Controlling the spatial organization of objects at the nanoscale is a key challenge in enabling their technological application(1-3). Biomolecular assemblies are attractive nanostructures owing to their biocompatibility, straightforward chemical modifiability, inherent molecular recognition properties and their availability for bottom-up fabrication(4-16). Aromatic peptide nanotubes are self-assembled nanostructures with unique physical and chemical stability and remarkable mechanical rigidity(14-16). Their application in the fabrication of metallic nanowires and in the improvement of the sensitivity of electrochemical biosensors have already been demonstrated(14-17). Here we show the formation of a vertically aligned nanoforest by axial unidirectional growth of a dense array of these peptide tubes. We also achieved horizontal alignment of the tubes through noncovalent coating of the tubes with a ferrofluid and the application of an external magnetic field. Taken together, our results demonstrate the ability to form a two-dimensional dense array of nanotube assemblies with either vertical or horizontal patterns.