The interaction between turbulent flow and elastic fibers implanted on a flat wall is numerically investigated. The influence of the collective motion of the fibers on the large scale vortices above them is focused on. The vortices increase the momentum transfer between inside and outside of the canopy layer. They are characterized by the strong sweep and weak ejection.The turbulent flow is reproduced by the direct numerical simulation of the Navier-Stokes equation of incompressible fluid. Each flexible fiber is modeled to be a one-dimensional object connected by Lagrangian markers, and geometric non-linearity is taken into account. The interaction between fluid flow and fibers is solved by an immersed-boundary method. In this research, a parameter study is conducted for investigating the effect of the properties of fibers such as length, elasticity and number density on the turbulent flow. The results of the spectral analysis imply that the fibers oscillate not at the frequency of the characteristic vibration but at the frequency of the velocity fluctuation when the Young's modulus of the fibers is low. The profiles of Reynolds stress for different fiber lengths show that the momentum is transferred more extensively between inside and outside of the canopy layer when the fibers show an in-phase motion.