Eau et forêt première partie: L'influence des arbres sur la quantité des eaux

Abstract

Located at the interface between the air and the ground, trees play an essential role in the accomplishment of the water cycle. The main influence of trees is on the return of water to the atmosphere via evapotranspiration as well as on the interception of rainfall and seepage of water into the soil. Forests are the second most important land use mode in terms of returning water to the atmosphere, coming after bodies of water and humid zones. They also afford a cover which, while it does not accentuate rainfall, does not diminish it and efficiently retains water, thereby limiting the runoff and enhancing seepage. The quantitative influence of wooded environments, in particular forests - in this case temperate - has been explored by studies which emphasise the importance of these relationships even though the latter are difficult to quantify with any degree of precision. It is equally difficult to draw general conclusions due to the great variety of environments involved. In addition to climatic conditions, the composition of the forest cover causes significant variations in water interception. For this reason, foresters have a role to play in the expression of forest characteristics through their silvicultural practices. © AgroParisTech, 2013.