Formula: see text]-vertex trees having fixed number of vertices with degree 2 (because the number of segments of a tree [Formula: see text] can be determined from the number of vertices of [Formula: see text] having degree 2 and vice versa).

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Marques, Taísa Mendes, and Walter A. Boeger. "Proposal of Tiddergasilus gen. nov. (Ergasilidae: Cyclopoida) for T. iheringi comb. nov. from the gills of Hoplias malabaricus (Erythrinidae: Characiformes) from Brazil." Zoologia 35 (March 14, 2018): 1–6. http://dx.doi.org/10.3897/zoologia.35.e21577.

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Ergasilus von Nordmann, 1832 is the type and the most speciose genus of Ergasilidae, with more than 150 valid species. The first species of this genus, Ergasilusiheringi Tidd, 1942, was described from the Neotropical Region, from the gills of Hopliasmalabaricus (Bloch, 1794). Since then, 35 new species of Ergasilidae have been described from the Neotropics. However, a reanalysis of the available type specimens of E.iheringi revealed features that suggest that it represents a lineage independent from Ergasilus. Consequently, we propose Tiddergasilus gen. nov. (Ergasilidae: Cyclopoida) to accommodate T.iheringi (Tidd, 1942) comb. nov. The species was re-examined and redescribed based on available type specimens. Tiddergasilus gen. nov. is characterized by species with exopod of leg 4 2-segmented; antenna small and robust, with a short second segment (approximately three times shorter than the first segment), and claw with a unique morphology (short, recurved with a sub-proximal indentation in the inner margin). A phylogenetic analysis, based on a matrix of 15 taxa and 16 morphological characters in PAUP* software 4.0a152, resulted in 15 equally parsimonious trees. Based on this analysis, Tiddergasilus is closely related to a group composed of Neotropical species of Ergasilus – sharing with them antennule with 6-segments. When the highly homoplastic character “number of segments in the antennule” is removed from the analysis, Tiddergasilus forms a polytomy with the clade of genera of the former Vaigamidae, Ergasilus, and the clade Rhinergasilus+Brasergasilus+Pindapixara.

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KIM, DAE-NYEON, HOANG-HON TRINH, and KANG-HYUN JO. "OBJECT RECOGNITION BY SEGMENTED REGIONS USING MULTIPLE CUES ON OUTDOOR ENVIRONMENT." International Journal of Information Acquisition 04, no. 03 (September 2007): 205–13. http://dx.doi.org/10.1142/s0219878907001290.

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This work describes a method to allow objects for autonomous robot navigation on outdoor environment. The proposition of the method segments and recognizes the object from an image taken by moving robot on outdoor environment. We classify the object natural and artificial. We classify trees as natural objects and buildings as artificial objects. Then we define their characteristics individually. In the process, we segment objects included by preprocessing using multiple cues and show the method of segmentation based on low-level features using multiple cues. Multiple cues are color, line segment, context information, HCM (Hue Co-occurrence Matrix), PCs (Principal Components), vanishing point. Objects can be recognized when we combine predefined multiple cues. The correct object recognition of proposed system is over 92% among our test database which consist of about 1200 images. We accomplish the result of image segmentation using multiple cues and object recognition through experiments.

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Nicolae, Ileana-Diana V. D., Petre-Marian T. Nicolae, Paul P. Popescu, and Anca I. Purcaru. "Comparative study of wavelet based techniques for electromagnetic noise evaluation and removal." ITM Web of Conferences 34 (2020): 02005. http://dx.doi.org/10.1051/itmconf/20203402005.

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Signals acquired from an industrial environment with many sources of electromagnetic interferences may be polluted by white noise. Polluted data segments with many steady consecutive periods can be used (sometimes unsuccessful) for the estimation of a denoised period from the steady acquired data by using the mean signal method. For data segments with at least 4 periods, when only certain segments (shorter than a period) can be considered steady, hybrid algorithms can be used to automatically evaluate the power of noise and afterward to perform the noise removal by using wavelet thrashing trees. This paper deals with 2 additional denoising techniques. The 1-st one is based on the Wavelet Package Transform and allows for the separation of the noise components which pollute a data segment of at least one period. The second approached denoising technique is also addressing one period data segments and estimates ﬁrstly the power of noise by using the energies of the vectors of details from the ﬁrst 2 levels of a tree used by decompositions with the Stationary Wavelet Transform. The estimated power of noise is afterward used to establish the number of levels in the wavelet thrashing trees. In this last stage, two wavelet mothers were used. Simulated and real test signals were used and performance comparisons were performed.

