scholarly journals A Numerical Rating System for Crown Classes of Southern Hardwoods

2001 ◽  
Vol 25 (4) ◽  
pp. 154-158 ◽  
Author(s):  
J.S. Meadows ◽  
E.C. Burkhardt ◽  
R.L. Johnson ◽  
J.D. Hodges
Keyword(s):  
Rating System ◽  
Tree Crown ◽  
Direct Sunlight ◽  
Individual Tree ◽  
System Use ◽  
Numerical Rating ◽  
Crown Characteristics ◽  
Time Required ◽  
Total Point ◽  
Stand Conditions

Abstract A numerical rating system to delineate crown classes of southern hardwoods is described. The system is based on four criteria: (1) amount of direct sunlight from above, (2) amount of direct sunlight from the sides, (3) crown balance, and (4) relative crown size. The total point value assigned places the tree within one of the four crown classes. The rating system can be used to train inexperienced hardwood foresters and should give experienced foresters a better grasp of those factors important in hardwood crown classification. Time required to evaluate a tree varies by tree, by stand conditions, and by observer, but experienced users of the system can easily rate most trees in 30–45 seconds. The rating system is particularly useful in situations where an individual tree appears to be borderline between two crown classes. For researchers, the system provides: (1) an expression of individual-tree crown characteristics, and (2) documentation of changes in crown position and condition. In two tests comparing the numerical rating system with the conventional crown classification system, use of the rating system consistently improved the ability of participants to correctly identify crown classes. Dominant and suppressed trees were the easiest to assess with the numerical rating system, whereas codominant and intermediate trees were the most difficult. Agreement between participants and experts in identification of crown classes increased with the level of the participants' forestry knowledge and experience. In one test, a group of participants attending a continuing-education hardwood shortcourse, but with little to moderate hardwood experience, correctly identified the crown class of 78% of the trees after only 1 hr of training. South. J. Appl. For. 25(4):154–158.

Selection of Risks for Life Insurance

1932 ◽  
Vol 63 (2) ◽  
pp. 173-217 ◽  
Author(s):  
Arthur Hunter
Keyword(s):  
Board Of Directors ◽  
Life Insurance ◽  
Medical Director ◽  
Rating System ◽  
Sufficient Knowledge ◽  
Numerical Rating ◽  
Selection Of

The method of selecting risks has undergone radical changes during the span of one man’s lifetime. In the early days of my experience all proposals for life insurance were submitted to a Board of Directors which consisted mainly of landed proprietors, lawyers and accountants. They were assumed to have sufficient knowledge to determine which lives should be accepted, which should be rejected and which should be charged an extra premium, with the aid of the medical adviser and of the actuary. The former was usually a prominent physician who based his judgment on impressions and observations, and the latter on the meagre statistics then in existence. Contrast that with the method in use in the principal American companies at the present time. The majority of the proposals are not submitted to a medical director, actuary or underwriter, but are passed upon by lay reviewers with or without the use of a numerical rating system. Experience has shown that such a practice is safe, as in one-half or more of the proposals there is nothing of moment against the risk, and, unless the amount of insurance is large, the time of experts can be given with greater advantage to the more difficult types of cases.

scholarly journals Crown structure of Picea omorika trees in the plantation

2012 ◽  
Vol 64 (2) ◽  
pp. 605-611 ◽  
Author(s):  
M. Krstic ◽  
N. Stavretovic ◽  
V. Isajev ◽  
I. Bjelanovic
Keyword(s):  
Tree Height ◽  
Tree Crown ◽  
Crown Length ◽  
Crown Structure ◽  
Parabolic Function ◽  
Picea Omorika ◽  
Serbian Spruce ◽  
The Relationship ◽  
Total Tree ◽  
Stand Conditions

The study was carried out in Serbian spruce (Picea omorika Panc/Purkyn?) plantations in the western Serbia. The paper presents results of the analysis of crown development. The following elements were analyzed: total tree height, height of the crown base, absolute and relative crown length, maximal crown diameter, coefficient of crown spreading and degree of crown girth. We discuss approaches to the modeling of tree crown growth and development, growing under favorable environmental and stand conditions, without anomalies in development. In order to establish the relationship between analyzed factors, regression analyses were applied. Data fitting was by the analytic method, by the implementation of Prodan?s functions of growth, linear and parabolic function. Received models can be used for the simulation of various growth and developing processes in forest.

scholarly journals Individual tree crown delineation and tree species classification with hyperspectral and LiDAR data

PeerJ ◽  
2019 ◽  
Vol 6 ◽  
pp. e6227 ◽  
Author(s):  
Michele Dalponte ◽  
Lorenzo Frizzera ◽  
Damiano Gianelle
Keyword(s):  
Remote Sensing ◽  
Tree Species ◽  
Data Science ◽  
Remote Sensing Data ◽  
Tree Crown ◽  
Species Classification ◽  
Individual Tree ◽  
Sensing Data ◽  
Tree Species Classification ◽  
Selection Of

