Publication

Gaining a good knowledge of air motion in forest vegetation is a necessary step towards a better understanding of a number major abiotic impacts on the trees such as wind risk, pollutant and nutrient deposition, frost, material dispersion and transport, and energy, water and carbon exchanges. In a recent survey study, Raupach et al. [Raupach, M.R., Finnigan, J.J., Brunet, Y., 1996. Bound.-Layer Meteorol. 78, 351-382] reviewed the current state of knowledge about air flow under ideal conditions (neutral to slightly unstable conditions, homogeneous and extensive canopy, flat terrain). This paper extends the knowledge by employing advances in our understanding of the flow in 'non-ideal' situations. The paper is divided into four topic areas: canopy flow under stable stratification, disturbed flow (forest edge, forest clearing, sparse canopy), canopy flow over complex terrain, and extreme wind events. Discussion of the latter two topics is of limited scope because of the scanty literature. A detailed account is given to the nighttime canopy wave phenomenon, broad patterns of the transitional flow across forest edges, and models of various complexities of the disturbed flows. Both observational and modeling aspects are discussed wherever possible. This synthesis study has identified a number of important questions in need of further research. (C) 2000 Elsevier Science B.V. All rights reserved.