  We show that topology of the low-energy band structure in bilayer graphene
critically depends on mechanical deformations of the crystal which may easily
develop in suspended graphene flakes. We describe the Lifshitz transition that
takes place in strained bilayers upon splitting the parabollic bands at
intermediate energies into several Dirac cones at the energy scale of few meV.
Then, we show how this affects the electron Landau level spectra and the
quantum Hall effect.
