Abstract
<p>Trees supply a multitude of ecosystem services (e.g. carbon storage, suppression of air pollution, oxygen, shade, recreation etc.) not only in forested areas but also in urban landscapes. Many of these services are positively correlated with tree size and structure. The assessment of carbon storage potential via the quantification of above ground biomass (AGB) is of special importance. However, quantification of AGB is difficult and applied allometries are often based on forest trees, which are subject to very different growing conditions, competition and form compared to urban trees. In this contribution, we highlight the potential of terrestrial laser scanning (TLS) techniques to extract high detailed information on tree structure and AGB with a focus on urban trees.</p><p>A total of 55 urban trees distributed over eight cities in Switzerland were measured using TLS and traditional forest inventory techniques before they were felled and weighted. Tree structure, volumes and AGB from the TLS point clouds were extracted using Quantitative Structure Modelling (QSM). TLS derived AGB estimates were compared to allometric estimates dependent on diameter at breast height only. The allometric models were established within the Swiss National Forest Inventory and are therefore optimised for forest trees.</p><p>TLS derived AGB estimates showed good performance when compared to destructively harvested references with an R<sup>2</sup> of 0.954 (RMSE = 556 kg), compared to an R<sup>2</sup> of 0.837 (RMSE = 1159 kg) for allometrically derived AGB estimates. A correlation analysis showed that different TLS derived wood volume estimates as well as trunk diameters and tree crown metrics show high correlation in describing total wood AGB.</p><p>The presented results show that TLS based wood volume estimates show high potential to estimate tree AGB independent of tree species, size and form. This allows us to retrieve highly accurate, non-destructive AGB estimates that could be used to establish new allometric equations without the need of extensive destructive harvest.</p>
Highlights
Key Results Estimates of above-ground biomass (AGB) derived by terrestrial laser scanning (TLS) showed good performance when compared with destructively harvested references, with an R2 of 0.954 (RMSE = 556 kg) compared with 0.837 (RMSE = 1159 kg) for allometrically derived AGB estimates
These results show that more AGB is TLS based small wood biomass
In this study we reconstructed the 3-D structure of urban trees using TLS acquisitions at very high resolution and estimated AGB from the 3-D point cloud using a quantitative structure modelling (QSM) modelling
Summary
Urban areas are predicted to increase in size as a fraction of total land cover (Seto et al, 2012; Hutyra et al, 2014). With this increase, alongside ongoing climate change, the role of urban trees becomes increasingly important, providing wellrecognized ecosystem services. Alongside ongoing climate change, the role of urban trees becomes increasingly important, providing wellrecognized ecosystem services These include mitigation of the urban ‘heat island’ effect and local climate regulation (Armson et al, 2012), their importance in biodiversity conservation (Goddard et al, 2010) and abating air pollution (Baró et al, 2014), and their benefits for well-being and aesthetics (Kardan et al, 2015). As urban trees encounter environmental and neighbourhood circumstances different from those of their forest counterparts, they often show a higher dynamic and plasticity with higher mortality (Tigges et al, 2017) and often faster growth rates (Pretzsch et al, 2017), and they tend to develop relatively large crowns and branches
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call