Paulownia is a desired hardwood. You can start making money buy selling some thinned or coppiced trees. The fuzzy leaves build great soil, and are biomass rich. The leaves are also
profitable. The leaves can be raked, and baled for animal
feed. For your own animals or to
sell or trade. Since the trees grow so fast, they are good candidates for copping, for
spoons handles, poles, and walking canes or staffs. Larger trees being good for furniture. You can take cuttings and sell babies. They are nitrogen lovers, and a large tree that will consume a lot of nutrients. So, your idea of heavy supplements, ie, comfrey and legumes is a great one, and a good start to prepare the soil for whatever your heart desires to grow. The trees do prefer low ph soils, so I'd imagine things such as blue berries and other acid loving plants would not like the same soil. Just my 2 cents.