Silvilaser 2019 - Poster Presentations »
Carbon sequestration potential and wood quality aspects of southern African trees extended to agroforestry systems – an assessment through 3D data
Southern Africa is faced with several impacting and interrelated issues such as climate change, degraded landscapes, food insecurity and other severe economic, social and environmental challenges. We selected the southern African region to address these pressing issues by exploiting technological advancements for the accurate estimation of aboveground biomass of trees. Simultaneously, the employment of innovative and integrated land use systems such as agroforestry systems (combining agricultural crops and trees) is expected to be part of the solution by supporting resilience against a changing climate. Through inclusion of trees within farmed landscapes increased carbon sequestration, water retention, soil erosion control and enhancement of rural livelihoods can be achieved. In order to promote trees and agroforestry systems, the application of terrestrial laser scanning technology is of high interest and importance. A non-destructive methodology to estimate the aboveground carbon sequestration potential of tree species growing in southern African landscapes is applied under the framework of the ASAP project (“Agroforestry in southern Africa – new pathways of innovative land use systems under a changing climate”, grant number 01LL1803 funded by the German Federal Ministry of Education and Research). We use 3D data derived from single trees scanned in multiple positions for the assessment of tree volume. In this context, the tree volume data estimated through quantitative structure models (QSMs) is used as basis for calculating the aboveground tree biomass. For this purpose, we combine the tree volume with species specific wood density. The use of QSMs enables a truthful description and examination of the topological (branching structure), geometric and volumetric properties of the woody structure of a tree. The eventual absence of 3D data specific to agroforestry trees is overcome by selecting sample trees growing in more open landscape conditions (open forests, solitary grown trees such as trees outside forests). Standard tree parameters such as height to crown base, crown volume and tree height, help to quantify the tree impact on the neighboring crops. Equally important are TLS-detectable tree attributes that relate to wood quality and efficient wood utilization (e.g. stem volume, sweep, taper, branchiness). Furthermore, we place a special focus on the biomass distribution between different tree components (e.g. between stem and branch fractions) and on distinct tree species occurring in agroforestry systems.