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<p>Parameterizing the effect of vertically-distributed vegetation through an effective roughness (<span class="inline-formula"><i>z</i>_0,eff</span>) – whereby momentum loss through a three-dimensional foliage volume is represented as momentum loss over an area at one vertical level – can facilitate the use of forest data in flow models, to any level of detail, and simultaneously reduce computational cost. Results of numerical experiments and comparison with observations show that a modelling approach based on <span class="inline-formula"><i>z</i>_0,eff</span> can estimate wind speed and turbulence levels over forested areas, at heights of interest for wind energy applications (<span class="inline-formula">∼60</span>&thinsp;m and higher), but only above flat terrain. Caution must be exercised in the application of such a model to zones of forest edges. Advanced flow models capable of incorporating local (distributed) drag forces are recommended for complex terrain covered by forest.</p>