The impact of forests on the overland and base flow is considered, and their role in preserving small rivers from pollution and from becoming shallow. It is shown that trees and shrubs prevent the banks from abrasion and erosion, and also exert
a positive impact on the temperature of the water. Data on the width of protective belts that are provided along the rivers are presented, the qualitative composition of the flow that is being formed in basins with forests of different density is analyzed
. The impact of different species on the volume of the flow and on other elements of the budjet of the basin is estimated. Possible ways of raising the role of forests in preserving rivers are considered in brief. (Ed.).