Original scientific paper
https://doi.org/10.31298/sl.146.5-6.2
Comparison of crown damage assessment on analog and digital infrared color (CIR) aerial photographs
Jelena Kolić
; Fakultet šumarstva i drvene tehnologije Sveučilišta u Zagrebu
Renata Pernar
; Fakultet šumarstva i drvene tehnologije Sveučilišta u Zagrebu
Ante Seletković
; Fakultet šumarstva i drvene tehnologije Sveučilišta u Zagrebu
Mirna Samaržija
; Senj
Mario Ančić
; Fakultet šumarstva i drvene tehnologije Sveučilišta u Zagrebu
Abstract
Efforts to mitigate negative consequences of massive forest dieback include the implementation of economic measures, monitoring the health status of individual trees i.e. assessment of crown damage. Apart from terrestrial methods, forest health is also determined with remote sensing methods, which involve interpretation of color infrared (CIR) aerial photographs.
The inventory of forest damage by using aerial photography is based on the establishment of the degree of damage to individual trees (crowns) using a well-designed photo interpretation key. Reliable statistical data of forest damage can be obtained on the basis of photo interpretation of CIR aerial photography.
Inventories of forest damage have so far been conducted with photo interpretation of analog aerial photographs on analytical stereo instruments. With the advancement of technology, analog images have been replaced by digital and analytical stereo instruments – by digital photogrammetric workstations, and interpretation is done on the computer screen.
The main goal of the research was to compare the results of crown damage assessment on analog and digital ICK aerial photographs of the same area, which is why it was necessary to convert aerial photographs from 1989 by scanning into digital form, and convert digital images from 2008 into analog form.
Analog and digital aerial photographs from two recording periods (1989 and 2008) were interpreted for a part of the management units Josip Kozarac and Opeke. At each point of a 100x100 m grid, 4 nearest trees (crowns) were estimated and damage indicators (damage-O, mean damage-SO, damage index-IO, mean damage1-SO1) were calculated for individual tree species, for all the interpreted species together, per surveying strips, and for the total research area.
On the basis of calculated damage indicators obtained by interpreting analog and digital images from 1989 and 2008, it was found that there was no statistically significant difference between the results in terms of tree health assessment.
The conducted research improved the existing methods of assessing the health status of individual trees and stands, and pointed out the possibilities of applying digital CIR aerial photographs in forestry.
Keywords
crown damage assessment; visual interpretation; analog CIR aerial photographs; digital CIR aerial photographs; mirror stereoscope; digital photogrammetric workstation
Hrčak ID:
279972
URI
Publication date:
30.6.2022.
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