An ancient woodland is a woodland that has existed continuously since before the English Civil War. Prior to this, planting of new woodland was uncommon, so such a wood was likely to have developed naturally. The Otherworld is strongly associated in common knowledge with these woodlands, leading to a significant number of folk tales on people who are led astray in the woods, and thus into the Otherworld.
While modern scientific study has confirmed this relationship, the nature of the connection between woodlands and the Otherworld did not become clear until the failure of the Romanticists’ Preservation Plantations to bring the Otherworld back to places that had lost their connections. Since then, studies have confirmed that connection is more correlation than causation, in that developments such as creating new fields, engineering larger roads, and building new houses and commercial or industrial estates means that woodlands are cleared – and the Otherworld recedes from modern technology. This is often referred to as The Allergy.
However, it is worth remembering that the decline of ancient woodlands bears a common cause and pattern to the loss of connection to the Otherworld, as ably explained by Oliver Rackham in his great work, The History of the Countryside. This, combined with the fact that the Otherworld appears to be made of a number of woodland ecosystem, suggests that modern forestry may still hold the key to Otherworld studies.