Quantification of Circadian Movement of Small-Leaved Lime (Tilia cordata Mill.) Saplings With Short Interval Terrestrial Laser Scanning

Abstract

The goal of the study was to quantify and identify patterns in circadian movements of small-leaved lime (Tillia cordata) saplings with the help of terrestrial laser scanning (TLS). The movements were monitored every 60 min 24 h a day and every 30 min in the hour of sunrise and sunset. In order to exclude wind effects the monitored saplings were indoors. The resulting point clouds were used in creating a time series of branch and foliage movements with high precision. The circadian vertical movement of saplings was evaluated through target points, which has a potential of capturing the point-wise movement more accurately. Our results clearly show that small saplings move their branches and leaves during 24 h in complex ways and that is difficult to identify general patterns. Since we worked with small saplings and our movement threshold was 5 mm, we detected random fluctuation-oscillation as the most common movement in monitored saplings. The results highlight the potential of TLS measurements in support of chronobiology and the possibilities to analyze circadian movements of saplings in controlled environment.

A Long-Term Terrestrial Laser Scanning Measurement Station to Continuously Monitor Structural and Phenological Dynamics of Boreal Forest Canopy

“…The feasibility of terrestrial LiDAR data to detect and monitor long-term vegetation dynamics in forest and crop areas have been discussed in previous works, including plant growth ( Yu et al, 2004 , 2006 ; Olivier et al, 2017 ; Guo et al, 2019 ), DBH increase ( Liang et al, 2012 ), AGB change ( Kaasalainen et al, 2014 ; Srinivasan et al, 2014 ) and spring sprouting and flowering ( Olsoy et al, 2014 ; Calders et al, 2015 ). Recently, new studies have also used TLS data for monitoring short-term phenomena, such as circadian rhythms and foliar nyctinasty in different plants and tree species ( Puttonen et al, 2015 , 2016 , 2019 ; Zlinszky et al, 2017 ; Herrero-Huerta et al, 2018 ; Bakay and Moravčík, 2020 ). These studies highlight the high potential of setting up a permanent TLS measurement station as a new non-destructive tool for boreal forest dynamics monitoring.…”

“…Circadian movements up to 10 cm were identified on branch tips. Recently, Bakay and Moravčík (2020) monitored branch and leaf displacement in lime trees under a controlled environment using high precision 24-h TLS time series. These authors proposed a new method of movement quantification of monitored saplings focused on target point monitoring.…”

“…Over the last 5 years, new studies have detected and quantified circadian movements in the tree branches and foliage of fullgrown trees using TLS data acquired with short timescale measurements that have had an hourly or even more frequent scanning repetition rate (Puttonen et al, 2015(Puttonen et al, , 2016(Puttonen et al, , 2019Zlinszky et al, 2017;Herrero-Huerta et al, 2018;Bakay and Moravčík, 2020). Puttonen et al (2016) used TLS time series acquired in two geographically different locations (Finland and Austria) to detect short-term vegetation dynamics.…”

Presentation_1.pdf

“…The feasibility of terrestrial LiDAR data to detect and monitor long-term vegetation dynamics in forest and crop areas have been discussed in previous works, including plant growth (Yu et al, 2004(Yu et al, , 2006Olivier et al, 2017;Guo et al, 2019), DBH increase (Liang et al, 2012), AGB change (Kaasalainen et al, 2014;Srinivasan et al, 2014) and spring sprouting and flowering (Olsoy et al, 2014;Calders et al, 2015). Recently, new studies have also used TLS data for monitoring short-term phenomena, such as circadian rhythms and foliar nyctinasty in different plants and tree species (Puttonen et al, 2015(Puttonen et al, , 2016(Puttonen et al, , 2019Zlinszky et al, 2017;Herrero-Huerta et al, 2018;Bakay and Moravčík, 2020). These studies highlight the high potential of setting up a permanent TLS measurement station as a new non-destructive tool for boreal forest dynamics monitoring.…”

“…Circadian movements up to 10 cm were identified on branch tips. Recently, Bakay and Moravčík (2020) monitored branch and leaf displacement in lime trees under a controlled environment using high precision 24h TLS time series. These authors proposed a new method of movement quantification of monitored saplings focused on target point monitoring.…”