ancient soil

Soil typically takes centuries to develop to maturity (see soil-forming factors), representing its climax state if considered as an ecosystem. Similarly, the most diverse climax vegetation is likely to be found only on ancient soil The value of undisturbed ancient soil is less well recognized than the value of ancient woodland or ancient trees because less is known about the ecology of the soil and much of its biodiversity is small or microscopic.

This definition is abridged from A – Z of tree terms: A companion to British arboriculture.
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