scholarly journals An Improved Tree Height Measurement Technique Tested on Mature Southern Pines

2008 ◽  
Vol 32 (1) ◽  
pp. 38-43 ◽  
Author(s):  
Don C. Bragg
Keyword(s):  
Tree Height ◽  
Real Point ◽  
Horizontal Distance ◽  
Height Measurement ◽  
Similar Triangle ◽  
Height Determination ◽  
Southern Pines ◽  
Crown Shape ◽  
Tangent Method ◽  
Similar Triangles

Abstract Virtually all techniques for tree height determination follow one of two principles: similar triangles or the tangent method. Most people apply the latter approach, which uses the tangents of the angles to the top and bottom and a true horizontal distance to the subject tree. However, few adjust this method for ground slope, tree lean, crown shape, and crown configuration, making errors commonplace. Given documented discrepancies exceeding 30% with current methods, a reevaluation of height measurement is in order. The sine method is an alternative that measures a real point in the crown. Hence, it is not subject to the same assumptions as the similar triangle and tangent approaches. In addition, the sine method is insensitive to distance from tree or observer position and can not overestimate tree height. The advantages of the sine approach are shown with mature southern pines from Arkansas.

Impact of training on different observers in forest inventory

2021 ◽  
Vol 31 (1) ◽  
pp. 12-22
Author(s):  
P. Paudel ◽  
P. Beckschäfer ◽  
C. Kleinn
Keyword(s):  
Forest Inventory ◽  
Tree Height ◽  
Measurement Procedure ◽  
Horizontal Distance ◽  
Limited Information ◽  
Quality Of Data ◽  
Height Measurement ◽  
Forest Inventories ◽  
The Mean ◽  
Level Of Training

Observers with different experience levels are involved in the measurement of large number of sample plots during forest inventories, particularly in national forest inventories. However, limited information exist on the quality of data produced by different observers in forest inventory after certain levels of training. This study tries to evaluate the measurement error in forest inventory associated with observers' experience after initial and field-based training for measuring the most fundamental variables- DBH (cm), total tree height (m), and horizontal distance (m) together with bearing (azimuth) to tree from the plot-centre. On completing the second level of training, the mean of the differences in DBH measurement decreased for both the ‘experienced’ and ‘inexperienced’ groups. The mean of the differences in height measurement in the case of the experienced observers was very low as compared to the inexperienced ones. However, the mean of the differences in azimuth measurement showed that the experienced groups were overestimating by at least 1 degree. There was no trend in deviation of measurement for all four variables regardless of tree size. The decrease in the mean and error of differences in measurements after second training showed that field-based training with supervision and training on the use of instruments at laboratories were required for inexperienced surveyors whereas update in working and measurement procedure would be sufficient for the experienced ones.

scholarly journals Development and Testing of a New Ground Measurement Tool to Assist in Forest GIS Surveys

Forests ◽  
2019 ◽  
Vol 10 (8) ◽  
pp. 643 ◽  
Author(s):  
Guangpeng Fan ◽  
Feixiang Chen ◽  
Yan Li ◽  
Binbin Liu ◽  
Xu Fan
Keyword(s):  
Root Mean Square Error ◽  
Mobile Phone ◽  
Mean Square Error ◽  
Tree Species ◽  
Tree Height ◽  
Measurement Tool ◽  
Mean Square ◽  
Height Measurement ◽  
Test Dataset ◽  
Ground Measurement

