Forest Structural Complexity Tool—An Open Source, Fully-Automated Tool for Measuring Forest Point Clouds

Forest mensuration remains critical in managing our forests sustainably, however, capturing such measurements remains costly, time-consuming and provides minimal amounts of information such as diameter at breast height (DBH), location, and height. Plot scale remote sensing techniques show great promise in extracting detailed forest measurements rapidly and cheaply, however, they have been held back from large-scale implementation due to the complex and time-consuming workflows required to utilize them. This work is focused on describing and evaluating an approach to create a robust, sensor-agnostic and fully automated forest point cloud measurement tool called the Forest Structural Complexity Tool (FSCT). The performance of FSCT is evaluated using 49 forest plots of terrestrial laser scanned (TLS) point clouds and 7022 destructively sampled manual diameter measurements of the stems. FSCT was able to match 5141 of the reference diameter measurements fully automatically with mean, median and root mean squared errors (RMSE) of 0.032 m, 0.02 m, and 0.103 m respectively. A video demonstration is also provided to qualitatively demonstrate the diversity of point cloud datasets that the tool is capable of measuring. FSCT is provided as open source, with the goal of enabling plot scale remote sensing techniques to replace most structural forest mensuration in research and industry. Future work on this project will seek to make incremental improvements to this methodology to further improve the reliability and accuracy of this tool in most high-resolution forest point clouds.

Stacked-timber ratio and stem volume of horse chestnut trees within Kyiv City urban stands

Urban forest are influenced by urban environment, what has a negative effect on the vital activities of the trees. Growth environment of trees on urban territories and in natural areas are completely different. Research data was collected in urban forest stands of Kyiv city during thinnings. Special methodological characteristics of the measuring of main biometrical tree parameters in urban area are explained in this work. Importantly, chestnut trees have morphological feature which stems are branching on the certain height leading to occurrence of the several main branches. Modelling tree stem volume, the most important pattern to find was a mathematical dependence of form factors on the main tree biometrical parameters. Basic descriptive statistics of chestnut trees parameters were estimated. It is defined that the percentage of trunk volume decreases with an increase of tree diameter and in trees over 60 cm can make up to 30% of the total tree volume. Carrying out a correlation analysis of model trees, it was examined that form factors of tree stems were highly linked to the branching height. Based on the statistical analysis it was estimated that developed mathematical model reflected empirical data adequately and could be validated according to the current forest mensuration accuracy requirements properly. Moreover, a bias of the developed form factor model examined using Student t-criteria is not significant. Respective information-support tables to estimate stem volume of chestnut trees were created based on the developed form factor model, harnessing the classical formula of forest mensuration. Given stem volume tables created considering physiological features of chestnut trees under urban environment conditions can be utilized by the organizations which manage forest stands and parks within settlements.

Trends in Management of Tropical Forests

Forests are important plant communities that consist of trees and other woody vegetation that performs life-supporting functions on Earth. This chapter presents the application concepts necessary to link remote sensing data and geographic information system to conservation, restoration, and sustainable management of tropical forests. Despite the rising global concern, there is still continuous destruction of tropical forests at an alarming rate. This chapter assessed various approaches for conservation, restoration, and sustainable management of tropical forests using remote sensed data and geographic information system. This involves their applications to biodiversity conservation, forest ecophysiology, forest trees' disease and insect interactions, forest mensuration, forest resources monitoring and evaluation, forest fires, land use and land cover dynamics, and vegetation cover.

DETERMINAÇÃO DE ALTURA EM Pinus taeda L. UTILIZANDO VEÍCULO AÉREO NÃO TRIPULADO

Este trabalho teve como objetivo determinar a altura total, de 30 árvores em um plantio de Pinus taeda, com apoio de tecnologias de geoprocessamento. Obteve-se a alturas por meio de aerolevantamento e também com o método convencional (com hipsômetro), avaliando estatisticamente os resultados. Foram adquiridas imagens com Aeronave Remotamente Pilotada (ARP), utilizando pontos de controle, que serviram para a relação das coordenadas da imagem com as do terreno. A geração do Modelo Digital do Terreno (MDT), foi realizada por meio de topografia convencional, fornecendo dados para a planialtimetria local, ao longo do alinhamento do plantio. Para obtenção das alturas, aplicou-se a subtração entre as altitudes do MDS e do MDT, sendo consideradas como tratamento 1. Com hipsômetro, foram mensuradas as alturas das mesmas árvores, sendo consideradas como tratamento 2 e posteriormente foi aplicado teste t, para a comparação entre as médias, usando significância estatística de 5% de probabilidade. Foi observada a diferença média de 4,05%, entre tratamentos, fato que orienta a viabilidade da metodologia através do uso de imagens obtidas por ARP, havendo diferença estatística significativa entre diferentes formas de obtenção dos dados. Porém, verificou-se a maior precisão e menor dispersão, naqueles dados coletados com metodologia apoiada por imagem, sendo necessário destacar que o hipsômetro, é um método indireto de medição, que apresentar sub ou superestimado das alturas.Palavras-chave: aerolevantamento; mensuração florestal; modelo digital de terreno; modelo digital de superfície. DETERMINATION OF HEIGHT In Pinus taeda L. USING UNCONSCIOUS AIR VEHICLE ABSTRACT: The objective of this work was to determine the total height of 30 trees in a plantation of Pinus taeda, with the support of geoprocessing technologies. Height was obtained by means of aerial survey and also with the conventional method (with hypsometer), statistically evaluating the results. Images were obtained with Remotely Pilot Aircraft (ARP), using control points, which served to relate the coordinates of the image with those of the terrain. The generation of the Digital Terrain Model (TDM) was performed by means of conventional topography, providing data for local planialtimetry along the alignment of the plantation. In order to obtain the heights, the subtraction was applied between the MDS and MDT altitudes, being considered as treatment 1. With a hypsometer, the heights of the same trees were measured, being considered as treatment 2 and later t-test was applied for the comparison between means, using statistical significance of 5% probability. The mean difference of 4.05% between treatments was observed. This fact guides the viability of the methodology through the use of ARP images, and there is a statistically significant difference between different ways of obtaining the data. However, it was verified the greater precision and less dispersion, in those data collected with methodology supported by image, being necessary to emphasize that the hypsometer, is an indirect method of measurement, that presents sub or overestimated of the heights.Keywords: aerial survey; forest mensuration; digital terrain model; digital surface model.