Trees and forests play multiple roles in J. R. R. Tolkien's fantasy world of Middle-earth, some such as Old Man Willow indeed serving as characters in the plot. Both for Tolkien personally, and in his Middle-earth writings, caring about trees really mattered. Indeed, the Tolkien scholar Matthew Dickerson wrote "It would be difficult to overestimate the importance of trees in the writings of J. R. R. Tolkien." Commentators have written that trees gave Tolkien a way of expressing his eco-criticism, opposed to damaging industrialisation.