In present forest surveys, some problems occur because of the cost and time required when using external tools to acquire tree measurement. Therefore, it is of great importance to develop a new cost-saving and time-saving ground measurement method implemented in a forest geographic information system (GIS) survey. To obtain a better solution, this paper presents the design and implementation of a new ground measurement tool in which mobile devices play a very important role. Based on terrestrial photogrammetry, location-based services (LBS), and computer vision, the tool assists forest GIS surveys in obtaining important forest structure factors such as tree position, diameter at breast height (DBH), tree height, and tree species. This paper selected two plots to verify the accuracy of the ground measurement tool. Experiments show that the root mean square error (RMSE) of the position coordinates of the trees was 0.222 m and 0.229 m, respectively, and the relative root mean square error (rRMSE) was close to 0. The rRMSE of the DBH measurement was 10.17% and 13.38%, and the relative Bias (rBias) of the DBH measurement was −0.88% and −2.41%. The rRMSE of tree height measurement was 6.74% and 6.69%, and the rBias of tree height measurement was −1.69% and −1.27%, which conforms to the forest investigation requirements. In addition, workers usually make visual observations of trees and then combine their personal knowledge or experience to identify tree species, which may lead to the situations when they cannot distinguish tree species due to insufficient knowledge or experience. Based on MobileNets, a lightweight convolutional neural network designed for mobile phone, a model was trained to assist workers in identifying tree species. The dataset was collected from some forest parks in Beijing. The accuracy of the tree species recognition model was 94.02% on a test dataset and 93.21% on a test dataset in the mobile phone. This provides an effective reference for workers to identify tree species and can assist in artificial identification of tree species. Experiments show that this solution using the ground measurement tool saves time and cost for forest resources GIS surveys.

scholarly journals ACCURACY ASSESSMENT OF CROWN DELINEATION METHODS FOR THE INDIVIDUAL TREES USING LIDAR DATA

2016 ◽  
Vol XLI-B8 ◽  
pp. 585-588
Author(s):  
K. T Chang ◽  
C. Lin ◽  
Y. C. Lin ◽  
J. K. Liu
Keyword(s):  
Forest Canopy ◽  
Accuracy Assessment ◽  
Tree Height ◽  
Experimental Results ◽  
Estimation Methods ◽  
Surface Model ◽  
Individual Tree ◽  
Free Process ◽  
Crown Shape ◽  
Individual Trees

Forest canopy density and height are used as variables in a number of environmental applications, including the estimation of biomass, forest extent and condition, and biodiversity. The airborne Light Detection and Ranging (LiDAR) is very useful to estimate forest canopy parameters according to the generated canopy height models (CHMs). The purpose of this work is to introduce an algorithm to delineate crown parameters, e.g. tree height and crown radii based on the generated rasterized CHMs. And accuracy assessment for the extraction of volumetric parameters of a single tree is also performed via manual measurement using corresponding aerial photo pairs. A LiDAR dataset of a golf course acquired by Leica ALS70-HP is used in this study. Two algorithms, i.e. a traditional one with the subtraction of a digital elevation model (DEM) from a digital surface model (DSM), and a pit-free approach are conducted to generate the CHMs firstly. Then two algorithms, a multilevel morphological active-contour (MMAC) and a variable window filter (VWF), are implemented and used in this study for individual tree delineation. Finally, experimental results of two automatic estimation methods for individual trees can be evaluated with manually measured stand-level parameters, i.e. tree height and crown diameter. The resulting CHM generated by a simple subtraction is full of empty pixels (called "pits") that will give vital impact on subsequent analysis for individual tree delineation. The experimental results indicated that if more individual trees can be extracted, tree crown shape will became more completely in the CHM data after the pit-free process.

scholarly journals Growth features of apple varieties and forms with natural and compact crown types

2021 ◽  
Vol 845 (1) ◽  
pp. 012014
Author(s):  
A S Zemisov ◽  
A N Youshkov ◽  
N N Saveleva ◽  
L V Grigoreva ◽  
N V Borzykh ◽  
...  
Keyword(s):  
Tree Height ◽  
Cost Effective ◽  
Federal State ◽  
Scientific Center ◽  
Apple Varieties ◽  
Crown Volume ◽  
Crown Shape ◽  
The Rich ◽  
Growth Features ◽  
High Degree

Abstract This research explores the compactness of apple varieties and forms with different types of crown. Orchards on semi-vigorous rootstocks with density and high density planting systems are cost-effective in modern horticulture. For making such gardens, it is necessary to have trees with special compact crown shape. They ensure the high-quality fruits production, meeting the requirements of world standards. To date the most perspective apple varieties and forms for domestic intensive gardening from the rich gene pool of the Selection and Genetic Center of Federal State Scientific Institution «I. V. Michurin Federal Scientific Center» are identified. Varieties of folk domestic and foreign breeding took part in the creation of new genotypes. Apple varieties and promising forms (more than 160 genotypes), including from near and far abroad selection, were used as materials for crown features studying. We conducted our study by the following indicators: tree height, crown volume, “degree of compactness” and the shoot-forming ability. We found that the genotypes Sholokhovskoye, Zvezda Artemyeva, 25-7(11), 40-9(8), 36-8(21), 40-9(6), 8-7(72), 40-9(7), 36-8(17), 62-5(140) have optimal crown parameters. We recommend their use for industrial horticulture and further breeding to create restrained growth, low-volume crown, and a high degree of compactness varieties.