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Herfarth, Lamadé, Fischer, Chiu, Cardenas, Thorn, Vetter, Grenacher, and Meinzer. "The Effect of Virtual Reality and Training on Liver Operation Planning." Swiss Surgery 8, no. 2 (April 1, 2002): 67–73. http://dx.doi.org/10.1024/1023-9332.8.2.67.

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Objective: The three-dimensional relation of a liver tumour to the intrahepatic vascular trees is basis of operation planning in liver surgery. Yet it has not been proven whether 3D reconstruction and further computerised processing will enhance precision of operation planning in liver surgery which has been based on the liver segment classification of Couinaud up to now. Design: Our interdisciplinary group (department of Surgery, German Cancer Research Center and Department of Radiology) has developed a new interactive computer-based quantitative 3D operation planning system for liver surgery which is being introduced into the clinical routine. The system quantifies the organ structures semiautomatically, defines resection planes depending on safety margins and the vascular trees, and presents the data in digital movies as well as in quantitative reports. We conducted a clinical trial to evaluate whether 3D reconstruction will lead to an improved operation planning. Data of 7 virtual patients were presented to a total of 81 surgeons in different levels of training. The tumours had to be assigned to a liver segment and subsequently drawn together with the operation proposals into a liver model. The precision of both was measured quantitatively for each surgeon and stratified concerning 2D and different types of 3D presentations. Results: The 3D anatomy can be visualised in high quality which results in good perception of the third dimension (depth). Tumour assignment to liver segments was significantly correlated to the level of training (p < 0.05). There was a significant increase (p < 0.001) in the precision of tumour localisation by 51% and resection proposal from 2D through 3D reconstructions by 13%-21%. Quantitative differences of the simplified Couinaud's classification of the liver segments compared to the true vascular anatomy of up to 40% were found. Conclusion: The impact of individual 3D-reconstruction on surgical planning has been proven to be significant and increases precision quantitatively. The merit of Couinaud's classification may be enhanced by individualisation of the segment borders in future.

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Saint-Germain, Michel, Pierre Drapeau, and Christian Hébert. "Xylophagous insect species composition and patterns of substratum use on fire-killed black spruce in central Quebec." Canadian Journal of Forest Research 34, no. 3 (March 1, 2004): 677–85. http://dx.doi.org/10.1139/x03-235.

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Several xylophagous insect species have adapted to recurrent fires in boreal forests and use high-quality habitats created by these disturbances. To characterize the xylophagous insect assemblages of fire-killed black spruce and their patterns of substratum use, eighty-four 40 cm long bole segments were cut in 2000 and 2001 according to tree diameter, segment height, and fire severity criteria in a 1999 burn in the Grands-Jardins provincial park, Quebec, Canada. The segments were suspended in rearing cages, and neonates were collected until November 2001. The cerambycid Mono chamus scutellatus (Say) and the scolytids Dryocoetes affaber (Mann.) and Polygraphus rufipennis (Kirby) were the most common beetles collected. For all common taxa, more neonates emerged from larger-diameter trees. Few neonates emerged from the upper parts of the trees, and none of the species were specialist of the upper parts of the tree. Fire severity had a drastic effect, and heavily charred trees yielded very few insects. The effect of fire severity on insect colonization density varies widely among tree species. This effect may be linked to varying bark thickness and to bark's insulating potential against water loss during the fire. The host's vigor before its death, measured from growth rings of the last 10 years, had a positive effect on cerambycid emergence, but no effect on scolytids.

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Maibier, Martin, Bettina Reglin, Bianca Nitzsche, Weiwei Xiang, Wen Wei Rong, Björn Hoffmann, Valentin Djonov, Timothy W. Secomb, and Axel R. Pries. "Structure and hemodynamics of vascular networks in the chorioallantoic membrane of the chicken." American Journal of Physiology-Heart and Circulatory Physiology 311, no. 4 (October 1, 2016): H913—H926. http://dx.doi.org/10.1152/ajpheart.00786.2015.

