"Sacred Tree and Holy Grove", a new Kvasir Symbol Database entry
While rarely represented in popular culture today and essentially absent from extensions of historic ancient Germanic paganism (such as modern heathenry), sacred trees and holy groves—alongside the concept of ‘tree-ness’—appear by all indications to have been a central focus for the ancient Germanic peoples.
In addition to summarizing the record and recommending further reading, the entry touches on topics such as the environmental role of sacred groves in India today, and groves among the Indo-European peoples (and beyond).