1. Forest soils: a diverse, non-renewable and fragile resource

1.1 Soil formation factors and diversity

Soil formation depends on five major factors: (i) parent material*, (ii) climate, (iii) topography, (iv) living organisms, including humans, and (v) time. .

The transformation of the parent material, or a mixture of parent materials, into a differentiated, functional soil (i.e. one capable of providing different ecological functions, see introduction) involves a series of elementary phenomena, either simultaneous or successive...