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The chick chorioallantoic membrane (CAM) is extensively used as an in vivo model. Here, structure and hemodynamics of CAM vessel trees were analyzed and compared with predictions of Murray's law. CAM microvascular networks of Hamburger-Hamilton stage 40 chick embryos were scanned by videomicroscopy. Three networks with ∼3,800, 580, and 480 segments were digitally reconstructed, neglecting the capillary mesh. Vessel diameters ( D) and segment lengths were measured, and generation numbers and junctional exponents at bifurcations were derived. In selected vessels, flow velocities ( v) and hematocrit were measured. Hemodynamic simulations, incorporating the branching of capillaries from preterminal vessels, were used to estimate v, volume flow, shear stress (τ), and pressure for all segments of the largest network. For individual arteriovenous flow pathways, terminal arterial and venous generation numbers are negatively correlated, leading to low variability of total topological and morphological pathway lengths. Arteriolar velocity is proportional to diameter ( v∝ D1.03 measured, v∝ D0.93 modeling), giving nearly uniform τ levels (τ∝ D0.05). Venular trees exhibit slightly higher exponents ( v∝ D1.3, τ∝ D0.38). Junctional exponents at divergent and convergent bifurcations were 2.05 ± 1.13 and 1.97 ± 0.95 (mean ± SD) in contrast to the value 3 predicted by Murray's law. In accordance with Murray's law, τ levels are (nearly) maintained in CAM arterial (venular) trees, suggesting vascular adaptation to shear stress. Arterial and venous trees show an interdigitating arrangement providing homogeneous flow pathway properties and have preterminal capillary branches. These properties may facilitate efficient oxygen exchange in the CAM during rapid embryonic growth.

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Zhang, Minjie, Chengyong Wang, and Shuchao Li. "Extremal trees of given segment sequence with respect to some eccentricity-based invariants." Discrete Applied Mathematics 284 (September 2020): 111–23. http://dx.doi.org/10.1016/j.dam.2020.03.018.

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Li, Shuchao, and Shujing Wang. "Extremal cover cost and reverse cover cost of trees with given segment sequence." Discrete Mathematics 343, no. 4 (April 2020): 111791. http://dx.doi.org/10.1016/j.disc.2019.111791.

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Renaud, Gabriel, Pedro Neves, Edson Luiz Folador, Carlos Gil Ferreira, and Fabio Passetti. "Segtor: Rapid Annotation of Genomic Coordinates and Single Nucleotide Variations Using Segment Trees." PLoS ONE 6, no. 11 (November 1, 2011): e26715. http://dx.doi.org/10.1371/journal.pone.0026715.

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Zhang, Yan, and Hai Wei Xie. "Simulation and Analysis of Three-Dimensional Arterial Trees." Applied Mechanics and Materials 475-476 (December 2013): 1603–6. http://dx.doi.org/10.4028/www.scientific.net/amm.475-476.1603.

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For hemodynamic simulation and heat transfer analysis of blood, it is necessary to generate a three-dimensional model of arterial tree. Referring to the approach of Constrained Constructive Optimization (CCO), a new method based on bifurcation law, Poiseuilles law and mass conservation was proposed to model arterial trees directly in simulation objects. The formulas for calculating the bifurcation ratios and the way to determine the location of bifurcation point were presented in the paper. In this model, the radius of the root segment was constant, the terminal pressure was unknown and the bifurcation exponent was variable. In order to demonstrate the feasibility of this method, an arterial tree was constructed in a spherical tissue.

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Świętoń, Edyta, and Krzysztof Śmietanka. "Phylogenetic study of H5 low pathogenic avian influenza viruses detected in wild birds in Poland in 2010−2015." Journal of Veterinary Research 61, no. 4 (December 1, 2017): 381–89. http://dx.doi.org/10.1515/jvetres-2017-0054.