3D Reconstruction and Digital Preservation of Ancient Building Based on 3DGIS

2011 ◽  
Vol 94-96 ◽  
pp. 1962-1966
Author(s):  
Jing Wei Wang ◽  
Yan Jiang ◽  
Dong Ling Ma
Keyword(s):  
3D Reconstruction ◽  
Data Acquisition ◽  
Digital Preservation ◽  
Horizontal Distance ◽  
Height Measurement ◽  
Total Station ◽  
3D Data ◽  
Contact Data

In this paper, the work of data acquisition is devided into the horizontal distance and height measurement according to the features of 3D data obtained from ancient building. The non-prism total station is used to achieve the non-damage and non-contact data acquisition from the ancient building. Moreover, the method of 3D reconstruction and digital preservation of ancient building is introduced based on 3DGIS, which has practical value based on its efficiency and reliable accuracy.

scholarly journals Mesure de la hauteur des arbres avec la perche Sokkisha : Test de précision

1995 ◽  
Vol 71 (5) ◽  
pp. 616-620 ◽  
Author(s):  
Richard Zarnovican ◽  
Jean De Grâce
Keyword(s):  
Prediction Interval ◽  
Tree Height ◽  
Balsam Fir ◽  
Negative Bias ◽  
Tolerance Interval ◽  
Probability Level ◽  
Height Measurement ◽  
Quadratic Error ◽  
North Shore ◽  
The Mean

The accuracy of measuring tree height using a Sokkisha pole compared with that obtained using a tape measure was tested. This test was conducted in young thinned balsam fir stands in the Upper North Shore region of the province of Quebec. The results show a slightly negative bias, -0.06 m or -1.03%, significantly different from zero at the 95% probability level. A study of the precision shows that the mean quadratic error does not exceed ±0.11 m or ±1.77%. Using the prediction interval, we can be 95% confident that in a single future measurement, the error will be around ±0.21 m or ±3.49%. According to tolerance interval, we can be 95% confident that at least 95% of the population of errors produced by using the pole will fall between ±0.23 m or ±3.9%. Key words: Test of accuracy, measuring poles, tree height measurement, mensuration, balsam fir.

Tree height and crown shape, as results of competitive games

1985 ◽  
Vol 112 (2) ◽  
pp. 279-297 ◽  
Author(s):  
Yoh Iwasa ◽  
Dan Cohen ◽  
Jesus Alberto Leon
Keyword(s):  
Tree Height ◽  
Crown Shape ◽  
Competitive Games

scholarly journals Accuracy of smartphone applications in the field measurements of tree height

2015 ◽  
Vol 57 (4) ◽  
pp. 240-244 ◽  
Author(s):  
Szymon Bijak ◽  
Jakub Sarzyński
Keyword(s):  
Accurate Determination ◽  
Tree Height ◽  
Field Measurements ◽  
Measurement Tool ◽  
Smartphone Applications ◽  
Height Determination ◽  
Relative Errors ◽  
Actual Height ◽  
Forest Practice ◽  
Scots Pine Stands

Abstract As tree height is one of the important variables measured in forestry, much effort is made to provide its fast, easy and accurate determination. We analysed precision of two widely available smartphone applications (Smart Measure and Measure Height) during the field measurements of tree height. The data was collected in three Scots pine stands in central Poland. We found negative systematic error of both tested applications regardless the distance of the measurement (15 or 20 m). RMSE values of the height estimates varied from 1.01 to 2.46 m depending on the application used and the distance of the measurement. Value of the calculated absolute and relative errors significantly (p < 0.015) positively depended on the actual height of the measured trees and was more diverse for higher trees. Smartphone applications seem to be promising measurement tool for tree height determination, however as for the time being they require improvement before wider introduction into the forest practice.

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