Sistema de medición de bajo costo para determinar la respiración de tronco de los áboles “Tree-Hugger”

Abstract

Compared to studies about soil or leaf respiration which have been conducted much more frequent, measurement of stem respiration is rather rare. However, when aiming to understand and determine the forest ecosystem CO2 balances, it is crucial to also obtain stem respiration as a net source of CO2. The reason for the low amount of stem respiration measurements are not only technical difficulties in assessing stem respiration itself (e.g., generate proper sealing of chambers enclosed on the tree bark), but also economic limitations, since most commercial GHG measurement systems are rather expensive. Hence, their acquisition can be challenging in regions where resources are limited, such as the Global South, wherefore information on full CO2 balances of forest ecosystems also including the different balance components such as stem respiration are usually underrepresented when compared to the Global North. To allow for stem respiration measurements also under resource limited conditions, here it is presented a low-cost automatic chamber system for stem respiration “Tree-Hugger”. The system is based on Arduino and a non-dispersive infrared (NDIR; SCD 30) (171.82 EUR/765,450 COP) CO2 sensor to determine CO2 concentration changes during chamber closure. To validate the systems precision and trueness (overall accuracy), a row of laboratory and field tests was conducted, whose results are presented within this thesis. Finally, the system was applied during a longer-term field study (February to June) aiming to detect seasonal differences in stem respiration between two different tree species. It could be shown, that the developed system delivers accurate results and is able to determine not only differences in stem respiration between different tree species, but also the underlying temperature dependency and due to its automatic measurement of diurnal cycle underlying diurnally in stem respiration fluxes. In view of this, the “Tree-Hugger” could contribute to complementing studies related to the carbon (C) balance of the world's forest ecosystems, especially those in the Global South.