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AbstractIntroduction:The genomes of nine H5 subtypes of low pathogenic avian influenza virus (LPAIV) strains identified in wild birds in Poland between 2010 and 2015 were sequenced, and their phylogenetic relationship was determined.Material and Methods:AIV genome segments were amplified by RT-PCR and the PCR products were sequenced using Sanger method. Phylogenetic trees were generated in MEGA6 software and digital genotyping approach was used to visualise the relationship between analysed strains and other AIVs.Results:High genetic diversity was found in the analysed strains as multiple subgroups were identified in phylogenetic trees. In the HA tree, Polish strains clustered in two distinct subclades. High diversity was found for PB2, PB1, PA and NP, since 5-8 sublineages could be distinguished. Each strain had a different gene constellation, although relationship of as much as six out of eight gene segments was observed between two isolates. A relationship with poultry isolates was found for at least one segment of each Polish strain.Conclusion:The genome configuration of tested strains indicates extensive reassortment, although the preference for specific gene constellation could be noticed. A significant relationship with isolates of poultry origin underlines the need for constant monitoring of the AIV gene pool circulating in the natural reservoir.

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George*, Laurie J., and John E. Preece. "The Influence of Location of Main Stem Segment Origin on Forcing and Rooting of Softwood Shoots of Betula nigra L." HortScience 39, no. 4 (July 2004): 890C—890. http://dx.doi.org/10.21273/hortsci.39.4.890c.

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The objective of this study was to investigate the effects of the position on the main stem that large stem segments were harvested from on forcing and subsequent rooting of Betula nigra L. (river birch) softwood shoots. The main trunks of eight adult-phase native trees (four trees per run of the experiment) were cut into 50-cm long segments from the ground up. The segments placed in horizontally in 52 × 25 × 6.5 cm (l × w × h) flats containing perlite and were positioned so the bottom one-third of the stem was within the medium. Shoots were forced under natural photoperiod and intermittent mist. This experiment was conducted twice. Data were collected weekly for fourteen weeks on the number of softwood shoots each segment produced, shoot length, number of rootable shoots (>6 cm long), the length of time that the stem segments produced rootable shoots, and the rootability of these shoots treated with 3000 ppm IBA in talc. The number of harvested shoots was greater in Run 1, with the basal segments producing the most harvestable shoots. However, the upper segments in Run 2 produced the most harvestable shoots. Softwood shoots that rooted were placed under intermittent mist. Out of the 540 harvested shoots for both runs, 82.4% rooted, with the majority of those from Run 1. Shoots harvested from this run began producing roots about 6 weeks after harvest, and continued until the end of the experiment. Run 2 shoots began root initiation about 3 weeks after harvest and ended about 2 weeks before the end of the experiment. Run 1 had an mean of 8.3 roots per shoot and Run 2 had an mean of 6.2 roots. The relationship between juvenility and shoot forcing and subsequent rooting will be discussed.

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TAN, XUEHOU. "FINDING AN OPTIMAL BRIDGE BETWEEN TWO POLYGONS." International Journal of Computational Geometry & Applications 12, no. 03 (June 2002): 249–61. http://dx.doi.org/10.1142/s0218195902000852.

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Let π(a,b) denote the shortest path between two points a, b inside a simple polygon P, which totally lies in P. The geodesic distance between a and b in P is defined as the length of π(a,b), denoted by gd(a,b), in contrast with the Euclidean distance between a and b in the plane, denoted by d(a,b). Given two disjoint polygons P and Q in the plane, the bridge problem asks for a line segment (optimal bridge) that connects a point p on the boundary of P and a point q on the boundary of Q such that the sum of three distances gd(p′,p), d(p,q) and gd(q,q′), with any p′ ∈ P and any q′ ∈ Q, is minimized. We present an O(n log 3 n) time algorithm for finding an optimal bridge between two simple polygons. This significantly improves upon the previous O(n2) time bound. Our result is obtained by making substantial use of a hierarchical structure that consists of segment trees, range trees and persistent search trees, and a structure that supports dynamic ray shooting and shortest path queries as well.

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Schreiner, Wolfgang, Friederike Neumann, Martin Neumann, Rudolf Karch, Adelheid End, and Susanne M. Roedler. "Limited Bifurcation Asymmetry in Coronary Arterial Tree Models Generated by Constrained Constructive Optimization." Journal of General Physiology 109, no. 2 (February 1, 1997): 129–40. http://dx.doi.org/10.1085/jgp.109.2.129.

