The role of forests in reducing hydrogeomorphic hazards

Increasingly, forests are being valued for goods and services beyond wood fibre; one of these is protection forests. Functions provided by natural and managed forests have been associated with reduced hazards from floods, debris floods, debris flows, snow avalanches and rockfalls. Maintaining a high level of protection may require active management, as forests are dynamic and the protection capabilities are strongly determined by forest condition. The nature of protection provided varies depending upon the hazard processes and pathways, and the relative spatial orientation of the hazard, the forest, and the features being protected. Hazard processes and pathways need to be understood for protection forest management so that the expected protective functions can be well predicted. Protective functions of forests include: 1) retaining material in upslope positions; and 2) containing, confining and resisting material during transport and deposition. These effects are primarily realized through: 1) soil conditioning and macropore creation; 2) root reinforcement and 3) presence of above ground structural elements. Recognition of these functions of protection forests and their relations with hydrogeomorphic hazards will contribute to the best management of protection forests