An evaluation of the pressure-covariance terms in higher-order turbulence closure models within and above a plant canopy has been lacking due to difficulties in measuring static pressure perturbations. Here we study static pressure behavior in shear-driven flow within and above a sparse forest canopy using the resolved-scale output from a large-eddy simulation (LES). A set of four Poisson equations were solved to examine the role of mean shear, turbulence-turbulence interaction, canopy drag and subgrid-scale stress in creating pressure perturbations and their relative importance. It was found that the mean shear and turbulence-turbulence interaction components are the major sources of pressure perturbations in the upper forest and immediately above while the canopy drag and subgrid-scale stress terms are negligible. Closure schemes and corresponding empirical constants for the pressure transport and the pressure redistribution terms were also evaluated. The sensitivity of a higher-order closure model to the empirical constants obtained, and the limitations of the LES analysis will also be discussed.