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Models of coronary arterial trees are generated by the algorithm of constrained constructive optimization (CCO). In a given perfusion area a binary branching network of straight cylindrical tubes is generated by successively adding terminal segments to the growing structure. In each step the site of connection is chosen according to an optimization target function (total intravascular volume), and in any stage of development the tree fulfills physiologic boundary conditions (constraints involving pressures, flows and bifurcation rules). CCO generates structures which in many aspects resemble real coronary arterial trees, except for very asymmetric bifurcations, occurring when a large branch gives off a tiny terminal segment. In the present work we evaluate an additional constraint within CCO, namely imposing a limit on the asymmetry of bifurcations during the construction process. Model trees are grown with different limits imposed, and the effects on structure are studied both phenomenologically and via statistical descriptors. As the limit to asymmetry is tightened, blood is conveyed to the perfusion sites via detours rather than directly and the comparison with measured data shows the structure to change from a conveying to a delivering type of function. Simultaneously total intravascular volume, surface and sum of segments' lengths increase. It is shown why and how local bifurcation asymmetry is able to determine the global structure of the optimized arterial tree model. Surprisingly, the pressure profile from inlet to terminals, being a functional characteristic, remains unaffected.

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Hu, Da Li, Liang Zhong Yi, Zheng Pei, and Bing Luo. "Voice Activity Detection with Decision Trees in Noisy Environments." Applied Mechanics and Materials 128-129 (October 2011): 749–52. http://dx.doi.org/10.4028/www.scientific.net/amm.128-129.749.

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An improved project based on double thresholds method in noisy environments is proposed for robust endpoints detection. Firstly, in this method, the distribution of zero crossing rate (ZCR) on the preprocessed signal is taken into account, and then the speech signal is divided into different parts to obtain appropriate thresholds with decision trees on the basis of the ZCR distribution. Finally, the double thresholds method, focusing on different importance of the energy and ZCR, is taken in the corresponding situation to determine the input segment is speech or non-speech. Simulation results indicate that the proposed method with decision trees obtains more accurate data than the traditional double thresholds method.

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Suzuki, Taro, Shunichi Shiozawa, Atsushi Yamaba, and Yoshiharu Amano. "Forest Data Collection by UAV Lidar-Based 3D Mapping: Segmentation of Individual Tree Information from 3D Point Clouds." International Journal of Automation Technology 15, no. 3 (May 5, 2021): 313–23. http://dx.doi.org/10.20965/ijat.2021.p0313.

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In this study, we develop a system for efficiently measuring detailed information of trees in a forest environment using a small unmanned aerial vehicle (UAV) equipped with light detection and ranging (lidar). The main purpose of forest measurement is to predict the volume of wood for harvesting and delineating forest boundaries by tree location. Herein, we propose a method for extracting the position, number of trees, and vertical height of trees from a set of three-dimensional (3D) point clouds acquired by a UAV lidar system. The point cloud obtained from a UAV is dense in the tree’s crown, and the trunk 3D points are sparse because the crown of the tree obstructs the laser beam. Therefore, it is difficult to extract single-tree information from 3D point clouds because the characteristics of 3D point clouds differ significantly from those of conventional 3D point clouds using ground-based laser scanners. In this study, we segment the forest point cloud into three regions with different densities of point clouds, i.e., canopy, trunk, and ground, and process each region individually to extract the target information. By comparing a ground laser survey and the proposed method in an actual forest environment, it is discovered that the number of trees in an area measuring 100 m × 100 m is 94.6% of the total number of trees. The root mean square error of the tree position is 0.3 m, whereas that of the vertical height is 2.3 m, indicating that single-tree information can be measured with sufficient accuracy for forest management.

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Parker, Robert C. "Field and Computer Application of Mesavage and Girard Form Class Volume Tables." Southern Journal of Applied Forestry 22, no. 2 (May 1, 1998): 81–87. http://dx.doi.org/10.1093/sjaf/22.2.81.

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Abstract Mesavage and Girard form class volume tables for estimating board foot volume of standing trees remain the most widely used volume tables in the East and South even though newer, more versatile and sophisticated volume functions are available. The volume tables are being misused by foresters because the merchantability standards of the average, upper-log taper table used to derive the volume tables does not show that merchantable top diameters and form class applications require appropriate sampling and accurate measurement of form on selected trees. The original upper-log tapers, developed from averages of actual tree measurements and ocular estimates, were fitted to a regression model to smooth the inconsistencies of the table values. The resulting Mesavage and Girard "taper equation" is used to obtain upper stem diameters for trees of known Girard form class, dbh, and merchantable height. The taper equation shows that top-limit diameter increases with both tree size (dbh and height) and Girard form class, and any attempt to apply form class volume tables to a fixed-top diameter on inventory trees would produce erroneous cruise volumes. The derived taper equation can be used in an iterative procedure during computer applications to obtain single tree volumes as the sum of log segment volumes for segments of user-defined length. A hierarchy of suggested form class application options is presented along with suggestion sampling, measurement, and stratification procedures. South. J. Appl. For. 22(2):81-87.

