Methodology of Calculating the Number of Trees Based on ALS Data for Forestry Applications for the Area of Samławki Forest District

Wioleta Błaszczak-Bąk,Joanna Janicka,Krystian Chudzikiewicz,Tomasz Kozakiewicz,Grzegorz Bąk

doi:10.3390/rs14010016

Wioleta Błaszczak-Bąk, Joanna Janicka + Show 3 more

Open Access

https://doi.org/10.3390/rs14010016

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Journal: Remote Sensing	Publication Date: Dec 21, 2021
Citations: 5	License type: CC BY 4.0

Affiliation: University of Warmia and Mazury in Olsztyn

Abstract

Airborne Laser Scanning (ALS) is a technology often used to study forest areas. The main area of application of ALS in forests is collecting data to determine the height of individual trees and entire stands, tree density and stand biomass. The content of the ALS data is also classified, i.e., registered objects are identified, including the species affiliation of individual trees. Important information for forest districts includes other parameters related to the structure and share of stands and the number of trees in the forest district. The main goal of this study was to propose the new ALS data processing methodology for detecting single trees in the Samławki Forest District. The idea of the proposed methodology is to indicate a free and accessible solution for any user (at least in Poland). This new ALS data processing methodology contributes to research on the use of ALS data in forest districts to maintain up-to-date and accurate stand statistics. This methodology was based on free data from the geoportal.gov.pl portal and free software, which allowed to minimize the costs of preparing data for the needs of forestry activities. In cooperation with the Samławki Forest District, the proposed methodology was used to detect the number and heights of trees for two forest addresses 13b and 30a, and then to calculate the volume of stands. As a result, the volume of the analyzed stands was calculated, obtaining values differing from the nominal ones included in the FMP (Forest Management Plan) by about 25% and 5%, respectively, for larch and oak.

Highlights

The main area of application of Airborne Laser Scanning (ALS) in forests is from the very beginning collecting data to determine the height of individual trees and entire stands, tree density and the reserve of stands [1,2]
There were attempts to classify the content of ALS data, i.e., to identify registered objects, including the species affiliation of individual trees
The aim of the study was to propose a new methodology for tree detection with the use of ALS data

Summary

Introduction

The main area of application of Airborne Laser Scanning (ALS) in forests is from the very beginning collecting data to determine the height of individual trees and entire stands, tree density and the reserve (biomass) of stands [1,2]. There were attempts to classify the content of ALS data, i.e., to identify registered objects, including the species affiliation of individual trees. There are two main approaches for using ALS to characterize forest resources [7]: (1) an area-based approach typically providing data at stand level and (2) a single-tree approach where individual trees are the basic unit of the assessment. The detection of single trees requires, above all, an appropriate scanning density, season and specific purpose of the study. Not all trees are usually detected and there is still a need to find a new methodology for tree detection

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