An international data science challenge, called National Ecological Observatory Network—National Institute of Standards and Technology data science evaluation, was set up in autumn 2017 with the goal to improve the use of remote sensing data in ecological applications. The competition was divided into three tasks: (1) individual tree crown (ITC) delineation, for identifying the location and size of individual trees; (2) alignment between field surveyed trees and ITCs delineated on remote sensing data; and (3) tree species classification. In this paper, the methods and results of team Fondazione Edmund Mach (FEM) are presented. The ITC delineation (Task 1 of the challenge) was done using a region growing method applied to a near-infrared band of the hyperspectral images. The optimization of the parameters of the delineation algorithm was done in a supervised way on the basis of the Jaccard score using the training set provided by the organizers. The alignment (Task 2) between the delineated ITCs and the field surveyed trees was done using the Euclidean distance among the position, the height, and the crown radius of the ITCs and the field surveyed trees. The classification (Task 3) was performed using a support vector machine classifier applied to a selection of the hyperspectral bands and the canopy height model. The selection of the bands was done using the sequential forward floating selection method and the Jeffries Matusita distance. The results of the three tasks were very promising: team FEM ranked first in the data science competition in Task 1 and 2, and second in Task 3. The Jaccard score of the delineated crowns was 0.3402, and the results showed that the proposed approach delineated both small and large crowns. The alignment was correctly done for all the test samples. The classification results were good (overall accuracy of 88.1%, kappa accuracy of 75.7%, and mean class accuracy of 61.5%), although the accuracy was biased toward the most represented species.

scholarly journals A Region-Based Hierarchical Cross-Section Analysis for Individual Tree Crown Delineation Using ALS Data

2017 ◽  
Vol 9 (10) ◽  
pp. 1084 ◽  
Author(s):  
Yinghui Zhao ◽  
Yuanshuo Hao ◽  
Zhen Zhen ◽  
Ying Quan
Keyword(s):  
Cross Section ◽  
Tree Crown ◽  
Individual Tree ◽  
Crown Delineation ◽  
Tree Crown Delineation ◽  
Section Analysis

scholarly journals ARBOR: A new framework for assessing the accuracy of individual tree crown delineation from remotely-sensed data

2019 ◽  
Vol 231 ◽  
pp. 111256
Author(s):  
Jon Murray ◽  
David Gullick ◽  
George Alan Blackburn ◽  
James Duncan Whyatt ◽  
Christopher Edwards
Keyword(s):  
Remotely Sensed ◽  
Tree Crown ◽  
Remotely Sensed Data ◽  
Individual Tree ◽  
Crown Delineation ◽  
Tree Crown Delineation ◽  
New Framework

Individual Tree Measurement in Tropical Environment using Terrestrial Laser Scanning

2015 ◽  
Vol 73 (5) ◽  
Author(s):  
Muhammad Zulkarnain Abdul Rahman ◽  
Zulkepli Majid ◽  
Md Afif Abu Bakar ◽  
Abd Wahid Rasib ◽  
Wan Hazli Wan Kadir
Keyword(s):  
Laser Scanning ◽  
Mean Squared Error ◽  
Tree Height ◽  
Point Clouds ◽  
Tree Crown ◽  
Individual Tree ◽  
Branch Diameter ◽  
Reference Tree ◽  
Crown Volume ◽  
Tree Branch

Detailed forest inventory and mensuration of individual trees have drawn attention of research society mainly to support sustainable forest management. This study aims at estimating individual tree attributes from high density point cloud obtained by terrestrial laser scanner (TLS). The point clouds were obtained over single reference tree and group of trees in forest area. The reference tree is treated as benchmark since detailed measurements of branch diameter were made on selected branches with different sizes and locations. Diameter at breast height (DBH) was measured for trees in forest. Furthermore tree height, height to crown base, crown volume and tree branch volume were also estimated for each tree. Branch diameter is estimated directly from the point clouds based on semi-automatic approach of model fitting i.e. sphere, ellipse and cylinder. Tree branch volume is estimated based on the volume of the fitted models. Tree height and height to crown base are computed using histogram analysis of the point clouds elevation. Tree crown volume is estimated by fitting a convex-hull on the tree crown. The results show that the Root Mean Squared Error (RMSE) of the estimated tree branch diameter does not have a specific trend with branch sizes and number of points used for fitting process. This explains complicated distribution of point clouds over the branches. Overall cylinder model produces good results with most branch sizes and number of point clouds for fitting. The cylinder fitting approach shows significantly better estimation results compared to sphere and ellipse fitting models.   

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