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KIRKPATRICK, DAVID, and JACK SNOEYINK. "COMPUTING CONSTRAINED SHORTEST SEGMENTS: BUTTERFLY WINGSPANS IN LOGARITHMIC TIME." International Journal of Computational Geometry & Applications 09, no. 01 (February 1999): 53–62. http://dx.doi.org/10.1142/s0218195999000054.

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We give a logarithmic-time algorithm to compute the shortest segment joining two convex n-gons A and B while avoiding another convex n-gon C. Our algorithm uses a tentative prune-and-search technique on standard representations of the polygons as arrays or balanced binary search trees.

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Chan, Benny K. K., and Priscilla T. Y. Leung. "Antennular morphology of the cypris larvae of the mangrove barnacle Fistulobalanus albicostatus (Cirripedia: Thoracica: Balanomorpha)." Journal of the Marine Biological Association of the United Kingdom 87, no. 4 (July 30, 2007): 913–15. http://dx.doi.org/10.1017/s0025315407055786.

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Previous studies on the ultrastructure of barnacle cypris larvae suggest that cypris morphology, especially the antennules which play a key role in selecting the final substratum for settlement, may show variations between species existing in different habitats. In the present study, the cypris morphology of the barnacle Fistulobalanus (Balanus) albicostatus, which predominantly lives on trunks of mangrove trees was investigated using scanning electron microscopy and compared with that of species from other habitats that have already been described. The antennular segments II and III of F. albicostatus each bear one post-axial seta. The third segment consists of an attachment disc surrounded by a thin cuticular velum and the fourth segment exhibits four sub-terminal setae and five terminal setae. The morphology of the cypris antennules of F. albicostatus is similar to other balanomorph barnacles which inhabit hard shores, revealing that the antennular morphology does not have diagnostic variations between species from the different intertidal habitats. The morphology of the caudal rami (used in the evaluation of the substratum microtopography), however, appears to vary among barnacles living on different substrata.

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Poinar Jr., George, and Fernando E. Vega. "A New Genus of Cylindrical Bark Beetle (Coleoptera: Zopheridae: Colydiinae) in mid-Cretaceous Burmese Amber." Biosis:Biological Systems 1, no. 4 (December 15, 2020): 134–40. http://dx.doi.org/10.37819/biosis.001.04.0087.

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A bizarre cylindrical bark beetle from mid-Cretaceous Burmese amber is described as Stegastochlidus saraemcheana, a new genus and species in the subfamily Colydiinae of the family Zopheridae. The male beetle is characterized by elongate protuberances covering its entire dorsal surface, a tarsal formula of 4-4-4 and ten-segmented antennae with the terminal segment expanded into a small club. The fossil is considered to have been a possible predator that lived among moss, lichens and fungi either attached to trees trunks or on the forest floor. A close association with fungi is indicated by strands of conidia attached to the cuticle of the beetle.

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Schreiner, W., M. Neumann, F. Neumann, S. M. Roedler, A. End, P. Buxbaum, M. R. Müller, and P. Spieckermann. "The branching angles in computer-generated optimized models of arterial trees." Journal of General Physiology 103, no. 6 (June 1, 1994): 975–89. http://dx.doi.org/10.1085/jgp.103.6.975.

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The structure of a complex arterial tree model is generated on the computer using the newly developed method of "constrained constructive optimization." The model tree is grown step by step, at each stage of development fulfilling invariant boundary conditions for pressures and flows. The development of structure is governed by adopting minimum volume inside the vessels as target function. The resulting model tree is analyzed regarding the relations between branching angles and segment radii. Results show good agreement with morphometric measurements on corrosion casts of human coronary arteries reported in the literature.

