Evaluation of height changes in uneven-aged spruce–fir–beech forest with freely available nationwide lidar and aerial photogrammetry data

Pintar, Anže Martin (author), Skudnik, Mitja (author)

Tree height and vertical forest structure are important attributes in forestry, but their traditional measurement or assessment in the field is expensive, time-consuming, and often inaccurate. One of the main advantages of using remote sensing data to estimate vertical forest structure is the ability to obtain accurate data for larger areas in a more time- and cost-efficient manner. Temporal changes are also important for estimating and analysing tree heights, and in many countries, national airborne laser scanning (ALS) surveys have been conducted either only once or at specific, longer intervals, whereas aerial surveys are more often arranged in cycles with shorter intervals. In this study, we reviewed all freely available national airborne remote sensing data describing three-dimensional forest structures in Slovenia and compared them with traditional field measurements in an area dominated by uneven-aged forests. The comparison of ALS and digital aerial photogrammetry (DAP) data revealed that freely available national ALS data provide better estimates of dominant forest heights, vertical structural diversity, and their changes compared to cyclic DAP data, but they are still useful due to their temporally dense data. Up-to-date data are very important for forest management and the study of forest resilience and resistance to disturbance. Based on field measurements (2013 and 2023) and all remote sensing data, dominant and maximum heights are statistically significantly higher in uneven-aged forests than in mature, even-aged forests. Canopy height diversity (CHD) information, derived from lidar ALS and DAP data, has also proven to be suitable for distinguishing between even-aged and uneven-aged forests. The CHD$_{ALS}$ 2023 was 1.64, and the CHD$_{CAS}$ 2022 was 1.38 in uneven-aged stands, which were statistically significantly higher than in even-aged forest stands.

• Language: English
• Keywords: uneven-aged forest, freely available national airborne remote sensing data, lidar, aerial photography, dominant height, canopy height diversity, periodic annual increment
• Work type: Article
• Typology: 1.01 - Original Scientific Article
• Organization: BF - Biotechnical Faculty
• Publication status: Published
• Publication version: Version of Record
• Year: 2025
• Number of pages: 16 str.
• Numbering: Vol. 16, iss. 1, art. 35
• PID: 20.500.12556/RUL-166381
• UDC: 630*58
• ISSN on article: 1999-4907
• DOI: 10.3390/f16010035
• COBISS.SI-ID: 221512707
• Publication date in RUL: 10.01.2025

Record is a part of a journal

• Title: Forests
• Shortened title: Forests
• Publisher: MDPI
• ISSN: 1999-4907
• COBISS.SI-ID: 3872166

Licences

• License: CC BY 4.0, Creative Commons Attribution 4.0 International
• Link: http://creativecommons.org/licenses/by/4.0/
• Description: This is the standard Creative Commons license that gives others maximum freedom to do what they want with the work as long as they credit the author.

Secondary language

• Language: Slovenian
• Keywords: raznodobni gozdovi, prosto dostopni nacionalni podatki daljinskega zaznavanja iz zraka, lidar, fotografiranje iz zraka, prevladujoča višina, višinska raznolikost krošnje, periodični letni prirastek