A model is presented to predict the reflection of sound at forest edges. A single tree is modelled as a vertical cylinder. For the reflection at a cylinder an analytical solution is given based on the theory of scattering of spherical waves. The entire forest is represented by a line of cylinders placed along the forest edge. The spacing between the cylinders is defined as a function of frequency and geometrical properties to account for contributions from the depth of the forest. As a consequence of this model assumption of a single line of reflecting cylinders, a variable segmentation of the forest edge and the use of look-up tables for the reflectivity of a single cylinder, a straightforward calculation procedure can be achieved, which allows an implementation in engineering sound propagation models. A validation of the model showed good agreement with measurements. Nevertheless the measurements indicated a tendency to overestimate the levels at frequencies above 1 kHz. Further measurements should be conducted to shed light on this question and to expand additional aspects such as meteorological influences on forest reflections and the behaviour over hilly terrain where a vertical directivity pattern will become important.