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Yoshizawa, Nobuo, Ikuhiro Satoh, Sinso Yokota, and Toshinaga Idei. "Response of Differentiating Tracheids to Stem Inclination in Young Trees of Taxus Cuspidata." IAWA Journal 13, no. 2 (1992): 187–94. http://dx.doi.org/10.1163/22941932-90001267.

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Differences in response among differentiating tracheids to the stimulus of stem inclination were examined at three heights in stems of young trees of Taxus cuspidata Sieb. et Zucc. A change in the orientation of the helical cell wall thickenings from an S- to a Z-helix with a simultaneous absence of an S3 layer were the first anatomical responses to appear. These changes first occurred in differentiating xylem on the underside of the upper segment of the stem after 4 days inclination. The gravistimulus for compression wood formation was transmitted basipetally within the stem as the tilting period was increased. After 10 days, the xylem on the underside of the upper segment of the stem contained five mature cells with a Z-helix, indicating that deposition of the thickenings required 2 days. The present results suggest that the rate of cambial division and xylem differentiation differs longitudinally in an inclined stem. For Taxus cuspidata, a change in the orientation of the helical thickenings should be a useful marker for deciding whether or not the differentiating cells have perceived the stimulus for compression wood formation.

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Chervov, Alexander, Jonathan Bac, and Andrei Zinovyev. "Minimum Spanning vs. Principal Trees for Structured Approximations of Multi-Dimensional Datasets." Entropy 22, no. 11 (November 11, 2020): 1274. http://dx.doi.org/10.3390/e22111274.

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Construction of graph-based approximations for multi-dimensional data point clouds is widely used in a variety of areas. Notable examples of applications of such approximators are cellular trajectory inference in single-cell data analysis, analysis of clinical trajectories from synchronic datasets, and skeletonization of images. Several methods have been proposed to construct such approximating graphs, with some based on computation of minimum spanning trees and some based on principal graphs generalizing principal curves. In this article we propose a methodology to compare and benchmark these two graph-based data approximation approaches, as well as to define their hyperparameters. The main idea is to avoid comparing graphs directly, but at first to induce clustering of the data point cloud from the graph approximation and, secondly, to use well-established methods to compare and score the data cloud partitioning induced by the graphs. In particular, mutual information-based approaches prove to be useful in this context. The induced clustering is based on decomposing a graph into non-branching segments, and then clustering the data point cloud by the nearest segment. Such a method allows efficient comparison of graph-based data approximations of arbitrary topology and complexity. The method is implemented in Python using the standard scikit-learn library which provides high speed and efficiency. As a demonstration of the methodology we analyse and compare graph-based data approximation methods using synthetic as well as real-life single cell datasets.

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Gordeev, L. "Generalizations of the Kruskal-Friedman theorems." Journal of Symbolic Logic 55, no. 1 (March 1990): 157–81. http://dx.doi.org/10.2307/2274960.

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AbstractKruskal proved that finite trees are well-quasi-ordered by hom(e)omorphic embeddability. Friedman observed that this statement is not provable in predicative analysis. Friedman also proposed (see in [Simpson]) some stronger variants of the Kruskal theorem dealing with finite labeled trees under hom(e)omorphic embeddability with a certain gap-condition, where labels are arbitrary finite ordinals from a fixed initial segment of ω. The corresponding limit statement, expressing that for all initial segments of ω these labeled trees are well-quasi-ordered, is provable in -CA, but not in the analogous theory -CA0 with induction restricted to sets. Schütte and Simpson proved that the one-dimensional case of Friedman's limit statement dealing with finite labeled intervals is not provable in Peano arithmetic. However, Friedman's gap-condition fails for finite trees labeled with transfinite ordinals. In [Gordeev 1] I proposed another gap-condition and proved the resulting one-dimensional modified statements for all (countable) transfinite ordinal-labels. The corresponding universal modified one-dimensional statement UM1 is provable in (in fact, is equivalent to) the familiar theory ATR0 whose proof-theoretic ordinal is Γ0. In [Gordeev 1] I also announced that, in the general case of arbitrarily-branching finite trees labeled with transfinite ordinals, in the proof-theoretic sense the hierarchy of the limit modified statements M<λ (which are denoted by LMλ in the present note) is as strong as the hierarchy of the familiar theories of iterated inductive definitions (more precisely, see [Gordeev 1, Concluding Remark 3]). In this note I present a “positive” proof of the full universal modified statement UM, together with a short proof of the crucial “reverse” results which is based on Okada's interpretation of the well-established ordinal notations of Buchholz corresponding to the theories of iterated inductive definitions. Formally the results are summarized in §5 below.

