It is this image that stands as a contrast to the problem that Tolkien sets up in The Lord of the Rings--the separation of the Ents and the Entwives, who are neither face to face, nor side by side, and this image that we can interrogate using the tale of the Ents, and vice versa.
Auden that the Ents derive from "a mere piece of experience, the difference of the 'male' and 'female' attitude to wild things, the difference between unpossessive love and gardening," which insight figures prominently into discussions of the gendering of the Ents and Entwives (Letters 212n).
Most scholarly treatment of the Ents maintains some balance between the Ents as representative of Nature, Tolkien's creative inspiration for the Ents, the Ents' overall function within the power structures of the narrative, and the gendered division of nature that the Ents and Entwives seem to represent.
Uniquely, in Tolkien in the Land of Heroes, Anne Petty situates the Ents and Entwives among the "tales of love and loss" in the legendarium, seeing the story of the Ents and the Entwives as "Tolkien's veiled way of saying that one should not take their [sic] lovers for granted" (210), and Corey Olsen identifies in the Ents' and Entwives' relationship a squandered opportunity for each to complement the efforts of the other as stewards of Middle Earth.
Chance argues convincingly that the gendered divide is largely to blame for the Ents' long sorrow: "When the Darkness came, gradually the difference between male and female widened until the Entwives became only a memory--lost entirely to the Ents" (Mythology 61).
The Entwives are more settled; they have progressed to the farming stage.
The Entwives have much in common with hobbits, particularly with Samwise Gamgee.
Because the Ents and Entwives are separated, however, neither can withstand evil.