This introductory chapter discusses the history and the relevance of studying soils, moves on to the principles and processes of soil formation and outlines the importance of soils for forest growth and survival. This is undoubtedly a very broad task. We cannot introduce all the details of all the processes involved and will therefore attempt to offer the reader a good and concise view of the fundamentals of the processes and mechanisms involved.

There is little mileage in trying to put forward a succinct definition of soil. This is mainly because the term ‘soil’ means different things to different people. Sitting at the interface between the atmosphere and the lithosphere, and forming part of the hydro- and biospheres (White 1979), soils have found many uses and hence many definitions. An engineer sees the soil as a loose material providing support; a hydrologist views it as a reservoir and a water purification structure; an ecologist would be interested in all life that it supports; and a farmer would want to know its structure and nutrient content. Naturally, since this is a forest soil ecology book, a forester or a forest ecologist would look at the soil through the prism of the relationship between trees and the underlying soil, how they influence each other and how they form integral parts of any forest ecosystem.

History of forest soil studies

People have always been interested in how plants grow and what the role of the soil is in this process.