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Zhang, Xianliang, Junxia Li, Xiaobo Liu, and Zhenju Chen. "Improved EEMD-based standardization method for developing long tree-ring chronologies." Journal of Forestry Research 31, no. 6 (June 27, 2019): 2217–24. http://dx.doi.org/10.1007/s11676-019-01002-y.

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Abstract Long tree-ring chronologies can be developed by overlapping data from living trees with data from fossil trees through cross-dating. However, low-frequency climate signals are lost when standardizing tree-ring series due to the “segment length curse”. To alleviate the segment length curse and thus improve the standardization method for developing long tree-ring chronologies, here we first calculated a mean value for all the tree ring series by overlapping all of the tree ring series. The growth trend of the mean tree ring width (i.e., cumulated average growth trend of all the series) was determined using ensemble empirical mode decomposition. Then the chronology was developed by dividing the mean value by the growth trend of the mean value. Our improved method alleviated the problem of trend distortion. Long-term signals were better preserved using the improved method than in previous detrending methods. The chronologies developed using the improved method were better correlated with climate than those developed using conservative methods. The improved standardization method alleviates trend distortion and retains more of the low-frequency climate signals.

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Ma, Zhenyu, Yong Pang, Di Wang, Xiaojun Liang, Bowei Chen, Hao Lu, Holger Weinacker, and Barbara Koch. "Individual Tree Crown Segmentation of a Larch Plantation Using Airborne Laser Scanning Data Based on Region Growing and Canopy Morphology Features." Remote Sensing 12, no. 7 (March 27, 2020): 1078. http://dx.doi.org/10.3390/rs12071078.

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The detection of individual trees in a larch plantation could improve the management efficiency and production prediction. This study introduced a two-stage individual tree crown (ITC) segmentation method for airborne light detection and ranging (LiDAR) point clouds, focusing on larch plantation forests with different stem densities. The two-stage segmentation method consists of the region growing and morphology segmentation, which combines advantages of the region growing characteristics and the detailed morphology structures of tree crowns. The framework comprises five steps: (1) determination of the initial dominant segments using a region growing algorithm, (2) identification of segments to be redefined based on the 2D hull convex area of each segment, (3) establishment and selection of profiles based on the tree structures, (4) determination of the number of trees using the correlation coefficient of residuals between Gaussian fitting and the tree canopy shape described in each profile, and (5) k-means segmentation to obtain the point cloud of a single tree. The accuracy was evaluated in terms of correct matching, recall, precision, and F-score in eight plots with different stem densities. Results showed that the proposed method significantly increased ITC detections compared with that of using only the region growing algorithm, where the correct matching rate increased from 73.5% to 86.1%, and the recall value increased from 0.78 to 0.89.

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Antony, F., L. R. Schimleck, R. F. Daniels, A. Clark, and D. B. Hall. "Modeling the longitudinal variation in wood specific gravity of planted loblolly pine (Pinus taeda) in the United States." Canadian Journal of Forest Research 40, no. 12 (December 2010): 2439–51. http://dx.doi.org/10.1139/x10-187.

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Loblolly pine (Pinus taeda L.) is a major plantation species grown in the southern United States, producing wood having a multitude of uses including pulp and lumber production. Specific gravity (SG) is an important property used to measure the quality of wood produced, and it varies regionally and within the tree with height and radius. SG at different height levels was measured from 407 trees representing 135 plantations across the natural range of loblolly pine. A three-segment quadratic model and a semiparametric model were proposed to explain the vertical and regional variations in SG. Both models were in agreement that a stem can be divided into three segments based on the vertical variation in SG. Based on the fitted models, the mean trend in SG of trees from the southern Atlantic Coastal Plain and Gulf Coastal Plain was observed to be higher than in other physiographical regions (Upper Coastal Plain, Hilly Coastal Plain, northern Atlantic Coastal Plain, and Piedmont). Maps showing the regional variation in disk SG at a specified height were also developed. Maps indicated that the stands in the southern Atlantic Coastal Plain and Gulf Coastal Plain have the highest SG at a given height level.

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Journal articles on the topic 'Segment trees'

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