PhD defense – Johannes Michael Hafner

On the 29.04.2022, Johannes Michael Hafner successfully defended his PhD work with the title “Development of a component-based assessment framework to evaluate fuelwood energy systems of smallholder farmers in sub-humid and semi-arid regions in Tanzania - Modelling cooking-related demand and on-farm supply of fuelwood.”

The PhD defense was conducted virtually; the doctoral committee was headed by Prof Dr. Dagmar Mithöfer (Professorship in management agricultural value chains at Humboldt-Universität zu Berlin).

During his PhD work, Mr. Hafner has been enrolled at the Albrecht Daniel Thaer-Institute at the Faculty of Life Sciences of Humboldt-Universität zu Berlin. He was supervised by Prof. Dr. Klaus Müller (Professorship in Economics and Politics of Rural Areas at Humboldt-Universität zu Berlin; Co-Head of Research Area 2 "Land use and governance" at ZALF), PD Dr. Stefan Sieber (Head of the working group “Sustainable Land Use in Developing Countries” at ZALF) and Dr. Anthony Kimaro (Country representative of World Agroforestry Tanzania).

Within his PhD, Mr. Hafner focused on the development of a framework to assess and model fuelwood demand and on-farm fuelwood production to determine fuel sufficiency levels of smallholder farmers in semi-arid Tanzania. He conducted multi-annual performance assessments of different cook stove systems and agroforestry fuelwood production systems. Central findings of the research encompassed that improved cook stoves reduce the fuelwood and time spent during cooking compared to three-stone fire stove when operated with common off-farm and with on-farm fuelwood. Using qualitative assessment methods such as participatory impact assessments, Mr. Hafner identified locally perceived most important criteria which can benefit improved cook stove adoption in the case study sites. His final published work included the estimation and modelling of on-farm fuelwood production of G. sepium and pigeon pea within different agroforestry systems.

Mr. Hafner developed and published his framework within four peer-reviewed articles. His developed framework enables farmers to estimate their fuelwood consumption during cooking and on-farm production potential to improve farmland planning for fuelwood security. With precise farmland planning, households can substitute fuelwood from off-farm sites with on-farm produced fuelwood which includes multiple socio-economic benefits.

The doctoral committee rated the PhD with an overall grade of magna cum laude.