This research investigates alternative biomass feedstocks for environmentally improved composites in the aviation industry. It addresses challenges and opportunities associated with biomass use and proposes a sustainable biomass feedstock for bio-methanol production as a carbon fibre precursor for composites. The aim is to evaluate the environmental implications and practical considerations of utilizing this feedstock for sustainable bioeconomy models.

The study emphasizes the importance of lightweight carbon fibre composites in meeting emission reduction targets in aviation. It identifies biomass feedstocks for methanol production as a viable strategy for manufacturing sustainable composites. However, the sustainability of this approach is highly dependent on the strategies for biomass sourcing. A need to move from bioeconomy models based on the extraction of resources towards restorative systems based on Ecosystem Service (ES) provisioning is identified as the solution to deal with the sustainability challenges of biomass use. Agroforestry systems, integrating energy crops in farmlands, and in particular short rotation silvoarable systems (crops and short rotation trees integration), are identified as promising strategies for sustainable biomass production while enhancing ES provisioning and agricultural lands' resilience.

The subsequent research questions explore Life Cycle Assessment (LCA) results comparing different alternatives for methanol production. Silvoarable systems show favourable climate change and fossil fuel depletion performance when compared to natural gas-based methanol, but other impact categories do not offer significant advantages due to higher electricity consumption. The use of forest residues for methanol production performed better than the silvoarable alternative in most of the impact categories, but when more productive silvoarable plantations are considered or non-local sourcing of forest residues is necessary, silvoarable systems are as good or better than these systems. The alternative of using marginal lands for short rotation production had a lower performance compared with the silvoarable system mainly due to the lower productivity of these systems, however, this could also be considered as good feedstock for methanol production particularly if these are grown in floodplains to improve the yields of the system. Considerations of the aviation industry's environmental impact and supply chain are briefly included. While bio-based composites offer carbon emissions savings, these reductions are minimal compared to the overall aviation emissions. Cost considerations pose challenges, with bio-methanol alternatives currently having higher production costs. Suggestions include CO2 emissions taxes, subsidies, and optimized supply chain processes to bridge this gap.

In conclusion, this research provides valuable insights into the potential of short-rotation silvoarable systems as sustainable biomass feedstock providers for composite manufacturing. While the LCA results demonstrate promising environmental advantages, the results are limited to the narrow scope of this study. Therefore, further exploring and studying these systems is required if these systems are aimed to be considered future biomass providers.
The findings offer Airbus and other industries an opportunity to embrace sustainable bioeconomy models, contributing to environmental footprint mitigation and restoration of equilibrium with natural systems.

The food sector plays a crucial role in exceeding several planetary boundaries. Currently, humanity has the challenge to stay between these boundaries. Food forests are an approach for improving ecosystems in soil quality, sequestering carbon and enhancing biodiversity while providing food. However, this concept is yet nearly unstudied in temperate regions. Accordingly, this study attempted to investigate aboveground and belowground storage, carbon fluxes, and the build-up rate in the transition from grassland to a food forest through an in-depth case study in a temperate region. In order to analyse all key carbon pools, a plotless method was applied for the coppice, hedgerows, fruit and nut-bearing trees, and a plot-based method for the grass, herbs, litter and soil organic carbon (SOC).
Overall, the results showed exponential growth in aboveground carbon in the living biomass, though remarkably different patterns for SOC over the first 5.5 years. The ground layer (e.g. grass, herbs, and litter) is a significant source of aboveground carbon in young food forests (95% in year 3.5 to 36% in year 5.5). The trees compartments showed an exponential increase, and the total stored carbon biomass in the food forests at the age of 5.5 is 6.0 t C ha-1 yr-1. The SOC differed over the years, which is 115 t C ha-1 in the grassland and depicts 78 to 136 t C ha-1in year 5.5. Finally, the food forest has the potential to sequester around 4.4 t C ha-1 yr-1 in above and belowground biomass, functioning as active carbon sinks already within the first five years of the case study. Coppice and hedgerows have proven to be vital in sequestering carbon in living biomass. Further research should investigate older food forests in temperate regions while bearing in mind the potential of coppices and hedgerows. In addition, a better understanding of belowground carbon is essential for assessing the net carbon impact of carbon farming initiatives, as the soil stores most of the carbon.

Agriculture is a major driver of exceeding the planetary boundaries. Therefore, it is a principal sector that requires sustainable change. Agroforestry, described as the deliberate planting of trees on farm land or integrating farmers into forests, is one of the proposed solutions and has gained a lot of (renewed) attention in the Netherlands and elsewhere. A food forest, one of the subcategories, is defined as a human designed system with a variety of edible species grown in vertical layers based on the example of a natural forest. The aim of this research was to provide a more solid basis for the quantification of yields for temperate food forests together with describing advantages regarding nutrients (N, P) and water. To this end, a focal study plot of food forest Schijndel was analysed in which future yields and nutritional carrying capacities (NCCs) were modelled for 2020-2049 with an extrapolation to 2067. Results were compared with conventional fruit-, carbohydrate cropping-, nutand meat systems. The results for this focal study plot showed a slow but steady yield increase towards a fresh weight yield of 7.1 t/ha in 2049 together with a balanced nutritional supply in terms of NCC for kcal (11.0 persons/ha), carbohydrates (13.1 persons/ha), proteins (11.6 persons/ha), fats (13.1 persons/ha) and fibres (23.0 persons/ha) in 2049. Nutritional results were in general significantly higher than few previous studies. The comparison between cultivation systems showed that the food forest plot had the highest overall NCC. Furthermore, the study plot scored high in the category of fats, modest for proteins and was not competitive with the best performing systems among carbohydrates, fibres and kcal. It is hypothesized that a food forest scores high in micronutrient provision as well, although this could not be substantiated in this study. Additionally, several environmental advantages such as reduced nutrient leaching, self-sufficiency and improved on-farm water cycling were indicated. Although, effects such as high annual nutrient removal and high N deposition on those parameters are yet insufficiently understood. In conclusion, a food forest is a more balanced system which takes more time to develop itself than most conventional systems, but offers continuous and (probably) durable yields. The main limitations in this research were the fact that applicable yield data was not readily available together with a premature literature body on effects such as shading on yields. Further research should be redirected towards measuring actual yields, nutrient- and water characteristics and compare those to systems with comparable soil and climate conditions such as adjacent fields together with a further economic assessment for which this study can provide a basis